DE102013112196A1 - Method for recovering mechanical energy from compressed gas in compressed gas reservoir, involves controlling quasi-isothermal expansion of compressed gas, to produce electrical energy from mechanical work of working machine - Google Patents

Abstract

The expansion of compressed gas in expansion chamber (E) is controlled such that the change amount of temperature of gas during mass quasi-isothermal expansion is less than half of that occurs during full-adiabatic expansion. The displacement of liquid (1) due to expanding gas (2), from expansion chamber into working machine (A) e.g. water turbine is performed through opening. The mechanical work produced by liquid flowing in working machine is converted into electrical energy by generator. An independent claim is included for a compressed gas storage plant.

Description

Technical area

The invention relates to an approximately isothermally operating compressed gas storage power plant, especially a compressed air storage power plant. The power plant should also offer the opportunity to be operated at short-term high power demand from the power grid trouble-free teiladiabatisch or almost completely adiabatic.

State of the art

In compressed air storage power plants, the problem arises that gas cools during relaxation as it passes through the gas turbine by the Arbeitsverrichtung and condenses moisture and then damage the turbine. The expanding gas must not cool down too much! In addition, a significant portion of the energy was lost, which had to be applied in the production of compressed air, because it generates heat, and during the expansion, the gas gets the energy to work from its internal energy, and this is especially its molecular velocity or Warmth. Therefore, it is attempted to supply the heat generated during the production of compressed air to the gas before its expansion again. Such previous compressed air storage power plants with heat recovery have between compressed air reservoir (often a salt cavern) and working machine (often a gas turbine) on a heat storage, after passing through the air expands approximately adiabatically. One speaks therefore of adiabatic compressed air storage power plants. In order to achieve a high degree of efficiency in the conversion of thermal energy into mechanical energy and ultimately electrical energy, the highest possible temperature of the heat accumulator has been erroneously sought, because the efficiency η of the conversion of pure heat into mechanical (and ultimately electrical energy) is maximally so great like the efficiency of a so-called Carnot machine. This is: η = (T _high - T _deep ) / T _high wherein T is _high, the temperature at which the arbeitsverrichtende in the machine medium enters the Carnot machine and T _low, the temperature at which it exits according to performance of mechanical work from the machine. No cyclically operating (pure) heat engine can be more efficient than the Carnot machine! (Otherwise, the construction of a second type perpetuum mobile would be possible!) Since the low temperature T _{deep is} mostly of the order of the ambient temperature, the equation implies the need for a high temperature T _high in order to achieve a high efficiency η. A compressed air storage power plant is now but no heat engine for which the Carnot law would apply strictly! Rather, it is a "stored potential energy back-conversion machine" which is intended to recover as much of the heat energy released in compressed air production as possible. However, the above-mentioned Carnot efficiency sits so firmly in the minds of the engineers that this has probably helped to focus on adiabatic-working engines, especially since most of us now or earlier surrounding mechanical combustion engines (explosion engines, gas turbines, Stirling engines, steam engines ) Heat engines are / were subjected to the Carnot efficiency. As a high-temperature-holding material for adiabatic working compressed air storage power plant, for example, ceramic is known. Such a memory for the purpose of heating compressed air, which has been stored in a subterranean compressed air storage, is eg in the EP 1857614 B1 described. By such and other heat storage, the compressed air passes through the loading of the compressed air reservoir from the compressor to the compressed air reservoir, while their heat generated by the compression of heat in him. The discharge of the compressed air storage takes place from the compressed air storage through the heat storage into a working machine, an approximately adiabatic working gas expansion turbine, in which then the compressed air their energy enriched by the heat energy of the heat storage partially converts into mechanical work. Partly, to further increase the temperature of the compressed air and thus of their energy content, even a combustible gas (eg natural gas) is burned in the compressed air. The described compressed air power plants operate at pressures of compressed air at the entrance to the working machine of about 50 to 60 bar and at the outlet of about normal pressure (1 bar). Also approximate adiabatically operating compressed air power plants are described, in which the expansion process runs in several stages over several machines. In the described compressed air power plants, the compressed air reservoir is never fully emptied (eg only from 60 to 50 bar). Only a part of the energy contained in it is used, the rest always remains in the memory. This in turn means that the effective storage density of energy for such a memory is significantly smaller than for one in which the pressure in the memory can be reduced to a lower pressure. However, this is not possible due to the pressure-dependent efficiency of the attached electricity generating gas turbine. Due to the large pressure gradient between the entry into the working machine and the heat storage requires a very high temperature, so that during the expansion and Arbeitsverrichtung of the gas in the gas turbine, which leads to a cooling of the gas, no condensation processes occur that would damage the turbine blades.

The adiabatic heat storage device according to the prior art must therefore, in order to absorb the heat generated during the compression of the air during loading of the compressed air reservoir and to be able to release it again with high efficiency, for high temperatures greater than 400 ° C, preferably greater than 500 ° C. or even greater than 600 ° C be designed. This necessary temperature tolerance is a consequence of the (quasi) adiabatic compression of the air resulting heat, which depends on the final pressure to which the air is to be compressed. The work machine / turbine must be designed for these temperatures. These high temperatures in combination with high pressures, both in the heat storage, as well as in the work machine, require expensive materials, which still have disadvantages compared to low-temperature materials. By a multi-stage leadership of the expansion process in several successive work machines with reheating the parts-expanded air between the machines in a heat storage can reduce this problem, but not completely resolve.

In order to avoid the problems described, isothermal or quasi-isothermal compressed air storage power plants are therefore described in the prior art. In the DE 10 2011 106 040 A1 describes a pumped storage power plant in which the hydrostatic water pressure at the turbine originating from the potential energy of the higher water reservoir is replaced by an air pressure acting on the water surface. The heat required to maintain the temperature of the gas during expansion is transferred from the liquid to the gas. This happens, for example, over its large liquid surface during spraying. The gas contained in the system is retained in this and is cyclically compressed and relaxed, while it moves the liquid like a piston and thereby generates electrical energy by means of a generator. The entire compressed air reservoir thus represents here a part of the working machine, a gas expansion engine, its outer wall is, so to speak, the "cylinder wall" of this "single-cylinder engine". A similar system is also described earlier by the company IVE GmbH, Cochem, eg in the WO 2004/020793 A1 , Compressed air from a compressed air reservoir in this case presses water from a pressure vessel in a higher water tank. The compressed air absorbs heat from the water and the environment. The pressure vessel from which the water is forced out by the compressed air is greater than the compressed air reservoir and the compressed air reservoir is practically emptied in a work cycle. The gas is also retained in the system and is later displaced from the pressure vessel by the water in the higher water tank.

These prior art compressed air hydro power plants require large volumes of compressed air and working water. This is because the compressed air increases in volume as it expands, with an isothermal expansion of 60 to e.g. 2 bar by a factor of 30! The water-containing space must therefore be greater than the storage volume of the compressed air. This not only leads to higher manufacturing costs of this cavity due to the size, but also to stability problems, since the cavity is at least initially under the same high pressure as the working gas and the wall is also exposed alternately to the action of water and air.

The regulation of such compressed air power plants is also complex control technology, since the pressure of the gas decreases over time and the turbine must adapt to the decreasing pressure to keep their efficiency sufficiently high, but at the same time the flow rate must also be changed to those in the electricity grid to be able to serve the required fluctuating performance requirements. In the JP 2007231760 A is a Perpetuum mobile described with a closed water cycle in which an electric pump air pump is operated. The air of this air pump operates a mammoth pump, which carries water to a higher position in a tank. At the exit from the mammoth pump, a pulse turbine is driven, which again generates electrical energy. The water in the upper basin also flows through a downpipe in a lower basin and also drives a turbine, which generates electrical energy. In the WO 2012/017243 A1 For example, there is described a mammoth pump having a plurality of risers into which electrically powered compressors introduce air, and a downcomer in which an electrical energy turbine is disposed. The described mammoth pumps are not very suitable for the use of high pressure compressed air because of low efficiency, because at the inlet of the compressed air into the water, the compressed air expands suddenly not isothermal to a volume that the pressure at the corresponding hydrostatic pressure corresponds, and then begins to ascend and continue to expand slowly. This expansion is then approximately isothermal at not too large air bubbles, but the efficiency is reduced by the fact that during As the air bubbles rise, water also flows from the top downwards through the air bubbles, the energy of which is later no longer available for energy!

Object of the invention

The object of the invention is to provide a compressed gas storage power plant, especially compressed air storage power plant, which operates quasiisothermally in normal operation. The compressed gas storage power plant should also react insensitive to whether it is operated quasi-isothermally (regular operation) or temporarily (high power requirement) with a high adiabatic proportion.

Presentation of the invention

The object is solved by the features specified in the characterizing part of claim 1. The compressed gas storage power plant thereby becomes a pressurized gas liquid power plant. The invention is based on an isothermal or approximately isothermal method of expansion of compressed air, because the theory says that it would be advantageous to operate a compressed air storage power plant, or general compressed gas storage power plant, approximately isothermal. In the following isothermal always approximated isothermal or quasiiothermal, since an ideal isothermal behavior exists only theoretically and can not be realized in practice because of the finiteness of time. One can abbreviate these times a bit by not coming to a complete temperature compensation, but maintains a significant residual temperature gradient, which of course the efficiency is worse. Nevertheless, the sufficiently rapid transfer of heat from the working gas into the storage material (for example, water, but also a solid or other substance) of the heat exchanger remains in and above all for Arbeitsverrichtung out of the memory out a problem! Because while you can usually take a long time to load the heat storage, heat must be transferred as needed quickly when unloading the memory to be able to serve energy requirements of the power grid in the short term! In the following, for the sake of simplicity, the estimation of the effects is always based on the behavior of an ideal gas, since the calculations of real gases are extremely complicated. However, the resulting deviations are not too great for gases such as air. (This is different for carbon dioxide or natural gas, for example.) However, using the principle of the invention, the use of such real gases does not change anything (even if condensed phases occur), even if the calculation becomes more complicated!

Furthermore, in the following is often spoken of gas or liquid. However, according to the invention, the use of air and water or aqueous solutions (e.g., salt water) is preferred.

The maximum volume work that an (ideal) gas performs in isothermal expansion from a volume V ₁ to a volume V ₂ is: W = -nRT · ln (V ₂ / V ₁ ) where n is the number of moles of gas, R is the general gas constant (8.314 J / (mol · K)) and T is the absolute temperature in Kelvin (K). In addition, for an ideal gas: pV = nRT pV is 10 ⁷ Nm, ie 10 ⁷ joules or 10 MJ for 1 cubic meter of an ideal gas that is under 100 bar pressure (about 10 ⁷ N / m ² ). The work that such a cubic meter of gas at isothermal expansion, starting from a pressure of 100 bar (10 MPa) to ambient pressure of 1 bar supplied (expansion of 1 cubic meter to 100 cubic meters), would thus be 10 ⁷ · ln100 Joule = 10 ⁷ · 4.605 Joule, about 46 MJ. The same energy would be contained in 1 cubic meter of water, which was stored at about 4600 meters altitude and dropped from there, which he would have reached down to a speed of about 303 meters per second. Or it would be contained in 920 cubic meters of water, which moved at 10 meters per second, for which they would have to fall free for example 1 second in the Earth's gravity field, which would correspond to 5 meters in height.

The invention achieves energy-efficient energy storage in a compressed gas by quasi-isothermal expansion of the gas. Preferably, the gas is also quasiisothermally compressed to load the memory. The quasi-isothermal expansion of the gas is the compromise between the theoretically possible and the practically meaningful. It has proven to be particularly favorable according to the invention, when gas whose pressure is reduced by half expansion, its temperature only by less than half, preferably less than one-fifth of the amount, more preferably by less than one-tenth of the amount changed, by which this temperature would have decreased with an adiabatic expansion! (It might be approximated that the isothermal rate of expansion should be greater than 50%, preferably greater than 80%, more preferably greater than 90%.) For an ideal gas, according to Poisson, for the temperature after adiabatic expansion (or Compression) and especially for air with κ = 1.4:

vorzugsweise:

noch bevorzugter:

According to the invention, therefore, the definition of quasi-isothermia in general, or in particular for the case of air, should be:

preferably:

even more preferred:

For a temperature T ₁ of 20 ° C (293 K), therefore, for the (preferred) special case of the air, the temperature change with a halving of the pressure should be controlled so that it is less than 26.3 ° C, preferably less than 10 , 5 ° C, more preferably less than 5.3 ° C (instead of 52.7 ° C as in a purely adiabatic expansion). In this way, it is possible to achieve a sufficiently high efficiency in gas expansion for economic purposes. Although it is of course theoretically favorable to aim for isothermism as perfectly as possible, it is still sufficient according to the invention to move in the above-mentioned range of the temperature change of the gas at a halving of the gas pressure! This makes the control of the operation of the power plant easy! In a particularly preferred embodiment, even at the end of the entire expansion process no change in temperature in the expanding compressed gas should have taken place, which is greater than 20 ° C. The quasi-isothermia defined here includes both a slight hypothermia (gas is slightly colder after expansion), and hyperthermia (gas is slightly warmer after expansion), because it is defined by the change by the amount of temperature difference and not by the Reduction of temperature! As a slight hypothermia here the most common application of the invention is referred to, namely, when the gas expands under contact with a liquid which initially has the same or slightly lower temperature than the gas, so that the gas is subsequently cooled slightly. Poor hyperthermia is the case here when the gas expands under contact with a liquid which initially has a higher temperature than the gas. This can occur, for example, if the tempering liquid was heated, for example by waste heat (eg from the compression machines and / or other waste heat sources) above its original temperature and the initial pressure gas temperature, or the tempering liquid even electrically by means of excess electrical energy produced (eg regenerative Energy sources) was heated to this elevated temperature. The liquid, which actually serves to temper the gas during expansion, then simultaneously represents a very large energy store for excess energy in excess production times! But even if the liquid used for tempering the expanding gas at the beginning of the expansion has a slightly higher temperature than the gas, of course, the process can also be performed so that the temperature of the entire gas / liquid system after expansion slightly below the initial temperature of the gas. In such a case, the process is then hyperthermic, then hypothermic. Both in hyperthermic process control and in hypothermic process control, the overall process contains a small adiabatic component, but according to the invention should contribute less than 50%, preferably less than 20%, more preferably less than 10% to energy production!

• a.) Ein Druckgas wird als als mechanischer Energiespeicher ähnlich einer mechanischen Feder eingesetzt.
• b.) Zur Energiegewinnung aus dem Druckgas wird eine in einem druckstabilen Expansionsraum mit starren Wänden befindliche Flüssigkeit durch in diesem Expansionsraum befindliches und dort expandierendes Druckgas in Bewegung versetzt und aus diesem verdrängt.
• c.) Die Expansion des Druckgases im Expansionsraum wird so gesteuert, daß sie in dem Maße quasiisotherm verläuft, daß bei einer Druckhalbierung nur eine Temperaturänderung des Gases auftritt, die weniger als die Hälfte, vorzugsweise weniger als ein Fünftel, noch bevorzugter weniger als ein Zehntel derer beträgt, die bei einer volladiabatischen Expansion aufträte.
• d.) Die Quasiisothermie wird dadurch erreicht, daß im Inneren (!) des Expansionsraumes mindestens ein Teil der reinen Flüssigkeit oder ein Teil der Flüssigkeit, in der noch mindestens ein anderer Stoff gelöst ist, auch zum Temperieren des Druckgases während (!) der Expansion verwendet wird oder zum Wiederaufwärmen eines im Expansionsraum befindlichen Feststoffes dient, der zur Temperierung des im Expansionsraum expandierenden Druckgases während (!) dessen Expansion verwendet wird und hierzu die Eigenschaft eines temporären Kurzzeitwärmespeichers und Wärmetauschers aufweist.
• e.) Die Verdrängung der Flüssigkeit durch das expandierende Gas aus dem Expansionsraum heraus erfolgt über eine Öffnung im Mantel des Expansionsraumes hindurch über eine Zuleitung in mindestens eine außerhalb des Expansionsraumes befindliche Arbeitsmaschine für Flüssigkeiten (z.B. Wasserturbine) hinein. Die durch die Arbeitsmaschine strömende Flüssigkeit erzeugt dort mechanische Arbeit. Die mechanische Arbeit der Arbeitsmaschine wird dabei vorzugsweise mittels eines Generators weiter in elektrische Energie umgewandelt, sie kann aber auch direkt verwendet werden.
• f.) Es tritt also kein Gas als Gasphase in die Arbeitsmaschine ein! Lediglich durch in der Flüssigkeit gelöstes Gas oder durch Verwirbelung von Gasblasen treten eventuell geringfügige Gasmengen in die Arbeitsmaschine ein.

The basic principle of the invention provides the following features:

• a.) A compressed gas is used as a mechanical energy storage similar to a mechanical spring.
• b.) To generate energy from the pressurized gas, a liquid located in a pressure-stable expansion chamber with rigid walls is set in motion by displaced gas in this expansion space and expanding there, and displaced therefrom.
• c.) The expansion of the pressurized gas in the expansion space is controlled to be quasi-isothermal to the extent that at half pressure only a temperature change of the gas occurs which is less than one half, preferably less than one fifth, more preferably less than one tenth which occurs in a fully adiabatic expansion.
• d.) The Quasiisothermie is achieved by the fact that in the interior (!) Of the expansion space at least a portion of the pure liquid or a portion of the liquid in which at least one other substance is dissolved, also for tempering the compressed gas during (!) Expansion is used or used for reheating a solid located in the expansion space, which is used to control the temperature of the expanding expansion gas in the expansion space during expansion (!) and this has the property of a temporary short-term heat storage and heat exchanger.
• e.) The displacement of the liquid by the expanding gas from the expansion space takes place via an opening in the shell of the expansion space through a feed line into at least one outside of the expansion space located working machine for liquids (eg water turbine) into it. The liquid flowing through the working machine generates mechanical work there. The mechanical work of the work machine is preferably further converted by means of a generator into electrical energy, but it can also be used directly.
• f.) Thus, no gas enters the working machine as a gas phase! Only by dissolved in the liquid gas or by turbulence of gas bubbles may occur small amounts of gas in the machine.

