AU6415498A

AU6415498A - Equipment and process for heat energy storage

Info

Publication number: AU6415498A
Application number: AU64154/98A
Authority: AU
Inventors: Gabor Gode
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-10
Filing date: 1998-03-09
Publication date: 1998-09-29
Also published as: HU9700202D0; JP2001504208A; CN1229466A; HUP9700202A3; PL329948A1; CZ9804043A3; KR20000010920A; NO985216D0; CA2253928A1; WO1998040684A1; TR199802272T1; ID22084A; IL126961A0; BR9804892A; HUP9700202A2

Description

EQUIPMENT AND PROCESS FOR HEAT ENERGY STORAGE

Energy reserves in the world are not endless; their - especially the crude oil - exploitation is more and more cost-demanding. The dwindling petroleum supply is the most critical that may cause serious energy supply shortages and disturbances since substitution of the the petroleum derivatives is not solved yet. At the same time the contamination resulting from burning fossile sources of energy causes heavy environmental pollution. Carbon dioxide content of the atmosphere keeps increasing that promotes the dangerous glasshouse effect. Sulphur dioxide content of the atmosphere leads to acidic rains that worsens the biosphere significantly.

An efficient, cost-effective heat storage would mean enormous advantages especially in the area of condensation waste heat utilization of the solar energy as well as thermal and nuclear power plants. At present energy demands are getting higher. Use of the solar energy is increasing and will become critical in the energy supply in the next century. Spreading of the concentrators allows substitution of the petroleum derivatives. Its significance is provided by decreasing construction costs of the concentrators, their attainable best efficiency, operational benefits in high heat ranges leading to several kinds of usages, the favourable environmental protection character as well as the fact that time-scale of this free energy source is endless.

Only disadvantage of the solar energy utilization - including heat energy collection with concentrators in first of all - is the periodic nature regarding the alternating seasons and periods of day. Entire elimination of the disadvantages resulting from the a.m. periodic nature can only be solved by an efficient heat storage allowing e.g. satisfying all heating and warm water demands with solar energy in a way that sun radiation collected from spring to autumn is stored for winter. Another heat storage utilization is to supply continuous heat energy for industrial, agricultural, food industrial and processing activities with stored, solar or other heat sources.

As for solar equipment using concentrators there are enormous possibilities concerning substitution of the convential energy sources in several areas including heating and warm water supply of flats, utilities, office buildings, industrial and processing plants, animal keeping sites, foil tents, glasshouses as well as some agricultural and food industrial (drying, heat processing) operations etc. Utilization of all these possibilities could spread solar energy usage largely.

Making use of condensation waste heat of thermal and nuclear power plants, mobile variant of the heat-storage equipment could solve constant heat supply of industrial and processing units as well as utilities requiring substantial heat capacities in a way that the mobile equipment or tank vehicle/container of high heat-storage capacity are connected to the condensation system or other connecting point of the mentioned power plants and after a quick filling the stored heat capacity is delivered and transferred to the end-user equipment directly or an installed heat-storage equipment, with the quick discharge method. These mobile heat-storage units could also be used efficiently for bridging distances between the heat producing centres and the end-users, connected to the convential heating systems and heat suppliers.

At present different forms of heat-storage procedures are known. As for types of storage systems, there are equipment for sensible and latent heat storage. Solid materials are most suitable for storing sensible heat. A heated and cooled solid body can store heat without phase-changing. Sensible enthalpy determines storage capacity. Within this heat-storage method there are two procedures: where solid bodies transport heat themselves from the container e. g. in pebble bedding systems or where the solid body remains in the container and heat is transported by a liquid medium or gas.

If the storage medium is a solid body and an adequate layout is applied, the "thermoclin" effect can be implemented quite easily: in a thin cylinder the heat-transport medium is flowing axially and this is characterized by short heat transport distances, large heat transfer surface but axially a low thermal conductivity. Along the height of the heat-storage vessel, during the charge and discharge heat is distributed in three ways: in the first case heat-transfer surface and heat-transfer coefficient is low compared with the flowing quantity (e.g. cowper system) and in the second case the relation is inverse (e.g. pebble bedding). In both cases there is axial heat transfer, too, that makes temperature diagram more flat. In the third case a temporary heat range develops and wanders up and down during the charge - discharge as a blending range in a clean liquid container of displacement type. Its advantage that the outlet temperature is nearly constant until the end of discharge. However, its disadvantage is that the heat-transfer liquid must be flown through the all system and its pressure is decreased while heat transfer occurs in a relatively narrow, temporary zone only.

