Patent Application
20200096262
The invention relates to a latent heat storage system having a latent heat storage device and to a method for operating a latent heat storage system.
From EP 2614330 A1, an ice storage system is known, in which an extraction heat exchanger extracts heat from an ice storage device during the healing period, until the ice storage device is thermally unloaded. During the thermal unloading, a predetermined volume around die extraction heat exchanger has completely solidified into ice. This occurs in a controlled manner. The water around the heat exchange pipes of the extraction heat exchanger solidifies in a targeted manner from the inside to the outside. In order to reload the ice storage device, after the heating period, heat is introduced into the ice storage device via a regeneration heat exchanger. In the process, the ice around the extraction heat exchanger likewise thaws again in a targeted and directed manner. The hydraulic circuits for the extraction and for the regeneration have to be strictly separated in order to avoid an uncontrolled thawing or freezing, which makes the ice storage device uncontrollable and in the most disadvantageous case can damage or even destroy the heat exchanger pipes due to the chipping off of ice.
It is desirable to create a latent heat storage system which has an increased efficiency.
It is also desirable to create an advantageous method for operating such a latent heat storage system.
The invention starts, according to an aspect thereof, from a latent heat storage system which comprises at least one latent heat storage device which contains a storage medium with latent heat, at least one extraction circuit by means of which, during normal operation, in accordance with the intended purpose, heat can be removed from the storage medium, and at least one regeneration circuit by means of which, during normal operation, in accordance with the intended purpose, heat can be supplied into the storage medium. The at least one latent heat storage device comprises at least one extraction heat exchanger which is in contact with the storage medium and can be connected to the extraction circuit, and at least one regeneration arrangement within the storage medium, which can be connected to the regeneration circuit.
It is proposed that a coupling device is provided, by means of which at least temporarily the at least one extraction heat exchanger can be coupled to the at least one regeneration arrangement for common heat extraction from the storage medium or for common heat supply into the storage medium.
“Heat which can be extracted from the storage medium in accordance with the intended purpose” should be understood to mean that, during normal operation, the extraction heat exchanger extracts heat from the storage medium and cools said storage medium in the process. Preferably, heat can be extracted until the thermal unloading of a region around the extraction heat exchanger. This is the case during normal operation, for example, in winter. From the beginning of the cold season to the end of the cold season, the volume around the extraction heat exchanger solidifies gradually. In the case in which water is used as storage medium, a monolithic ice block forms in a controlled manner, in which the extraction heat exchanger is embedded. The heat transfer from the storage medium into the heat carrier medium in the extraction heat exchanger occurs via the monolithic ice block. In the extraction circuit, the extraction heat exchanger is preferably connected to a heat pump, which raises the extracted heat to a higher temperature level which can be used by a consumer. A typical heat carrier medium in the extraction circuit can be, for example, a sol or a glycol-water mixture.
“Heat which can be supplied into the storage medium in accordance with the intended purpose” should be understood to mean that, during normal operation, the regeneration arrangement releases heat into the storage medium and heats said storage medium in the process. As a result of the heat supply, the thermally unloaded latent heat storage device can be loaded and/or a thermal unloading can be delayed. Preferably, the solidified region around the extraction heat exchanger is thawed again. This is the case during normal operation, for example, in summer. Preferably, from the beginning of the warm season to the end of the warm season, the solidified volume around the extraction heat exchanger liquefies gradually in a controlled manner, wherein the extraction heat exchanger embedded therein is exposed again. In the case of water as storage medium, the monolithic ice block is thaw ed in a controlled manner. The heat transfer from the heated storage medium into the heat carrier medium in the extraction heat exchanger occurs via the melting monolithic ice block. If heat continues to be supplied via the regeneration arrangement, the temperature of the storage medium rises correspondingly.
