阅读说明：本技术 用于热井的最佳能量存储和重获的装置和方法 (Apparatus and method for optimal energy storage and recovery for thermal wells ) 是由 A·科斯基-拉科嫩 于 2018-11-28 设计创作，主要内容包括：本发明涉及一种用于热井的最佳能量存储和重获的装置和方法。这种装置由地下的中心储器(2,12)和以基本上同心且圆形的方式围绕中心储器的孔井(3)构成,其中存在两个或更多个这样的圆形部(4)。中心储器井和孔井布置成通过管线(6)彼此流动连通并且与一个或多个热源(9)流动连通,从而将热能引导至系统,所述圆形部设有阀(8),以便将传热流体依次引导至一个圆形部或圆形部的一部分。(The present invention relates to an apparatus and method for optimal energy storage and recovery for a thermal well. Such a device is constituted by a central reservoir (2, 12) underground and a bore well (3) surrounding the central reservoir in a substantially concentric and circular manner, wherein two or more such circular portions (4) are present. The central reservoir well and the bore well are arranged in flow communication with each other and with one or more heat sources (9) through a line (6) for conducting thermal energy to the system, said circular portion being provided with a valve (8) for conducting the heat transfer fluid to one circular portion or a part of a circular portion in turn.)

1. An apparatus for optimal energy storage and recovery for a thermal well,

the device comprises:

a central reservoir (2, 12) below ground,

surrounding the bore well (3) of the central reservoir (2, 12) in a substantially concentric manner, there being two or more circular portions (4), wherein

The central reservoir (2, 12) and the bore well (3) are arranged in flow communication with each other by means of a line (6) and with one or more heat sources (9) directing thermal energy to the system,

the circular portions (4) are provided with valves (8) controlled by a control unit (7) to direct the heat transfer fluid to one circular portion in turn,

it is characterized in that

The bore wells (3) along the circular portion (4) are connected in groups by the lines (6) such that the groups from a sector (S) surround the central reservoir (2) in a circular manner and receive thermal energy, respectively.

2. The device according to claim 1, characterized in that the central reservoir (2) comprises a closed storage tank (12) formed by a central well, which storage tank is advantageously an underground storage tank.

3. The apparatus according to claim 2, wherein the storage tank (12) formed by the centerwell is insulated from its surroundings by an insulating material.

4. A method for optimal storage and retrieval of a hot well, wherein,

thermal energy collected into the heat transfer fluid from one or more heat sources (9) is conducted via a line (6) to a central reservoir (2, 12) in the ground and further to the well bores (3) which are in fluid communication with the central reservoir and which are arranged in a substantially circular manner such that

Proceeding from the central reservoir (2, 12) and along the outermost circle to the well, transferring thermal energy to one well (3) and the circle (4) of the circle of wells in sequence,

it is characterized in that

Directing the heat transfer fluid first to the central reservoir (2, 12) and then from the central reservoir further to one well, group of wells or circle (4), proceeding to the well along the radially outermost circle,

-continuously comparing the temperature of the heat transfer fluid generated by the heat source (9) with the prevailing temperature of the various portions of the regenerator,

Directing the heat transfer fluid to the regenerator section when the temperature of the heat transfer fluid exceeds the prevailing temperature of the regenerator section encountered to even out the temperature difference, and

the heat transfer fluid continues to be sequentially delivered to the well bore at a portion of the circular portion or radially outward of the circular portion.

5. The method of claim 4, wherein the heat transfer fluid is formed by extending the heat transfer fluid to a heat exchanger (10) connected to a heat source.

6. The method according to claim 4, wherein the heat transfer fluid is formed by a storage fluid in the central reservoir (2, 12).

7. A method according to any of claims 4-6, characterized in that the heat transfer fluid is led to the hole well (3) one circular portion (4) and its sector (S) in turn, wherein,

when each outermost circular sector has reached its target temperature according to the set temperature profile, a move occurs to heat the next adjacent sector (S).

8. Method according to claim 7, characterized in that the central angle of the sector (S) can be set from 15 to 90 degrees.

9. Method according to claim 8, characterized in that the central angle of the sector (S) can most advantageously be set from 45 to 60 degrees.

10. Method according to any of claims 4-9, characterized in that thermal energy is extracted from the heat accumulator (1) by leading a heat transfer fluid mainly to the pored round part with the coldest heat content.

Technical Field

The present invention relates to a device according to claim 1, by means of which the subsurface heat well used as a heat accumulator can be replenished and harvested with optimum thermal economy.