Specific heat-storage capacity of solid storage mediums and also their heat change range is usually large but in most cases it is not utilized entirely. Among the metals cast iron has the highest heat-storage capacity but its relatively heavy weight per volume is not advantageous. As for heat-storage capacity, alumina (A12O3) and magnesia (MgO) have a high heat capacity but they are expensive materials.

Heat storage via latent heat is not in relation with heat change but phase change of the storage medium at constant temperature. Most latent heat connects to the transition from liquid to gaseous phase. Its disadvantage is that heat storage capacity of the wapor phase is quite low that's why such storage type applying latent heat is not used. Storing latent heat means melting heat storage including slight volume change only. Advantage of the heat storage based on phase change that besides the latent heat, sensible heat of the liquid and solid phase can also be used. Latent heat container is a system of constant pressure and mass. On higher temperature its storage capacity is also higher. Applying a blend of two components, especially of eutectic or more components, one can decrease the melting point without decreasing enthalpy of the phase transition significantly.

As for the storage mediums we can distinguish clean materials as well as systems of two and three components.

Among the clean materials litium fluorid (LiF) has the highest melting heat and litium hidroxide (LiOH) with a very favourable melting point has nearly as good latent heat as LiF . These materials has only one disadvantage that their pure form is expensive; blending them with other materials of good heat storage capacity forming eutectic one can decrease these disadvantages.

Application of systems of two components is very favourable because their melting point is in a better, lower range, high energy density can be attained at a relatively low melting point and well heat-storable but expensive materials may be blended in a way that heat-storage capacity remains nearly the same. Within this two-component system one can distinguish eutectical and distectical blends. Eutectical blends are the most convenient because of their advantageous characteristics.

Thermal characteristics of the three-component systems are similarly good like the two-components ones but their melting point and price is lower, therefore, these are very suitable for cost-efficient, economic heat-storage.

We must note gas storage under pressure and the other heat-storage systems e.g. sorption heat-storage and also the thermochemical heat-storage yet.

Gas storage under pressure includes the underground, compressed air storage systems exceeding the 100.000 m3 where gas turbine, peak-load power plants are operated. When storing under compressed air, isothermal discharge can be implemented if discharge is slow and heat change with the environment occurs or a separate latent heat-storage system is applied. Heat-storage can be improved if additional heat-storage capacity - e.g. latent heat store is available when temperature decrease gets lower during discharge and does not induce high heat stresses unnecessarily. Energy density increases more than linearly in the function of the increasing storage pressure that's why high pressures are suggested for the storage under compressed air (above 50 bar). All these circumstances hinder significant spreading of this system.

There are four basic solutions for the sorption storage. In the first one heat is added to the sorbent material, desorbed material is led to the gas container operating under constant or sliding pressure. Cooling the gas increases storage capacity. It is a disadvantage of the system that energy density is low.

In the second solution: if gas is condensed at environmental or similar temperature it requires less volume. Condensation heat is conducted into the environment. During discharge the environmental heat re-evaporates the liquid so that all energy is lost.

In the third solution liquid storage is substituted for sorption storage which works with additional absorber medium and is able to absorb and deabsorb gas at environmental temperature.

In the fourth solution sorption storage and heat engine is combined. If discharge valve is opened the steam flows from the boiler through a steam engine to the container, the developed heat is led to the boiler so that raising of steam goes on. Its disadvantage is that energy density is low because of low mass density of the absorbing salt though value of the sorption heat is favourable.

Essence of the thermochemical storage is that heat energy is stored in the form of bonding energy of the reversible chemical reactions. The reaction may occur in the presence of catalyzer or without it. After the reaction the participating materials are separated and stored separately. In this process unused evaporation heat develops during the condensation (charge) and it impairs storage efficiency. Another disadvantage is that life cycle of the catalyzers is quite adverse.

Comparing storage capacities shows that in case of thermal storage systems energy density is 12.5 % with liquid storage medium, 25 % at solid storage with metal medium and 37.5 % at solid storage with nonmetal medium and phase-changing storage medium.