The regeneration arrangement is advantageously connected in the extraction circuit to one or more heat sources. Advantageously, a heat source is an air-source collector which collects heat from the environmental air. Optionally, heat sources such as exhaust heat from refrigeration machines, exhaust air from refrigerators and the like can be connected alternatively or additionally at least temporarily. A typical heat carrier medium in the regeneration circuit can be, for example, a sol or a glycol-water mixture. This is preferably the case when the regeneration arrangement is a heat exchanger. Alternatively, an “open” regeneration arrangement can be provided, in which, at least in a section of the regeneration circuit, the storage medium itself is used as heat carrier medium, and the regeneration arrangement has one or more outlets for the heat carrier medium into the storage medium and one or more inlets for the storage medium into the regeneration circuit. In the regeneration circuit, advantageously, a heat exchanger can be arranged, which transfers heat from one or more heat sources to the heat carrier medium circulating in the section of the regeneration circuit, formed by the storage medium.
As long as solidified storage medium is present in the latent heat storage device, or as long as the storage medium is still sufficiently cold, it is possible to cool via the regeneration circuit. For example, in summer, a residence can be cooled. The cold heat carrier medium in the regeneration circuit can cool, for example, a residential area via a heat exchanger.
The at least one extraction heat exchanger and the at least one regeneration arrangement are adjusted to one another, so that a seasonal thawing and solidifying of the storage medium can occur in a manageable manner. The extraction circuit and the regeneration circuit are here necessarily hydraulically separated.
Advantageously, according to the invention, nevertheless in certain operating phases with connecting together, in particular with a series connection or a parallel connection, of extraction heat exchanger and regeneration arrangement, a common heat extraction or a common heat supply by means of extraction heat exchanger and regeneration arrangement can occur. Preferably, the heat pump of the extraction circuit is not in operation in these operating phases. In particular, in the operating phases, no solidified storage medium or only very little is present in the latent heat storage device. Here, in a coupled arrangement, the same heat carrier medium of the at least one extraction heat exchanger and of the at least one regeneration arrangement can flow through the components, or an indirect coupling can be provided, in which the heat of one heat carrier medium is transferred, for example, via a heat exchanger, to the other heat carrier medium. The heat exchanger is used as system separation between the different heat carrier media, preferably when an “open” regeneration arrangement is provided.
With the coupling according to the invention, in the operating phases, it can advantageously be achieved that, phase-wise, more heat can be made available to the latent heat storage device, and said latent heat storage device can be regenerated more rapidly, or, if reinforced cooling is necessary, the increased cooling demand can be met. Thus, for example, in midsummer, it is possible to cool advantageously and efficiently from the latent heat storage device. As needed, the storage medium can be regenerated in a targeted more rapid manner by heat supply in regeneration arrangement and extraction heat exchanger. Depending on the demand for cooling or regeneration, the coupling can occur accordingly.
According to an advantageous embodiment, the coupling device, for at least temporary common heat extraction from the storage medium, can connect the at least one regeneration arrangement of the regeneration circuit and the at least one extraction heat exchanger jointly to a heat source, or, for temporary common heat supply into the storage medium, the coupling device can connect the at least one extraction heat exchanger and the at least one regeneration arrangement of the at least one regeneration circuit jointly to a heat sink. The heat sink can be an air-source collector device which absorbs heat from the environmental air. Optionally, heat sources such as exhaust heat front refrigeration machines, exhaust air from refrigerators and the like can be connected alternatively or additionally at least temporarily as heat source. The heat sink can be, for example, an ice storage device. The storage medium can be heated more rapidly.
According to an advantageous embodiment, the at least one regeneration circuit can have a regeneration heat exchanger as regeneration arrangement. In particular, the heat carrier media from extraction heat exchanger and regeneration heat exchanger can be led, for common heat removal from the storage medium, or for common heat supply into the storage medium, into a common supply line to the heat source or to the heat sink. Advantageously, in a series connection of extraction heat exchanger and regeneration heat exchanger, the heat carrier medium can flow in series through the two heat exchangers. In an advantageous parallel connection of regeneration arrangement and extraction heat exchanger, the heat carrier media can be mixed with one another downstream of the heat exchanger.
Alternatively, the regeneration arrangement of the at least one regeneration circuit can have the storage medium as heat carrier medium, and, for common heat extraction from the storage medium or for common heat supply into the storage medium, can be coupled via a heat exchanger in the regeneration circuit with the heat carrier medium of the at least one extraction heat exchanger. In this case, the regeneration arrangement can be open toward the storage medium, and, in particular, it can have one or more outlets and one or more inlets for the heat carrier medium in the form of the storage medium.