The invention can be carried out according to several variants:

Option A:

The compressed gas enters via a supply line in batches from an external compressed gas storage in serving as an expansion space pressure vessel, which is filled at least for the most part with liquid. The expansion space is the working space in which the mechanical energy stored in the compressed gas is released quasi-isothermally.

The expansion space is understood to mean the space between the filling opening (s) and the liquid outlet opening, which can be filled with fluid and in which the gas expands. The expansion space may thus also be a cavity in which there are additionally solids with a closed, solid surface (for example, bedrock, pipes open at the bottom, or vessels filled with liquid). Each print batch is expanded on its own. The expansion of the compressed gas in the compressed gas storage thus takes place in successive cycles in the expansion space, so that a new compressed gas charge is only returned to the expansion space when the previous expansion cycle / duty cycle of the gas is completed. The expansion space filled with liquid again works like the cylinder of a motor, but unlike this one can be shaped much more arbitrarily, since the liquid level changing in height above the outlet opening corresponds to a piston sealing itself (!) Against the wall!

Variant B:

• a.) Das Druckgas ist durch eine stabile, gut wärmeleitende, aber verformbare Schicht von der das expandierende Gas temperierenden Flüssigkeit getrennt. Das Gas befindet sich somit in vielen kleineren Behältern mit verformbarer Wandung ähnlich Ballons, die von Flüssigkeit umgeben sind. Auf diese Weise weist das Druckgas eine große relative Oberfläche zur Flüssigkeit auf. Außer dem Gas können die kleinen geschlossenen Gasbehälter auch noch andere Stoffe enthalten, z.B. Flüssigkeiten oder Feststoffe.
• b.) Das Druckgas befindet sich in langgestreckten, senkrechten oder geneigten, unten offenen Behältern, die auch eine starre Wand aufweisen können. Das Druckgas füllt dabei nur einen Bruchteil des Volumens im obersten Bereich dieser Behälter aus und zwar nur so wenig davon, daß es nach vollständiger Expansion noch nicht unten aus dem Behälter austritt, sondern dort nur Flüssigkeit hinausdrängt, die zuvor darin war.

The entire compressed gas is already within the expansion space during an expansion cycle and compression cycle. The expansion space is therefore equal to the compressed gas storage. The following subvariants a.) And b.) Are possible:

• a.) The compressed gas is separated by a stable, good heat-conducting, but deformable layer of the expanding gas-tempering liquid. The gas is thus in many smaller containers with deformable wall similar to balloons, which are surrounded by liquid. In this way, the compressed gas has a large relative surface area to the liquid. In addition to the gas, the small closed gas containers may also contain other substances, such as liquids or solids.
• b.) The compressed gas is in elongated, vertical or inclined, open-bottomed containers, which may also have a rigid wall. The compressed gas fills out only a fraction of the volume in the uppermost region of these containers and indeed only so little that it does not exit the bottom of the container after complete expansion, but there pushes out only liquid that was previously in it.

The small gas containers according to sub-variants a.) Or b.), Which are referred to below as small-scale gas tanks, are located in a pressure vessel serving as an expansion space, the residual volume of which is at least mostly, preferably completely, filled with liquid. The expansion space is the working space in which the stored energy in the compressed gas is released quasiisothermic.

The small gas containers are preferably fixed relative to the pressure vessel, so each small gas tank remains so during a gas expansion in place. Small gas tanks of sub-variant a.) Can also float freely in the expansion space. The expansion space has at least one opening through which, upon expansion of the gas in the small gas tanks, the liquid can escape from the expansion space and enter a fluid machine (e.g., a water turbine). The separating layer between compressed gas and liquid is preferably thin. In a simple embodiment, the pressurized gas is e.g. stored in stretchy elastomeric balloons. Another embodiment envisages using non-expandable balloons which are wrinkled or flaccid at high internal pressure in the expansion space and become more pliable upon gas expansion (similar to so-called stratospheric balloons in which the carrier gas always increases with increasing altitude above the ground and with decreasing air pressure can stretch more). As a balloon envelope are thin, stretch-resistant films, especially bidirectionally stretched films, such as Mylar. Due to the density difference between liquid and gas, the gas always collects in the upper part of the small gas tank until this area is completely filled. Only then does the small gas tank continue to fill down with the expanding gas. Since the gas remains in the small gas tanks, the entire pressure gas must be outside surrounded by a pressure vessel as an expansion space. To prevent this pressure vessel from becoming too large, several or many such pressure vessels may be provided as expansion spaces, each of which contains a portion of the total compressed gas in small gas tanks in which the gas can change its volume with pressure. Each of the expansion spaces has a connection line to a work machine through which the liquid exits the expansion spaces as a result of gas expansion in the small gas tanks. Each of the expansion spaces can have its own work machine, or a work machine can be assigned to a plurality of expansion spaces and be successively or simultaneously flowed through by them with liquid. It must be ensured that only such expansion spaces are simultaneously connected to the working machine when the pressure in the expansion chambers is the same, otherwise fluid can flow from one expansion space back to another, and even if this is prevented by valves, sinks the efficiency of the conversion of compressed gas energy into mechanical work. Each expansion space can also be linked to several work machines that have optimum efficiencies for the conversion of fluid pressure into mechanical energy for certain pressure ranges. These machines are then flowed through with decreasing pressure in the expansion space successively according to their optimal working range of the liquid from the expansion space.

The variants A and B can also occur simultaneously in an expansion space.

Both variant A and variant B are characterized in that the liquid which is driven by the expanding gas through the working machine, has an almost constant temperature, which is far enough from the freezing point, so that there is no risk of icing of the working machine , This also applies in the case of a normally falling operation in the non-quasi-isothermal region, during which the temperature of the gas can drop below the freezing temperature of the liquid. However, those parts of the liquid which come into contact with the cooled gas have no direct access to the working machine without being previously heated by other liquid parts! The power plant according to the invention is, unlike known power plants, extremely redundant in its operation, so it can be operated completely trouble-free under very variable conditions! It is very tolerant to sudden changes in operating conditions!

In normal operation, however, the power plant runs as defined quasi-isothermally! For both Variant A and Variant B, the relative surfaces of liquid and gas, with or without a separating layer in between, should be large enough to allow rapid heat transfer between liquid and gas! In variant A, the expanding compressed gas and the tempering liquid or the tempering solid (short-term heat storage) in direct contact have a sufficiently large relative surface in common. In variant B is at least partially a heat-conducting separating layer in between. With a sufficiently large relative surface is meant that the contact area between tempering liquid and expanding gas is so large that the process in the given time window quasiisothermally according to the definition given above, a slight hypothermia or hyperthermia is therefore possible. Furthermore, it is preferably acted upon that thermally insulating stationary gas layers are destroyed between expanding pressurized gas and tempering liquid. This is done by sufficient relative movement of gas and liquid to each other.

• 1.) Die das expandierende Druckgas temperierende Flüssigkeit (vorzugweise die gleiche, wie die, die auch als aus dem Expansionsraum verdrängte Arbeitsflüssigkeit in der Arbeitsmaschine, z.B. Turbine, dient; es kann aber auch eine andere sein, z.B. eine Salzlösung statt normalem Wasser, wenn normales Wasser als Arbeitsflüssigkeit verwendet wird, oder Süßwasser, wenn Meerwasser als Arbeitsflüssigkeit dient) wird in Tropfen- oder Tröpfchenform in das expandierende Druckgas eingebracht, z.B. eingesprüht. Eine ausreichende relative Bewegung von Gas und temperierender Flüssigkeit bzw. temperierendem Flüssigkeitsanteil zueinander ist hierbei meistens gewährleistet. Die temperierende Flüssigkeit, die in Tropfen-/Tröpfchenform eingebracht wird, kann a.) von gleicher Temperatur sein wie die schon im Expansionsraum befindliche Flüssigkeit, die als Arbeitsflüssigkeit dient b.) eine andere Temperatur aufweisen als die im Expansionsraum befindliche Flüssigkeit; insbesondere kann sie eine höhere Temperatur aufweisen, die z.B. von Abwärmeaufnahme oder Überschußenergieeintrag aus regenerativen Energiequellen herrührt.
• 2.) Das expandierende Druckgas wird im unteren Bereich des Expansionsraumes als Gasblasen in die temperierende und als Arbeitsflüssigkeit in der Arbeitsmaschine dienende Flüssigkeit eingebracht, z.B. eingedüst. Es steigen dann Gasblasen in der Flüssigkeit auf. Je kleiner die Gasblasen sind, umso langsamer steigen sie auf. Beim Aufsteigen findet auch schon der Expansionsprozeß statt, wodurch die Gasblasen größer werden und etwas schneller aufsteigen. Dies alles geschieht außerhalb der Arbeitsmaschine im Expansionsraum. In der Arbeitsmaschine selbst findet praktisch keine Gasexpansion mehr statt, da lediglich in der Flüssigkeit gelöstes Gas in die Arbeitsmaschine eintritt und dort in geringem Umfang durch Druckabfall in der Flüssigkeit austreten kann.
• 3.) Die Flüssigkeit wird im Expansionsraum während der Gasexpansion stark bewegt, so daß z.B. Wellen entstehen, wodurch auch das Gas (vor allem direkt darüber) bewegt wird und wärmeisolierende ruhende Gasschichten oder Flüssigkeitsschichten zerstört werden.
• 4.) Das Druckgas wird aus dem Druckgasspeicher chargenweise in hinreichend kleine Behälter innerhalb des Expansionsraumes eingefüllt und expandiert dann darin. Das expandierte Gas wird nach seiner Arbeitsverrichtung in die „Umgebung“ entlassen. Diese Kleingasbehälter können elastisch ausdehnbar sein. Einfacher ist aber eine unten offene Behälterart, z.B. langgestreckte oben geschlossene Rohre: Das Druckgas befindet sich aufgrund seiner geringeren Dichte im Oberteil dieser Rohre und drückt die darunter befindliche Flüssigkeit während der Expansion hinaus. Die Rohrwandung wird dabei durch die das Rohr umgebende Flüssigkeit temperiert und temperiert dann das darin expandierende Gas. Da die Rohre sich vorzugsweise im druckstabilen Expansionsraum befinden, können sie selbst eine dünne Wandung aufweisen, da zwischen Außenseite und Innenseite praktisch kein Druckunterschied besteht. (Befinden sich die Rohre nicht in einem druckstabilen Expansionsraum, so müssen sie selbst druckstabil sein. Die Rohre stellen dann selbst kleine druckstabile Expansionsräume mit Zuleitung zu einer Arbeitsmaschine dar. Dafür braucht dann ein umgebender temperierender Flüssigkeitstank nicht druckstabil zu sein!)

There are several options for variant A to keep the surface sufficiently large:

• 1.) The liquid tempering the expanding pressurized gas (preferably the same as that which also serves as working fluid displaced from the expansion space in the working machine, eg turbine, but it may also be another one, eg saline instead of normal water, if normal water is used as the working fluid, or fresh water when seawater serves as the working fluid) is introduced in droplet or droplet form in the expanding compressed gas, eg sprayed. A sufficient relative movement of gas and tempering liquid or tempering liquid portion to each other is usually ensured here. The tempering liquid, which is introduced in droplet / droplet form, can be a.) Of the same temperature as the liquid already in the expansion space, which serves as working liquid b.) Have a different temperature than the liquid located in the expansion space; In particular, it may have a higher temperature, for example due to waste heat absorption or excess energy input from regenerative energy sources.
• 2.) The expanding compressed gas is introduced in the lower region of the expansion space as gas bubbles in the temperature-controlling and serving as working fluid in the working machine liquid, eg injected. Gas bubbles then rise in the liquid. The smaller the gas bubbles are, the slower they rise. When ascending, the expansion process already takes place, causing the gas bubbles to grow larger and rise slightly faster. All this happens outside the work machine in the expansion room. In the work machine itself virtually no gas expansion takes place, since only dissolved in the liquid gas enters the machine and there may leak to a small extent by pressure drop in the liquid.
• 3.) The liquid is strongly moved in the expansion space during gas expansion, so that, for example, waves, whereby the gas (especially directly above it) is moved and thermally insulating stationary gas layers or liquid layers are destroyed.
• 4.) The compressed gas is filled from the compressed gas storage batchwise into sufficiently small containers within the expansion space and then expands therein. The expanded gas is discharged after its work in the "environment". These small gas containers can be elastically expandable. However, a container type which is open at the bottom is simpler, eg elongated tubes closed at the top: Due to its lower density, the compressed gas is located in the top of these tubes and pushes the liquid underneath during the expansion. The tube wall is tempered by the liquid surrounding the tube and then tempered the expanding gas therein. Since the tubes are preferably in the pressure-stable expansion space, they may themselves have a thin wall, since there is virtually no pressure difference between the outside and the inside. (If the pipes are not in a pressure-stable expansion chamber, they must themselves be pressure-stable.) The pipes then themselves form small pressure-stable expansion chambers with supply to a working machine.

For variant B, the gas-containing small gas containers are sufficiently small or have a large surface area (e.g., thin and elongated), so that the temperature of the expanding gas through the liquid surrounding the containers in the pressure vessel is defined as quasi-isothermal. Containers of this type are referred to below as a small gas tank. These small gas tanks may also contain other substances besides gas, e.g. tempering fluid or fiber.

The chosen method depends on how much time is available for the temperature control of the gas! Large expansion chambers or pressure vessels with a large number of small gas tanks in it allow e.g. at lower expansion capacity per volume larger drops or gas bubbles or small gas tank. The necessary size of the droplets or gas bubbles or small gas containers can be estimated with the known equations for heat transfer, although not accurate. More precise adjustments are made by a few additional attempts.

• a.) mit einem begrenzten Flüssigkeitsvolumen durchgeführt werden, das mindestens so groß ist wie das Volumen des Expansionsraumes und von dem für jeden neuen Arbeitszyklus wenigstens ein Teil erneut in den Expansionsraum eingebracht wird, eventuell nach einer vorherigen Erwärmung, z.B. mittels Verlustwärme aus Betriebsprozessen oder auch durch Überschußenergie aus regenerativen Energien. Die Flüssigkeit wird dann in einem geschlossenen Kreislauf geführt.
• b.) mit einem „unbegrenzten“ Flüssigkeitsvolumen durchgeführt werden. Es tritt dann also bei jedem Zyklus neue Flüssigkeit in den Expansionsraum ein. Dies ist dann möglich, wenn die Flüssigkeit Wasser ist, z.B. aus einem Fluß, See oder Meer. Es kann natürlich auch neues Wasser mit schon verwendetem Wasser gemischt im Expansionsraum zur Gastemperierung eingesetzt werden.

The invention according to variants A and B can

• a.) are carried out with a limited volume of liquid which is at least as large as the volume of the expansion space and of which at least a part is introduced again for each new working cycle in the expansion space, possibly after a previous heating, for example by means of heat loss from operating processes or by excess energy from regenerative energies. The liquid is then passed in a closed circuit.
• b.) with an "unlimited" volume of liquid. Thus, new fluid enters the expansion space every cycle. This is possible if the liquid is water, eg from a river, lake or sea. Of course, new water mixed with already used water can be used in the expansion chamber for the gas tempering.

• 1.) Der Expansionsraum weist mindestens eine Verbindung zum Druckgasspeicher (oder auch, falls vorhanden, mehreren Druckgasspeichern) auf, die mit einem Ventil geöffnet und verschlossen werden kann. (Als Ventile werden in der gesamten Anmeldung allgemeine Bauteile bezeichnet, die eine Regelung des Durchflusses von Fluiden gestatten, und zwar kontinuierlich oder diskontinuierlich (z.B. offen/geschlossen). Der Begriff Ventil umfaßt also in dieser Anmeldung z.B. auch Bauteile wie Absperrklappen oder Absperrschieber).)
• 2.) Er weist auch (mindestens) eine Öffnung mit Ventil auf, durch die expandiertes bzw. teilexpandiertes Gas den Arbeitsraum ins Freie oder ein druckniedriges Großreservoir („die Umgebung“) verläßt.
• 3.) Er weist mindestens eine Austrittsöffnung auf, durch die die Flüssigkeit aus dem Expansionsraum in die Arbeitsmaschine eintritt. Zwischen Austrittsöffnung und Arbeitsmaschine befindet sich ebenfalls ein Ventil, das geöffnet und geschlossen werden kann, bevorzugt graduell, zur Leistungssteuerung der Arbeitsmaschine. Bevorzugt ist die Arbeitsmaschine oberhalb des Niveaus des Bodens des Expansionsraumes angeordnet und ist mit diesem über ein Steigrohr mit großem Innendurchmesser (daraus folgt eine geringe Strömungsgeschwindigkeit darin) verbunden, das verhindert, daß Gesteinsstücke oder schwerer Grobschmutz in die Arbeitsmaschine geraten. Oder es befindet sich zwischen Expansionsraum und Arbeitsmaschine eine Zuleitung, die mindestens ein solches Steigrohr enthält. Hinter dem Steigrohr darf es dann auch wieder abwärts gehen.

An expansion space according to variant A has the following features:

• 1.) The expansion chamber has at least one connection to the compressed gas storage (or, if present, several compressed gas storage), which can be opened and closed with a valve. (As valves throughout the application general components are referred to, which allow a control of the flow of fluids, either continuously or discontinuously (eg open / closed) The term valve thus includes in this application, for example, components such as butterfly valves or gate valve). )
• 2.) It also has (at least) an opening with valve through which expanded or partially expanded gas leaves the working space to the outside or a low-pressure large reservoir ("the environment").
• 3.) It has at least one outlet opening through which the liquid from the expansion space enters the working machine. Between the outlet opening and working machine is also a valve that can be opened and closed, preferably gradually, for power control of the machine. Preferably, the work machine is disposed above the level of the bottom of the expansion space and connected thereto by a riser pipe having a large inner diameter (resulting in a low flow velocity therein) which prevents rock pieces or heavy coarse dirt from entering the work machine. Or it is located between expansion space and work machine a supply line containing at least one such riser. Behind the riser, it may then go down again.