Latent heat-storage can get higher energy density than the sensible heat- storage. Saturation pressure of the pressurized systems exceeds the atmospheric pressure and requires use of pressure-tight vessel, therefore, these systems are not economic. At least one pressure-tight vessel is necessary for the sorption heat-storage and several pressure-tight vessels of different pressures are necessary for the thermochemical heat-storage if the materials to be reacted are stored in liquid state; these and the lower energy densities mean disadvantage of these systems.

Latent heat-storage systems are better than the above mentioned ones because their constant discharge temperature provides better efficiency than at sensible heat-storage where temperature decreases. Their another advantage is that sensible heat of the solid phase, latent heat of the phase-change and sensible heat of the liquid phase can be used for heat usage.

In the process according to the invention it was the basic conception that phase-changing, solid storage mediums with nonmetal carrier of the highest energy density and constant discharge temperature are the most favourable among the heat-storage systems presently known and applied. However, these heat-storage mediums can not meet requirements concerning the cost-effectiveness, reversibility, favourable melting temperature and corrosion resistance to structural/construction materials in all cases. Taking this fact into consideration the procedure according to the invention solves application of such eutectics - e.g. sodium hydroxide (NaOH), sodium hydroxide - sodium nitrate (NaOH - NaNO3), sodium hydroxide - litium hydroxide (NaOH - LiOH) and litium cloride - litium hydroxide (LiCl - LiOH) - that show constant reversibility according to the performed experiments and have advantageous melting point, high heat-storage capacity and corrosion resistance to the structural materials in the respect of the usage.

The US patent description Regist. No. 4.244.350 describes a different solution including a heat container operated with solar energy; a heat transfer procedure is realized here. In the process overheated steam is generated in a superheating pipeline system via heating steam. However, efficiency of the equipment is low and its structure is not suitable for long-term heat storage.

The US patent description Regist. No. 4.391 .267 describes a heat- storage material; the main point is that a liquid crystalline melt changes to crystalline form - on a specific temperature - in a spontaneous way or artificially via coring. During coring an additive is added to the melt which forms a blend upon dissolving. The additive may contain disodium hydrogene phosphate, dipotassium hydrogene phosphate or their ammonium- or sodium equivalent. The additive in the solidifying material helps control of crystal size and growth as well as prevents crystallization of the melt in a wrong form.

Essence of the solution is that the material - melt during heating - stores the heat needed for the phase-change and emits heat during the recrystallization. However, this description describes only a process helping crystallization but does not deal with permanent reuse of the crystalline material. Additional disadvantage is that it does not solve solar heating of the crystalline material so does not allow neither utilization of the solar energy for heating nor reuse of the crystalline material.

The US patent description Regist. No. 4.355.627 describes a heat- storage system operating with solar collector or heat pump. It is the main thing here that separate heat tanks of regular geometry make a pile in a large container. Shells of the heat-storage units contain heat transfer material e. g. glass, metal particles and include the heat-storage material itself.

Shortage of this variant is that it does not utilize heated crystalline melt, i. e. phase-change heat for heat storage; therefore, it is not suitable for obtaining high heat-storage capacity and long-term heat storage.

According to the intended purposes subject of the invention is a procedure for thermal energy storage, especially for solar energy or other heat source of high temperature e.g. thermal or nuclear power plants. In this procedure heat transferred from the heat source via a heat transfer agent is stored by the means of phase-changing method: there is a crystalline material, possibly an eutectic, of advantageous heat-storage capacity in the heat container of the heat-storage equipment; this material is heated by the heat transfer agent arriving from the heat source until the melted crystalline material is filled with heat and stores it. Then in discharge mode heat transfer agent is circulated and the melt is cooled until the end of the phase-change, i. e. the recrystallization, i. e. its optimal cooling down. This way the stored heat is extracted; during this process such crystalline materials, eutectics are applied that are able to keep globally their reversibility during the phase- changing process repeated more times; that react with the used structural materials slightly ot not at all; that are not too corrosive and their thermal parameters allow the high phase-changing heat storage.