The heat exchanger in the regeneration circuit is advantageously used as separation between different heat carrier media in the regeneration circuit. A contamination of the storage medium in the case of temporary coupling of regeneration arrangement and extraction heat exchanger can be avoided.
According to an advantageous embodiment, the coupling device can comprise a mixing element that can be closed-loop and/or open-loop controlled. This is advantageous particularly for a parallel connection of the at least one extraction heat exchanger and the at least one regeneration arrangement. The quantities of the heat carrier media which are mixed together can be set as needed. Thus, a volume flow from the extraction heat exchanger or from the regeneration arrangement can be continuously set depending on demand in a mixture of the heat carrier media, until a required set point temperature and/or set point power in the heat supply for the regeneration or the heat extraction for the cooling has been reached.
According to an advantageously embodiment, a closed-loop and/or open-loop control device can be provided, which actuates the coupling device depending on at least one operating parameter of the latent heat storage device and/or of the latent heat storage system. Advantageously, a volume flow of the heat carrier media to be mixed can be set. For example, in the case of a maximum demand for regeneration or cooling, the closed-loop and/or open-loop control device can set a maximum through flow it the coupling device, while, in the case of lower demands, the coupling device, for example a mixing element, admixes a smaller volume flow, for example, of the heat carrier medium from the extraction heat exchanger.
According to an additional aspect of the invention, a method is proposed for operating a latent heat storage system, wherein the latent heat storage system comprises at least one latent heat storage device which contains a storage medium with latent heat, at least one extraction circuit by means of which, during normal operation, in accordance with the intended purpose, heat is extracted from the storage medium, and at least one regeneration circuit by means of which, during normal operation, in accordance with the intended purpose, heat is supplied into the storage medium. The at least one latent heat storage device comprises at least one extraction heat exchanger in contact with the storage medium, which is connected to the extraction circuit, and at least one regeneration region within the storage medium, which is connected to the regeneration circuit. At least temporarily, the at least one extraction heat exchanger is coupled to the at least one regeneration arrangement for common heat extraction from the storage medium or for common heal supply into the storage medium.
In contrast to the normal operation explained above, a heat pump connected to the extraction heat exchanger is not in operation during the coupling.
With the coupling according to the invention, in which the at least one extraction heat exchanger and the at least one regeneration arrangement can be connected in series or in parallel, it is advantageously possible to achieve that, phase-wise, more heat is made available to the latent heat storage device, and said latent heat storage device can be regenerated more rapidly and/or the storage medium can be heated more rapidly, or, in the case of a cooling demand, more heat can be dissipated. Thus, for example, in midsummer, it is possible to cool advantageously and efficiently from the latent heat storage device. As needed, the storage medium can be regenerated in a targeted manner more rapidly by heat supply in regeneration arrangement and extraction heat exchanger. Depending on the requirement for cooling or regeneration, the coupling can occur correspondingly.
According to an advantageous method step, the at least one extraction heat exchanger can be coupled to the at least one regeneration arrangement only up to a predetermined icing degree of the extraction heat exchanger with respect to a volume capable of freezing in accordance with the intended purpose, preferably up to an icing degree of at most 10% with respect to a volume of the latent heat storage device, capable of freezing in accordance with the intended purpose.
The term “volume capable of freezing” should be understood to mean that it is the volume in which the solidified storage medium is present, which can be water ice. However, in principle, another storage medium with latent heat can also be provided.
Advantageously, it is provided that the maximum volume capable of freezing is smaller than the holding capacity of the latent heat storage device. Preferably, the volume capable of freezing is also surrounded at maximum icing degree by liquid storage medium. The size of the maximum volume capable of freezing can be predetermined primarily by the design of the extraction hear exchanger. The latent heat storage device can be designed so that, under normal conditions, the maximum volume capable of freezing can always be surrounded by liquid storage medium.
According to an advantageous method step, in a first operating mode, for common heat supply into the storage medium, the at least one extraction heat exchanger and the regeneration arrangement of the at least one regeneration circuit can be connected together and connected to a heat source. Advantageously, a regeneration of the storage medium in the latent heat storage device can be improved. In particular, the first operating mode can be set when the temperature of the storage medium is less than 10° C., preferably less than 7° C., particularly preferably at most 5° C.