• a.) In den verbliebenen Gasraum wird nun Druckgas mit dem im Druckgasspeicher herrschenden Druck eingeleitet. Das Ventil hinter der Austrittsöffnung aus dem Expansionsraum ist dabei vorzugsweise zur Arbeitsmaschine hin ganz oder teilweise geschlossen, so daß sich ein Druck oberhalb der Flüssigkeit aufbaut, der dem Druck im Druckgasspeicher entspricht.
• b.) Ist der Expansionsraum ganz mit Flüssigkeit gefüllt (die bevorzugte Ausführung), ist das Ventil hinter der Austrittsöffnung zur Arbeitsmaschine hin mindestens teilweise geöffnet und das Druckgas schiebt einen Teil der Flüssigkeit durch die Austrittsöffnung in die Arbeitsmaschine, wo die mechanische Energie der Flüssigkeit in eine andere mechanische Bewegung umgewandelt wird. Dies geschieht praktisch isotherm, da der Druckabfall des Druckgases beim Einleiten nur minimal ist, weil der Druckgasspeicher deutlich größer ist als das nun abgezweigte Teilvolumen für den Arbeitszyklus.

The working method of the power plant according to the invention according to variant A is as follows:
The pressurized gas liquid power plant according to the invention works like a quasi-isothermal compressed air motor with a self-sealing piston:
The expansion space is at the beginning of a power stroke largely (a.)) Or completely (b.)) Filled with liquid.

• a.) In the remaining gas space now pressurized gas is introduced with the pressure prevailing in the compressed gas storage pressure. The valve behind the outlet opening from the expansion chamber is preferably completely or partially closed towards the working machine, so that a pressure builds up above the liquid, which corresponds to the pressure in the compressed gas storage.
• b.) Is the expansion space completely filled with liquid (the preferred embodiment), the valve behind the outlet opening to the working machine is at least partially open and the compressed gas pushes a portion of the liquid through the outlet opening in the working machine, where the mechanical energy of the liquid in another mechanical movement is converted. This is practically isothermal, since the pressure drop of the compressed gas during discharge is only minimal, because the compressed gas storage is significantly greater than the now diverted sub-volume for the duty cycle.

Subsequently, the valve is closed in the connection to the compressed gas storage. Care must be taken that the volume occupied by the pressurized gas in the expansion space is only so great that, after the working expansion of the gas, the liquid is just displaced from the expansion space or, preferably, some liquid remains therein. In that case, there is no risk of gas entering the work machine, which is a high-efficiency hydrodynamic machine and not a gas engine / gas expansion turbine.

Liquid, on the surface of which a gas pressure of, for example, 60 bar acts, is equivalent to the water of a reservoir lake, which is located approximately 600 meters above a water turbine! To compress 60 cubic meters of (ideal) gas from ambient pressure (about 1 bar) isothermally to 60 bar (it then occupies only 1 cubic meter of volume), it takes about 24000 kJ of energy (equivalent to about 6000 kcal). This energy is also released from the gas in an isothermal expansion, similar to an elastic spring. A compressed gas storage tank with 100,000 cubic meters of (ideal) gas at 60 bar has an energy content of approximately 2.4 billion kilojoules, ie 2.4 trillion joules (with isothermal expansion down to 1 bar). An output of 100 MW could be delivered from this compressed gas storage 24,000 seconds (almost 7 hours). However, this only applies to a conversion with 100% efficiency. Of course, this is impossible in practice. Connected to such a compressed gas storage is, for example, an expansion space of 10,000 cubic meters. This expansion space is initially filled with 10,000 cubic meters of liquid, from the beginning until the closure of the valve between compressed gas storage and expansion space 150 cubic meters are displaced by compressed gas, which 150 cubic meters of liquid in the working machine (eg Francis turbine) at an almost constant pressure of about 60 bar generate an energy that would give 150 cubic meters of water, which fell from a height of 600 meters in a turbine. That's 900,000,000 joules (900 MJ). If you let the compressed gas for 9 seconds from the compressed gas storage, the liquid at a uniform speed through the machine, thereby producing just 100 MW of power. These 150 cubic meters of gas then expand quasiisothermically from 60 bar to 1 bar and 9000 cubic meters, displacing 8850 cubic meters of liquid, but the pressure of the liquid decreases from 60 bar to 1 bar and thereby (according to the equation W = -NRT · ln (V ₂ / V ₁ ) for isothermal gas expansion) approximately 3.6 billion joules (3600 MJ) of energy are generated. If the total process takes 36 seconds, then one has again generated a power of 100 MW. Subsequently, the degassing valve is opened at the expansion space leading into the atmosphere or into a low-pressure gas container ("the environment"), closing the valve to the work machine and re-flooding the expansion space with liquid. Very particularly preferred is the use of air as a gas, because only this can be released easily and yet really harmless to the outside. Then you close the degassing valve, re-opens the valve to the compressed gas storage and the work machine and a new cycle begins. This time, however, no longer starts at 60 bar, but slightly lower (at 59.91 bar), since 150 out of the 100,000 cubic meters have already been taken.

By repeating cycles of operation, the compressed gas reservoir is evacuated over time to a certain extent, e.g. also depends on which support pressure must remain in gas for stability reasons.

If a (preferably subterranean) compressed gas storage, e.g. filled with very coarse bulk material, this supports the wall! Even if later wall parts (for example rock) break off, this does not matter, because the break has an end at the latest when the compressed gas storage is everywhere filled with wall contact with bulk material, just wall demolition material. However, since the bulk material occupies volume that is not filled by energy-containing compressed gas, the compressed gas storage space must be chosen significantly larger. It can be achieved in the compressed gas storage by coarse bulk material usable for energy storage void volume of about 20 to 30%. The bulk material must therefore be coarse, so that the flow of air is not obstructed. The interconnected voids should have an average diameter of more than 5 centimeters, preferably more than 10 centimeters. Although a bulk material-filled compressed gas storage has less filling volume than an empty space, but it has the advantage that it can be filled with gas quasiisotherm easier because the bulk material serves as a heat-absorbing heat accumulator with a large surface area.

Preferably, the entire power plant operates with more than one expansion space, each expansion space being in a different phase of the work cycle. This helps to even out the power output of the entire power plant.

Since the expansion space during a working cycle is not constantly below the maximum pressure, because there is no constantly open connection to the compressed gas storage, it is possible to divide the expansion space in which the work cycle runs into several parts expansion spaces in which run parts of the duty cycle at different pressures ! This has the advantage that it is not necessary to design the entire expansion space stable against the maximum pressure, which is expensive because of the large volume of the total expansion space, if the expansion space should be placed above ground and not set up in an underground cavern. In the case of a division into several parts expansion spaces it would then be possible, e.g. create a first part expansion space containing the compressed gas of e.g. 60 bar to 15 bar relaxed, thus allowing a fourfold increase in volume. This first part expansion space, because it is still relatively small, would be relatively easy to stabilize (approximation: "boiler formula") and could also be made from inexpensive materials, e.g. prestressed concrete (possibly with gas-tight "inliner").

In a second part expansion chamber, the pre-expanded gas would then be further expanded, for example from 15 bar to a final pressure of approximately 1 to 2 bar or even only to approximately 5 bar. At the second Teilxpansionsraum then enclose a third, last Teilxpansionsraum. It will be appreciated that during the course of the sub-cycles, the connection between the part expansion space (s) where the subcycle is about to run and the subexpansion space (s) is closed and the fluid enters the or a work machine via a separate path, and only after completion of the respective subcycle a connection between the preceding parts expansion space and the subsequent one is opened, so that the partially expanded compressed gas can also expand in this and perform its subcycle by displacement of the liquid located there. The parts expansion spaces may simply be arranged independently and spatially separated with connections between them. For example, a part of the expansion areas (eg the high-pressure part spaces, above ground In another embodiment, however, each of the following parts expansion chambers are onion-like arranged around the first high-pressure part expansion space, which brings stability advantages. This results in particular stability advantages when the compressed gas liquid power plant "mehrzylindrig" is executed (that is equipped with several expansion spaces A, B, ..., in which run phase Za, Zb, ... run) and in which the first part expansion space surrounding Partial expansion chamber for work cycle Za already a partial work cycle of a phase-shifted cycle Zb another "cylinder" (expansion space B) is performed, because then supports the lower pressure of this cycle Zb in this surrounding part expansion space, the wall of the first part expansion space. In this case, therefore, the parts expansion spaces of the different working cycles Za, Zb,... Of the expansion spaces A, B,... Temporally change their spatial location in order to optimally support the walls, in particular the parts expansion areas under high pressure.

An expansion area can also be completely or partially located in the ground. In one embodiment, the expansion space is formed substantially conical or frusto-conical. However, the conical wall (viewed in longitudinal section through the cone) need not be straight, but may also be curved. Also, the bottom and the top of the truncated cone need not be even. Preferably, they are even curved in order to better absorb the internal pressure in the expansion space can. The upper part of such a (as previously defined) "cone", in which the compressed gas is at the highest pressure can also be due to the small radius (high stability!) Above the ground. The lower part of the cone is preferably in the ground and the ground pressure stabilizes the walls, making them less stable than if they were above the surface of the earth. The deeper the "cone" is in the ground, the weaker the walls of this expansion space can be. Another way of economically placing an expansion space in the ground is to embed it in the groundwater and subsequently freeze it around the expansion space (e.g., with freezing lances). The soil expands and the walls are placed under an inward bias that counteracts the internal pressure in the expansion space. If the expansion chamber, with somewhat reduced efficiency, with a circulated liquid (eg an aqueous salt solution or antifreeze mixture) is operated, whose temperature is at least 10 ° C below the freezing temperature of water, the wall of the expansion chamber has a temperature below 0 ° C and the expansion space surrounds itself with a stable layer of icy ground, so that the walls of the expansion space may be correspondingly weak. It is also possible to place the entire expansion space in a large above-ground container with water-soaked ground, which is then frozen through. Then you have an expansion space wall whose strength comes to a large extent from frozen ground! If fibers are also introduced into the soil, this "ice concrete" can absorb a considerable amount of traction! And eventually cracks in it could be repaired very well by melting and re-freezing! If the fiber content is very high, ice without a soil component could also be used as an "ice concrete wall"! A particularly cheap to produce "ice concrete" with fiber content is Pykrete, which consists of 14% sawdust and 86% water. The tensile strength of pyrites is about 4.8 MPa in Wikipedia (compared to concrete with 1.7 MPa and ice with 1.1 MPa). Pykrete has a compressive strength of 7.6 MPa (compared to 17.2 MPa concrete and 3.4 MPa ice). The density of pyrites is 980 kilograms per cubic meter (concrete 2500, ice 910). By using fibers other than wood chips, especially the tensile strength can be significantly increased!

In order to improve the efficiency of the power plant, it is possible to use not only one kind of work machine, but two or more different, each of which is optimized for a particular fluid pressure range. For the high liquid pressures (from 70 to about 2 bar), e.g. a Francis turbine (or related construction) (efficiency about 90% for water) and for the medium or low fluid pressure range (4 to 2 bar) a Kaplan turbine (or related construction) (efficiency 80-95% for water ).

For liquid pressures above 70 bar is preferably used a pelton-type turbine (efficiency 90-95% for water). A Francis turbine can be used over the widest pressure range. However, Pelton-type turbines are best controlled with varying throughput.

When using a plurality of expansion spaces E ₁ , E ₂ , ... Not every expansion space must have one or more machines, but it can be alternately flowed by different expansion spaces depending on the cycle time in which the expansion space is currently the work machines.

As already mentioned, about 24,000 kJ of isothermal energy are contained in one cubic meter of compressed compressed gas of 60 bar. (The term "isothermal energy" refers to the energy that can be recovered as mechanical work by isothermal expansion to 1 bar.) Unlike adiabatic expansion, the "isothermal energy" (of an ideal gas) is independent of the molecular structure of the gas! ) If this cubic meter of compressed gas is expanded from 60 bar isothermally to 2 cubic meters at 30 bar, these 2 cubic meters still contain approximately 20,000 kJ of "isothermal energy" (10,000 kJ per cubic meter). This means that the isothermal expansion to twice the volume releases about 4000 kJ per cubic meter of pressurized gas of 60 bar. If the 2 cubic meters of compressed gas are subsequently expanded isothermally from 30 bar to 6 cubic meters of 10 bar, these 6 cubic meters then still contain about 14,000 kJ (2300 kJ per cubic meter). With the expansion of 2 cubic meters from 30 bar to 6 cubic meters of 10 bar, about 6000 kJ will be released. If these 6 cubic meters are expanded isothermally from 10 bar to 12 cubic meters of 5 bar, these 12 cubic meters still contain about 9,500 kJ (800 kJ per cubic meter). With the expansion of 6 cubic meters of compressed gas from 10 bar to 5 bar, about 4,500 kJ are released. If these 12 cubic meters of compressed gas are expanded from 5 bar to 30 cubic meters of 2 bar, these 30 cubic meters still contain about 3800 kJ (about 130 kJ per cubic meter). With the expansion of 12 cubic meters of compressed gas from 5 bar to 30 cubic meters of compressed gas at 2 bar, approximately 5,700 kJ will be released. The residual energy content of 3800 kJ represents only about 15% of the initial energy. Approximately 85% of the initial energy was taken from the compressed gas. The compressed gas of 2 bar can now be discharged via the degassing valve and its energy would then be lost. However, it could still run during release via a low-pressure gas turbine and thereby release a portion of its remaining energy, which would increase the overall efficiency. This is especially possible if the compressed gas is air, or the compressed gas would be discharged into a "non-pressurized" container (eg expandable film container).

Preferably, the low-pressure gas would previously be slightly raised in its temperature in order to prevent condensation phenomena in the turbine. This can be done, for example, in the simplest case of air by burning some natural gas in this low-pressure air. Alternatively, if one has a suitable low pressure liquid working machine available for this, the 30 cubic meters of 2 bar could be further isothermally expanded, eg to 40 cubic meters of 1.5 bar. In these 40 cubic meters would then be 2.400 kJ of energy contained (60 kJ per cubic meter). When expanding so again 1400 kJ would be free. Thus, the isothermally expanded gas of 1.5 bar would contain only about 10% of the initial energy, 90% would already be converted into mechanical work. Of the remaining 10%, a considerable part could be recovered by means of a gas turbine, because in the adiabatic expansion from 1.5 to 1 bar no strong change in temperature began. Again, however, a prior increase in the low-pressure gas temperature is still useful. Otherwise you could easily escape in the case of air through the vent valve without Arbeitsverrichtung what the apparatus required reduced. Another method of making good use of a residual pressure gas energy is to use this energy to bring the liquid previously displaced by the expanded gas from the expansion spaces back into another expansion space for the next work cycle. This is facilitated by the fact that the expansion spaces during the filling with liquid have a connection to the outside air or to a non-pressurized gas container and therefore can be filled without pressure. It must be present for such a filling a connection of the gas space of the expansion space E ₁ , in which just finished a cycle with the liquid reservoir R. Then liquid is pressed from the reservoir R via another line in an empty pressure-less expansion space E ₂ , the degassing valve is currently open.

For a good controllability of the power generation, it makes sense to choose the expansion space as large as possible, because then the changes in pressure in slower going on and thus are more controllable. How big you ultimately choose depends on the local conditions (stability of the mountains, already existing cavities, etc.). Smaller expansion spaces or partial expansion spaces can also be artificially applied above ground or in the vicinity of the earth's surface, e.g. also with a concrete or steel jacket. A smaller size of the expansion spaces can be compensated by a variety of the same. The size of the expansion areas is feasible within a wide range of about 1 to 100,000 cubic meters.

The quasi-isotherm in the expansion space is achieved by the heat exchange with liquid located there. It makes sense here to spray the liquid in this room or rain down from above. The most sensible methods are similar to lawn sprinklers, since in this case the liquid has longer gas contact than if it trickled down only from above. By an oblique injection of liquid can also produce a circulation roll of the gas in the expansion space, whereby the heat exchange improves. On the other hand, there is the possibility to perform a passive very low-maintenance sprinkling of the gas space above the liquid level: For this purpose are at or slightly below the ceiling of the expansion space trough-like structures with sieve bottom or container with sieve bottom and degassing valves at the top. After filling the expansion space with liquid these wells or containers are also flooded / filled. As the gas expands, the liquid level in the expansion chamber sinks below the trough bottom / sieve tray and the liquid in the trough trickles down through the sieve openings (as though from a shower head), warming / tempering the cooling gas as it expands. The tubs must therefore contain at least the amount of liquid needed to ensure sufficient quasi-isothermia and the openings must be so small and at the same time large enough for the liquid to flow out of the tubs until the end of the expansion cycle of the gas in the expansion space. The necessary size and number of openings can be estimated approximately by means of Hagen-Poiseuille law and then optimized in the experiment. Control of the rate of discharge over the number of orifices is simpler than over the diameter of the orifices, since the outflow to the number of orifices is linear, whereas the size of the orifices and flow therethrough are highly nonlinear. Preferably, the outflow from the tubs is controllable, for example through the openings temporarily covering slide.

um das 18,6-fache zunehmen. On the amount of liquid and its temperature can be too strong a decrease in the mixture temperature gas / liquid in the expansion space prevent. Above all, water or aqueous solutions prove to be very cheap here! By weight, water has about four times greater heat capacity than air (about 4.2 kJ / (kg · K) versus about 1 kJ / (kg · K)). Thus, relatively little water can already prevent a sharp drop in temperature during gas expansion. Example calculation with water and air: If 1 kilogram of compressed air (simplified and idealized) of 293 K (20 ° C) and 60 bar (that is about 12.9 liters of compressed air) adiabatically expanded to 1 bar, so would their volume according to the equation

increase by 18.6 times.

