DE102015013896B3 - Low-temperature thermal power plant - Google Patents

Abstract

The invention relates to a low-temperature thermal power plant, comprising an evaporator unit (1) with an evaporating heat exchanger to which heat can be supplied by means of heating water, wherein water can be evaporated by means of the evaporator unit (1) and a live steam can be provided, and has a single-acting piston / cylinder unit (2). with a cylinder head (2.1), a cylinder (2.2), a piston (2.3) and a crankshaft (2.4), via the cylinder head (2.1) the live steam in the cylinder (2.2) can be introduced and wherein the piston (2.3) axially is movably received in the cylinder (2.2) and wherein an axial movement of the piston (2.3) by an expansion of the live steam in the cylinder (2.2) is provided and wherein the crankshaft (2.4) in a crankcase (2.5) and recorded with the piston (2.3) connected and is able to convert the axial movement of the piston (2.3) in a rotational movement and wherein the crankshaft (2.4) with a work machine (3) is connectable, by means of which from the rotational movement of the crankshaft (2.4) electrical energy can be generated, and comprising a condenser unit (4) with a condensation heat exchanger, from which by means of cooling water heat can be dissipated, the condenser unit (4) with the Piston / cylinder unit (2) connected and is capable of condensing a from the piston / cylinder unit (2) released Abdampf to water, and comprising a feed pump unit (5), with which the condensed water from the condenser unit (4 ) and the evaporator unit (1) can be fed. It is characterized in that the low-temperature heat engine has a vacuum pump unit (6), with which the evaporator unit (1), the piston / cylinder unit (2), the condenser unit (4) and the feed pump unit (5) can be acted upon by a negative pressure.

Description

The invention relates to a low-temperature thermal power plant for converting thermal energy into mechanical energy under the conditions of a heat source with a low temperature and a low temperature gradient between the heat source and the heat sink.

According to the state of the art, heat engines are known for converting thermal energy into mechanical energy in various configurations. In particular, according to the prior art solutions of water-based steam power processes are known in which the thermal energy is caused by external combustion. Such water-based solutions operate at high temperatures and high pressures, which causes the disadvantage of necessary significant safety expenses. Secondly, due to the system, the high temperatures are required for providing the evaporation and the high pressures, which has the disadvantage that low-temperature heat sources such as geothermal or solar thermal or many heat sources from operational process waste heat are practically not applicable.

One approach to using low temperature heat sources is the art of using ORC solutions that utilize the low evaporation temperature of certain organic compounds. The disadvantage here consists in particular in the safety-related expenses arising from the possible risk posed by the organic compounds, in particular by contamination and flammability.

The publication DE 10 2008 013 673 B3 describes a piston steam engine for a solar powered Rankine cycle. The drive energy of the piston steam engine is obtained from solar generated steam. The machine described consists of at least three cylinders, each associated with a piston. The pistons are connected by connecting rods to a crankshaft, wherein by means of openings in the crankshaft, the cylinders are alternately connected via inlet channels to an inlet and via outlet channels to an outlet. The movement of the pistons and the resulting rotation of the crankshaft causes each cylinder to be connected once to the inlet and once to the outlet in one revolution.

Furthermore, in the document DE 10 2004 041 669 A1 discloses a hot water heating system with a heat exchanger having a Feuerungsstelle. The heat exchanger is designed here as a steam generator, connected to the steam outlet, a steam-powered engine. Their exhaust steam outlet is connected to a further heat exchanger for condensing the exhaust steam, wherein the exhaust steam is used for heat dissipation to a hot water circuit. From a condensate collector connected to the heat exchanger, the condensate is finally fed back to the steam generator via a return line.

A method and an arrangement for the recovery of heat energy are also from the document DE 27 31 959 A1 known. It describes a low-pressure steam engine in a closed circuit with a steam turbine, a condenser, a pump and an evaporator. The evaporator is associated with a first heat exchanger for receiving the energy which can not be used directly to a heat source, while the condenser is associated with a further heat exchanger for supplying the heat energy to a heating system.

A generic piston steam engine is also in the US 2009/0 100 832 A1 described. Characteristic here is that the working fluid is introduced in liquid form into the working chamber of a cylinder at a time near the top dead center of the piston.