According to an advantageous method step, in a second operating mode, for common heat extraction from the storage medium, the regeneration arrangement of the at least one regeneration circuit and the at least one extraction heat exchanger can be connected together and connected to a heat sink. In particular, the second operating mode can be set when the temperature of the storage medium is greater than 5° C., preferably greater than 7° C., particularly preferably more than 10° C.
According to an advantageous method step, in partial-load operation, a coupling strength between extraction heat exchanger and regeneration arrangement can be changed depending on a set point temperature of the heat carrier media and or a set point power of heat source or heat sink. The latent heat storage system can advantageously provide heat and cold quickly and efficiently.
According to an advantageous method step, in full-load operation, flow through the extraction heat exchanger and the regeneration arrangement can be at a maximum. Advantageously, a coupling device, for example, a mixing element, can be opened maximally in such an operating mode with short response time.
Additional advantages result from the following description of the drawing. In the drawings, embodiment examples of the invention are represented. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art expediently will also consider the features individually and combine them into reasonable additional combinations.
In the drawings, in an exemplary manner:
In the figures, identical or equivalent components are numbered with identical reference numerals. The figures merely show examples and are understood to be non-limiting.
Direction terminology used below with terms such as “left,” “right,” “top,” “bottom,” “in front of,” “behind,” “after,” and the like are only used to improve the understanding of the figures and are never intended to represent a limitation of the generality. The represented components and elements, their design and use can vary depending on the considerations of a person skilled in the an and can be adapted to the respective applications.
The latent heat storage device 10 comprises an extraction heat exchanger 32 in contact with the storage medium 20, in particular immersed therein, which is connected to the extraction circuit 30, and a regeneration arrangement 42 within the storage medium 20, which is connected to the regeneration circuit 40. The latent heat storage device 10 comprises a surrounding wall 12, for example, a housing, which is preferably provided or arranged in the ground and which is filled with the storage medium 20. Optionally, the storage medium 20 can also be provided directly in the ground, for example, as a pond installation or cavern. A region 14 of the ground which acts thermally on the latent heat storage device 10 by heat supply or heat absorption is indicated with a double dashed line. The latent heat storage device 10 itself can here act as a geothermal probe.
In the extraction circuit 30, the extraction heat exchanger 32 is connected via lines 112, 114 to a heat pump 104. The heat pump 104 raises the temperature level of the heat carrier medium 34 and supplies a consumer 130 with heat at a correspondingly higher level.
The heat carrier medium 34 is circulated in the extraction circuit 30 with a feed pump 106. By means of a circuit not designated in further detail, the heat pump 104 supplies a consumer 130, for example, a building, a residence or the like, with heat and conveys a corresponding heat carrier medium with a conveyance means 110.
In the regeneration circuit 40, the regeneration arrangement 42 is connected via lines 116, 118 to a heat source 102. For example, the regeneration arrangement 42 is provided in the form of a regeneration heat exchanger 46 which is arranged in the storage medium 20, and which, for example, is connected to an air-source collector as heat source 102 and which absorbs heat of the environmental air. The heat carrier medium 44 in the regeneration circuit 40 is circulated with a pump 108.
During normal operation, the extraction heat exchanger 32 extracts heat from the storage medium 20 and cools said storage medium in the process. Preferably, heat can be extracted until the thermal unloading of a predetermined region 36 around the extraction heat exchanger 32. This is the case during normal operation, for example, during the winter. From the beginning of the cold season to the end of the cold season, the volume 36 solidifies gradually around the extraction hear exchanger 32. When water is used as storage medium 20, a monolithic ice block forms in a controlled manner, which, in the completely unloaded state of the storage medium 20, maximally assumes the volume 36 in which the extraction heat exchanger 32 is embedded. The predetermined volume 36 results substantially from the design of the extraction heat exchanger 32.
The heat transfer from the storage medium 20 into the heat carrier medium 34 in the extraction heat exchanger 32 occurs via the monolithic ice block. In the extraction circuit 20, the extraction heat exchanger 32 is connected to the heat pump 104, which raises the extracted heat to a higher temperature level which can be used by the consumer 130. A typical heat carrier medium 20 in the extraction circuit 30 can be, for example, a sol or a glycol-water mixture.