For the temperature after adiabatic expansion, the equation holds

Thus, the temperature is

The expanded air would thus have lost about 202 degrees of temperature. To heat up that one kilo of cold air to about 283 K (10 ° C) you needed about 200 kilojoules. This amount of heat could be emitted from about 5 kilos of water, which would thereby be cooled from 20 ° C to 10 ° C or from 30 ° C to 20 ° C, or 10 kilos of water, from 20 ° C to 15 ° C or from 25 ° C to 20 ° C, or 1 kilo of water, which would be cooled from 70 ° C to 20 ° C. If the adiabatically expanded air were reheated to approximately 10 ° C by mixing with water, its pressure would increase (with the volume held constant), approximately in accordance with the general gas equation. Since the pressure at constant volume is proportional to the absolute temperature, the air would then be under a pressure of 283 / 90.9 · 1 bar = 3.11 bar. It could then be expanded again adiabatically to 1 bar, where it cooled down a bit (but much less than before), then heated again by means of water, etc., until at the end air at 1 bar at a temperature of 10 ° C would have , These many processes connected in series can be combined into a single one in which the water is already supplied during the expansion of the air (but at the latest before the end of the expansion). The greater the temperature difference between the compressed air and the water, the faster the heat transfer from the water to the air. It also loses efficiency because the water would have to be brought to the elevated temperature beforehand, whereas water from ambient temperature (seasonal fluctuating) would always be available without energy consumption. As already mentioned, however, the tempering water could also have been heated by waste heat or excess energy from times of overproduction, so that even a higher energy could be obtained from the stored compressed air energy because part of the thermal excess energy would also be converted into mechanical energy! This is the case of quasi-isothermia previously defined as hyperthermia.

Another way to achieve an approximate isotherm of the expanding gas is to fill the expansion space with a heat-storing solid so that the liquid can flow through it without cavities in it, while the compressed gas expands, thereby displacing the liquid from the expansion space ! The solid has two functions: it tempered the expanding compressed gas, and it is on its surface carrier of liquid, which also tempered the expanding compressed gas. The liquid drips down from the solid and thus sprinkles the expanding compressed gas. When cooled down, it drips again onto the solid and, as a thin liquid film, heats up very quickly there and can then temper again expanding compressed gas. In fact, even most of the expansion process, a thin liquid film is a carrier of heat between solid and gas. The solid may be e.g. simply act around a coarse pile of rock, which also helps stabilize the wall of the expansion space, if it should be underground. In order to increase the void fraction (the pressure vessel may then be smaller and then easier to build stably), artificially created structures, e.g. Concrete pipe parts to be used as a bed. But it can also be e.g. honeycomb structures or specially layered artificial bodies are erected. Grass pavers, stacked, also result in larger voids, and even larger, when poured. The heat content of the solid provides the heat necessary to maintain quasi-isothermicity, with the solid cooling slightly during the expansion of the duckg gas. It is reheated each time the expansion space is refilled with liquid (which has a higher temperature than the solid). Since in such an expansion space, the gas circulation is greatly reduced, it is advantageous if the solid in the upper region of the expansion space has a larger relative surface area than in the lower. Because then the upper gas content, which comes in the expansion with only a little new solid in contact, still tempered well. In the case of a rock bed, this means e.g. a smaller grain size. However, in order to prevent the finer grains from sagging into the underlying larger ones and reducing their void fraction, it is preferable to have well liquid-permeable separating layers, e.g. Mesh or wire mesh with a mesh size smaller than the grain size. The aggregates may be successively introduced layer by layer into the expansion space with separation layers of the appropriate mesh size, or whole sacks of the rock are introduced into the expansion space, the bag material being a net. The net can be made of plastic, but it can also be made of metal and e.g. also be a gabion. Gabions can also be stacked to produce even greater void fraction.

When the compressed gas is stored in underground reservoirs (eg salt caverns), it has a temperature that is at least the temperature of the surrounding soil at that depth (plus residual heat because the compression is not completely isothermal, or intentionally not isothermal performs). The heat of the compressed air in the underground storage depends on the so-called geothermal depth. On average, the temperature increases with the depth by about 3 degrees Celsius per 100 meters, in some areas more, in others less. At a depth of 600 meters, temperatures of about 30 degrees Celsius are expected on average.

Example calculation of a temperature control of expanding air by water: When 13 liters of compressed air (60 bar) of 20 ° C (that is about 1000 grams or 34.5 moles of air) during expansion with 8 liters (about 8000 grams) of finely divided water of 20 ° C would be mixed, so would arise from a mixture in the air and water initially in volume in the ratio 13: 8 (about 1.5: 1) would be mixed, after the almost isothermal relaxation to 1 bar, a mixture of, for example, about 10 ° C. in which the proportion of air to water in volume amounts to about 780: 8 = 97: 1. (However, this only if one assumes that no water from the liquid state into the gas phase passes, which is not strictly the case, because it evaporates so some water to 100% relative humidity is reached!) It makes sense, the water but not on added once at the beginning of the expansion process, but continuously or at small intervals throughout the expansion process. At the conservation of energy and final temperature of water and air that does not change anything. To stay with the earlier example of an expansion chamber of 10,000 cubic meters, into which initially 150 cubic meters of compressed air of 60 bar are introduced: To let this 150 cubic meters of compressed air, which weigh about 11,500 kilograms to cool not more than 10 degrees, are about 92,000 kilograms Water (about 92 cubic meters) of the same temperature for tempering necessary. If these 92 cubic meters of water, for example, with an overpressure of 3 bar, as is common in water networks, sprinkled in the expansion space by sprinklers (ie the pressurized soil water removed in the expansion chamber and sprayed with a 3 bar higher pressure top again), so consumed that is, an energy of W = p · V of 27.6 MJ, which would be significantly less than 1% of the "isothermal energy" stored in the 150 cubic meters of compressed air.

Preferably, pressurized gas liquid power plants find their application directly next to existing hydroelectric power plants or pumped storage power plants, or they are then part of the same.

A pressurized gas liquid power plant according to the invention is then used to transport water which has fallen down in the conventional pumped storage power station and has generated energy back up into the storage lake (directly by means of mechanical pumps or via the intermediate step of electrical energy and drive of electric pumps). This has the advantage that the compressed gas liquid power plant according to the invention does not have to be regulated exactly in its performance. It only has to keep the storage lake sufficiently full for a long period of time. The matured, adjustable in their power output generators pumped storage power plant or hydroelectric power plant, it is then fed exactly regulated electrical energy into the electrical grid. The relatively constant water level of the lake allows this exact regulation! As a result, the compressed gas liquid power plants according to the invention become cheaper because they do not require expensive exact power control! This is already available at the storage lake power plant! Of course, particularly preferred for such a case is the use of water as liquid and air as gas. The storage lake can then also be used as a very large thermal reservoir of liquid for such a compressed air water power plant in addition to the storage of location energy. Since such compressed gas liquid power plants with attached storage lake require only a limited amount of water, which is guided by pressurized gas energy in the cycle, allow pressurized gas liquid power plants of this type, the water turbines of the reservoir allow run until the compressed gas energy is used up. For this purpose, in principle only relatively small water reservoirs are needed, which do not even have to be designed as aboveground lakes, but also, environmentally harmless and invisible, high-altitude underground caverns can be. According to the invention, in addition to existing hydroelectric power plants and pumped storage power plants, compressed air-tight underground caverns can be produced, which are preferably filled with compressed air with the aid of excess regenerative energy. (Above-ground compressed gas storage are of course also possible, but usually more expensive.) When energy needs in the power grid now start the hydroelectric power plants to generate electrical energy, while or later, the pressurized gas liquid power plant, the high-altitude reservoir repeatedly filled with water, so that they are so Long water will contain how much pressurized gas energy is available to replenish it. In order to not only be able to draw off electrical energy from the pumped-storage power plants over a longer period of time, but also to increase the power if required, it makes sense to expand the pumped-storage power plants in terms of performance, e.g. create more downpipes and turbines. This is possible because the water of the reservoir is constantly refilled by compressed gas energy. So it is not necessary to increase the performance, create more environmentally damaging pumped storage lakes!

In the event that a pressurized gas liquid power plant according to the invention is to be used without existing pumped storage power plant, the power output is controlled by controlling the flow rate through the working machine, usually a turbine, whereby automatically the expansion speed of the pressurized gas is controlled in the expansion space. In pressurized gas liquid power plants having more than one expansion space, the output is made uniform by partially compensating for unevenness in expansion in the different expansion spaces, similarly to the case of multi-cylinder engines. But it is also possible to simplify the scheme by coupling the power plant with one or more energy storage devices (in this case no pumped storage tanks), which temporarily absorb surpluses and release them again in the event of a power shortage of the working machine. These energy storage for power balancing need not be large, so that they are not expensive. It may be with them e.g. to act a flywheel storage or to a Hubspeicher or spring storage. It is also possible to use short time Energieübeschüsse again for compressing compressed gas and feeding it into the compressed gas storage. Or the energy peaks are used to heat the tempering liquid. In principle, battery storage is possible, as well as other not too expensive memory types with the possibility of fast coupling and decoupling of energy.

An inventive compressed gas liquid power plant preferably has at least one temperature sensor in the gas space of the expansion space. However, the temperature sensor can also be an infrared measuring device or else a laser similar to LIDAR, which allows temperatures and also flows to be measured even at points away from the device. The temperature sensor is preferably in the volume of the expansion space, which is filled at the beginning of an expansion cycle with not yet expanded compressed gas, because in this gas volume takes place in the absence of convection and the largest temperature change. The temperature sensor (s) should preferably not be constantly with but in the case of a tempering liquid spraying spray device be provided with a mounted against the direction of the spray device cover so that the temperature-controlling liquid does not constantly heated the temperature. In the case of tempering sprinkler baths, the temperature sensor would be protected upwards, for example with a kind of "lampshade" of the tempering liquid. Preferably, the expansion chamber also contains a pressure sensor. This may be located in the gas space or in the liquid space, but preferably in a location with low flow velocity, since this affects the pressure measurement (Bernoulli).

Furthermore, the pressurized gas liquid power plant according to the invention has an automatic control device, which allows to regulate the power output of the pressurized gas liquid power plant from the measured values of the at least one temperature sensor and possibly also a pressure sensor. The power output is controlled by the flow rate through the work machine depending on the prevailing pressure in the expansion space. The control device automatically reduces the flow through the working machine, if measured values of the at least one temperature sensor indicate that the stored definition value of the quasi-isotherm would be exceeded and the efficiency therefore decreases too much. Preferably, however, not only a single definition value of quasi-isothermia is stored in the control device, which value is associated with a certain minimum acceptable efficiency, but at least two definition values are stored! This allows the control device in exceptionally short-term high power requirement of the power grid to serve them through the compressed gas liquid power plant. The control device then accepted in the short term, a lower quality requirement for the Quasiisothermie and allows a significantly increased flow of liquid through the machine, but at a reduced efficiency! The gas temperature in the expansion area may then be lower in these exceptional cases, as a rule. Another option of the control device is to increase the sprayed amount of heat transfer fluid or the tempering, which surrounds the small gas tank variant B in reinforced convection, so that increases the heat transfer between gas and liquid and the quasi-isothermal again better fulfilled becomes. In a variant of the invention, the control device also allows an emergency operation in almost fully adiabatic area. Technically, the compressed gas liquid power plant according to the invention namely (unlike compressed air power plants with gas turbine) able to withstand this harmless, because all the cooling in the expansion space affect (apart from the reduced efficiency!) Not harmful to the working machine, since the gas is not in the Work machine penetrates. After refilling the expansion chamber with liquid, the areas previously cooled by the cold gas are again heated to high liquid temperature very quickly!

For storage operation of the pressurized gas liquid power plant:
As with the expansion, isothermal compression is thermodynamically most favorable for the compression of the gas! However, the compressed gas liquid power plant according to the invention can be operated both with isothermally or quasi-isothermally compressed compressed gas and otherwise, for example multi-stage adiabatic, compressed compressed gas. The delivery of heat to the liquid (preferably water) resulting from the approximate isothermal compression of the gas (preferably air) occurs either indirectly via conventional gas heat exchangers described in the prior art, most simply tubes which are passed through the liquid. Or the heat is released by direct contact between heated gas and liquid. For this purpose, the pressurized gas is injected directly into the liquid in a pressure vessel, where it then flows along. Suitable for this purpose are, above all, tower-like structures similar to the gas scrubbers described in the prior art, in which the gas enters at the bottom, rises against gravity, and the fluid thereby also mixes well, and then exits at the top. The liquid in these direct heat exchangers is under the pressure of the compressed gas. In the case of multi-stage compression of the gas, for example, such a direct heat exchanger is located behind each compression stage and the rearmost in the series is in connection with and under the pressure of the compressed gas storage. Behind the compression machine and before the direct heat exchanger is preferably at least one check valve, which prevents backflow of liquid into the compression machine. A further advantage for further safety is a non-return valve between the compression machine and the direct heat exchanger in which any water flowing back is collected before it can reach the compression machine. The high pressure direct heat exchanger is preferably underground. Drying of water humidified air by conventional gas drying methods prior to entry into a compressed air storage is not absolutely necessary, especially if the walls of the compressed air reservoir are insensitive to water (eg rock) or sufficiently thick (eg salt cavern). At long intervals, water or brine that has accumulated on the floor could then be pumped out.

An approximately isothermally guided compressed gas liquid power plant (eg compressed air water power plant) can also be operated with compressed gas (eg compressed air) of substantially higher pressure than the previously envisaged single or multi-stage adiabatic compressed air storage power plants! The reason for this is that all compression heat is dissipated at low temperature relatively promptly during compression and the compressed gas never high, the containers / lines or work machines stressing temperatures! Because it is the combination of high temperature and high pressure at the same time that makes the controllability of materials so difficult! Thus, gas (eg air) can also be approximately isothermally compressed one or more stages to eg about 300 bar. For the isothermal volume work of an ideal gas, the following applies: W = n · R · T · ln (p _high / p _low ) = n · R · T · ln (V _large / V _small ) (W work, n number of moles, R general gas constant, T absolute temperature, natural logarithm of high pressure by low pressure or volume after expansion by volume before expansion, n · R · T for 1 cubic meter of air at 1 bar and 300 Kelvin about 100 kJ)

Example calculation for air: Accordingly, e.g. 300 cubic meters of air of 1 bar, which were isothermally compressed to 1 cubic meter at 300 bar, based on a subsequent isothermal expansion to 1 bar again an energy of about 30,000 kJ · ln300 = 170,000 kJ. The energy density of the compressed air of 300 bar is therefore 170,000 kJ per cubic meter for an isothermal expansion. 300 cubic meters of air, which were isothermally compressed from 1 bar to 60 bar and then occupy 5 cubic meters, based on a later isothermal expansion to 1 bar again, an energy of about 30,000 kJ · ln60 = 123,000 kJ. However, these occupy 5 times the volume, so that the energy density of the compressed air of 60 bar only about 25,000 kJ per cubic meter. This means that the energy density at 300 bar is almost 7 times as high as 60 bar! Thus, at 300 bar, a compressed air reservoir of 100,000 cubic meters accommodates an approximately 17 billion kilojoules (17 trillion joules) of energy recoverable through an isothermal process versus only 2.5 billion kilojoules (2.5 trillion joules) at 60 bar. 17 trillion joules corresponds to the potential energy of 1.7 trillion kilograms (1.7 billion tons) in 1 meter height or 17 million cubic meters of water in a 100 meter high storage lake! This is after all a reservoir lake of 1 square kilometer area and 17 meters average depth! It can be seen that by relatively small underground compressed air storage high pressure relatively large, landscape-consuming aboveground storage tanks can be replaced! It can also be seen that approximately isothermal compressed air storage power plants may have lower storage costs than adiabatic ones because they can operate at higher pressures. Exploited natural gas deposits may e.g. be filled up to pressures of 300 bar!

Not all types of caverns are dense under high pressures. Although salt caverns are particularly dense, they can only be loaded up to about 80 bar. Assuming (analogous to the ADELE project of an adiabatic compressed air storage power plant) a compressed air reservoir in a salt cavern of 500,000 cubic meters, which is approximately below 60 bar and unloaded from the 10% (working range about 57 to 63 bar), so according to the invention reasonably isothermally extracted about 50,000 cubic meters of compressed air with an average pressure of about 60 bar and fed back later. These 50,000 cubic meters of about 60 bar correspond to about 3,000,000 cubic meters of 1 bar.

