FR2914404A1 - Heat storing and restoring system for e.g. residential building, has storage exchanger positioned between excess heat source and environment receiving heat, where stored heat provokes from recuperation of heat lost by heat source - Google Patents

Abstract

The system (1) has fluidic circuits (7, 8) linking a water/water type storage exchanger (2) and water/air type restoration exchanger (3) to an aquifer (5). The heat is stored in the aquifer and restored into a heat consuming entity e.g. building, during a period (t1) i.e. summer and period i.e. winter, respectively. The exchanger (2) is positioned between an excess heat source (11) e.g. factory (11A), and environment (E) e.g. river, receiving heat. The stored heat provokes from recuperation of heat lost by the source. The aquifer is placed, in sub-soil, near the source and entity. An independent claim is also included for a method for storing heat in sub-soil and restoration of heat in a surface.

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to systems for

  storage of heat in the basement for subsequent recovery of the stored heat. The invention also relates to a method for storing heat in the basement and returning heat to the surface. The invention applies in particular to the heating of buildings.

  STATE OF THE PRIOR ART It is known to use geothermal heat pump systems for building heating in a cold period. Typically, a geothermal heat pump uses the heat contained in the ground to supply a heating network (a floor heating, radiators, etc ....) of a building. This type of heat pump has separate fluid circuits for the collection and heating. The heat pump ensures the movement of the fluid in the various fluid circuits and the transfer of heat from one circuit to the other circuit. The capture circuit captures the heat contained in the ground via horizontal loops, or vertical loops. Such a system is totally dependent on the soil temperature and therefore the amount of heat available in the soil.

  Furthermore, it is also known from patent EP 1 462 736 to produce heat to store it in a porous formation containing water still known as aquifer, and to restore it during the winter by the intermediate of a reversible heat pump. Such a system requires specific means for producing heat to be stored.

  Finally, it is a fact that many industries, for example the factories producing electricity or manufacturing certain products, reject in their direct environment (atmosphere, river, etc.) more or less significant quantities of heat resulting from their operation. These quantities of heat are rejected during the operation of these industries, that is to say generally throughout the year. Although it is known to use this heat rejected during the heating period (winter and mid-season), especially in district heating systems, the water discharged is rarely exploitable directly because typically less than 20 C. The heat discharged out heating period (summer and mid-season) is lost. In addition, the cooling water (water of rivers and streams) being hotter in summer, the water is much hotter in summer than in winter, often causing a warming of rivers and rivers beyond allowed limits.

  SUMMARY OF THE INVENTION An object of the invention is to provide a system and a method for storing heat in the basement and returning heat to the surface to solve at least one of the problems of the state of the prior art. In particular, an object of the invention is to improve the energy efficiency of complex systems including heat producers such as industries, and heat consumers such as residential, commercial, storage buildings. , industrial or office, or greenhouses of agricultural production.

  According to the invention, there is provided a heat storage system in the basement and surface heat recovery comprising a first storage heat exchanger and a second heat exchanger located on the surface, an aquifer layer lying in the basement , at least one fluidic circuit coupling the exchangers to the aquifer layer, at least one pump for moving a fluid in the fluid circuit, the heat being stored in the aquifer for a first period of time, the heat being returned to a entity consuming heat for a second period of time. The first storage exchanger is positioned between an excess heat source and the environment receiving the excess heat. Stored heat from the recovery of at least a portion of the heat lost by the excess heat source.

  According to other optional aspects, the surplus heat source lost may be a plant, or a power plant, or a district heating plant, or a co-generator. The heat source discharges excess heat into the atmosphere, or a river, or the sea. The first storage exchanger may be of the water / water exchanger type.

  The means for reducing the water temperature can be positioned between the heat source and the water / water heat exchanger. The means for reducing the water temperature can be a mixing basin. The rendering exchanger can be positioned in the heat-consuming entity, the consuming entity being a building. The second heat exchanger may be of the water / air exchanger type. The first storage exchanger and the second storage exchanger can be coupled to the aquifer layer by two separate fluid circuits. The first storage exchanger and the second storage exchanger can be coupled to the aquifer layer by a single fluid circuit and a valve for coupling the aquifer layer to the first storage exchanger or the second storage exchanger.

  According to another aspect of the invention, it is also proposed a method of storing heat underground and surface heat recovery comprising the following steps: - a heat recovery step lying on the surface, - a step of storage comprising transferring heat from the surface to an underground aquifer, the heat being stored for a first period of time, and a stored heat recovery step comprising transferring a portion of the heat heat stored in the aquifer layer to the surface, the stored heat being restored for a second period of time. The heat recovered at the surface corresponds to at least a portion of a heat lost by an excess heat source.