Additional character of the heat energy storage equipment according to the invention is that heating-cooling pipelines of the heat-storage tank are equipped with ribbed surface to improve heat loss and heat reception. At the installed equipment heating pipes of the heat exchanger are also ribbed to get better heat loss.

Advantageous characters of the heat energy storage equipment according to the invention are improved by the fact that the monitoring, status detection and control means are connected to computertechnics means e.g. to a computer.

Advantageous construction form of the heat energy storage equipment of mobile system according to the invention is where pipe ends on the heating- cooling pipelines and on the initial parts of the heat container of the equipment are equipped with such connecting pieces that can be connected to condensation system of the convential heating systems as well as thermal or nuclear power plants or other heat transfer points in order to fill the mobile heat-storage equipment with heat energy.

Purpose of the heat-storage equipment and procedure according to the invention is to eliminate shortages of the known constructions and procedures, to store the heat energy obtained by concentrators and the condensation waste heat of the thermal and nuclear power plants for a long-term period; it is realized via a heat-storage equipment layout operating with the most efficient heat-storage method, the phase-changing heat storage as well as via minimalizing the convection losses. Further pupose is to allow making use of the stored heat in several ways.

Another purpose is to provide the received and stored heat energy for the consumers directly without constructing service conduit systems but via mobile heat-storage equipment. This way additional advantages could be reached by the means of utilization of free energy source and the most economic heat transport.

Our additional aim is to apply the best heat-storage process where phase-change heat of crystalline materials is utilized; in the technical literature and also in the practice this is the most favourable heat-storage process but implies many technical problems yet. This process should be applied in a way to implement a stabile, efficient, economic heat-storage process with such crystalline blends and eutectics that show permanent reversibility /verified experimentally/, have advantageous melting point, high melting heat and heat-storage capacity and is anti-corrosive to the structural materials used in the implementation, construction.

According to the intended purposes the equipment according to the invention is mainly suitable for storing heat energy obtained from solar energy collection equipment. The equipment according to the invention contains the following: one or more sun-following concentrator heat-collection assembly/assemblies collecting sun radiation; a receiver containing a heat transfer agent to receive the concentrated solar heat - this receiver is located in the focus of the concentrator heat collection assembly; primery and secondary pipeline for the hot agent and the cooled agent transfer that connects the heat collection assembly with the heat container and is equipped with one or more circulation unit(s) /e.g. circulation pump/.

The heat-storage equipment includes a heat container filled with a crystalline material being suitable for phase-changing heat storage. In this container heating-cooling pipelines for the heat filling and extraction of the stored heat are installed and imbedded in a crystalline material or its melt. Outlet part(s) of the pipelines are connected - through valves - to primary pipelines for transporting the heat-carrying agent and the secondary pipelines led to the heat-collection assembly, one or more /or sometimes without/ heat exchanger(s) as well as are connected to one or more heat utilization equipment.

The heat container, the heat exchanger, the primary and secondary pipelines for transporting the heat-carrying agent and the interconnection pipes are covered with heat insulation. The heat container, the pipelines and the heat exchanger are equipped with status sensing and control devices for determining or modifying features of the heat-carrying agents as well as measuring and detecting temperatures of the above mentioned agents.

Heat container of the heat-storage equipment and primary part of the pipeline for transporting the heat transfer agent are connected -

- via interconnection pipes - to an expansion tank filled with inert gas, mostly nitrogene. There are basic units of the heat container and the relating assemblies in a quantity that conforms to the heat-storage and usage requirements.

Purpose of the invention is to make a group of equipment for heat energy storage where the heat-storage equipment of mobile system as the basical unit is supplied. It can be delivered by vehicles, in containers (railway tank etc. ); one or more heat container(s) is supplied with crystalline material, heating and cooling pipelines, outlet connection pipe ends and connection elements, heat insulation covering, equipped with temperature gauge, status sensing and control devices.

Additional advantage of the heat-storage equipment according to the invention is that warm water supplying equipment, for inst. a boiler can be connected to that.

Further benefits of application areas of the heat-storage equipment according to the invention are that the heat utilization equipment connected to the heat-storage equipment can satisfy any heat requirement e.g. they can serve for several heating activities through heat transfer- or heat transmission units, when connected to climatic units they can serve for their heating- cooling activity, when connected to absorption cooling systems they can serve for their heating-cooling activity, when connected to heat transport unit of driers they can serve for drying activities and besides the above they can supply heat requirement of all kinds of industrial and processing activities and operations.