During normal operation, the regeneration arrangement 42 releases heat into the storage medium 20 and in the process it heats said storage medium. Due to the heat supply, the thermally unloaded latent heat storage device 10 can be thermally loaded. Preferably, with unloaded or partially unloaded storage medium 20, the storage medium 20 which has solidified around the extraction heat exchanger 32 is thawed again. This is the case during normal operation, for example, during the summer. Preferably, from the beginning of the warm season to the end of the warm season, the solidified storage medium 20 around the extraction heat exchanger 32 gradually in a controlled manner liquefies due to the heat supply, wherein the extraction heat exchanger 32 embedded therein is exposed again In the case in which water is used as storage medium 20, the monolithic ice block is thawed in a controlled manner. The heat transfer from the heated storage medium 20 into the heat carrier medium 34 in the extraction heat exchanger 32 occurs via the melting monolithic ice block. If, in the case of completely melted storage medium 20, heat continues to be supplied via the regeneration arrangement 40, the temperature of the storage medium 20 rises correspondingly.
Extraction circuit 30 and regeneration circuit 40 are strictly separated hydraulically during normal operation due to their different functions.
The regeneration device 42 is designed as regeneration heat exchanger 46, in which a heat carrier medium 44 circulates, which preferably corresponds to the heat carrier medium 34 from the extraction circuit 30, for example, a sol or a water-glycol mixture.
Between the extraction heat exchanger 32 and the regeneration heat exchanger 46, a coupling device 50 is provided, by means of which the extraction heat exchanger 32 is temporarily coupled to the one regeneration heat exchanger 42 for common heat extraction from the storage medium 20 or for common heat supply into the storage medium 20. In the embodiment example shown, the regeneration arrangement 42 and the extraction heat exchanger 32 are fluidically connected in parallel. Optionally, a series connection can be provided alternatively.
In the common circuit 48, the heat carrier medium 34 of the extraction heat exchanger 32 and the heat carrier medium 44 of the regeneration heat exchanger 46 circulate into the storage medium 20, for common heat extraction from the storage medium 20, or for common heat supply into the storage medium 20.
The coupling device 50 is designed here as mixing element 52, so that the extraction heat exchanger 32 of the hitherto extraction circuit 30, in a defined manner, with a predeterminable volume flow of its heat carrier medium 34, can be admixed with the volume flow of the heat carrier medium 44 of the regeneration circuit 40. For this purpose, a closed-loop and/or open-loop control device 60 controls the coupling device 50 depending on at least one operating parameter of the latent heat exchanger system 100 and or of the latent heat storage device 10.
For temporary common heat extraction from the storage medium 20, the coupling device 50 connects the regeneration arrangement 42 in the form of the regeneration heat exchanger 46 and the extraction heat exchanger 32 jointly to a component which can be a heat source 70 or a heat sink 80. Connection lines 66, 68 connect the supply and discharge lines 112, 114 and 116, 118 of the hitherto extraction circuit 30 and of the hitherto regeneration circuit 40. The coupling device 50 is arranged in the hitherto regeneration circuit 40, and a line 114 of the extraction heat exchanger 32 is connected to the coupling device 50, for example, a mixing element 52.
The heat source 70 can in particular be the heat source 102, for example, an air-source collector which absorbs the heat from environmental air and introduces it via the regeneration device 46 into the latent heat storage device 10. Alternatively or additionally, other heat sources can also be provided individually or in any possible combinations.
The air-source collector can be mounted, for example, as a roof collector on a building roof of a building, wherein the building overall can represent the consumer 130.
The heat source 70 can also be a heat exchanger by which a cooling demand can be covered. Thus, in summer, with the still cold storage medium 20, for example, the building can be cooled.
In the case of an increased regeneration demand of the latent heat storage device 10, the coupling between extraction heat exchanger 32 and regeneration arrangement 42 is used to supply as much heat as possible to the latent heat storage device 10 and accordingly heat rapidly. Correspondingly, the coupling device 50 sets the volume flow from the extraction heat exchanger 32.