The object of the present invention is to provide overcoming the disadvantages of the prior art, a device for converting thermal energy into mechanical energy, which heat sources low temperature with low temperature difference can use the heat sink, which has a high reliability and safety is simple ,

The object is achieved by a low temperature heat engine with the features listed in claim 1. Preferred developments emerge from the subclaims.

A low temperature heat engine according to the invention comprises an evaporator unit, a piston / cylinder unit, a condenser unit and a feed pump unit. The evaporator unit, the piston / cylinder unit, the condenser unit and the feed pump unit are summarized below also referred to as pressure-carrying units.

The evaporator unit according to the invention is able to evaporate water as an energy source for the low-temperature thermal power plant and to provide a corresponding live steam. For this purpose, the evaporator unit in the present case has an evaporation heat exchanger to which heat can be supplied by means of heating water and with which the evaporation of heat from the heating water into the water is provided and the live steam is generated. The heating water is preferably provided from a Heizwasservorlauf a boiler of a building heating system.

The evaporation heat exchanger is preferably designed as a plate heat exchanger, whereby a high Effekivität a heat transfer within the evaporative heat exchanger and to the water to be evaporated is made possible. The high efficiency is due in particular to the high heat transfer between the heating water flowing in the plate heat exchanger and the water to be heated, which is achieved by a large effective inner and outer surface of the plate heat exchanger and the flow conditions in the interior of the plate heat exchanger. In addition, the evaporator unit may have a vapor separator for separating accumulating condensate or liquid particles from the live steam. Such an optional vapor separator is thus part of a pressurized unit.

The evaporator unit is connected to the piston / cylinder unit, wherein the live steam is provided releasably by the evaporator unit to the piston / cylinder unit. The supply of the live steam to the piston / cylinder unit is preferably carried out by a vapor stream formed and due to the heat of vaporization stored in the live steam.

The piston / cylinder unit according to the invention is designed as a single-acting piston / cylinder unit and in this case has a cylinder head, a cylinder, a piston and a crankshaft, wherein the piston is arranged axially movable in the cylinder and connected to the crankshaft.

By means of the cylinder head, the live steam provided by the evaporator unit can be introduced into the cylinder.

Pistons and cylinders are made of aluminum, for example, with the piston additionally having an anodization in the jacket area to increase the surface hardness and the cylinder having a coating of nickel. In particular, to reduce moving mass fractions, the piston may also consist of graphite or plastic.

The axial movement of the piston is effected according to the invention by an expansion of the live steam in the cylinder. In this case, the low-temperature thermal power plant utilizes the property of the live steam that, given correspondingly low ambient pressures, it can cause a very high volume change work and in this way can provide an expansion volume required for the movement of the piston.

The stored energy in the live steam in the present case provides for a stable provision of the axial movement of the piston and thus of the working range of the low-temperature thermal power plant.

The single-acting design of the piston / cylinder unit favors that their working space can be kept hot and thus condenses in this only a very small part of the live steam during expansion. Due to the greatly reduced in this way water content of the live steam drops on the one hand, the fluidic and mechanical resistance in the working space. On the other hand, in this area, only a small heat emission of the live steam to the piston and the cylinder wall, whereby the live steam is extracted only little energy and can be done by this correspondingly much work. Conversely, even in accordance with an advantageous further development described in more detail later, heat can be supplied to the live steam during the expansion by means of a cylinder-head heater. After expansion, the live steam is present in the form of exhaust steam, which is discharged from the piston / cylinder unit via an exhaust steam outlet, for example in the form of an outlet slot inside the cylinder, which is run over by the piston in its top dead center.

The axial movement of the piston caused by the expansion of the live steam is transferred from the latter to the crankshaft and thereby converted into a rotational movement. In the present case, the crankshaft can be connected to a work machine with which the rotational movement can be achieved desired electrical energy can be provided. The work machine is in this case formed in particular by a generator.

In addition, the crankshaft is housed in a crankcase, which is designed such that a large part of the exhaust steam, which can not be discharged via the Dampfauslassschlitz from the cylinder flows in an upward movement of the piston in the crankcase. For this purpose, the piston is preferably associated with a piston valve, via which the part of the exhaust steam can be discharged into the crankcase. To achieve the fastest possible condensation of the part of the exhaust steam in the crankcase, this preferably has a cooling, which is fed for example by a cold water supply, which is a heating return of the building heating. The condensate thus formed from the part of the exhaust steam can then be fed back to the evaporator unit via an associated condensate tank.