Invention is described in the followings on the base of the figures showing construction examples.

Figure 1 shows 2 heat container of the 1 heat-storage equipment as basic unit, the 1 1 heat exchanger connected to the 2 heat container, the 1 1 a warm water supplying-storing boiler and the 18 expansion tank containing the inert gas.

Figure 1 shows 2 heat container of the 1 heat-storage equipment; 2 heat conatiner is filled with 3 crystalline heat-storage medium before operation. In this 3 crystalline material and its 3 a melt are imbedded the 4 heating- cooling pipelines that transport the 20 heat-carrying agent.

One can see in the figure that the 8 primary pipeline - starting from the 7a heat source of the 7 heat collection assembly and transporting heat- carrying agent is led through the 21 circulation pump, the 6 valve and the 5 inlet pipe end to the 4 heating-cooling pipelines of the 2 heat container. Then it returns to the 5 pipe end of the 4 heating-cooling pipeline through the 6 valve and the 9 secondary pipeline to the 7a heat source of the 7 heat collection assembly and here the cycle for heating the 2. heat container ends.

Figure 1 also shows how the 1 1 heat exchanger connects to the 2 heat container through 6 valves and 10 connection pipes; the 1 1 heat exchanger is connected to the 12 heat utilization equipment with pipelines.

Cooling-discharge cycle is closed by this 20 heat transfer agent flow that starts at the 2 heat container and flows through the 6 valve and the 1 0 connection pipeline to the 1 1 heat exchanger and then returns to the 2 heat container.

One can observe in the Figure 1 that the 2 heat container, the 1 1 heat exchanger as well as the 8 primary and the 9 secondary pipelines are covered with 13 heat insulation. 14 temperature monitor assembly is provided for temperature measurement and detection as well as 1 5 status-sensing elements and 16 control devices are provided for modifying specific characteristics in the 2 heat container, the 3 heat-storage medium, the 8 primary and the 9 secondary pipeline, the 1 1 heat exchanger and the 20 heat transfer agent.

Figure 1 also shows that the 2 heat container and the 20 primary pipeline for conveying heat transfer agent is connected with the 18 expansion tank filled with inert gas, through the 17 connection pipeline.

The figure shows a favourable construction where 4 heating- cooling pipelines of the 2 heat container and heating pipelines of the 1 1 heat exchanger have a 23 ribbed surface in order to improve the heat transfer.

Figure 1 also shows that the 14 temperature monitor, the 15 status sensing and the 16 control device - belonging to the 1 heat-storage equipment - are interconnected with a 25 computertechnics means e.g. a computer.

An additional advantageous construction of the patent is shown in the Figure 1 where a l i a warm water boiler is connected to the 1 heat-storage equipment.

Figure 2 depicts 7 heat collection unit of a solar energy utilization equipment with the 7a absorber heat source located in the focus of the 7 heat collection unit. This heat source fills heat to the 2 heat container through the 8 primary and the 9 secondary pipelines, the 6 valves and the 21 circulation pump. Figure 3 represents the 1 heat-storage equipment located in a 26 container of mobile system. One can see in this figure the 4 heating-cooling pipelines led in the 2 heat containers filled with the 3 crystalline material; these pipelines are equipped with 5 outlet pipe ends, 19 switches, 13 heat insulation, 14 temperature gauge, 15 status sensing device and 16 control device.

Figure 3 shows an alternative construction of the 26 heat container of mobile system where 4 heating-cooling pipelines of the 2 heat container are supplied with ribbed surface in order to reach a better heat transfer.

Figure 3 also shows that the 14 temperature monitor, the 1 5 status sensing and the 16 control device along the 24 controller are interconnected with a 25 computertechnics means e. g. a computer.

Figure 3 also depicts that 5 pipe ends on the inlet and outlet parts of the 4 heating-cooling pipelines of the 2 heat container of the 26 mobile heat container are equipped with 27 connection units that can be connected to condensation system or other heat transfer points of conventional heating systems, thermal or nuclear power plants in order to fill heat energy to the 26 heat container of mobile system.

Figure 3 a shows the 2 heat container connected to climatic unit and absorption cooler.