These 3,000,000 cubic meters of air weigh about 3,900,000 kilograms. Isothermal compression (which, in terms of the thermodynamic efficiency, most favorable type of compression) of this amount of gas requires as much energy as it can release later in isothermal expansion again. According to the numerical values given above, this energy is for the 3,000,000 cubic meters in isothermal compression at 300 Kelvin to a pressure of 60 bar W = 3,000,000 + 100kJ + ln60 = 1.23 billion kJ This energy is completely absorbed by the environment in isothermal compression, because the internal energy of the (ideal) gas remains the same during isothermal compression and the energy supplied flows as heat into the environment. If one wants to store this energy in a finite volume environment, this does not remain isothermal, but heats up. If you store the energy in water, one kilo of water per degree Celsius of temperature increase can absorb about 4.2 kJ of energy. 293,000,000 kilograms of water, corresponding to 293,000 cubic meters, could absorb this amount of energy with a temperature increase of 1 degree. If one allows a still quasi-isothermal increase in temperature by 10 degrees Celsius, then only 29,300 cubic meters of water would be needed. With a still quasi-isothermal increase by 20 degrees Celsius it would be 14,650 cubic meters of water. (Since not completely isothermally compressed, the value is a bit, but not much, above.) That would be equivalent to about 7 Olympic swimming pools or a small pond from 50 to 50 meters at 5.86 meters depth (eg also easy with pond liner, clay soil or similar executed) or a cube with 24.5 meters side length. Of course, if you let a higher temperature increase of the water, the required volume of water decreased accordingly. This water would then again (batchwise, since the compressed air is tapped only in batches) used to compensate for the cooling during gas expansion. The expansion space of the compressed air water power plant would be smaller than the water heat storage in most embodiments. Of course, this depends on how warm you want the water to be and how big you want to build the expansion space of the compressed air power plant. (With an "open system" (eg sea) one needed no stockpiling of the water.) The 50,000 cubic meters compressed air of on average 60 bar, which could be taken from the compressed air storage according to the above example, contained an "isothermal energy" of 1,230,000,000 kJ or 1.23 trillion joules. 1.23 trillion joules corresponds to the potential energy of 123 billion kilograms (123 million tons) in 1 meter height or of 1.23 million cubic meters of water in a 100 meter high reservoir lake! This is after all a storage lake of 1 square kilometer area and 1.23 meters average depth, or a circular lake of 600 meters in diameter and an average depth of 4.5 meters. (For comparison: The storage tank of the pumped storage plant Goldisthal has an approximately 10-fold volume.) A arranged next to a pumped storage power plant compressed air hydro power plant could thus make good use of this large water supply for intermediate storage of dissipated in the isothermal compression heat energy. The temperature changes of the water in the reservoir lake would be minimal!

The figures show schematically some possible embodiments of the invention.

1a shows the basic diagram of a simple power plant according to variant A with an expansion space E and a working machine A.

1b shows the same power plant, but with two expansion spaces E1 and E2 and a working machine A.

2a shows the basic scheme of a simple power plant according to variant B with an expansion space E and a working machine A, which can also work as a pump P.

2 B shows the same basic scheme, but with separate pump P.

2c shows a power plant according to variant B with several expansion spaces E1 to En, and a working machine A can also work as a pump.

2d shows a power plant according to variant B with several expansion spaces E1 to En, a working machine A and a separate pump P.

3a shows the basic scheme of a power plant according to variant A or B with several, in the illustrated case, three expansion spaces of different sizes for different pressure ranges and with each expansion space each connected machine for the respective pressure range in the upstream expansion space.

3b shows the basic scheme of a power plant as in 3a in which the expansion spaces are nested.

4a shows the basic diagram of a power plant according to variant A or B, in which an expansion space is connected to two working machines for different pressure ranges.

4b shows an embodiment for variant A, which works similar to a two-cylinder engine.

The 5a to 5d represent the basic scheme of a power plant according to variant A with three expansion spaces and three working machines, which are in different Phases of the working cycle or filling are located. Each expansion room has its own work machine assigned only to it.

The 6 and the 7a to 7d represent the basic scheme of a power plant according to variant A with several expansion spaces and multiple machines that are in different phases of the duty cycle or the filling. Each work machine is connected to each of the expansion rooms. 6 represents a scheme with three machines at three expansion spaces, the 7a to 7d represent a scheme with fewer machines than expansion spaces, namely two machines at three expansion spaces.

The 8th show a selection of different forms of expansion spaces. In principle, however, expansion chambers are pressure vessels, and other forms of pressure vessels, as described in the prior art for the required pressures, are also possible. Supply lines and discharges into the expansion areas are in the 8th (and also in the 11 . 13 and 14 ) not shown. Compressed gas supply lines and discharges are, however, usually at the top or at least in the upper region of the expansion space, liquid supply and discharge are usually at the bottom or at least in the lower part of the expansion space.

The 9 shows an expansion space with riser.

The 10 show some examples of expansion spaces with small gas containers contained therein for variant B of the invention.

The 11 show expansion areas that are supported by icing coats VM.

12 shows the scheme of a pumped storage power plant that can be refilled by the energy of a pressurized gas power plant.

The 13 show some possibilities of gas temperature control.

The 14 show a particularly simple execution option for a method according to variant B.

15 shows an embodiment of a method according to variant A with expansion spaces within the compressed gas storage D.

The 16 show schematic pressure / volume curves with different process control.

In the figures are lines 8th and 9 that cross others and are not connected to them, dashed lines. In 1a the basic scheme of a very simple version of a power plant according to variant A is shown. A compressed gas reservoir D represents the compressed gas reservoir, from the subsets of gas 2 Batchwise introduced via a preferably continuously or in several stages controllable valve V _DE in an expansion space E. However, the valve V _DE can also be non-controllable and have only the possible states open and closed. When introducing the subset of the compressed gas 2 in the expansion space E is already liquid 1 displaced from the expansion space E through the preferably controllable valve V _EA through into the working machine A. (This process takes place at almost constant pressure, ie isobaric or quasi-isobaric!) Thereafter, in the expansion space E above the liquid 1 Under pressure decrease an expansion of the subset of the gas 2 instead of the liquid 1 displaced by the preferably controllable valve V _EA in a working machine A. The temperature of the gas 2 in the expansion space E during the expansion is not shown in this simple scheme, but takes place as previously and later described.

The pressure of the liquid 1 at the entrance to work machine A due to the relative incompressibility of the liquid 1 practically corresponds to the actual gas pressure in the expansion space E (minus friction losses), is in the work machine A by means of movement of the liquid 1 converted into mechanical work. The pressure of the liquid drops 1 from the access of the working machine A (which may also consist of several subaggregates) until the end of sharply. From the working machine A, the liquid flows 1 with only a slight overpressure in a liquid reservoir R on. Preferably located between working machine A and reservoir R is a preferably controllable valve V _AR . Mitttels the valves V _EA and V _AR , the flow through the working machine A can be regulated. A further control is performed by not shown, known from the prior art, the usual internal actuators in the machine A. If it is the work machine, for example, a water turbine, so here also the setting angle of the blades and vanes, the flow rate of the liquid 1 change. The mechanical work produced results from W = p + V or, more precisely, differentially from dW = dp + dV. Once again, friction losses and "slip-through losses" must be subtracted by the working machine / turbine. The expansion space E is to the desired final pressure of the gas 2 of liquid 1 emptied. But it remains preferably a part of liquid 1 therein, which prevents the gas access to the working machine A. This in 1a shown power plant can only work as long as liquid 1 through the working machine A flows. Thereafter, only the expansion space E with liquid must again 1 be refilled before a new introduced subset compressed gas 2 from the compressed gas storage D can start a new cycle. A filling of the expansion space E happens with liquid 1 from the reservoir R. The reservoir R is shown in this embodiment as a converted container with a degassing valve V _RL . The reservoir R could also be open at the top. However, a closed container with valve allows better keeping the temperature of the liquid, especially if the container is still surrounded with heat-insulating walls. Then the liquid can 1 It is also kept in the long term at temperatures that are higher than the ambient temperature. In 1a the reservoir R is shown with a larger volume than that of the expansion space E. In principle, however, it only has to be the volume of the liquid displaced from the expansion space E. 1 contain. A larger volume of liquid allows the temperature of the liquid 1 to keep it constant if this is desired for operational reasons. However, a larger volume also allows an increased storage of heat energy, for example, waste heat or heating energy from excess wind power or excess solar energy, the expanding gas during discharge of the compressed gas storage D 2 then do additional mechanical work.

To fill the expansion space E after completion of an expansion cycle, liquid flows 1 back from the reservoir R through the valve V _RE in the expansion space E. For this purpose, the valve V _{EL is opened} at the top of the expansion space E, so that the expanded gas contained therein 2 can escape. Is the liquid level 10 in the reservoir above the upper edge of the expansion space E, so will the gas 1 passively completely displaced ("communicating tubes"). Is the liquid level 10 below the upper edge of the expansion space E, so is active liquid 1 pumped from the reservoir R in the expansion space E until it is filled. Optionally, the gas 2 which is diverted through the valve V _EL , are still passed through a gas turbine where it also generates a residual mechanical energy that can be converted into electrical energy.

In 1b an embodiment of the simple power plant is listed, which can work continuously until the compressed gas storage D is emptied on his minimum stability required for stability minimum internal pressure. For this purpose, this power plant has a second expansion space E2. (In principle, there may be more than two expansion spaces.) Then, the two expansion spaces E1 and E2 can work alternately and new with liquid 1 and then a compressed gas batch 2 be filled while expires at the same time in the other expansion space of the expansion cycle. So while in the second expansion space E2 refilling with liquid 1 from the reservoir R via the valve V _RE2 takes place, at the same time the expanded gas 2 escapes via the valve V _E2L (preferably via a power-generating gas turbine), runs in the expansion _space E1 from an expansion _{cycle, wherein} the liquid 1 is pressed by the working machine A. The refill happens in a shorter time than the one that needs an expansion cycle. As a result, the refilled expansion space E1 or E2 is always ready in time for a new expansion cycle before the expansion cycle is completed in the other expansion space. To complete the expansion _cycle in the expansion _space E1, the valve V _E1A between the expansion _space E1 and working _machine A is closed and simultaneously or shortly before the valve V _E2A between expansion space E2 and working machine A is opened, so that then introduced by the introduced into the expansion space E2 Druckgascharge 2 liquid 1 is pressed into the working machine A and then reaches the reservoir R. Simultaneously with the valve V _E2A or slightly earlier, the valve V _DE2 between compressed gas storage D and expansion chamber E2 is opened. The valve V _DE2 is then closed again as soon as the required amount of compressed gas 2 has entered the expansion space E2. Thereafter, the expansion of this compressed gas batch takes place 2 while, in the meantime, the expansion space E1 with liquid 1 is refilled. In 1b Only one work machine A is served by two expansion spaces E1 and E2. It is more advantageous, but more elaborate, to equip each expansion area with its own work machine.

Refilling the expansion chambers with liquid 1 happens passively depending on their relative altitude by gravity or by pumps that are not shown.

In 2a the basic scheme of a very simple embodiment of the invention according to variant B is shown. There is only one expansion space E, which is also the compressed gas storage D at the same time, in which all energy-storing compressed gas is contained. It is a closed reservoir R shown, but of course, a completely open is possible, but then preferably filled with water or a saline solution. To generate energy, the liquid contained in the small gas tank expansion space E is due to the gas expansion in the small gas tanks, not shown by the working machine A. pressed, whereby mechanical work is generated, which can generate electrical energy by means of an electric generator. The flow through the working machine A is preferably controlled by a valve V _EA between the expansion space and working machine A and a valve V _AR between the working machine A and liquid reservoir R. Furthermore, a control via actuators in the machine can be done. In a water turbine, for example, this would be the angle of attack of the turbine blades and guide devices. The gas in the small gas tanks can be fully expanded to operational end pressure possible, or it can also be stopped before the expansion. To load the reservoir D with compressed gas energy liquid from the reservoir R is pumped with the operated as a pump P work machine A back into the expansion space E, wherein the expanded gas is compressed in the small gas tanks and transfers the heat generated in the surrounding liquid. The compression occurs so slowly that the compression process is quasiisothermic, since this is favorable for a good efficiency. The compression can take place continuously or at intervals. The simultaneously serving as compressed gas storage D expansion space E can be as large as it is possible statically. If the expansion space E is under the earth or under a large layer of water, it can also have very high volumes, for example between 100,000 and 1,000,000 cubic meters, even at high storage pressures of 60 bar or more. If the expansion space E is above ground or near the surface, then the reasonable sizes are less than 100,000 cubic meters, preferably less than 10,000 cubic meters, more preferably less than 1000 cubic meters. In the figure, a degassing valve V _{EL is} shown at the expansion space E. This is not necessary. However, it makes it possible, possibly in the expansion space E from the small gas tank occurred gas discharged through this valve in order to achieve a complete liquid filling of the expansion space E outside of the small gas tank can. In 2 B is the same power plant, but with a separate from the working machine A pump P. Although a separate pump P means higher costs, but it has the advantage that any necessary maintenance work on the pump P can be performed when just the machine A for power generation is in operation, and at the working machine, if just the pump for energy storage running. In 2c is a similar power plant as in 2a represented according to variant B of the invention. However, the entire compressed gas is split into several (number n) shares, which are located within non-illustrated small gas tanks in different expansion spaces E1 to En, which are at the same time compressed gas storage D1 to Dn. The expansion spaces do not have to be the same size, but they can also have very different volumes. There is a working machine A, which is operated by all expansion spaces E1 to En with liquid. The same work machine A, which generates mechanical work in the discharge mode of the compressed gas storage power plant is used in the loading mode of the power plant as a pump that pumps liquid from the reservoir R back into the expansion spaces E1 to En. The expansion rooms can all be refilled at the same time, or only one can be filled and then only the next. A simultaneous filling leads to a better Quasiisothermie, because the pressure increase in the individual expansion spaces is slower and thus also the heating of the gas, which then has more time to transfer the heat to the liquid. The same applies to the filling for the emptying of the liquid from the expansion chambers during gas expansion: If all expansion chambers simultaneously press liquid into the working machine A, the change in pressure (and thus the change in the temperature of the gas in the gas volume variable small gas tanks) takes place in each single expansion space slower than if only one expansion space would press the same amount of liquid through the working machine A. Accordingly, the Quasiisothermie is better ensured when all expansion spaces operate the machine A simultaneously. Refilling the expansion chambers with liquid in turn has the advantage that one can always keep an expansion space under full pressure. In 2d is a similar design as in 2c illustrated, but in which a separate pump, the refilling of the expansion _spaces E1 to En worried with liquid via separate valves V _RE1 to V _REn . However, it can of course also be carried out with another management of the supply lines and a refilling with liquid from the reservoir R via the valves V _E1A to V _EnA .

In 3a shows an embodiment of a power plant with three expansion spaces, from which the liquid is successively displaced by the expanding gas. It may be both a power plant according to variant A, as well as a power plant according to variant B. In the case of a power plant according to variant A, the expansion space E1 has a valve V _DE1 to the compressed gas storage. Therefore, this valve and the supply line 9 shown in dashed lines in the figure. Depending on which variant is shown, the connection lines of the expansion chambers with each other are only liquid lines 8th (Variant B) or lines, 8th and 9 through which, depending on the time in the expansion cycle, either liquid 1 or gas 2 flows (variant A). The valve V _E1L , through which in an embodiment according to variant A, the expanded gas is discharged from the expansion _chambers during refilling with liquid, but makes sense in an embodiment according to variant B, because through such a valve eventually with time (due to any leaks in the small gas tanks) can be easily removed. The expansion chambers E2 and E3 may also still degassing valves (not shown) having a Refill with liquid. In one embodiment of a power plant like the one in 3a Gas expansion takes place in different expansion spaces, which are designed for different pressures. In the first expansion space E1, the highest pressure prevails. Therefore, this expansion space is most stable. By making this expansion space E1 smaller than the one following, it is nevertheless possible to keep the wall thicknesses of this expansion space relatively low and thus cost-effective (eg in accordance with the "boiler formula" approximation). DIN 2413 ). During the expansion of the gas in the expansion space E1, the valve V _E1E2 is closed to the next expansion chamber E2. The liquid displaced by the gas expansion is _forced through the open valve V _E1A1 into the working _machine A1, where it generates mechanical energy with which electrical energy can be generated. The liquid leaves the working _machine A1 in a reservoir R, preferably via a valve V _A1R . The gas expansion in the expansion space E1 is carried out only up to a certain, still relatively high pressure. At an initial pressure of 60 bar, the final pressure in this stage may be, for example, about 20 bar. After this pressure has been reached, valve V _{E1A1 is} closed and valve V _{E1E2 is opened} between expansion _space E1 and E2. Now, the liquid in the expansion space E2 is under the pressure that previously prevailed in the expansion space E1. (In the case of an embodiment according to variant B, care is taken that the content of the expansion space E2 was already below the final pressure of the expansion space E1, otherwise the gas in the small gas tanks of expansion space E2 would experience a sudden volume change!) In addition, the valve V _E2A2 between expansion _space E2 and work _machine A2 opened. The valve V _E2E3 to the expansion _space E3, however, is closed. It is then by the expansion of the gas in the expansion space E1 and E2 (it enters in variant A gas through the valve V _E1E2 from the expansion _space E1 in the expansion _space E2) the liquid of the expansion space E2 pressed by the working machine A2 and then leaves them into the liquid reservoir R, preferably via a valve V _A2R . Also, this gas expansion takes place only up to a certain pressure, which is not yet the final pressure of the overall process. For example, if the initial pressure at this expansion stage was 20 bar, the final pressure in this stage could be 6 bar. If this final pressure reached this stage, the valve V _{E2A2 is closed} to the working _machine A2 and the valve V _{E2E3 opened} to the expansion _space E3. In addition, the valve V _{E3A3 is opened} between the expansion _space E3 and the work _machine A3. Now the gas expands in the expansion spaces E1, E2 and E3 and displaces the liquid from the expansion space E3. In variant A gas flows from the expansion space E2 in the expansion space E3. The displaced liquid generates mechanical work in the work machine A3 which can be used to generate electrical energy. The liquid flows behind the working machine in the reservoir R. If the liquid (and the gas) at the beginning of this expansion stage still under a pressure of 6 bar, for example, it leaves the machine only with a pressure of 1.5 bar or 2 bar. After most of the liquid has been displaced from the expansion space E3 and the target end pressure of the overall process has been reached, the refilling process of the expansion spaces E1, E2 and E3 can take place:
If the liquid level in the reservoir R higher than in the expansion spaces (otherwise be used for this purpose, a pump), so, by simply opening the valve V _RE3 between the reservoir R and the expansion chamber E3, and of the vent valve V _E1L to the expansion compartment E1, the liquid from the reservoir R in the expansion spaces flow back. This is done in the reverse order of gas expansion, ie from E3 to E2 to E1. If the expansion _chambers are completely filled with liquid, the valves V _E1L and V _{RE3 are} closed again. It is also possible to fill the expansion chambers with liquid at the same time. For this purpose, however, all expansion chambers should have degassing valves and each expansion space requires a connection to the reservoir R. In principle, the refilling can also take place via a bypass past the respective working machine. You then save pipes 8th one. In the 3a Each expansion space is equipped with its own working machine, which is optimized for the pressure range that is passed through in the respective expansion space. But it is also possible, all expansion spaces with the same machine on merged lines 8th and to connect valves or to connect two expansion spaces with a work machine and the third with a second. Although you lose some efficiency, but the overall process is simplified. 3b shows an execution as in 3a but the expansion spaces are nested inside each other. If the respective outer expansion space is under pressure, and the inner one is under pressure, then the pressure in the outer surrounding expansion space stabilizes the wall of the inner expansion space and the walls can be made thinner and thus less expensive! Again, of course, the power generation can be done with only a single or two machines.