In the case of a cooling demand of the building, the coupling between extraction heat exchanger 32 and regeneration arrangement 42 is used to supply sufficient cold to the building. Correspondingly to the cooling demand of the building, the coupling device 50 sets the volume flow from the extraction heat exchanger 32.
The regeneration arrangement 42 is designed as an “open” system and has inflows 47 and outflows 49 in the latent heat storage device 10. For example, the inflows 47 and outflows 49 can be formed by annular lines which comprise, along their circumference, openings for the passage of the storage medium 20. In the regeneration circuit 40, between heat source 70/heat sink 80 and regeneration arrangement 42, a heat exchanger 82 is arranged, which separates the regeneration the circuit 40 into two sections, wherein, in the region of the regeneration arrangement 42, the storage medium circulates as heat carrier medium and in the section of the regeneration circuit 40 between heat exchanger 82 and heat source 70/heat sink 80, a second heat carrier medium 44 circulates. Preferably, this is the same medium as the first heat carrier medium 34 of the extraction heat exchanger 32. The heat carrier medium of the regeneration arrangement 42 transfers its heat to the second heat carrier medium 44 of the regeneration circuit 40 via the heat exchanger 82.
The heat exchanger 82 separates the heat carrier circuits of the section of the regeneration circuit 40 with the open regeneration arrangement 42 and the heat carrier circuit 48. The heat earner circuit 48 comprises lines 90, 92 into which the heat from the heat carrier medium 34 of tire extraction heat exchanger 32 is introduced, and, indirectly via the heat exchanger 82, heat of the storage medium 20, as heat carrier medium of the regeneration arrangement 42, is introduced. The connection lines 66, 68 between extraction heat exchanger 32 and regeneration arrangement 42 open between heat source 70 or heat sink 80 and the heat exchanger 82 into the circuit 48 which can be driven by a conveyance means 120, for example, a pump. The coupling device 50 is arranged between components 70, 80 and heat exchanger 82.
The method according to the invention for operating a latent heat storage system 100 provides that at least temporarily the heat carrier medium 34 of the extraction heat exchanger 32 is coupled to the heat carrier medium 44 of the at least one regeneration arrangement 42 for common heat extraction from the storage medium 20 or for common heat supply into the storage medium 20. Extraction heat exchanger 32 and regeneration arrangement 42 are coupled only up to a predetermined icing degree of the extraction heat exchanger 32 with respect to a volume 36, which is capable of freezing in accordance with the intended purpose, of the extraction heat exchanger 32, preferably up to an icing degree of at most 10% with respect to a v olume 36, which is capable of freezing in accordance with the intended purpose, of the extraction heat exchanger 32.
In a first operating mode for common heat supply into the storage medium 20 or for providing cooling, the one extraction heat exchanger 32 and the regeneration arrangement 42 of the regeneration circuit 40 are connected together and connected to a heat source 70 or a heat sink 80.
In partial-load operation, a coupling strength between extraction heat exchanger 32 and regeneration arrangement 42 can be changed depending on a set point temperature of the heat carrier media 34, 44 and/or a set point power of heat source 70 or heat sink 80. In full-load operation, the flow through the extraction heat exchanger 32 and the regeneration arrangement 42 can be at a maximum.
In the case of a demand for regeneration power or cooling in step S100, the icing degree of the latent heat storage device is established as guide parameter in S102. If the icing degree is greater than a limit value, for example, greater than 10%, in S104, the coupling device 50 is closed and only the regeneration arrangement 42 is actuated by the closed-loop and/or open-loop control device 60. The hydraulic circuits 30, 40 are then separated correspondingly to the representation in
If the icing degree is at most equal to or less than the limit value, for example, if it is less than or equal to 10%, the coupling device in step S106 additionally switches on the extraction heat exchanger. This extraction heat exchanger can be additionally switched on continuously until a set point temperature and/or set point power is/are reached. In partial-load operation, in S108, the coupling device, for example, a mixing element, opens sufficiently in the direction of extraction heat exchanger until the set point temperature and/or set point power is/are reached. In the case of a power requirement in full-load operation, the coupling device opens in step S110 sufficiently so that the flow through extraction teat exchanger and regeneration arrangement is at maximum.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2017 112 409.8 | Jun 2017 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/064691 | 6/5/2018 | WO | 00 |