When operating the equipment according to the invention the solar equipment is located on the top of the building to be heated. This solar equipment may be among others a roll-parabolic collector where the 20 heat transfer agent - possibly thermal oil - is circulated in the 7a heat source, i. e. an absorber pipe located in the focus of the 7 heat collection unit. The thermal oil is heated by sun radiation concentrated by the parabolic mirror to the absorber pipe as heat source. This 20 hot heat transfer agent is led to the 4 heating-cooling pipeline system of the 2 heat container and circulated by the 21 circulation pump through the 8 primary pipeline, the 6 valve and the 5 inlet pipe end in the cellar of the building or a convenient closed room. During the circulation the hot 20 heat transfer agent is heating the 3 crystalline material in the 2 heat container. Then the cooled 20 heat transfer agent flows back to the 7a heat source of the 7 heat collection unit through the 5 outlet pipe end, the 6 valve and the 9 secondary pipeline and the filling cycle ends here.

In discharge mode the equipment operates in the following way: The 25 computer compares the impulse data obtained from temperature gauge or heat regulator located in the rooms to be heated or on the heat utilization equipment (e.g. a dryer) with the pre-entered program (softver) data. On the base of the results the computer switches the heating-discharging program on when the 20 heat transfer agent is circulated by the 21 circulation pump connected to the connection pipe, through the 10 connection pipe starting from 22 heating pipe of the 1 1 heat exchanger. At the same time the computer opens the 6 valve installed in the 5 outlet pipe end of the 8 primary and the 9 secondary pipeline. Now the 20 heat transfer agent begins to flow from the 1 1 heat exchanger through the 4 heating-cooling pipelines of the 2 heat container. During flowing the 20 heat transfer agent - flowing through the 4 heating-cooling pipelines of the 2 heat container - takes up phase- changing heat and later sensible heat of the 3 a melt of the 3 crystalline material, melted by solar energy. This flow gets warm and returning to the 1 1 heat exchanger - flowing through the 22 heating pipeline - heats the water in the 1 1 heat exchanger. The heated water in the 1 1 heat exchanger is transmitted by the 21 a circulation pump through the 8a primary pipeline to the 12 heat utilization equipment where the warm water flows back in the 1 1 heat exchanger through the 9a secondary pipeline, transfers the transmitted heat and the heating cycle ends at the same time.

A 1 1 a warm water boiler of throughput system is connected to the 2 heat container of the 1 heat-storage equipment in its filling and/or heating- discharging cycle or alternatively, is connected to the 1 1 heat exchanger with the 10a connection pipe. During the operation of the boiler, after the 14 temperature monitor impulse and after opening the installed thermostat and the 6 valves the 21 circulation pump circulates the 20 hot heat-carrying agent through the 10a connection pipes and the heating pipe of the boiler. The water in the 1 1 a warm water boiler gets warm and leaves the system through the warm water pipeline upon opening the taps located in the flat. Simultaneously, the cooled 20 heat-carrying agent returns to its original place after leaving the heating pipe of the 1 1 a warm water boiler.

The 1 heat-storage equipment is equipped with the next things: the 14 temperature monitoring gauge for measuring and showing temperatures of the 20 heat-carrying agent and the 3 heat-storage material; the 15 status sensing elements for determining the medium characteristics; and the 16 control device for modifying specific characteristics. These devices are connected to the 25 computer through the 24 central processor unit and enter data in the computer memory during operation continuously.

Comparing with the pre-entered data, the computer evaluates the entered data and according to the obtained results controls flow rate of the heat transfer agent via activating the 6 valves and other controls; or controls heat supply of the 1 1 heat exchanger and/or the warm water boiler via partial or entire opening the 6 valves.

All the above are required because flowing the 20 heat transfer agent /at the suitable rate/ prevents its overheating as well as heating- and warm water demands are met by controlled operation of the 6 valves and the 21 circulation pumps. Operation of the 26 mobile heat container is similar to the above 1 heat-storage equipment /installed/. It is the only difference between them that in the 26 type the 1 1 heat exchanger can be omitted and inlet- and outlet pipe ends of the 4 heating-cooling pipelines of the 2 heat container are equipped with 27 connection units allowing connection of the 26 mobile heat-storage equipment to the condensation system or other heat transfer points of conventional heating systems, thermal or nuclear power plants in order to fill them with heat energy.