The invention also relates to a method according to the preamble of claim 4, by means of which such an optimal storage and retrieval can be achieved.

Background

The storage of thermal energy is becoming more and more important so that the feasibility of the solar potential can be further improved. In northern latitudes, particularly in countries such as northern european countries and the northest region of the united states, where solar energy is typically only available in summer and the demand for heating is highest in winter, making feasible storage important. Over the past few decades, various techniques for storing thermal energy have been the subject of much research. In the above work, most of the experience of use is obtained from storing energy and utilizing geothermal heat from a hole well formed in a bedrock.

In geothermal systems, the bedrock surrounding the hole wells will cool down by about 3 degrees over a long period of normal loading. By directing the excess heat generated in the heating system to the bedrock, it is possible to reduce the amount of energy harvested from the thermal energy naturally present in the bedrock, so that the temperature of the bedrock can be maintained or even increased. In this way, the so-called heat recovery COP can be improved.

Wellbore thermal energy storage (BTES) is commonly used to store heat in rocky soils and soil layers. The depth of the bore wells used in such systems in bedrock regenerators is typically about 100 to 150 meters. In the soil layer, the depth of the bore hole depends to a large extent on the quality of the soil layer. The thermal energy storage of the well may be referred to as an "open" or "closed" storage, in which a heat transfer fluid circulates in a closed circuit (surface heat exchanger-GHX) in which heat is transferred to the soil layer or bedrock by conduction through the walls of the tubes installed in the closed circuit. One such solution is shown in patent publication US 2010/0307734. In open bore hole thermal accumulators, which may be implemented in bedrock, the water circulating in the system is in direct contact with the rock walls of the bore holes. It has been noted that the heat transfer efficiency of an open well regenerator is superior to that of a closed well regenerator. However, due to the metal And solids dissolved in water, chemical problems may arise in open systems, see, for example, Nordell, B.&M., (2006), Solar Energy and HeatStorage.

For example, research on such well-bore heat accumulators has been conducted in Ocotoko, Alberta, Canada, where a Drake Landing solar community was established in this area in 2007, with excess solar energy harvested in summer being stored underground.

Disclosure of Invention

It is therefore an object of the present invention to develop a device and a method using such a device such that the above problems can be solved to the maximum extent. The object of the invention is thus achieved by a method and a system which are characterized by what is disclosed in the characterizing parts of the independent claims 1 to 4. Preferred embodiments of the invention are disclosed in the dependent claims.

The basic idea of the invention is that by monitoring the temperature in different parts of the bore-well regenerator, it is possible to heat mainly said parts of the regenerator in case the temperature falls below a separately definable threshold.

With the present invention, significant advantages over the prior art can be achieved. The system according to the invention thus allows, for example, to utilize thermal energy without a specific heat exchanger. Since the temperature in the various sections of the heat accumulator is well known, the circulating fluid of the heating system connected thereto can be led to the exact area of the heat accumulator from which the target amount of energy can be harvested.

The storage of energy is more efficient because the system of the invention continuously monitors the temperature in different parts of the thermal storage and mainly heats said parts of the thermal storage in case the temperature has dropped below a separately definable threshold. The thermal energy directed to the system always reaches the part of the heat accumulator that is able to receive the transferred thermal energy.

Since it is possible to efficiently utilize the energy content delivered to the regenerator, it is also possible to avoid the need to connect different types of temporary or buffer regenerators to the system, which tends to increase the cost of the well thermal energy regenerator.

By connecting the wells of the system to independently controllable sectors, the number of lines required by the system can be greatly reduced while the flow pressure of the carrier fluid in the lines in the bore wells and in the accumulator is made uniform. Such an arrangement also allows for a simplified heat distribution system, better heat storage and recapture.

Further advantages of the invention will appear from the following more detailed description of particular embodiments of the invention.

Drawings

In the following, some preferred embodiments of the invention will be explained in more detail with reference to the drawings, in which

Figure 1 is a flow chart of a first embodiment of the apparatus,

fig. 2 shows a variant of the embodiment of fig. 1, showing a schematic positioning of the bore well and its pipelines during its execution,

figure 3 is an example of an implementation where the flow is performed in a bore well,

fig. 4 shows a second variant of the embodiment of fig. 1, showing a fan-shaped coupling of the bore hole and its pipelines,

FIGS. 5a and 5b are flow diagrams of different embodiments of the apparatus, an

Fig. 6 shows a schematic positioning of the storage tank and the bore well in the embodiment of fig. 5a and 5 b.