The piston / cylinder unit is also according to the invention connected to the condenser unit such that the majority of the exhaust steam, hereinafter referred to only as Abdampf, can be discharged by means of displacement by the piston from the cylinder into the condenser unit.

The condenser unit has in the present case a condensation heat exchanger, from which heat can be dissipated by means of cooling water. The cooling water is provided here by a cold water supply, which is preferably a heating return of a building heating. The condensation heat exchanger is preferably also designed as a plate heat exchanger and allows through the cooling water, a condensation of the exhaust steam to water, which can then also be supplied to the evaporator unit again. At the same time, the energy stored in the exhaust steam is released during the condensation as heat of condensation and can be supplied in thermal form, for example, a building heating almost lossless.

The promotion of the condensed water from the condenser unit back to the evaporator unit as well as the promotion of the part of the exhaust steam from the crankcase are provided according to the invention by the feed pump unit.

For this purpose, the feed pump unit has, as an essential component, preferably a feed pump, which is coupled to the crankshaft of the piston / cylinder unit. The feed pump may in this case be designed, for example, as a single-piston or multi-piston pump, which is cooled to avoid undesirable vapor formation in its intake region.

The low-temperature thermal power plant according to the invention is characterized in that it comprises a vacuum pump unit, by means of which the evaporator unit, the piston / cylinder unit, the condenser unit and the feed pump unit can be evacuated and thus subjected to a negative pressure. Under a negative pressure is understood in this context, a pressure below the atmospheric pressure according to the following definition.

The negative pressure in the live steam is understood to mean a pressure (absolute) of 0.12 bar to 0.95 bar and in the exhaust steam a pressure (absolute) of 0.01 bar to 0.47 bar. (The negative pressure in the feed pump unit and the condensate corresponds neglecting pressure drops due to flow on the suction side to the pressure in the exhaust steam and on the pump side to the pressure in live steam.) Here, the live steam is a temperature of 50 degrees Celsius to 98 degrees Celsius and in the exhaust steam a temperature of 10 degrees Celsius to 80 degrees Celsius. The pressures within the said ranges are adjusted so that there is a pressure gradient between the main steam side and the exhaust steam side, so that the steam can perform mechanical work by expansion. The low temperature heat engine according to the invention is operated within the specified ranges in such value pairs, as they are caused by the physical ratio of pressure and evaporation temperature.

For example, the following workspaces are preferably present: Example 1 Live steam: Pressure (absolute): 0.55 bar, temperature: 85 degrees Celsius, (at heating water temperature: 90 degrees Celsius) exhaust steam: Pressure (absolute): 0.1 bar, temperature 45 degrees Celsius (at cooling water temperature 40 degrees Celsius) Example 2: Live steam: Pressure (absolute): 0.65 bar, temperature: 90 degrees Celsius, (at heating water temperature: 95 degrees Celsius) exhaust steam: Pressure (absolute): 0.15 bar, temperature 50 degrees Celsius (at cooling water temperature 45 degrees Celsius) Example 3: Live steam: Pressure (absolute): 0.30 bar, temperature: 74 degrees Celsius, (at heating water temperature: 78 degrees Celsius) exhaust steam: Pressure (absolute): 0.08 bar, temperature 40 degrees Celsius (at cooling water temperature 35 degrees Celsius)

However, the following example is also considered as a possible working range according to the invention: Example 4 Live steam: Pressure (absolute): 0.30 bar, temperature: 74 degrees Celsius, (at heating water temperature: 78 degrees Celsius) exhaust steam: Pressure (absolute): 0.15 bar, temperature 50 degrees Celsius (at cooling water temperature 45 degrees Celsius)

The resulting fresh and exhaust steam pressures (with the corresponding temperatures) are critically dependent on the available heating and cooling water temperatures. For example, relatively hot fresh vapors with higher pressures and, in parallel, still fumes of very low pressure and temperature may form.