During operation the 26 mobile heat-storage equipment is connected to the mentioned heat sources by the means of the 27 connection structure. Then the 2 heat container of the 26 mobile heat-storage equipment is filled with heat by the 21 circulation pump via circulating the 20 heat-carrying agent.

When discharging the 26 mobile heat-storage equipment, the 1 2 heat utilization equipment or the installed 2 heat container is directly connected to the 27 connection unit switched to the 5 outlet pipe end of the 2 separate or interconnected heat container(s) located in a container at the place of the heat supply or transported there on its own wheels. Then the 6 valve is opened and after activation of the 21 circulation pump the stored heat is transferred to the 12 heat utilization equipment or the installed 2 heat container while circulating the 20 heat-carrying agent.

The procedure according to the invention embodies the next operations: the 3 crystalline material of favourable heat-storage capacity - possibly eutectic - in the 2 heat container of the 1 heat-storage equipment is heated by the 20 hot heat transfer agent arriving from the 7a heat source until it melts then is filled with heat during the phase-changing and it stores this heat. In discharge mode the 20 heat-carrying agent from the 1 1 heat exchanger or in case of the 26 mobile heat-storage equipment from the 12 heat utilization unit is circulated. The 3 a melt is cooled until the end of the phase-change i. e. the recrystallization or until reaching the required cooling temperature; this way the stored heat is transmitted.

During the procedure such crystalline materials or eutectics are applied that keep their reversibility during the more times repeated phase-changing, they do not or only slightly react with the applied structural materials, are not or slightly corrosive and their thermal parameters allow high phase-changing heat storage.

Additional advantage of the procedure according to the invention that not only utilization of heat storage by phase-changing latent heat is possible but also that of the sensible heat of the crystalline- and liquid phase.

Claims

PATENT CLAIMS

1 . Equipment for heat energy storage, possibly for solar heat storage where heat is collected by solar energy collection equipment. It consists of the following parts: one or more sun radiation concentrator assembly/assemblies, a receiver (including the heat-carrying agent that takes up heat of the concentrated sun radiation) belonging to and located in the focus of the above assembly, a primary pipeline for the transport of the hot heat-carrying agent connecting the heat collection assembly with the heat container as well as the secondary pipeline transporting the cooled heat-carrying agent. It is equipped with one or more unit(s) that circulates the heat-carrying agent e.g. with circulation pump and the latter is connected to the primary and/or secondary pipeline transporting the heat-carrying agent. It is c h a r a c t e r i z e d by the following:

The 1 heat-storage equipment has a 2 heat container filled with crystalline material realizing the phase-change. In this 2 heat container 4 heating-cooling pipelines transporting the heat-carrying agent are imbedded in the 3 crystalline material or its 3 a melt in order to fill it with heat and to utilize the stored heat. The 5 pipe end(s) of the a. m. pipelines are connected to one or more 12 heat utilization equipment through 6 valves, the 8 primary pipeline for transporting the heat-carrying agent and the 9 secondary pipelines led to the heat-collection assembly, the 10 connection pipes as well as one or more 1 1 /or sometimes without/ heat exchanger(s).

The 2 heat container, the 1 1 heat exchanger, the 8,9 primary and secondary pipelines for transporting the heat-carrying agent and the 10 interconnection pipes are covered with heat insulation. The 2 heat container, the heat-storage medium, the heat-carrying agent, the 8 pipelines for transporting the heat-carrying agent and the 1 1 heat exchanger are equipped with 14 temperature monitor gauge and 15, 16 status sensing and control devices for determining or modifying features of the heat-carrying agents as well as measuring and detecting temperatures of the above mentioned agents.

2 Heat container of the 1 heat-storage equipment and 8 primary part of the pipeline for transporting the heat transfer agent are connected - - via 17 interconnection pipes - to an 1 8 expansion tank filled with inert gas, mostly nitrogene. There are basic units of the heat container and the relating assemblies in a quantity that conforms to the heat-storage and usage requirements.