Detailed Description

The present drawings are not to scale and are schematic in nature, illustrating the general construction and operation of a preferred embodiment. The structural components denoted by reference numerals in the drawings then correspond to the structural components denoted by reference numerals in the present specification.

A first embodiment of the device according to fig. 1 and 2 comprises a regenerator 1 having a central reservoir 2 surrounded by a well 3 arranged in a circular manner. In this embodiment, it is advantageous to arrange the circular portions substantially concentrically, wherein there are two or more circular portions 4. Figure 1 shows, by way of example, three circular portions, and figure 2 shows two circular portions surrounding a central reservoir. As shown in fig. 1, there is one well in the middle of the field forming the central reservoir and surrounded by a circle with 6 wells, the next circle having 12 wells and the outermost circle having 18 wells, only a portion of which is shown in this figure. In fig. 2, on the other hand, there are 7 well forming a central reservoir in the middle of the field, surrounded by a circular portion having 12 wells and 18 wells. Obviously, there may be more wells for the circular portion, and there may be only two circular portions or more than three circular portions as desired. Furthermore, according to the figure, the circular portion need not be a circular portion, but a more organized shape is also an option. The number of rounds depends primarily on the amount of energy that can be transferred to the system from the solar collector or other suitable heat source connected thereto.

Advantageously, the above-mentioned hole wells are drilled not more than 60 meters deep, at least in the bedrock of finland. The reason is that the water flow in the bedrock is significantly stronger and deeper than this. For the reasons mentioned above, the uncontrolled heat dissipation from the bore hole to its surroundings becomes so high at deeper depths that the thermal energy directed to the bore hole will be largely lost. When the device is used under conditions other than soil and bedrock in finland, the geothermal properties at each location must be checked to ensure a favourable drilling depth. In the tests performed, the hole well has been drilled in finland using a fairly common drill bit, i.e. 140 mm in diameter on the soil layer above the rock and 115 mm in diameter in bedrock. The hole diameter of the hole well is substantially influenced by the construction of the commercially available collector to be installed in the hole well, so other hole sizes can be successfully used.

Collectors 5 installed in the bore are arranged in fluid communication with each other by means of a line 6 to form a closed flow circuit. The path of this flow can be controlled mainly by valves 8 fitted in each circular section and regulated by the control unit 7. Of course, each bore well 3 may also be equipped with its own valve, whereby both the circular portion 4 and the individual bore well 3 may regulate the flow precisely. As shown in fig. 1, in this embodiment there are two parallel lines fitting along each circle, one line having a collector input flow connected thereto and the other line having a collector output flow connected thereto, see also fig. 3. In this way, the bore wells along the same circular portion are connected in parallel with each other, so that it is possible to guide warm carrier fluid along the pipeline to each bore well separately. In the present embodiment, the above-mentioned carrier fluid is called a heat transfer fluid, the purpose of which is to heat the regenerator 1 around the bore well.

The bore wells 2, 3 according to the present embodiment and the solar collectors or other heat sources 9 connected to the system may even utilize a common flow system. Thus, the entire system may use the same heat transfer fluid, such as propylene glycol. This may avoid the use of one or more heat exchangers 10 that would otherwise be installed between the well and the heat source.

The arrangement of fig. 1 and 2 functions such that thermal energy is stored in a known manner into the heat transfer fluid from a solar collector or another heat source 9 (such as for example industrial waste heat) of a system suitable for this purpose. This heat energy is mainly used for heating the real estate 11 or similar connected to the system and/or for producing domestic hot water. After the primary use, the thermal energy remaining in the heat transfer fluid is conducted to the regenerator 1 according to the present embodiment. In this case, the thermal energy is transferred to the central reservoir 2 and the well 3 arranged around the central reservoir. In the embodiment according to fig. 1, the central reservoir comprises one well, whereas in the embodiment of fig. 2 the central reservoir comprises a plurality of wells. When the temperature at the central reservoir reaches the temperature of the heat transfer fluid, further thermal energy transfer is initiated for the wells and/or sectors and/or circles in sequence, starting from the well on the innermost circle and then proceeding along the outermost circle to the well. The flow of the heat transfer fluid is controlled by means of a control unit 7 and a conventional gate and three-way valve 8, which conventional gate and three-way valve 8 opens the flow path to the circle, sector or even a single well one after the other.