The reservoir in the 3 Of course, it can also be open, in the case of water also an open water. The valves V _E1E2f and V _E2E3f between the expansion _spaces E1 and E2 or E2 and E3 represent valves through which the gas contained in the expansion spaces E1 and E2 escape into the respective expansion space E2 or E3 during the filling process of the expansion spaces with liquid can, so that eventually all gas from all expansion _spaces through the valve V _E3L can be discharged into the environment.

In 4a a version is shown, which is possible for both variant A and variant B. For variant B, there is no connection to the compressed gas reservoir D, but the expansion space E is itself the compressed gas storage in which the compressed gas is stored in small gas tanks. The power plant according to 4 has two working machines (more are of course also possible) to improve the efficiency of the conversion of energy from the compressed gas, because work machines usually have certain areas where they have the highest efficiency, and with several machines with different work areas can be cover better during operation. The expanding and thus doing gas thus first presses the liquid through the valve V _EA1 through the working _machine optimized for this pressure range A1 and further through the optional valve V _A1R in the reservoir R. In this case, the valves V _EA2 , which is also optional valve V _A2R and the valve V _RE between expansion space and reservoir closed. Preferably, shortly before reaching the final pressure, from which the working _machine A2 has the higher efficiency, the valve V _{EA2 is} opened slowly, so that a continuous start-up of the working _machine A2 is ensured. Also, the valve V _EA1 is preferably not closed abruptly, but continuously operated. When the gas in the expansion space E has reached its final pressure of the overall process, the expansion space E can be filled again from the reservoir R with liquid. This can be done by bypasses around the machines around or as shown in the figure by a separate line from the reservoir R to the expansion space E. For this purpose, the valve V _{RE is} opened. If the liquid in the reservoir R is higher than in the expansion space E, then the expansion space E fills in the case of the variant A without active pumping, because the expanded gas escapes (in the process according to variant A) via the valve V _EL . In the case of variant B, the valve V _EL serves only as Notentgasungsventil for undesirable escaped from the small gas tanks gas and is normally closed. In the case of variant B, therefore, the liquid must be filled by means of pumps against the increasing pressure of the gas in the small gas tanks. 4a also represents the case in which two (or of course more) machines of the same type are connected to an expansion space and are also flowed through at the same time.

Since the mechanical power (which can be converted by a generator into electrical power) depends on the pressure and the amount of volumetric flow (it is true that dW = d (p + V), so the change in the work is equal to the change in the product of pressure and Volume), and the pressure is initially very high and very low at the end, inevitably the amount of liquid flowing through the working machine must initially be small and large at the end if the power is to be kept constant. This can be achieved in suitable machines in a single machine by regulating the flow. However, simpler work machines allow only a change in flow within a narrower range than would be required. In this case, the invention provides, as in the 4a pictured to connect two (or more) work machines to the expansion space E. First, only a working machine is flowed through and with increasing flow further machines are connected. Since these further, later switched-on machines do not have to withstand the high initial pressure, they may also be made less stable, but they may be suitable for larger volume flows, for example. Also in the versions of 4a Reservoir R may be open and, in the case of water, also open water. 4b shows an embodiment of the invention for variant A, in which two expansion spaces E ₁ and E ₂ alternately cycles by means of the gas expanding therein 2 perform and the other expansion space then serves as a liquid reservoir R ₂ and R _{1 of} the other. In the illustrated state just expanding gas 2 in the expansion space E ₂ and presses liquid 1 through the working machine A ₂ in the expansion space E ₁ inside, which serves as a liquid reservoir R ₂ at this time. For this purpose, the degassing valve V _{E1L is} open and the valve V _DE1 closed to the compressed gas _reservoir D. After then the gas 2 in the expansion space E _{2 is} expanded to Sollenddruck (the expansion space E ₁ is then filled with liquid), the valve V _E2A2 to the working _machine A _{2 is} closed. In addition, the valve V _{E2L is opened} from the expansion _space E ₂ to the environment. Furthermore, the valve V _{E1A1 is opened} from the expansion _space E ₁ to the working _machine A ₁ and the valve V _DE1 between compressed gas storage D and expansion _space E ₁ and introduced a compressed gas _{charge in} the expansion _space E ₁ , which then expands after closing the valve V _DE1 and thereby the liquid 1 through back through the working machine A ₁ back into the expansion space E ₂ , which serves as a liquid reservoir R _{1 of} the expansion space E ₁ at this time. The entire system then works like a two-cylinder engine with the compressed gas 2 as an "explosive" and liquid 1 as "cylinders". It is also possible to arrange more than two working machines between the expansion spaces, which exploit the occurring pressure ranges and volume flows with a higher degree of efficiency.

Of course, it is also possible to work with more than two expansion spaces, which replace each other in their function as expansion spaces E and R reservoir. If you have a bidirectional machine available, so you can also replace two machines between two expansion spaces by such a bidirectional.

In 5a is schematically illustrated an embodiment according to process variant A, in which there are three expansion spaces E1 to E3 considered at the same time in different working cycles. Each expansion room has its own work machine assigned to it. In principle, this structure (without connection line to an external compressed gas storage) but also for the variant B, but the structure for the variant A is more suitable. By such an arrangement, the power output of the power plant is made uniform, because at a certain time, not only the expanding gas in a single expansion space does work on liquid. Comparable is such an arrangement with a multi-cylinder engine. In the case shown, it is, so to speak, a three-cylinder engine in which perform three cylinders at any time work or two cylinders perform work and one of the cylinder just back from the reservoir R (which is shown in this figure as open, but also closed and with Degassing valve can be provided) is filled with liquid when he is doing no work. In 5a is expanding gas 2 in the expansion spaces E2 and E3, where the gas 2 in the expansion space E2 is still in an earlier stage of expansion and therefore has a higher pressure than that in the expansion space E3. The liquid level 10 in these expansion spaces move downwards (arrows) and liquid 1 from these expansion spaces is pressed into the working machines A2 and A3. During the working _{phases of} the expansion _chambers E2 and E3, the expansion _{space E1 is} just again with liquid when the valve V _E1L is open 1 filled. This can be done passively by simply running full when the liquid level 10 in the reservoir R is higher than the upper edge of the expansion space E1, or it can be done by active pumping against the low internal gas pressure and / or hydrostatic pressure in the expansion space E1. In the figure, the expansion space E1 is again almost completely liquid 1 filled, but the liquid level 10 is still moving upwards (arrow). 5b shows the same power plant some time later: Now, a duty cycle has also started in the expansion space E1 after compressed gas from the compressed gas reservoir D via the valve V _DE1 2 was introduced into the expansion space E1. liquid 1 from the expansion space E1 is pressed by the work machine A1. The expansion spaces E2 and E3 are still in a work cycle, therefore, now moves in all expansion spaces of the liquid level 10 downward.

5c shows one opposite 5b later time at which the expansion space E3 is being refilled from the reservoir R. The expansion space E2 is in the final phase of its working cycle. The expansion space E1 is in the middle of the work cycle. 5d shows one opposite 5c later time, to which the expansion space E3 again with liquid 1 filled and then with a charge of compressed gas 2 was loaded and again in a work cycle. Also, the expansion space E2 is shortly after its filling again in an incipient working cycle with high internal pressure of the gas 2 , The expansion space E1, however, is located on the liquid before the end of Arbeitsverrichtung 1 , Some time later, the condition of the 5a in front. Depending on the power requirement, however, it is also possible to shift the working cycles in the individual expansion spaces against each other, so that the state of the 5a not achieved, but only a similar one. By repeating the operations according to 5a to 5d For example, the compressed gas reservoir D can be discharged successively to its possible minimum end pressure. However, it can also be reloaded again beforehand if no power output of the compressed gas liquid power plant is more demanded and there is just an excess of energy from wind or solar power (or, of course, another energy source) available.

In the 6 and the 7a to 7d will be a power plant similar to the one in the 5 represented, but here each expansion space E1 to E3 is connected to a plurality of work machines A1 to A3, which are optimized for different pressure ranges. In 6 is a scheme with three work machines A1 to A3 shown in the 7a to 7d with two working machines A1 and A2. Each expansion chamber then presses liquid 1 chronologically successively through these machines A1 through A3. Each working machine is selected depending on the currently prevailing pressure in the expansion space and the optimal working range of the corresponding machine. In the figures, an open reservoir R is shown, but it may of course also be a closed with degassing. In 6 is just the expansion space E3 refilled from the reservoir R, therefore, the liquid level moves 10 up there (arrow). The valves V _E3A1 , V _E3A2 and V _E3A3 to the working machines A1, A2 and A3 are closed at this time, the valve V _RE3 , through which the liquid 1 from the reservoir R flows in and the valve V _E3L , through which the gas expanded in the previous cycle 2 escapes from the expansion space E3, however, are open. Depending on the position of the liquid level 10 in the reservoir R and the upper edge of the expansion space E3, the expansion space E3 fills passively, or / and it is actively helped with a pump. The expansion space E2 is at the beginning of a working cycle and the liquid level 10 descends through the oppressive gas 2 that the liquid 1 through the working machine A1, which is optimized for high pressures (eg 60 to 20 bar). The valves V _E2A2 and V _E2A3 to the work machines A2 and A3 are closed at this time, also, after completion of the introduction of the complete compressed gas charge 2 , the valve V _DE2 to the compressed gas reservoir D. The expansion space E1 is just about in the medium-pressure range of the duty cycle. Therefore, the liquid flows 1 , which is displaced from it, by the working machine A2, which is optimized for medium pressures (eg 20 to 5 bar). The valves V _E1A1 and V _E1A3 to the working machines A1 and A3 (optimized for pressures of eg 5 to 1.5 bar) are closed at this time.

In 7a is opposite 6 represented later time at which just the filling of the expansion space E3 is completed. In addition, this power plant has no work machine A3, but only two work machines A1 and A2 with another optimal working pressure range (eg work machine A1 for an upper pressure range of 60 to 10 bar and work machine 2 for a lower pressure range of 10 to 1.5 bar). Fewer machines also mean lower costs and less control effort. The valve V _RE3 and the valve V _E3L are closed, and next the valve V _{DE3 is opened} to the compressed gas _storage and the valve V _E3A1 to the working _machine A1 for the upper pressure range. The expansion space E2 is at the beginning of the lower pressure range of the duty cycle (the pressure of the gas 2 initially decreases rapidly as volume increases, later slower), and the fluid level continues to descend (arrow) through the pressurized gas, which now pushes fluid through work machine A2, which is optimized for lower pressures. The valve V _E2A2 is therefore open, the valve V _E2A1 to the working _machine A1, however, is closed at this time. The expansion space E1 has finished its cycle and is just getting new with liquid 1 from the reservoir R filled (liquid level rises: arrow). The valves V _E1A1 and V _E1A2 to the working machines A1 and A2 are closed at this time, whereas of course the valve V _RE1 is open to the reservoir R. Also, the degassing _valve V _E1L is open so that the gas expanded in the previous cycle 2 can escape. In 7b is opposite 7a represented later time at which just the expansion space E3 at the beginning of a duty cycle is still under relatively high pressure. The valve V _E3A2 to the working _machine A2 for the lower pressure range is therefore closed. The valve V _E3A1 to the working _machine A1 for the high pressure range, however, is open. The expansion space E2 is still in the low pressure range of the duty cycle and the liquid level 10 continues to descend (arrow) through the oppressive gas 2 that the liquid 1 through the working machine A2, which is optimized for low pressures. The valve V _E2A2 is therefore still open, the valve V _E2A1 to the working _machine A1, however, is still closed at this time. The expansion space E1 is still in the refilling phase from the reservoir R. In 7c is opposite 7b represented later point of time, to which is currently the expansion space E3 in the lower pressure range of a duty cycle. The valve V _E3A1 to the working _machine A1 for the high pressure range is therefore closed. V _E3A2 to the working _machine A2 for the lower pressure range, however, is open. The expansion space E2 has just finished its duty cycle and is about to be refilled with liquid from the reservoir R. The valves to the work machines are therefore closed and the valve V _RE2 is opened. Also, the degassing _valve V _E2L at the expansion _space E2 is opened. The expansion space E1 is just at the beginning of a working cycle for which the valve V _DE1 between compressed gas storage D and expansion space E1 is opened until the intended amount of compressed gas has flowed into the expansion space E1. The valve to the working machine A2 for the lower pressure range is closed, whereas the valve is open to the working machine A1 for the high pressure range, so that liquid by the pressure in the expansion space E1 (the valve V _{DE1 is} open approximately equal to that in the compressed gas storage, so relatively constant is) is pressed by the working machine A1. This is done at the beginning of this cycle, as long as the valve V _{DE1 is} still open, as already explained, at a relatively constant pressure, so that there is hardly any change in temperature of the gas. In this phase, it is therefore not absolutely necessary to bring the gas into contact with liquid via a common large surface. In 7d is opposite 7c represented later time at which the expansion space E3 has ended its duty cycle. The valves to the work machines are therefore closed. The valve V _RE3 to the reservoir R and the valve V _E3L into the environment is opened. The expansion space E2 is currently in the state of refilling with liquid from the reservoir R. The valves to the working machines are therefore closed and the valve V _RE2 is open. Also, the degassing _valve V _E2L at the expansion _space E2 is open. The expansion space E1 is currently in the lower pressure range of a duty cycle. Therefore, the valve to the high pressure area working machine A1 is closed, whereas the valve to the lower pressure area working machine A2 is opened, so that liquid is pushed by the working machine A2 by the gas pressure in the expansion space E1.

In 8a is a longitudinal section through a cylindrical expansion space E shown with spherical caps, which is used for power plants according to variant A or B. Inlet and outlet lines are not shown, nor the wall thickness. This results in accordance with customary structural calculations from the material used, the size and the maximum operating pressure.

Instead of a cylindrical expansion space and a polygonal cross-section is possible, especially at not too high pressures. The higher the pressure, the more corners the polygon must have. The expansion space can also, like a barrel, be composed of sub-segments ("staves"), which are enclosed by clamping means and held together. In 8b a spherical expansion space E is shown, which is usable for both variant A and variant B. A spherical expansion chamber has the greatest stability with minimum material consumption. 8c represents an approximately "pear-shaped" version of an expansion space E, which is usable for variant A and B. Preferably, such an expansion space is located at least with its lower wide area in the ground. In this way, the lower area can namely be carried out with a smaller wall thickness than if it were above ground. The wall thickness of such an expansion space can be made significantly thinner in the upper area than in the lower area (approximation: "boiler formula" or variant for wall thicknesses that make up more than 20% of the radius)! 8d represents a variant of an expansion space, which has a pressure-absorbing bottom similar to a champagne bottle. Also, such an expansion space E is preferably located with its lower portion in the ground. 8e exemplifies a "pear-shaped" expansion space E, which has three horizontal separation layers T ₁ , T ₂ , T ₃ , which have a good permeability to liquids. The separation layers make it possible to fill the spaces delimited by the separation layers with solids which do not mix with each other over the separation layers if the separation layer always only has openings smaller than the particle size of the solid defined by the separation layer. At least the release layer under a solid must have a size of the openings smaller than that of the solid above. In the simplest case, the separating layers are inserted sieves or nets with a correspondingly small mesh size. 8f shows an expansion space E as in 8a made with simple irregularly shaped bulk material (rock) 3 is filled, which serves as an intermediate heat storage and temperature control medium for the expanding gas. 8g shows an expansion space as in 8e , between its separating layers T ₁ , T ₂ , T ₃ with a simple bulk material 3 different grain size is filled.

9 shows the example of an expansion space E of the form as in 8a the possibility of not allowing the discharge of the displaced liquid through an opening in the lower region of the expansion space E, but the displaced liquid via a riser 4 at the top of the expansion space E in a working machine A and then further into an open or closed reservoir R deduce. The refilling of the expansion space E with liquid after each working cycle is then preferably carried out from the reservoir R via this riser 4 , Such an embodiment is particularly suitable for expansion spaces in which already existing or subsequently produced underground caverns are used with poorly defined inner wall surface as expansion spaces. The advantage of such an embodiment is that all inlets and outlets 8th . 9 in the expansion space E are close to each other, so that they can also be used in a common component (eg made of metal), which is then gas-tight, but easily replaceable, installed in a single slightly larger opening of the expansion space. In a version with riser 4 make sure that this is not too high, because the height of the liquid in the riser 4 the gas in the expansion space E compresses and therefore the pressure in the expansion space E can not fall below the hydrostatic pressure of the liquid column in the riser. When the working machine A is below the upper end of the riser 4 is, then the difference in height between the working machine A and liquid level in the expansion space E for the pressure is critical, to which the gas in the expansion space E can be expanded. If the working machine A is below the lowest liquid level reached in the expansion space E at the end of a working cycle, this gradient will even "suck" liquid out of the expansion space E and allow it to reach particularly low gas pressures at the end of the expansion. But it is also advantageous to make sure that the liquid column above the working machine A does not reach the height from which the liquid column can tear off to form a void. This height is in the case of water, for example, about 10 meters. The void is not really empty, but filled with liquid vapor, but voids could get into this when turning on the flow in the working machine A and generate cavitation damage there.