  The system and method according to the invention therefore allows recovery of unused and abandoned energy in nature. Thus, by virtue of the invention, when an aquifer is present in the subsoil near excess heat source and building to be heated, it is possible to value the heat that would otherwise have been lost and to use the heat. stored at the appropriate time. Also, cooling water discharged by industrialists during hot periods (summer) are less hot, thus avoiding interruption or degradation of their production. As a result, positive ecological and economic effects can be achieved. Other advantages will be presented in the detailed description of the invention which follows.

  DESCRIPTION OF THE FIGURES The present invention is illustrated by non-limiting examples in the accompanying Figures, in which like references indicate similar elements: FIG. 1 schematically represents the operation of the system 10 according to the invention outside a period of heating; Figure 2 shows schematically the operation of the system according to the invention during a heating period; and Figure 3 shows schematically an alternative embodiment of the system according to the invention out of a heating period. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 schematically show the operation of the system according to the invention.

  Figure 1 illustrates a step of storing heat in the basement. Such a step occurs during a first period of time t1, that is to say out of a heating period, typically in summer and mid-season (autumn or spring). A heat source 11 may be any industry that produces heat in its operation, also called heat energy, in excess of CP. Generally the heat produced in surplus CP, that is to say not used and rejected by the industry during its operation, is lost. The excess heat is released into the environment E, that is, into the atmosphere, rivers, rivers, sewers, etc. As an example, an industry may be a plant 11A (garbage incineration plant, metallurgical plant, textile factory, glass plant, etc ....), a power plant 11B, a district heating plant 11C, or a co-generator 11D (the co-generator is visible in Figure 3). Typically, an industry can produce CP surplus heat throughout the year by pumping water from a river or river E to an inlet temperature Ti (about 20 C) to cool its facilities and rejecting R water in the river or river E at an outlet temperature Ts (of the order of 29 C) greater than a few degrees centigrade at the inlet temperature Ti. This rejection will warm the river downstream of the industry. Equally, a cooling tower releases hot air into the atmosphere. The underground heat storage system and surface heat recovery 1 according to the invention comprises a first storage exchanger 2, a second recovery exchanger 3, a first fluid circuit 7, a second fluid circuit 8, a diaper aquifer 5 and pumps 9, 10. The aquifer layer 5 is in the basement 6. The first storage exchanger 2 and the second recovery exchanger 3 are at the surface 4.

  The first fluid circuit 7 and the second fluid circuit 8 respectively couple the storage exchanger 2 and the recovery exchanger 3 to the aquifer layer 5. A first pump 9 is intended to set the fluid in motion in the first fluid circuit 7 A second pump 10 is intended to set the fluid in motion in the second fluid circuit 8.

  The first storage exchanger 2 is positioned between the excess heat source 11 and the environment, for example a river E, receiving the excess heat evacuated. Advantageously, the first storage exchanger 2 can be positioned in the heat source 11. In the case where the heat source 11 rejects the excess heat in a river, the first storage exchanger 2 is advantageously of the water / water exchanger type and is positioned, for example, at the cooling water discharge pipe of the industry concerned in the river. In the case where the heat source 11 rejects the excess heat in the atmosphere, the first storage exchanger 2 is advantageously of the air / water exchanger type and is positioned, for example, at the level of the cooling tower of the industry. concerned in the atmosphere. During the first period of time t1, a heat recovery step lying on the surface, and a storage step are implemented.

  The storage step comprises the transfer of heat from the surface 4 to the aquifer layer 5. The first pump 9 is actuated and the cold fluid is pumped from the aquifer layer 5. The excess heat lost brought by the heat source 11 is transferred to the cold fluid pumped from the aquifer layer 5 through the storage exchanger 2. Then the warm fluid (of the order of 28 C) is reinjected into the aquifer layer 5. Obviously, losses can intervening between the heat source and the aquifer so that the stored heat CS comes from the recovery of at least a portion of the lost heat CP by the heat source 11. In this way, the temperature of the aquifer layer 5 is increased and the heat is stored CS in the aquifer 5 during the first time period t1. The legislation may prohibit the storage of hot water in the basement, it is therefore necessary to control that the temperature of the water injected into the aquifer layer 5 does not exceed the authorized limit. Advantageously, a means for reducing the water temperature 13 may be positioned between the heat source 11 and the storage exchanger 2 when this is necessary (for example when the heat source is a power generation plant 11B , a district heating station 11C, or a co-generator 11 D).