Therefore, always control the currently available cooling and Heizwassertemperaturen the pressure conditions (fresh and exhaust steam) in the low temperature heat engine according to the invention. Ultimately, this only changes the efficiency for branching off the mechanical energy. In this behavior, which can also be referred to as a passive control behavior, is at the same time a particular advantage of the low temperature heat engine according to the invention. The operating behavior can already be controlled by adjusting the heating and / or cooling water temperatures. An independent control unit of the low-temperature thermal power plant advantageously does not need.

In an advantageous application in building technology, these operating variables can even change several times within an operating phase of the machine because the heating and cooling temperatures fluctuate. Balancing regulations are possible (if at all) about cooling and Heizmediummassestrommengen, but not necessary for the maintenance of the operation of the low temperature heat engine according to the invention, as long as there is still a sufficient temperature gradient. In this operating behavior, which can also be described as a passive control behavior, is also a particular advantage of the low-temperature heat engine according to the invention.

Due to the negative pressure within the pressure-carrying units of the low-temperature thermal power plant, the above-mentioned, high volume change work of the live steam to provide the piston movement causes in the present case, at low pressures to deep into the negative pressure range already low water vapor or in the present case live steam quantities can make very high volume change work ,

The vacuum pump unit has the functions to remove the first air present, which is undesirable for the process, secondly to create a negative pressure and third to maintain the negative pressure during operation, since an absolute tightness is practically unattainable. The vacuum pump unit is preferably connected in the region of the condenser unit, since in principle the lowest pressure ("greatest vacuum") has to be provided within the condenser unit. This arrangement of the vacuum pump unit is based on the recognition that a high efficiency of the low temperature heat engine can be provided at low live steam pressures by a particularly low pressure and accordingly low temperatures on the condensation side. Furthermore Any remaining or penetrated air collects in the condenser unit so that it can be sucked off by the vacuum pump.

In particular, the following advantages are provided by the low-temperature thermal power plant according to the invention:
A particular advantage is that heat sources with very low temperature are sufficient for operation. Such a heat source can in particular also be a heating water flow from a boiler of a building heating system, from a buffer storage or from a solar collector system. It can be a heating water flow with, for example, 85 degrees Celsius and less. An advantage is thus also an economic energy production from biomass combustion including wood combustion possible. It is also possible to use process waste heat in a business environment. The advantage, therefore, is that from such a thermal energy source of low temperature, a part of the energy as mechanical energy, which can preferably be harnessed via a generator driven therewith as electrical energy, can be coupled out. In particular, there is an advantage that hot water in a liquid state at atmospheric pressure is usable as a heat source.

Particularly advantageous is the same time comparatively low required temperature sink, for example, 45 Kelvin, so that on the condensation side, a temperature level is applied, for example, 40 degrees Celsius, which remains usable as a flow temperature for space heating. In this case, the low-temperature thermal power plant according to the invention can be integrated into a heating system and a part of the heat energy, in particular in the event of excesses, will flow.

Due to the low temperatures and pressures, materials such as plastics can be used even in the moving components that allow additional efficiency advantages over conventional heat engines by low mass and low thermal conductivity.

In a constructive design of the low-temperature thermal power plant no pressure safety relevant requirements must be considered because there is no relative to the atmospheric pressure strained media in case of damage to the low-temperature thermal power plant. Furthermore, in the event of damage due to the principle, no steam can escape. In addition, the effect of atmospheric pressure causes an immediate stop of vapor formation within the system. There is thus neither an explosion nor a scalding hazard. A safety-relevant advantage also consists in the fact that in the event of damage to the pressure-carrying units, the mechanical processes automatically come to a standstill. Thus, a low-temperature heat engine according to the invention can be provided inexpensively and also operated particularly safely.

In a preferred embodiment of the low-temperature thermal power plant, the piston / cylinder unit has a cylinder heater.

The cylinder heater is in this case designed so that it encloses the cylinder at least in the head region, but preferably up to the exhaust steam outlet and is heated by the Heizwasserstrom, which is also used for the evaporation of the water. In this case, the heating water flow is preferably connected in series hydraulically in such a way that the heating water first flows through the cylinder heater and subsequently the evaporator unit. This ensures that the highest available temperature is present in the cylinder heater.