10a shows (in the empty state) an expansion space E, in this example in the form of an ellipsoid of revolution, with arranged therein downwardly open and closed at the top vertical tubes as a small gas tank K _o for an embodiment according to variant B of the invention. The small gas containers K _o are open at the bottom, because the liquid is heavier than the gas and therefore the gas does not exit the tubes at the bottom. However, in order for this not to happen in the expansion of the gas, of course, each tube may contain only so much gas that the lower edge of the tube at the end of the working cycle, when the pressure is lowest, is not yet reached by the expanded gas in the tube. If there is any gas leakage, it can be drained via the valve V _EL if necessary.

The fortifications of the pipes K _o on the wall of the expansion space E and each other are not shown for clarity. The small gas tank K _o contain over the surrounding liquid no gas with high pressure and therefore need not be made strong walls. Ideally, they should be as thin-walled as possible to allow good heat exchange between the gas in the small gas container K _o and the surrounding liquid. However, the material of the wall must be able to withstand the load changes between high pressure and low pressure, which is the case for most materials that contain little or no gas at the pressure ranges used. Gas, which dissolves in the liquid over time in the course of many working cycles over time, is now and then replaced and returned to the small gas tank K _o . This can be done for example by thin gas lines, not shown, which protrude from below a small piece in the pipe K _o . 10b represents the same expansion space E as in 10a but this time it's gas 2 and liquid 1 drawn in the interior. The gas 2 here is shown black, the liquid 1 White. The expansion space E is currently at a stage of the duty cycle in which the gas contained in the pipes K _o 2 about half the volume of the pipe. The valve V _EA to the work machine A is opened or partially open, and the valve V _RE to the reservoir R is closed. The illustrated state may also represent a filling at a time to which the gas 2 in the small gas containers K _o just once again compressed to half the volume. In this case, the valve V _EA to the working machine A is closed and the valve V _{RE is} opened, so that a pump liquid from the reservoir R against the compressed gas in the pipes 2 in the expansion space E can press. 10c represents an expansion space E as in 10a This time, however, this completely enclosed, soft small gas container contains K _g , eg elongated Mylarfolienbeutel. The attachment of the same to the wall and / or with each other is not shown. 10d shows an expansion space E as in 10c in which this time liquid 1 and gas 2 are shown. The liquid 1 is as white surface, the gas 2 shown as a black area. The illustrated state corresponds to the same time in the work cycle as in 10b shown. Because gas 2 lighter than liquid 1 is, it collects in the upper part of each small gas container K _g and the lower part is through the liquid 1 pressed together. If, unlike in 10d , Each small gas tank K _g is subdivided in its length in sub-container (if, for example, the elongated foil bag has welding transverse seams), then the gas 2 only up to the upper limiting Schweißquernaht wander upwards, and you get many small, spatially separate gas portions, which are distributed along the length of a small gas container K _g . The small volume of gas contained in each sub-tank has a lower buoyant force in the surrounding liquid than the larger volume of gas in a non-subdivided small-gas tank K _g . As a result, the force acting on the wall material of the upper side of the lower container (for example, a welding cross seam) is less than the force acting on the upper side of a non-subdivided small gas container K _g on the wall material of the same there. If a small gas tank K _{g is} subdivided into sub-containers, so its wall can thus be made weaker. 10e represents a substantially cylindrical expansion space E with fully closed soft small gas containers K _g , which if necessary via leads 9 can be refilled with gas at its upper end, if this should have partially escaped by diffusion over time and after many cycles through the thin wall (eg foil) of the small gas tank K _g . The supply pipes 9 in the small gas tank K _g are shown here as thick black lines. The refilling takes place via a valve V _CK by means of a compressor C or compressed gas cylinders. With such, the type of gas can be selected in a wide range, especially since this gas is hardly consumed, but the largest part goes through many cycles before he escaped from the small gas containers K _g . For example, a gas or gas mixture can be selected which has only a small change in the temperature during compression or expansion (ie has a low adiabatic exponent). These are mainly higher molecular weight gases with unsymmetrical molecular structure and soft, easily to chemical vibrations excitable chemical bonds. By a suitable admixture of gases (eg helium, hydrogen, but not mixed with oxygen or an oxygen-containing gas mixture), which are below the Joule-Thompson inversion temperature at the operating pressure, the temperature change in pressure changes in the small gas container K _{g can also} be kept as small as possible so that the volume changes can be made relatively quickly without leaving quasi-isothermia. 10f provides analogously 10e a substantially cylindrical expansion space E, but this time with bottom open small gas containers K _o (eg pipes). This embodiment can either be operated according to process variant B: Then, a valve V _CK serves only to replenish gas, which has gotten lost over time due to its solubility in the liquid from the small gas containers K _o . The illustrated embodiment can also be operated according to process variant A: Then, a valve V _{DK is used} to fill the small gas tank K _o with compressed gas from a compressed gas reservoir D after each working cycle of the gas. Of course, the expanded gas must be discharged at the end of each working cycle. This happens then over an additional line 9 and an additional valve V _KL (both shown in phantom), for example, as shown, outside of the expansion space E on the same line 9 may be connected, through which the small gas container K _o are filled for each new cycle. An expansion space E as in 10f can also be used on the same power plant both in operation according to variant A, as well as in operation according to variant B. Thus, for example, during the energy storage operation of the power plant first still existing expanded gas in the small gas containers K _o in the expansion space E be compressed again and only in the course of storing energy then the compressed gas reservoir D is loaded with external gas. It then has an already filled, immediately zoomable to the working operation expansion space E available, so slightly faster than if only compressed gas from the compressed gas storage D would have to be filled in the small gas tank K _o !

bei der a der Innenradius und b der Außenradius des Zylinders sind. Man sieht, daß für große Wanddicken s = b – a die Tangentialspannung viel geringer ist als gemäß Kesselformel! Das bedeutet, daß im Verhältnis zum Radius dicke Wände sich auch durch ihre Dicke selbst stabilisieren helfen und wesentlich geringere Wandstärken nötig sind als wenn man gemäß Kesselformel rechnete! 11c zeigt einen Expansionsraum E wie in 11b, aber diesmal ist auch der Expansionsraum E selbst gegen den Vereisungsmantel VM thermisch isoliert. Die thermische Isolierschicht 6 muß druckstabil gegen Drücke sein, wie sie im Expansionsraum E auftreten. Eine solche Ausführung gestattet es, die Flüssigkeit und das expandierende Gas im Expansionsraum E auch bei Temperaturen über 0°C zu halten. 11a shows an expansion space E (in this example cylindrical with spherical caps), which is located in the bottom B and is surrounded by a low-cost icing VM, which allows concrete, steel or other liquid-tight and preferably also gas-tight Material existing wall of the expansion space to keep substantially thinner than would be necessary without the icing. In extreme cases, the icing VM can absorb the entire pressure load. Inlets and outlets to the expansion space E are in the 11 not shown. 11b shows an expansion space E (as in 11a cylindrical with spherical caps), located above ground in a building with thermal insulation 6 is at least partially filled with the icing VM, which surrounds the expansion space E filled. The icing jacket may preferably consist of a fiber-reinforced ice shell, for example of Pykrete. For such large wall thicknesses of the icing jacket is the "kettle formula" σ = p · r / s for the tangential stress σ, which undergoes a wall of thickness s of a cylinder with radius r under an internal pressure p, no longer applicable. For example, in a better approximation, the following formula must be used for the tangential stress dependent on the radius r:

where a is the inner radius and b is the outer radius of the cylinder. It can be seen that for large wall thicknesses s = b - a the tangential stress is much lower than according to the boiler formula! This means that in relation to the radius thick walls also stabilize themselves by their thickness and much smaller wall thicknesses are needed than if you calculated according to boiler formula! 11c shows an expansion space E as in 11b but this time also the expansion space E itself is thermally insulated against the icing VM. The thermal insulation layer 6 must be pressure stable against pressures as they occur in the expansion space E. Such an embodiment makes it possible to keep the liquid and the expanding gas in the expansion space E even at temperatures above 0 ° C.

In this case, the icing VM is generated by external cooling. In the figure, this is done by suitably arranged freezing lances. The freezing lances are preferably closer to the expansion space E than to the building wall 11 to ensure an always closed icing VM around the expansion space E.

12 represents the scheme of a coupled with a pumped storage power plant compressed gas liquid power plant: From the pump storage PS crashes in energy demand water 1 in the pumped storage power plant PSK and generates there, very precisely controllable, the required electrical power in the power grid. The fallen water 1 with low potential energy is then preferably collected in an intermediate reservoir ZR and from this again with compressed gas energy from the working machine A from the compressed gas 2 is conveyed up into the pump reservoir PS. This cycle can be maintained as long as pressurized gas energy is available. Ideally, the water will 1 the pump reservoir PS also used for refilling the expansion space E. The compressed gas liquid power plant can also work with another liquid 1 and a separate reservoir R in a separate cycle. Of course, this liquid can also be water, eg very pure water. It makes sense if the compressed gas liquid power plant and the pumped storage power plant are in spatial proximity to each other. However, if the pressurized gas liquid power plant first electrical Energy wins, which in turn operates pumps that carry water again in the pumped storage PS, so the two cooperating power plants can also be spatially far apart from each other! The electrical energy generated during operation of the compressed gas liquid power plant is then passed via a power line to the pumped storage power plant and used there for pumping up water. Preferably, however, separate from the public power grid, independent power lines are used. A coupled with a pumped storage power plant compressed gas liquid power plant can also operate with only a single expansion space E. This is because it does not have to work continuously! The requested continuous power supply in the power grid is indeed supplied by the pumped storage power plant. The compressed gas liquid power plant may therefore fill the pump reservoir PS discontinuously again!

13a represents an expansion space E with spherical caps that with liquid 1 Partially filled and in the gas just 2 that expands through the liquid 1 it is sprinkled passively from tubs W and thereby tempered. Inlets and outlets in the expansion space E are in the 13 not shown. 13b also represents an expansion space E with spherical caps that with liquid 1 Partially filled and in the gas just 2 expanded, in which the temperature but by liquid 1 takes place, which is sprayed starting from a floating on the liquid raft with sprinkler S upwards, similar to lawn sprinkler systems. Many variants of conventional lawn sprinkler systems are also unchanged or almost unchanged in the case of water. The spraying is preferably carried out by an electric pump, which preferably draws its energy via a cable. When the raft is guided by sprayers S from a vertically tensioned rope or rod, this rope or rod may also contain the electrical cable. 13c represents an embodiment in which the temperature of the expanding gas 2 by spraying the liquid 1 starting from a provided with nozzle openings central spray tube S, in which a pump P liquid 1 suppressed. (Of course, there are several pipes possible, which also need not necessarily be perpendicular.) In such a tube, the lower nozzles should preferably have a smaller diameter than the upper (or there should be more nozzles in the upper area), so more liquid 1 through the upper exit. Below the liquid level 10 is the unnecessary leakage of liquid 1 through nozzles located there due to the density and viscosity of the surrounding liquid 1 opposite the exit into the gas 2 inhibited. 13d represents a version with central tube 8th through which a pump P liquid 1 pump up where it exits a spray / sprinkler S. The spraying device S consists, for example, of tubes extending radially from the central tube 8th extend out and are provided with spray openings, through the liquid 1 goes up, down and to the side. 13e shows an embodiment in which liquid 1 is introduced externally from a reservoir in the expansion space E. This can be done for example by an electric pump P, or by pressurizing the reservoir with compressed gas 2 from the compressed gas reservoir D. In the case shown, it is a warm reservoir WR, in which liquid 1 which has been brought to elevated temperature by waste heat or excess regenerative energy, thereby raising the overall "economic" efficiency because of heating the liquid 1 energy used would otherwise have been lost anyway or was available at a cheaper price than that which is subsequently earned for the energy generated by the pressurized gas liquid power plant. The warm reservoir WR has in the illustrated case a valve V _RL to the environment. If the reservoir VR is variable in volume (eg flexible or bellows-like walls), such a valve is not absolutely necessary. The liquid in the warm reservoir WR is preferably removed from the reservoir R (not shown), which receives the liquid from the expansion space E.

The 14 schematically show a very simple variation of an expansion chamber with therein small closed gas containers K _g for variant B of the invention. Inlets and outlets to the expansion space E are not shown.

The small gas tank K _g float in this embodiment freely movable in the liquid 1 , Through their buoyancy, they try to float up as much as possible and most of the liquid 1 collects below them, but the spaces between the small gas tanks are also liquid 1 filled. The small gas tanks are spherical in this case and of the same size. In the simplest case, it is gas-containing balloons with stretchable or foldable envelope. It can also be thin-walled plastic footballs. The size of the small gas tank K _g is dependent on the time in which the volume changes take place, but should preferably not be greater than 50 centimeters. 14a shows a time when the small gas tank K _{g are} fully expanded, so at the end of a cycle of the gas contained in them. 14b shows the state of complete compression of the small gas tank K _g . The shaded area schematically represents the volume of the small gas container K _g , which is greatly reduced in volume and / or deformed, and which accumulates at the tip of the expansion space narrowing in this example. The wall of the expansion space E is, as in the example, preferably inclined, because then the during energy generation in volume expanding small gas tank K _g can dodge down without jamming. The flatter the wall inclination and the smoother the inner wall surface of the expansion space E, the lower the risk of jamming, and also the wear on the small gas containers K _g is lower. Preferably, the shell of the small gas tank K _{g is} made of a material having a greater specific gravity than the liquid 1 , Because then sink defective small gas tank K _g , no gas 2 contain more, of course, with the time down and can be collected eg above a sieve. The small gas containers K _g may also contain, besides gas, a heavy additive which is the average density of casing material plus additive over the density of the liquid 1 elevated.

15 schematically shows an example in which the expansion space is within the compressed gas reservoir D. In the particularly preferred example shown, there are even two expansion spaces E ₁ and E ₂ within the compressed gas reservoir D, and the two expansion spaces alternately provide reservoirs R2 and R1 for the liquid during the energy-producing operation 1 It is just shown a state during which in the expansion space E _{2 of} the liquid level 10 through the expanding gas 2 is pressed down, causing fluid 1 is pressed from the expansion space E ₂ by the working machine A in the expansion space E1, at this time, the reservoir R ₂ for liquid 1 represents and is approximately under ambient _air pressure, because the valve V _E1L is open at this time, whereas the valve V _{DE1 is} closed.

Is everything gas 2 from the expansion space E1 through the line 9 escaped into the "environment", the valve V _{E1L is} closed, the valve V _E2L opened at the other expansion _space E ₂ and the valve V _{DE1 of} the expansion _space E ₁ to the compressed gas storage D temporarily open until a sufficiently large Druckgascharge 2 has penetrated into the expansion space E ₁ , where they are already liquid 1 displaced from the expansion space E ₁ , which flows back through the preferably bidirectionally workable working machine A in the expansion space E ₂ . If the work machine A is not bi-directionally capable, then a second machine for this return flow is necessary. Subsequently, the valve V _{DE1 is} closed and the gas 2 in the expansion space E ₁ continues to expand with simultaneous temperature control by sprayed liquid 1 until the whole expanded gas 2 from the expansion _space E ₂ via the valve V _E2L and the line 9 escaped into the "environment". Subsequently, the process returns from E ₂ to E ₁ . This can be done so long (principle "two-cylinder engine") until the required minimum pressure in the compressed gas storage D is reached. In the specific example with two expansion spaces, the reservoir R for the liquid is also located 1 within the compressed gas storage D, but of course it can also be outside. However, it is also in the case of only one expansion space in the compressed gas storage D to ensure that expansion space E and reservoir R are approximately at the same level, otherwise energy goes to the lifting of liquid 1 lost against gravity! The reservoir R can also encase the expansion space E, for example. An expansion space E, which is located in a compressed gas storage D, does not have to be statically made stable against a high internal pressure because it never contains a pressure that is greater than the external pressure in the compressed gas storage! A stable only against external pressure expansion space E is therefore very inexpensive, for example, also made of pressure-resistant concrete to build, because it stabilizes like a vault!

16a shows ideal trajectories of isothermal and adiabatic process control in the event that a volume unit (eg one cubic meter) of compressed gas at 61 bar begins an expansion that is isothermal (upper curve) and once adiabatic (dashed lower curve). The adiabatic rate applies to air whose adiabatic exponent is approximately 1.4. The values on the coordinate system indicate overpressure compared to the ambient air pressure 1 bar! The equations used for the isotherm or adiabatic are proportional to 60 / V and 60 / V ^1.4, respectively, and apply to "vacuum". But it can be relaxed to a maximum of ambient pressure, therefore, in practice, the ambient pressure is the zero line. (Not the absolute value of the internal pressure, but only the difference between internal pressure and ambient pressure can do work!) An expansion, which ends in the diagram at a pressure 1 bar, so in truth ends at 1 bar overpressure, ie about 2 bar and not one bar ! Accordingly, the gas expansion does not start at 60 bar, but at 60 bar overpressure, ie about 61 bar! An expansion to the pressure of the ambient pressure makes no technical sense, since the pressure differences are infinitesimally small at the end and the forces that result from the Druckdiferenz also infinitesimal small. You can then drive no frictional machines more. Theoretically interesting, however, is that isothermal expansion up to infinitesimal small pressures is able to convert ambient heat into mechanical work with high efficiency, as can easily be seen from the fact that the integral of the 1 / V function decreases with decreasing pressure Volume goes to infinity, also goes to infinity, albeit logarithmically! The isotherm cuts the 1 bar line at 60 volume units at point Q3, ie 60 times the original gas volume at 60 bar. The adiabatic precipitates steeper: It cuts the 1-bar line already at the point Q2 at about 18.6 volume units. For the energy generated according to the diagram by isothermal expansion of a volume unit from 60 bar to 1 bar, the following applies: W _i = nRT + ln (V ₂ / V ₁ ) = nRT + ln60 = nRT + 4.094 (This is the area between the isotherm and the V-axis from point Q1 to point Q3.) For the energy generated by adiabatic expansion of a volume unit from 60 bar to 1 bar, (after integration of the adiabatic equation): W _a = nRT + (1 / -0.4) + ((V ₂ ) ^-0.4 - (V ₁ ) ^-0.4 ) = nRT + (-2.5) + (18.6 ^{-0, 4} - 1 - ^0.4 ) = nRT + (-2.5) + (0.311 - 1) = nRT + 1.724 (This is the area between adiabatic and V axis from point Q1 at 60 bar to point Q2 at 18.6 bar.) Thus, the energy gained by adiabatic expansion is only 42% of the energy produced by isothermal expansion is profitable! The temperature of the air after adiabatic expansion is from 60 bar to 1 bar T ₂ = T ₁ + (p ₂ / p ₁ ) ^{0.4 / 1.4} = T ₁ + (p ₂ / p ₁ ) ^0.286 = T ₁ + (1/60) ^0.286 = T ₁ + 0.31 For example, if the initial temperature of the air is 293 Kelvin (20 ° C), then it cools to about 91 Kelvin or -182 ° C through adiabatic expansion. What the isothermal expansion produces in terms of more energy versus the adiabatic, it gets from the heat of the environment! For isothermal as well as adiabatic expansion, in the case of a process according to variant A of the invention, in addition to the expansion work, there is also the proportion of energy which is released isobarically (actually quasi-isobarically) when the compressed gas charge is introduced into the expansion space. It is the rectangular area between the origin O of the coordinate system and the point Q1 at 60 bar. Compared with the expansion energies, it has the size nRT.