  In this first period of time t1, the second fluid circuit 8 and the return exchanger 3 are normally inactive.

  Figure 2 illustrates a step of restitution of the heat of the subsoil. Such a step occurs during a second period of time t2, that is to say during a heating period, typically in winters and mid-season (autumn or spring). The heat is restored CR to a heat-consuming entity 12 during the second time period t2. The consuming entity may be a building, for example a greenhouse 12A, a house 12B, and / or a residential, office, storage, industrial or commercial building 12C. Advantageously, the recovery exchanger 3 is positioned in the heat-consuming entity 12. In the case where the heat-consuming entity 12 uses a hot water heating system, the second heat exchanger 3 is advantageously of the heat exchanger type. water / water. For example, a known water / water heat exchanger is a conventional heat pump. In the case where the heat-consuming entity 12 uses a forced-air heating system, the second heat exchanger 3 is advantageously of the water / air exchanger type. For example, a known water / air exchanger is marketed by Fiwihex and described in patent EP 0 714 500. In the second time period t2, a heat recovery step in the aquifer layer , and a restitution step are implemented. The recovery step comprises the transfer of heat from the aquifer layer 5 to the surface 4. The second pump 10 is actuated and the warm fluid (of the order of 26 C) is pumped from the aquifer layer 5 to the 3. The stored heat CS is transferred from the aquifer layer 5 to the heat-consuming entity 12 via the recovery exchanger 3. Then, the cooled fluid (of the order of 13 C) is reinjected into the aquifer layer 5. In this way, the temperature of the aquifer layer 5 is decreased and the stored heat is restored CR to the heat-consuming entity 12 during the second time period t2. In this second period of time t2, the first fluid circuit 7 and the storage exchanger 2 are normally inactive. Thus, significant energy savings can be achieved with a lack of additional carbon dioxide emissions into the atmosphere by reusing the stored heat that would have been lost at an opportune time. In addition, the energy consumption of the system is limited to the electricity consumption for the operation of the pumps and possibly the fans connected to the air / water exchangers. Finally, the system of the invention does not consume groundwater and does not cause pollution of the underground water of the aquifer. Advantageously, during the second time period t2, as much water will be pumped as that stored during the first time period t1 in order to return the aquifer layer to a temperature substantially equivalent to the original temperature.

  In addition, the heat actually released into the environment, for example in a river or river, is reduced which allows to maintain the production of the industry concerned whatever the outside temperature mainly in summer and not to deteriorate the flora and the wildlife of the environment.

  Alternatively (not shown), the first pump 8 and the second pump 9 could respectively be integrated in the storage exchanger 2 and refund 3. Also, lifting pumps (not shown) could be provided under -sol 6 at the aquifer, a first lift pump in relation to the first fluid circuit 7 and a second in relation to the second fluid circuit 8. In the example of Figures 1 and 2, the first storage exchanger 2 and the second heat exchanger 3 are coupled to the aquifer layer 5 by two separate fluid circuits 7 and 8. Nevertheless, as an alternative (not shown), the first storage heat exchanger 2 and the second heat exchanger 3 could be coupled to the aquifer layer 5 by a single fluid circuit. In this case, at least one valve would be provided for coupling the aquifer layer 5 to the first storage exchanger 2 or the second recovery exchanger 3 as a function of the period of time (storage or retrieval).

  Figure 3 shows schematically an alternative embodiment of the system according to the invention out of a heating period. In this variant, the heat source 11 is a co-generator 11 D coupled to a digester 14 supplying biogas. The purpose of the digester 14 is to destroy, in particular, waste (for example from cattle farmers, the food industry, sewage sludge, etc.) throughout the year. Typically, during the cogeneration of biogas, the heat is used during the second period of time t2 (heating period - winters) through a heating network. During the first period of time t1 (excluding heating period - summer), the heat is released into the environment. In the example of FIG. 3, the cogeneration generates a fluid at a temperature of the order of 80.degree. C. to 95.degree. C. which is transferred to a mixing tank 16 via a primary fluid circuit 15. The pool mixer 16 is the means for reducing the temperature of the fluid. It is positioned between the heat source 11 and the water / water type storage exchanger 2. It makes it possible to reduce the temperature of the water to a temperature allowing storage in aquifer, that is to say compatible with the legislation, for example less than 30 C. The mixing tank 16 is coupled to the water / water heat exchanger 2 via an intermediate fluid circuit 17. Finally, a water at a temperature of the order of 28 C is injected into the aquifer layer 5. The stored heat CS in the aquifer layer 5 may be reused during the next heating period through a water / water heat exchanger or a water / air exchanger as described above. The alternative embodiment of the system according to the invention makes it possible to use almost completely the heat produced by the co-generator in order to enhance it. In particular, during the heating period, the addition of the heat produced by the co-generator and that stored in the aquifer makes it possible to multiply the heating capacity practically by a factor of two. In some countries, this is particularly advantageous because the legislation provides for an energy efficiency bonus based on the heat recovery rate produced by the co-generator. The system and the method according to the invention make it possible to apply to the entire premium. Consequently, the operator of a co-generator integrated in the system of the invention can also obtain an optimized efficiency in terms of the sale of electricity and heat. Finally, the system presented above transforms the costly process of waste disposal into a revenue-generating process extended to the supply of electricity and heat distributable throughout the year.