Thus, most of the thermal energy is stored in the central reservoir 2 of the heat accumulator 1, which thus obtains the highest temperature value. The temperature values of the bore wells 3 are allowed to gradually decrease as the radial distance from the central reservoir increases. Thus, the temperature values measured in the outermost peripheral wells of the device in question are significantly lower than the temperature measured in the central reservoir. The heat distribution according to the nature of the gaussian curve in the heat accumulator 1 ensures that the central reservoir can always be kept sufficiently warm. At the same time, maintaining the temperature of the central reservoir is achieved by as little heat transfer as possible.

Thus, the heating of the central reservoir 1 has proceeded to the outermost circular part, the device starts to maintain the thermal energy storage formed by the central reservoir 2 and the hole wells 3 surrounding the circular part 4 of the central reservoir. In this case, the control unit 7 continuously compares the temperature of the heat transfer fluid from the heat source with the temperature of the well, the circle or a part of the circle in question. When the temperature of the arriving heat transfer fluid exceeds the prevailing temperature of the regenerator portion encountered, the valve 8 is opened and the arriving heat transfer fluid is first directed to the regenerator portion. Thus, the portion of the regenerator radially outward from the center of the regenerator (i.e. the hole well or set of hole wells) is heated, which itself has a lower temperature than the arriving heat transfer fluid. The transfer of thermal energy contained in the heat transfer fluid then continues radially outward to the circular portion or a portion of the circular portion in sequence. This establishes a heat distribution which is as uniform as possible, wherein the central part of the regenerator is always hottest, wherein the temperature decreases uniformly towards the outer edge of the regenerator. This uniform heat distribution ensures maximum and temporarily longest thermal energy storage.

The heat profile maintained in the regenerator 1 depends on the geothermal characteristics of the bedrock or soil layer and, in a particular embodiment of the apparatus, this heat profile, together with the amount of thermal energy from one or more heat sources 9, forms the temperature profile of the regenerator. Such a temperature profile then forms the basic setting for the control unit 7. By controlling the valve 8 of the regenerator, the control unit changes the flow of the heat transfer fluid according to the temperature profile to the well 3 or group of wells that is optimal from the point of view of storage. During the storage process, the carrier fluid cup leads to an orifice well radially outward from the central reservoir of the regenerator. When the temperature of the arriving heat transfer fluid exceeds the prevailing temperature of the regenerator portion encountered, the carrier fluid is directed to that regenerator portion to increase its temperature to match the set temperature profile.

The heating of the central reservoir 1 has thus proceeded to the outermost circle, the device starting to maintain the thermal energy storage formed by the central reservoir 2 and the well 3 surrounding the circular portion 4 of the central reservoir. In this case, the control unit 7 continuously compares the temperature of the heat transfer fluid from the heat source with the target temperature of the bore well, the circular portion or a part of the circular portion in question. When the temperature of the arriving heat transfer fluid exceeds the prevailing temperature of the regenerator portion encountered, the valve 8 is opened and the arriving heat transfer fluid is first directed to the regenerator portion. In this embodiment of the device, the regenerator is also heated radially outward from the center by directing the heat transfer fluid to the regenerator section (i.e., the well or set of wells that have their own temperature lower than the temperature of the arriving heat transfer fluid). Thereafter, the transfer of thermal energy contained in the heat transfer fluid continues radially outward to the circular portion or a portion of the circular portion in sequence.

Fig. 2 depicts a second preferred embodiment of the device. Where the pipeline 6 is not adapted to surround the bore hole 3 only in a circular manner, but the circular portion is divided into sectors which are served by dedicated pairs of pipelines. With this arrangement, the distribution of heat transfer fluid to the desired well can be well controlled more quickly and accurately. By such an arrangement, heat transfer between the heat transfer fluid and the storage field is also more easily achieved on a sector basis. One of such sectors is schematically shown in fig. 2 with reference sign S. The size of the sectors may vary and they have a central angle of about 15 to 180 degrees, advantageously 45 to 60 degrees. As above, starting from the first part of the circular portion of the regenerator 1, where the temperature is lower than the temperature of the arriving heat transfer fluid, the thermal storage field is heated radially from the center of the regenerator towards the outside. The transfer of thermal energy to the heat accumulator thereafter continues in the sector radially outwards in turn to the circular portion or to a part of the circular portion. When the outermost circular sector has reached its target temperature, heating of the next adjacent sector is started. Based on this study, it was possible to achieve even higher heat transfer efficiencies than the alternative of directing the heat transfer fluid to all the well bores along the same circular portion at the same time.