• 1.) Die Druckgascharge wird mit 293 Kelvin bei 60 bar in den Expansionsraum eingebracht (Punkt Q1 im Diagramm). Anschließend wird Temperierflüssigkeit eingebracht/eingesprüht, wodurch die Gastemperatur auf 352 Kelvin ansteigt. Dadurch steigt auch der Druck des Gases, nämlich auf 72 bar (Punkt Q4 im Diagramm). Anschließend wird das Gas hypertherm bei 352 Kelvin expandiert, bis es bei 1 bar ein Volumen von 72 Volumeneinheiten aufweist (von Punkt Q4 bis Punkt Q6). Vorteil dieser Vorgehensweise ist eine höhere Energieausbeute! Nachteil ist aber, daß der Expansionsraum auf den höheren Druck ausgelegt werden muß, also stabiler und damit teurer gebaut werden muß!
• 2.) Die Druckgascharge wird mit 293 Kelvin bei 60 bar in den Expansionsraum eingebracht. Anschließend wird sie unter Einbringung von Temperierflüssigkeit isobar (bzw. quasiisobar) expandiert bis Punkt Q5. Ab dem Punkt Q5 findet anschließend eine normale hypertherme Expansion statt bis zum Punkt Q6 bei 72 Volumeneinheiten. Vorteil dieser Vorgehensweise ist, daß der Expansionsraum keine höheren Druckbeanspruchungen erfährt!

Thus, an isothermal duty cycle according to variant A produces a mechanical work of 5.094 + nRT, an adiabatic duty cycle such as 2.724 + nRT. Thus, an adiabatic duty cycle performs at least 53% of the work of an isothermal work cycle in the case of a variant A process. This means that a method according to variant A of the invention over such a variant B with otherwise the same gas temperature control has a higher efficiency, since the method according to variant B, the initial isobaric work is missing! 16b For a better illustration, an upwardly stretched section of the 16a represents. 16c represents an idealized case of operation in which hypertherm is being worked on. In the example shown, compressed gas is heated in the expansion space with liquid of elevated temperature, so that it has a 20% higher absolute temperature than the gas in the compressed gas storage. If the gas in the compressed gas storage, for example, a temperature of 293 Kelvin (about 20 ° C) and is introduced with this temperature in the expansion space, it is so by a sufficiently large amount of tempering liquid to a temperature of about 352 Kelvin (about 79 ° C) brought. The tempering liquid must have a temperature of more than 352 Kelvin for this purpose. For example, it can be at 362 Kelvin (89 ° C). For example, water does not boil at this temperature, even at normal atmospheric pressure. The hypertherm runs above the isotherm and it cuts the 1-bar line later than the isotherm, namely at 72 Volume units. The higher temperature also leads to a proportional pressure increase in the gas. Especially for variant A of the invention, the duty cycle can then proceed in two different ways:

• 1.) The compressed gas charge is introduced with 293 Kelvin at 60 bar into the expansion space (point Q1 in the diagram). Subsequently, tempering liquid is introduced / sprayed, whereby the gas temperature rises to 352 Kelvin. This also increases the pressure of the gas, namely to 72 bar (point Q4 in the diagram). Subsequently, the gas is hypertherm expanded at 352 Kelvin until it has a volume of 72 volume units at 1 bar (from point Q4 to point Q6). Advantage of this procedure is a higher energy yield! Disadvantage is that the expansion space must be designed for the higher pressure, so it must be built more stable and therefore more expensive!
• 2.) The compressed gas charge is introduced at 293 Kelvin at 60 bar into the expansion space. Subsequently, it is isobar (or quasi-isobar) expanded with the introduction of tempering liquid to point Q5. From point Q5, normal hyperthermic expansion then takes place up to point Q6 at 72 volume units. Advantage of this procedure is that the expansion chamber does not experience higher pressure loads!

The hypertherm-derived work from the gas expansion according to 1.) is at 20% higher temperature than the isotherm: W _h1 = 1.2 + nRT + ln (V ₂ / V ₁ ) = 1.2 + nRT + ln72 = 1.2 + nRT + 4.277 = 5.122 + nRT This is even 25.4% more energy than in an isothermal process. The hypertherm-derived work from the gas expansion according to 2.) is 20% higher than an isotherm: rectangular area below the junction Q1 to Q5 plus area below the hyperthermia from Q5 to Q6 Da Q5 is 1.2 volume units and Q6 is 72 Volume units, this means: W _h2 = nRT + (1.2 - 1) + 1.2 + + nRT (ln72 - ln1,2) = nRT + 0.2 + 1.2 + + 4.094 nRT = 0.2 + + 4.913 + nRT nRT = 5.113 + nRT The energy W _h2 obtained by gas expansion is therefore only slightly (0.37%) lower than W _h1 (5.132 + nRT). The heat component of the heat transfer liquid (the amount of heat that is transferred from the sprayed liquid to the gas) is completely converted into mechanical work! However, since the tempering liquid does not cool down to ambient temperature in the hyperthermal case, the thermal efficiency is not 100%. First of all, the temperature control liquid is heated from ambient temperature by waste heat (preferably countercurrently), and only a part of the amount of heat absorbed is subsequently converted into mechanical work ! The temperature control liquid remains above the ambient temperature. The thermal efficiency of the heat conversion into mechanical energy is therefore only the difference between the Einsprühtemperatur the bath liquid minus the temperature after the tempering divided by the difference between the Einsprühtemperatur and the ambient temperature. In the example shown, the thermal efficiency of the conversion of the waste heat is therefore (362 Kelvin - 352 Kelvin) / (362 Kelvin - 293 Kelvin) = 0.145, ie only 14.5%. The situation is different in the case of efficiency, if excess energy from regenerative energy production in the form of heat is stored in the bath liquid and the bath fluid is circulated, so it is used again and again after heating up! Because in this case, each time only a portion of the heat is converted into mechanical work, which corresponds to the temperature difference of the bath between the injection temperature and the temperature at the end of the tempering. But after a first loading of the bath liquid starting from the ambient temperature in all other cycles of the bath must be brought back to the temperature before spraying only from the temperature after completion of a tempering! This is possible with electrical heating practically with almost 100% efficiency. And this heat generated with almost 100% efficiency is then converted back into mechanical work with almost 100% efficiency! A liquid heat storage is thus a very cheap way to increase an isothermal or hyperthermes compressed gas storage power plant in its energy delivery option!

(On the other hand, waste heat can not be used 100% in a hyperthermal power plant because the fluid containing the waste heat after a heat exchanger (preferably countercurrent heat exchanger), in which it gives off heat to the heat transfer liquid, still has the temperature that the temperature of the liquid By contrast, an almost 100% conversion of waste heat into mechanical work is possible in an isothermal compressed gas liquid power plant operating approximately at ambient temperature, since in such a case the tempering liquid at the end of the tempering process is approximately ambient and with waste heat in the heat exchanger with almost 100% efficiency again to the later Einsprühtemperatur, which preferably corresponds to the temperature of the waste heat-carrying fluid, can be heated.) 16d represents in comparison to the isothermal and adiabatic case a hypothermic operation of the pressurized gas liquid power plant. Shown is only a section of the pV diagram, similar to in 16b , Of course, the hypothermia is below the isotherm, but above the adiabatic. It starts at a point Q7 at 60 bar, which is ideally equal to the point Q1. In the illustrated case, the hypothermia is uneven, due to inaccurate control of the temperature of the expanding gas. An exact control is not necessary! Again, the energy gained by expansion is equal to the area under the hypothermia, starting from Q7 (ideally equal to Q1) to Q8, where the hypothermic crosses the 1-bar line. The intersection is less than 60 volume units but more than 18.6 volume units. Accordingly, the mechanical work produced is between that of the isothermal case and that of the adiabatic case. The less the temperature of the expanding gas falls below the temperature of the gas at the beginning of the expansion, the closer to the isotherm lies the curve and the higher the efficiency of the compressed gas liquid power plant.

LIST OF REFERENCE NUMBERS

E, E _n

Expansion room, expansion room no. N with n = 1, 2, 3, ...

D, D _n

Compressed gas storage, compressed gas storage n. N with n = 1, 2, 3, ...

R, R _n

Liquid reservoir (open or closed) with n = 1, 2, 3, ...

WR

Warm reservoir for liquid 1

A, A _n

Working machine, working machine No. n with n = 1, 2, 3, ...

P

pump

T, T _n

liquid-permeable separating layer No. n with n = 1, 2, 3, ...

K

Small gas containers

B

Soil, "earth" rich

VM

icing jacket

ZR

Intermediate reservoir of a pumped storage power plant

W

sprinkling tub

S

Sprayer / sprinkler, sprinkler

K _o

Small gas tank, open at the bottom

K _g

Small gas tank, closed

PS

Pumped storage, e.g. a high altitude lake

PSK

Pumped storage power plant

V _EA

Valve between expansion space E and work machine A

V _AR

Valve between working machine A and reservoir R

V _RE

Valve between reservoir R and expansion space E

V _DE

Valve between compressed gas storage D and expansion space E

V _EL

Valve between expansion space and environment ("air"), degassing valve

V _RL

Valve between reservoir R and surroundings ("air")

V _EnAm

Valve between expansion space E no. N and working machine A no. M with n, m = 1, 2, 3, ...

V _AnR

Valve between working machine A no. N and reservoir R with n = 1, 2, 3, ...

V _REn

Valve between reservoir R and expansion chamber E no. N with n = 1, 2, 3, ...

V _DEn

Valve between compressed gas reservoir D and expansion chamber E no. N with n = 1, 2, 3, ...

V _EnL

Valve between expansion room no. N and surroundings ("air") with n = 1, 2, 3, ...

V _RP

Valve between reservoir R and pump P

V _EnEm

Valve between expansion space E no. N and expansion space E no. M with n, m = 1, 2, 3, ...

V _CK

Valve between compressor C and small gas tanks K _o or K _g

V _DK

Valve between compressed gas reservoir D and small gas tanks K _o

V _KL2

Valve between open small gas tanks K _o and surroundings ("air")

V _E1E2f

Gas / liquid valve between the expansion spaces E1 and E2

V _E2E3f

Gas / liquid valve between the expansion spaces E2 and E3

1

liquid

2

gas

3

Solid bed with voids

4

riser

5

earth's surface

6

Thermal insulation layer

7

freeze lance

8th

Lead liquid

9

Pipe gas

10

liquid level

11

building wall

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1857614 B1 [0002]
• DE 102011106040 A1 [0004]
• WO 2004/020793 A1 [0004]
• JP 2007231760 A [0006]
• WO 2012/017243 A1 [0006]

Cited non-patent literature

• DIN 2413 [0090]

Claims (12)

A method for recovering mechanical energy from previously compressed gas, which is stored in a compressed gas storage (D) as energy storage, characterized in that it comprises the following features: - For energy from the compressed gas ( 2 ) is a liquid in a pressure-stable expansion chamber (E) with rigid walls ( 1 ) by in this expansion space (E) expanding compressed gas ( 2 ) is set in motion and displaced from it - the expansion of the compressed gas ( 2 ) in the expansion space (E) is controlled so that it runs quasiisothermally to the extent that at a pressure halving only a change in temperature of the gas ( 2 ), which is less than half of what occurs in a fully adiabatic expansion - the quasi-isotherm is achieved in that in the interior of the expansion space (E) a portion of the pure liquid ( 1 ) or part of the liquid ( 1 ), in which at least one other substance is dissolved, also for tempering the compressed gas ( 2 ) is used during the expansion or for reheating a solid located in the expansion space (E) ( 3 ), which is used for the temperature control of the expansion gas (E) expanding compressed gas ( 2 ) is used and this has the property of a temporary temporary heat storage and heat exchanger - the displacement of the liquid ( 1 ) by the expanding gas ( 2 ) out of the expansion space (E) via an opening in the shell of the expansion space (E) through a supply line ( 8th ) in at least one outside of the expansion space (E) located working machine (A) for liquids ( 1 ) (eg water turbine) into it. The liquid flowing through the working machine (A) ( 1 ) generates mechanical work there. It occurs during the displacement of the liquid ( 1 ) from the expansion space (E) no gas ( 2 ) as gas phase in the working machine (A)! Only by in the liquid ( 1 ) dissolved gas ( 2 ) or by turbulence of gas bubbles may occur small amounts of gas ( 2 ) in the working machine (A). Process according to Claim 1, characterized in that the pressurized gas ( 2 ) from a outside of the expansion space (E) located compressed gas storage (D) in batches in the expansion space (E) is passed and that only after completion of an expansion cycle of this Druckgascharge ( 2 ) in the expansion space (E) and refilling the expansion space (E) with liquid ( 1 ) a new compressed gas batch ( 2 ) is introduced into the expansion space (E) for a new expansion cycle. Method according to Claim 1, characterized in that the expansion space (E) simultaneously serves as compressed gas reservoir (D) without connection to an external compressed gas reservoir (D) and the compressed gas ( 2 ) in this on a plurality of small gas container (K _g , K _o ) is divided and the gas ( 2 ) in these small gas tanks (K _g , K _o ), apart from the smaller refills necessary over time, always remain the same and are expanded for the discharge of mechanical energy, whereby liquid ( 1 ), which fills the remaining volume in the expansion space (E), displaces it from this and drives it into a working machine (A) and that the gas ( 2 ) is compressed to store energy by liquid ( 1 ) is pushed back into the expansion space (E), wherein the wall of the small gas containers (K _g , K _o ) either deforms flexibly, namely when energy is expelled or contracts or accumulates when energy is stored, or liquid ( 1 ) exits through an opening from the small gas containers K _o at the time of energy discharge or when storing energy and compressing the gas present in the small gas tank K _o ( 2 ) enters there. Method according to at least one of Claims 1 and 2, characterized in that the temperature of the gas ( 2 ) during expansion by liquid droplets ( 1 ) he follows. Process according to at least one of Claims 1, 2 and 4, characterized in that the liquid droplets ( 1 ) by means of pump-operated sprinkler systems (S) into the expanding gas ( 2 ) are sprayed. Method according to at least one of claims 1, 2, 4 and 5, characterized in that the spraying takes place from bottom to top and at an angle. Method according to at least one of Claims 1, 2, 4, 5 and 6, characterized in that the spraying takes place from the ceiling of the expansion space (E) downwards. Process according to at least one of Claims 1, 2 and 4, characterized in that the liquid droplets ( 1 ) Passively from at the ceiling of the expansion space (E) located trays or containers (W) with holes in the bottom in the expanding gas ( 2 ) rain down. Method according to at least one of Claims 1 and 3, characterized in that the temperature control of the gas volume which expands during the discharge of energy and contracts during energy storage ( 2 ) in the small gas tanks (K _g , K _o ) for the most part on the wall of the small gas tank (K _g , K _o ) and in the case of open bottom small gas tank K _{o in} addition to a smaller part on the direct contact surface gas ( 2 ) / Liquid ( 1 ) he follows. Compressed gas liquid power plant for carrying out the method according to at least one of claims 1 to 10, characterized in that it consists of at least the following sub-devices and resources: - a pressure-stable expansion space (E) in which the compressed gas ( 2 ) is expanded from a high pressure to a low pressure - at least one compressed gas reservoir (D) outside the expansion space (E) or within the expansion space (E) - at least one working machine (A) for liquids ( 1 ) - at least one supply line ( 8th ) from the lower area of the expansion space (E) to the working machine (A) - liquid ( 1 ) in working machine (A), supply line ( 8th ) to the working machine (A) and variable amounts of liquid ( 1 ) in the expansion space (E) - liquid ( 1 ) in the expansion space (E) for the temperature control of gas ( 2 ) which changes in volume - at least one temperature sensor in the expansion space (E) in the volume-changing gas ( 2 ) for controlling the quasi-isotherm of the volume-changing gas ( 2 ) - at least one automatic control device which controls the access of the liquid ( 1 ) in the working machine (A) and / or the access of tempering liquid ( 1 ) into or to the volume-changing gas ( 2 ) with the aid of the measured values of the at least one temperature sensor in order to determine the change in the volume of the gas ( 2 ) in the quasi-isothermal region. Device according to claim 10, characterized in that located at least one temperature sensor in the upper tenth of the expansion space (E) the gas volume ( 2 ) is arranged after this has reached its largest volume. Apparatus according to at least one of claims 10 and 11, characterized in that the automatic control device has stored variable parameters of quasi-heat so that in the case of an unplanned high power requirement in the power grid, the pressurized gas liquid power plant can still deliver this power, but with lower demands on the Quasiisothermie and thus lower efficiency.

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