  The figures and their descriptions made above illustrate the invention rather than limiting it. In particular, the invention has just been described in connection with particular examples of heat source and heat consuming entity.

  Nevertheless, it is obvious to one skilled in the art that the invention can be extended to other types of heat source and heat consuming entity.

  The particular example of hot water discharge in a river or river shown in Figure 1 and in the description is not limiting. The invention applies to the discharge of water or hot air by industry in the environment (atmosphere, river, river, sea, ocean, sewer, etc ....).

  Although the figures seem to show that the fluidic circuits inject and withdraw water into the aquifer at identical depths, the injection and the sampling can be done at very different depths. The reference signs in the claims are not limiting in nature. Verbs understand and include do not exclude the presence of elements other than those listed in the claims. The word one preceding an element does not exclude the presence of a plurality of such elements.

Claims (10)

  1. A subsurface heat storage system and surface heat recovery (1) comprising a first storage exchanger (2) and a second recovery exchanger (3) located at the surface (4), an aquifer (5) located in the basement (6), at least one fluidic circuit (7, 8) coupling the exchangers (2, 3) to the aquifer layer (5), at least one pump (9, 10) for putting in motion a fluid in the fluid circuit (7, 8), the heat being stored (CS) in the aquifer layer (5) during a first period of time (t1), the heat being returned (CR) to a consumer entity of heat (12) for a second period of time (t2), the system (1) is characterized in that the first storage exchanger (2) is positioned between an excess heat source (11) and the environment (E) receiving excess heat, the stored heat (CS) from the recovery of at least a portion of the lost heat (CP) by the a heat source (11).   2. The underground heat storage and surface heat recovery system according to claim 1, wherein the surplus heat source (11) lost is a plant (11A), or a power generation plant ( 11 B), or a district heating plant (11C), or a cogenerator (11 D).   3. The subsurface heat storage system and surface heat recovery according to one of the preceding claims, wherein the first storage exchanger (2) is of the water / water exchanger type.   4. The system of underground heat storage and surface heat recovery according to the preceding claim, wherein a means for reducing the water temperature (13) is positioned between the heat source (11) and the water / water exchanger (2). 11   5. The underground heat storage system and surface heat recovery according to the preceding claim, wherein the means for reducing the water temperature (13) is a mixing basin (16).   6. The subsurface heat storage system and surface heat recovery according to one of the preceding claims, wherein the recovery exchanger (3) is positioned in the heat-consuming entity (12), consuming entity being a building (12A, 12B, 12C).   7. The subsurface heat storage system and surface heat recovery according to one of the preceding claims, wherein the second heat exchanger (3) is of the water / air exchanger type.   8. The underground heat storage system and surface heat recovery according to one of claims 1 to 7, wherein the first storage heat exchanger (2) and the second heat exchanger (3) are coupled to the aquifer layer (5) by two separate fluid circuits (7, 8).   9. The underground heat storage system and surface heat recovery according to one of claims 1 to 7, wherein the first storage heat exchanger (2) and the second heat exchanger (3) are coupled to the aquifer layer (5) by a single fluid circuit and a valve for coupling the aquifer layer to the first storage exchanger or the second recovery exchanger.   10. A method of underground heat storage and surface heat recovery comprising the following steps: - a heat recovery step located on the surface, - a storage step comprising the transfer of heat from the surface to an underground aquifer layer, the heat being stored for a first period of time, and a stored heat recovery step comprising transferring a portion of heat stored in the aquifer layer to the surface, the stored heat being restored for a second period of time, the method is characterized in that the heat recovered at the surface 5 corresponds to at least a part of a heat lost by a surplus heat source.