The control unit 7 of the present device may also be adaptive. When the regenerator 1 is heated, the aim is to increase the temperature of each hole well, round or part of a round to match as good as possible a predetermined target temperature dictated by the basic settings of the control unit 7.

In this case, adaptability means that the control unit 7 of the device continuously monitors the energy received by the regenerator 1, the whole regenerator or part of the regenerator. The task of the control unit is therefore to always keep the amount of energy received by the heat accumulator as large as possible. This results in the flow of heat transfer fluid being directed to the next sector, for example when the temperature difference between the heat transfer fluid supplied to the sectors of the regenerator and the heat transfer fluid returned therefrom is below a preset threshold. However, the goal is to switch from one sector to the next so that the amount of energy received is always as high as possible.

Heating of the real estate 11 traditionally connected to the system and the production of hot water can be accomplished by utilizing the above-described solar collectors or other heat sources 9 connected to the system. In particular, in autumn and winter, the amount of thermal energy generated by solar collectors is generally too small, requiring additional heat sources. In this case, thermal energy can be retrieved from the heat accumulator 1 designed as described above. Thus, instead of directing the heat transfer fluid containing excess heat into the regenerator, heating of the cooler heat transfer fluid circulating therein is initiated. When utilizing the energy content of the regenerator, the process is carried out in the reverse order with respect to the previous process, i.e. the heat transfer fluid is first led in the device to the coldest hole or group of holes in terms of its heat content, from which it continues radially towards the center of the regenerator, advantageously to the circular portion 4, a part of the circular portion or the hole wells 2, 3 in turn.

When the temperature of the heat accumulator 1 is significantly higher than the heat source 9 for heating the real estate 11 and producing hot water, a significantly better efficiency than before can be obtained for the heat exchanger 10 of the real estate 11.

In the embodiment of FIG. 2, the sector control is implemented primarily with valves for a given well. A second, simpler preferred embodiment of the device is realized by the embodiment according to fig. 4. In this case the bore wells 3 are connected in separate groups by means of pipelines 6. These individually controlled groups form a sector S which surrounds the central reservoir 2 in a circular manner. In the exemplary embodiment of the figure, there are four sectors around the central reservoir along one circular portion 4. With such an arrangement, heat transfer between the heat transfer fluid and the storage field is even more easily achieved through the sectors. Also in this embodiment, the size of the sectors formed by the implemented group of wells may vary, with a central angle of about 15 to 180 degrees. In the embodiment according to the figures, the central angle of the sectors is 90 degrees. As above, starting from the first part of the circular portion of the regenerator 1, which is at a lower temperature than the temperature of the arriving heat transfer fluid, the storage field is heated radially outwards from the center of the regenerator. Thereafter, the transfer of thermal energy to the regenerator continues radially outward to the sectors and the circular portion in sequence.

In a fourth preferred embodiment according to fig. 5a, 5b and 6, an arrangement has been provided in which the central reservoir 2 is formed by a closed and advantageously underground storage tank 12. In the embodiment of the figures the tank is surrounded in a substantially concentric and circular manner by the bore well 3, with two or more circular portions 4. Of course, the location of the bore wells may be different from that disclosed without any major disadvantages for the operation. In this embodiment, the volume of the storage tank replacing the innermost bore well or the central reservoir formed by the innermost bore well of fig. 2 or 4 may vary in size from a few cubic meters to tens or even hundreds of cubic meters. In the tests carried out it has been found that: a small tank (advantageously 3 to 4 cubic meters) produces sufficient buffer heat storage up to the parallel 63 rd heat accumulator. In this case, the tank is advantageously completely insulated by conventional insulation material to avoid unnecessary heat losses.

Fig. 5d and 6 show by way of example three circular portions 4 surrounding the storage tank 12, the innermost circular portion having six hole wells 3, the central circular portion having 12 hole wells and the outermost circular portion having 18 hole wells. Obviously, there may be more wells for one circular portion, and there may be only two circular portions, or on the other hand more than three circular portions, as desired. The number of rounds and the size of the centerwell are primarily dependent on the amount of energy that can be transferred to the system from the solar collectors or other heat sources connected thereto.