This advantageous development is against the background that due to the pressure and temperature conditions according to the invention, overheating of the generated live steam, which could ensure an advantageous expansion behavior without premature condensation and with a proportion of pure gas expansion, is practically impossible.

By means of the cylinder heater, in the present case, a heating of the cylinder and in particular of the cylinder and preferably also piston walls is effected in the working space, thereby enabling heat to be released to the live steam in this area. In particular, heat is also tracked from the cylinder to the live steam during the expansion. As a result of this heat release, the expansion of the live steam, although not completely, is more closely approximated to an isothermal process as a technological advantage, so that, as already described above, a larger part of the working capacity of the live steam is retained when the piston is lowered. In this way, the low-temperature thermal power plant according to the invention can be operated in a process which not only has the characteristic of an exclusive steam engine, but partially also of a Stirling engine. In addition, the Main steam is kept dry by the heat input by counteracting condensation and reduces the resistances within the piston / cylinder unit by preventing premature water formation, resulting in an increase in the efficiency of the low temperature thermal power plant as a result.

In a further advantageous development, the piston-cylinder unit has a piston made of plastic. This development is possible because the low-temperature heat engine according to the invention exposes the piston only comparatively low thermal load, as it results from the specified temperature ranges, so that the first material failure can be avoided by thermal stress in a plastic piston and the second, the thermal expansion of a Plastic piston remains structurally manageable. Furthermore, due to the low pressure gradient between the live steam side and the exhaust steam side, the piston is subjected to relatively little mechanical stress so that a mechanical material failure of a plastic piston can also be avoided. The particular advantage is the low mass, so that less masses must be moved during operation, and in the possible cost-effective production. It is preferably a piston made of fiber-reinforced plastic.

In an alternative development, the piston-cylinder unit has a piston made of graphite. As with a plastic piston, there is an advantage in the low mass, so that fewer masses must be accelerated and decelerated during operation. In addition, there is a particular advantage in the self-lubricating properties of graphite.

In another advantageous development, the feed pump unit has a cooling. This has the particular advantage that the low-temperature heat engine can be operated even with very low temperature gradients and can perform mechanical work. In the case of the already present very low absolute pressures, unfavorable temperature-pressure working ranges on the suction side can lead to vapor formation due to the design-related pressure drop. The proper operation of the feed pump unit would then be disturbed by suction of a gaseous medium. By cooling this steam formation is counteracted. Thus, the working range of the low temperature heat engine according to the invention can be further expanded and the efficiency can be increased.

In a further advantageous development, the low-temperature thermal power plant additionally has a working machine with which mechanical energy can be converted into electrical energy, hereinafter also referred to as a generator. Furthermore, the crankshaft and rotating parts of the generator are arranged in a common pressure chamber. This development makes it possible to effectively increase the efficiency and reliability.

Since the generator is not a pressurized unit, there is the problem that the exit of the crankshaft from the passing crankcase to the engine's under-pressure drive shaft must be sealed as a moving member. In principle, this problem can be solved by suitable shaft seals, but there are always the disadvantages of additional costs, mechanical friction losses and residual leakage. This problem is solved by the training advantageous. The common pressure chamber can be formed, for example, in that all assemblies are taken up by a pressure-tight housing, in which the same negative pressure is set as that in the crankcase. The housing does not necessarily have to include all components, it is crucial that the area of the crankshaft outlet is detected. However, according to the development, it is also possible to integrate the generator or else only its rotating parts into the crankcase. In this case, the common pressure chamber is present in the crankcase. Due to the common pressure chamber can be dispensed with a pressure-tight sealing of the crankshaft to the drive shaft. The disadvantages associated with such a seal are overcome. According to this development, no moving parts need to be sealed under pressure difference.

The invention will be described as an embodiment with reference to

1 schematic schematic diagram
explained in more detail.

The 1 shows a low-temperature thermal power plant according to the invention in an embodiment according to claims 1 and 2 in a schematic schematic diagram, wherein the low-temperature thermal power plant is connected in this embodiment to a building heating (not shown) and is used to supply a corresponding building with electrical energy.

The low-temperature thermal power plant has in the present case an evaporator unit 1 , a piston / cylinder unit 2 , a working machine 3 , a capacitor unit 4 and a feed pump unit 5 and a vacuum pump unit 6 , wherein by means of the vacuum pump unit 6 all other, mentioned components of the low-temperature thermal power plant are vacuumized and thus can be acted upon by a negative pressure.