2. Pieces of equipment for heat storage, c h a r a c t e r i z e d by the following:

The 1 heat-storage equipment of mobile system as the basical unit is supplied. It can be delivered by vehicles, in containers (railway tank etc. ) or may be self-propelled; one or more 2 heat container(s) is supplied with 3 crystalline material, 4 heating and cooling pipelines, 5 outlet connection pipe ends and 19 connection elements, 13 heat insulation covering, equipped with 14 temperature gauge, 15 status sensing and 16 control devices.

3. Procedure for thermal energy storage, especially for solar energy or other heat source of high temperature e.g. thermal or nuclear power plants. This procedure is c h a r a c t e r i z e d by the following:

Heat energy - transferred from the heat source via a heat transfer agent - is stored by the means of phase-changing method: there is a 3 crystalline material, possibly an eutectic, of advantageous heat-storage capacity in the 2 heat container of the 1 heat-storage equipment; this 3 material is heated by the 20 hot heat transfer agent arriving from the 7a heat source until the 3 melted crystalline material is filled with heat and stores it. Then in discharge mode the 20 heat-carrying agent is circulated from the 11 heat exchanger and the 3a melt is cooled until the end of the phase-change, i.e. the recrystallization, i.e. its optimal cooling down. This way the stored heat is extracted; during this process such crystalline materials, eutectics are applied that are able to keep globally their reversibility during the phase-changing process repeated more times; that react with the used structural materials slightly ot not at all; that are not too corrosive and their thermal parameters allow the high phase-changing heat storage.

4. The heat-storage equipment according to the Claim item No. 1, c h a r a c t e r i z e d by the following:

4 Heating-cooling pipelines of the 2 heat-storage tank (heat container) are equipped with 23 ribbed surface to improve heat loss and heat reception. 22 Heating pipes of the 11 heat exchanger are also 23 ribbed to get better heat loss.

5. The heat-storage equipment according to the Claim item No.2, c h a r a c t e r i z e d by the following:

4 Heating-cooling pipelines of the 2 heat-storage tank (heat container) are equipped with 23 ribbed surface to improve heat loss and heat reception.

6. The pieces of equipment according to either the Claim item No. 1 or No.4, c h a r a c t e r i z e d by the following:

The 14 temperature monitor, the 15 status sensing and the 16 control device along the 24 controller are interconnected with a 25 computertechnics means e.g. a computer.

7. The pieces of equipment according to either the Claim item No.2 or No.5, ch a r ac t e ri z e d by the following:

8. The mobile, transportable pieces of heat-storage equipment according to the Claim item No.2, c h a r a c t e r i z e d by the following: The 5 pipe ends on the inlet and outlet parts of the 4 heating-cooling pipelines of the 2 heat container of the 1 heat-storage equipment are equipped with 27 connection units that can be connected to condensation system or other heat transfer points of conventional heating systems, thermal or nuclear power plants in order to fill heat energy in the 26 heat container of mobile system.

9. The pieces of equipment according to any of the Claim items No. 1, 4 or No.6, c h a r a c t e r i z e d by the following:

Warm water supplying equipment, mostly a warm water boiler can be connected to the 1 heat-storage equipment.

10. The pieces of equipment according to any of the Claim items No.2,5,7 or No.8, c h a r a c t e r i z e d by the following:

11. The pieces of equipment according to any of the Claim items No. 1,4,6 or No.9, c h a r a c t e r i z e d by the following:

The 12 heat utilization equipment connected to the 1 heat-storage equipment can satisfy any heat requirement e.g. they can serve for several heating activities through heat transfer- or heat transmission units, when connected to climatic units they can serve for their heating-cooling activity, when connected to absorption cooling systems they can serve for their heating-cooling activity, when connected to heat transport unit of driers they can serve for drying activities and besides the above they can supply heat requirement of all kinds of industrial and processing activities and operations.

12. The pieces of equipment according to any of the Claim items No. 2,5,7,8 and No.10, c h a r a c t e r i z e d by the following:

The 12 heat utilization equipment connected to the 1 heat-storage equipment can satisfy any heat requirement e.g. they can serve for several heating activities through heat transfer- or heat transmission units, when connected to climatic units they can serve for their heating-cooling activity, when connected to absorption cooling systems they can serve for their heating- cooling activity, when connected to heat transport unit of driers they can serve for drying activities and besides the above they can supply heat requirement of all kinds of industrial and processing activities and operations.