Multi-temperature level heat pump for storing thermal energy

Abstract

According to certain aspects of the application, a heat pump includes a first heat extraction unit and a second heat extraction unit to extract heat from a first heat source and a second heat source, respectively, within a first temperature range and a second temperature range, wherein the second temperature range is, on average, higher than the first temperature range. A fluid passageway defines a flow path through which the working fluid flows in series from the first heat extraction unit to the second heat extraction unit to a thermal reservoir. A pressure-reducing cascade is coupled to the passageway and disposed in series on the fluid circuit between the thermal reservoir and the first heat extraction unit. In addition, a compressor or a regenerator (or both) is coupled to the passageway and disposed in series on the fluid circuit between the first heat extraction unit and the second heat extraction unit.

Description

Technical Field

[0001] This invention relates to a multi-temperature heat pump that generates high-temperature heat energy for thermal energy storage. Background Technology

[0002] Energy storage is a crucial capability for regulating energy supply. Renewable energy sources are often intermittent and provide either too little or too much power relative to demand. Balancing energy production requires a mechanism for storing and recovering energy. For example, abundant electrical energy is often available during the day due to the large number of photovoltaic cells. Furthermore, daytime provides opportunities to collect heat at varying temperatures. However, not all heat sources are created equal. The economics of collecting a unit of heat varies significantly with temperature. For instance, collecting heat at room temperature is relatively inexpensive. However, extracting high-temperature heat from concentrated solar power is technically feasible but far more expensive.

[0003] A heat pump is an effective means of generating high-temperature heat energy from a temperature heat source and electrical energy. A traditional heat pump cycle includes the following steps: (a) extracting heat from a low-temperature heat storage body by evaporating the working fluid, (b) compressing the working fluid to increase the temperature, (c) condensing the fluid back into a liquid state by releasing the high-temperature heat, and (d) reducing the pressure to the initial value using an expansion valve.

[0004] While traditional heat pumps are effective at providing indoor heating, there are several challenges in using them for solar thermal collection:

[0005] a. The efficiency of the combined heat pump-heat engine cycle is far below 100%, which makes energy storage uneconomical;

[0006] b. A large temperature range usually requires a large pressure ratio, which necessitates expensive multi-stage compression;

[0007] c. In traditional heat pumps, heat collection and heat dissipation are constant-temperature processes, but heat sources and heat storage devices are usually more suitable for absorbing and dissipating heat over a wide temperature range.

[0008] Several configurations of heat pumps for energy storage have been described in the prior art. Solar-assisted heat pumps were developed in the 1970s and were recently improved by Aktas et al., “Designing a novel solar-assisted heat pump system with modification of a thermal energy storage unit,” Proceedings of the Institution of Mechanical Engineers, Part A, May 2019. It consists of either parallel operation of a solar collector and a heat pump or series operation of a solar collector and a heat pump. In both cases, no attempt is made to extract heat from non-overlapping temperature ranges.

[0009] In patent publication EP2241737B1, Hemrle et al. described a thermal storage system that pumps heat from a single cryogenic thermal storage unit to a thermal storage liquid that is transferred between two thermal storage units.

[0010] In patent US10288357, Laughlin et al. described an energy storage and harvesting system that pumps heat between a cold-side heat storage unit and a hot-side heat storage unit and uses a combination of a hot-side heat storage unit and an external heat source during a heat release cycle.

[0011] In view of the above, the object of the present invention is to provide an improved heat pump and its operating method.

[0012] Another object of the present invention is to provide a heat pump and method that can be effectively used to harvest energy from multiple energy sources at different temperatures.

[0013] Another object of the present invention is to provide a heat pump and method that can be used effectively to harvest energy from solar energy or other high-temperature energy sources. Summary of the Invention

[0014] The above is one of the objectives achieved by the present invention, which in some respects provides a heat pump comprising a first heat extraction unit that provides thermal coupling between a working fluid and a first heat source to extract heat from the first heat source within a first temperature range; a second heat extraction unit that provides thermal coupling between the working fluid and the second heat source to extract heat from the second heat source within a second temperature range; and a heat storage unit. The second temperature range is on average higher than the first temperature range. A channel connecting the first heat extraction unit, the second heat extraction unit, and the heat storage unit defines a fluid loop through which the working fluid passes. Continuous flow from the first heat extraction unit to the second heat extraction unit and up to the heat storage unit can be directly or indirectly (e.g., through one or more intermediate units) from each such unit to the next unit. A pressure reducing stage is connected to the channel and arranged in series in the fluid loop between the heat storage unit and the first heat extraction unit. Furthermore, a compressor or regenerator (or both) is connected to the channel and arranged in the fluid loop between the first heat extraction unit and the second heat extraction unit.