The evaporator unit 1 and the condenser unit 4 have in the embodiment shown here in each case a plate heat exchanger (not shown), wherein the plate heat exchanger of the evaporator unit 1 as evaporator and the plate heat exchanger of the condenser unit 4 work as a capacitor.

By means of the evaporator unit 1 In the present case, water can be evaporated as an energy source of the low-temperature thermal power plant, the evaporator unit 1 from a Heizwasservourlauf 15 the boiler of the connected building heating is supplied with heating water and wherein evaporated by the heating water and a corresponding heat transfer within the evaporator, the water and a live steam is generated.

The live steam is via a live steam system 12 with steam separator 8th from the evaporator unit 1 the piston / cylinder unit 2 supplied, wherein the supply is provided by means of a forming vapor stream.

The piston / cylinder unit 2 points as in 1 shown a cylinder head 2.1 , a cylinder 2.2 , a piston 2.3 and a crankshaft 2.4 on which is in a crankcase 2.5 is included. About the cylinder head 2.1 the live steam, in particular by means of one or more inlet valves (not shown) flows into the cylinder 2.2 , in which then takes place an expansion of the live steam.

The piston 2.3 which is in the cylinder 2.2 is received axially movable, due to the expansion of the live steam in the cylinder 2.2 offset in an axial downward movement. At the same time is the piston 2.3 at his, the cylinder head 2.1 opposite end to the crankshaft 2.4 connected so that the axial movement of the piston 2.3 on the crankshaft 2.4 transferred and thus converted into a rotational movement. The rotational movement is through the crankshaft 2.4 on a machine connected to this 3 , which in the present case is designed as a generator, transmitted and converted into this in the desired electrical energy to supply the building.

Due to the vacuum pump unit 6 Provided negative pressure is presently a particularly efficient energy production based on water as an environmentally friendly and cost-effective energy source allows, since the live steam at pressures below atmospheric pressure is able to perform a high volume change work during expansion, which via the piston 2.2 and the crankshaft 2.4 for the work machine 3 can be made usable.

After the expansion of the live steam is present as Abdampf, which during an upward movement of the piston 2.3 via a steam outlet (not shown) from the cylinder 2.2 in an exhaust steam system 13 is dissipated.

It has been found that a particularly good and lasting workability of the live steam during its expansion in the cylinder 2.1 can be obtained when the expansion is kept in a characteristic that has some isothermal properties. To favor such an isothermal expansion, the piston / cylinder unit has 2 According to an advantageous development of a cylinder heater 2.6 on which the cylinder 2.2 in the expansion region of the live steam at least partially encloses and which also by the Heizwasservorlauf 15 is fed with heating water. In addition, the crankcase 2.5 with a cold water supply 17 , Derived from the heating return of the radiator of the building heating, connected and has a crankcase cooling 2.7 on. By means of the crankcase cooling 2.7 In the present case, this causes a part of the exhaust steam, which does not have the steam outlet in the exhaust steam system 13 is discharged and into the crankcase 2.5 passes, can condense in this immediately and that the condensate thus obtained in a lower condensate tank 9 discharged and by means of a return pump 11 in cooperation with the valve 7 again the evaporator unit 1 can be supplied.

About the exhaust steam system 13 is the piston / cylinder unit 2 with the condenser unit 4 connected so that the exhaust steam of the condenser unit 4 can be supplied. The condenser unit 4 , and there its plate heat exchanger, is via the cold water supply 17 from the radiators of the building heating supplied with cold water, so that by means of the condenser unit 4 a condensation of the exhaust steam is effected. In the present embodiment, the crankcase cooling 2.7 and the condenser unit 4 hydraulically connected in series, the cold water supply 17 first in the crankcase cooling 2.7 and only subsequently the capacitor unit is passed. In the condenser unit 4 On the one hand, the energy stored in the exhaust steam is released and can be supplied in thermal form via the cold water return of the building heating almost lossless. On the other hand, a condensate provided by the condensation becomes one with the condenser unit 4 connected main condensate tank 10 fed and then from this via the condensate system 14 again the evaporator unit 1 fed.