The bore wells 3 are arranged in fluid communication with each other by means of a pipeline 6. As mentioned above, the collectors 5 installed in the bore wells are arranged in flow communication with each other by means of a line 6 to form a closed flow circuit, see also fig. 3. The routing of this flow can be controlled mainly by valves 8 adapted to each circuit and regulated by the control unit 7. As shown in fig. 5b and 6, there are two parallel lines in each circle, one with a collector input flow connected thereto and the other with a collector output flow connected thereto. Thus, the wells along the same circular portion are connected in parallel with each other. The course of the flow may be controlled mainly by a shutter (shutter) and a three-way valve fitted in each circular portion. In this way it is possible to lead warm carrier fluid along the pipeline to the bore well, with the purpose of heating the heat accumulator surrounding the bore well. Of course, each bore well may also be equipped with its own valve, so that the circular portion, a part of the circular portion and the individual bore well 3 may all regulate the flow precisely.

The system operates such that the carrier fluid in the tank 12, referred to in this embodiment as the storage fluid, which may be ordinary (ground) water, is heated by thermal energy obtained from an external heat source, as described above. In order to transfer heat to the storage fluid in the tank 12, a first heat exchanger coil 13 and its pump 14 have been fitted therein. If the storage fluid in the tank is heated by means of a plurality of heat sources 9 generating thermal energy, a dedicated heat exchanger needs to be arranged in the tank for each heat source.

When the temperature of the fluid stored in the tank 11 exceeds the target temperature according to the predetermined thermal profile, thermal energy originating from the heat source 9 is directed along the next circle to the well or group of wells. In this case, the transfer of the energy generated by the solar collectors from the tank by means of the pump 15 is started, for example, by: for example, the transfer to the circularly arranged hole wells takes place by means of the storage fluid starting from the innermost circular portion and proceeding to the outermost circular portion in sequence along the line 6, but continuously maintaining the temperature of the already heated regenerator.

When the heating has proceeded to the outermost circular part 4, the system starts to maintain the thermal energy accumulator 1 formed by the storage tank 12 and the bore well 3. In this case, the temperature of the stored fluid in the tank is continuously compared with the temperature prevailing in each well or group of wells. The comparison is always carried out with one well or a group of wells in succession, the storage field proceeding radially outwards from the centre. When the current temperature of the first part of the accumulator encountered is lower than the temperature of the storage fluid in the tank, the valve 8 is opened, so that the storage fluid is led to this part of the accumulator. Thereafter, the transfer of thermal energy to the bore hole continues radially outward to the bore hole or the circular portion in sequence. Thus, the regenerator portion, which is radially outward from the center of the regenerator, has its own temperature lower than the temperature of the storage fluid in the tank, is always heated. This will establish a heat distribution which is as uniform as possible, in which the storage fluid of the centrally located tank is always hottest, with the temperature decreasing uniformly towards the outer edge of the heat accumulator. This uniform heat distribution ensures the widest possible storage of thermal energy.

Also in this embodiment it is obviously possible to apply the above-described arrangement, wherein the heat transfer fluid is led to the well, the circular portion and its sectors in sequence. The size of the sectors may vary, the central angle of the sectors being approximately 15 to 180 degrees, advantageously 45 to 60 degrees. Also in this embodiment, starting from the part of the circular portion of the regenerator whose temperature is lower than the temperature of the storage fluid in the tank, the storage field is thus heated radially outwards starting from the center of the regenerator. The transfer of thermal energy to the heat accumulator thereafter continues in the sector radially outwards in turn to the circular portion or a part of the circular portion. When the outermost circular sector has reached its target temperature, heating of the next adjacent sector is started.

Conventionally, heating of the real estate 11 and the generation of hot water may be achieved by utilizing the above-described solar collectors. Especially in autumn and winter the amount of thermal energy generated by the solar collectors is too small and requires additional heat sources. In this case it is possible to recover heat energy from the heat accumulator 1, the temperature of which heat accumulator 1 is significantly higher than the heat source 9 for heating the real estate 11 and producing hot water, which substantially increases the efficiency of the real estate heat exchanger 10. In an embodiment of the device the transfer of thermal energy takes place such that when the temperature of the storage fluid in the tank 12 drops below a certain set value, a flow controlled by the pump 15 is started between the tank 12 and the hole wells 3, whereby thermal energy is transferred from the heat accumulator by the storage fluid flowing back to the tank one after the other from a hole well or group of hole wells arranged in a circular manner.

On the other hand, the temperature of the stored fluid in the tank 12 may be increased by a heat pump 16 connected to the tank. Advantageously, the same heat pump is used to heat the real estate and produce hot water in the manner mentioned above.

Those skilled in the art will find that: it is obvious that with the advancement of technology, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.