The return of the condensate is in this case by the feed pump unit 5 provided. The feed pump unit 5 is presently designed as a single or multi-piston pump. The feed pump unit 5 has a cooling 2.8 on, which in the embodiment heat exchanging with the crankcase cooling 2.7 connected is.

The vacuum pump unit 6 to generate the negative pressure within the low-temperature thermal power plant is present at an upper outlet of the main condensate tank 10 arranged and preferably designed as a rotary valve or diaphragm vacuum pump. Over the upper part of the gas space of the main condensate tank 10 and those with the main condensate tank 10 connected capacitor unit 4 is the vacuum pump unit 6 capable of discharging air and vapors accumulating therefrom from the interior of all components of the low temperature thermal power plant, the overhead arrangement of the vacuum pump unit 6 a risk of direct suction of condensate is effectively avoided. By the arrangement of the vacuum pump unit 6 In addition, particularly advantageous can be the negative pressure on the exhaust steam side and thus in the range of the lowest pressure.

LIST OF REFERENCE NUMBERS

1

evaporator unit

2

Piston / cylinder unit

2.1

cylinder head

2.2

cylinder

2.3

piston

2.4

crankshaft

2.5

crankcase

2.6

barrel heating

2.7

crankcase cooling

3

working machine

4

condenser unit

5

Feed pump unit

6

vacuum unit

7

Valve

8th

steam separator

9

lower condensate tank

10

Main condensate tank

11

Return pump

12

Steam system

13

Abdampfsystem

14

condensate system

15

Heating water flow

16

Heating water

17

Chilled water flow

18

Cold water return

19

venting system

Claims (6)

Low temperature heat engine, comprising an evaporator unit ( 1 ) with an evaporative heat exchanger, which heat can be supplied by heating water, wherein by means of the evaporator unit ( 1 ) Water can be evaporated and a live steam can be provided, and comprising a single-acting piston / cylinder unit ( 2 ) with a cylinder head ( 2.1 ), a cylinder ( 2.2 ), a piston ( 2.3 ) and a crankshaft ( 2.4 ), whereby over the cylinder head ( 2.1 ) the live steam in the cylinder ( 2.2 ) and wherein the piston ( 2.3 ) axially movable in the cylinder ( 2.2 ) and wherein an axial movement of the piston ( 2.3 ) by an expansion of the live steam in the cylinder ( 2.2 ) and wherein the crankshaft ( 2.4 ) in a crankcase ( 2.5 ) and with the piston ( 2.3 ) and is capable of controlling the axial movement of the piston ( 2.3 ) in a rotational movement and wherein the crankshaft ( 2.4 ) with a working machine ( 3 ) is connectable, by means of which from the rotational movement of the crankshaft ( 2.4 ) electrical energy can be generated, and having a capacitor unit ( 4 ) with a condensation heat exchanger, from which heat can be dissipated by means of cooling water, wherein the condenser unit ( 4 ) with the piston / cylinder unit ( 2 ) and is capable of removing one from the piston / cylinder unit ( 2 ) condensed exhaust to water, and comprising a feed pump unit ( 5 ), with which the condensed water from the condenser unit ( 4 ) and the evaporator unit ( 1 ), characterized in that the low-temperature thermal power plant is a vacuum pump unit ( 6 ), with which the evaporator unit ( 1 ), the piston / cylinder unit ( 2 ), the capacitor unit ( 4 ) and the feed pump unit ( 5 ) can be acted upon by a negative pressure. Low temperature heat engine according to claim 1, characterized in that the piston / cylinder unit ( 2 ) a cylinder heater ( 2.6 ) having. Low temperature heat engine according to one of the preceding claims, characterized in that the piston / cylinder unit ( 2 ) has a piston made of plastic. Low temperature heat engine according to claim 1 or 2, characterized in that the piston / cylinder unit ( 2 ) has a piston made of graphite. Low temperature thermal power plant according to one of the preceding claims, characterized in that the feed pump unit ( 5 ) a cooling ( 2.8 ) having. Low-temperature thermal power plant according to one of the preceding claims, characterized in that the low-temperature thermal power plant is a working machine ( 3 ), and that the crankshaft ( 2.4 ) and rotating parts of the working machine ( 3 ) are arranged in a common pressure chamber.

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