[0015] A related aspect of the present invention provides a heat pump, for example, as described above, wherein the first and second temperature ranges are different, i.e., do not overlap.

[0016] Other related aspects of the invention provide a heat pump, for example, as described above, which includes both the regenerator and the compressor, wherein the regenerator is disposed in a fluid loop to extract heat from the working fluid leaving the heat storage tank and transfer the heat to the working fluid leaving the first heat extraction unit.

[0017] Another related aspect of the invention provides a heat pump, for example, as described above, wherein a first compressor is disposed in a fluid circuit downstream of a second heating unit. According to yet another related aspect of the invention, the first compressor is disposed in a fluid circuit upstream of the second heating unit.

[0018] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the working fluid is C6K perfluoroketone, propane, butane, isobutane, butene, pentane, isopentane, neopentane, D4 ​​(octamethylcyclotetrasiloxane), D5 (decamethylcyclopentasiloxane), D6 (dodecylmethylcyclohexasiloxane), MDM (octamethyltrisiloxane), MD2M (decamethyltetrasiloxane), MD3M (dodecylpentasiloxane), MD4M (tetradecylmethylhexasiloxane) or other hydrocarbons, perfluorocarbons, perfluoroketones, hydrofluorocarbons, hydrofluoroolefins or siloxanes.

[0019] Other related aspects of the invention provide a heat pump, for example, as described above, wherein the regenerator is a countercurrent finned tube regenerator.

[0020] Another related aspect of the invention provides a heat pump, for example, as described above, wherein thermal coupling between a first heat source and a working fluid in a first heat extraction unit results in the evaporation of the working fluid and / or the provision of evaporation energy to the fluid.

[0021] Other related aspects of the invention provide a heat pump, for example, as described above, comprising one or more additional heat extraction units coupled to a channel, wherein a working fluid flows through the additional heat extraction units between a second heat extraction unit and a heat storage tank.

[0022] Another related aspect of the invention provides a heat pump, for example, as described above, which can operate in a heat storage cycle to store heat energy in a heat storage tank and can operate in a heat release cycle to remove heat energy from the heat storage tank.

[0023] Another related aspect of the invention provides a heat pump, for example, as described above, wherein a first heat extraction unit includes a heat exchanger that transfers heat from a low-temperature heat source to a working fluid.

[0024] Other related aspects of the invention provide a heat pump, for example, as described above, wherein a low-temperature heat source provides sufficient thermal energy to evaporate the working fluid.

[0025] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the low-temperature heat source is any one of waste heat from an industrial process, thermal energy from the environment, and hot water collected from solar thermal energy.

[0026] Other related aspects of the invention provide a heat pump, for example, as described above, wherein the working fluid is C6K perfluoroketone, propane, butane, isobutane, butene, pentane, isopentane, neopentane, D4, D5, D6, MDM, MD2M, MD3M, MD4M or other hydrocarbons, perfluorocarbons, perfluoroketones, hydrofluorocarbons, hydrofluoroolefins or siloxanes.

[0027] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the second heat extraction unit provides either direct or indirect heating of the working fluid by a second heat source.

[0028] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the second heat extraction unit includes a heat exchanger that transfers heat from a second heat source to a working fluid.

[0029] Other related aspects of the invention provide a heat pump, for example, as described above, wherein the second heat source is a high-temperature solar collector.

[0030] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the heat storage device contains sand.

[0031] Another related aspect of the invention provides a heat pump, for example, as described above, which operates in a heat storage cycle, wherein the working fluid (i) changes from a liquid phase to a gas phase when absorbing heat from the first heat source in the first heat extraction unit, (ii) experiences a temperature increase in either the first compressor or the regenerator, (iii) absorbs additional heat from the second heat source in the second heat extraction unit, (iv) delivers heat to the heat source, and (v) undergoes a pressure drop during a decompression phase before re-entering the first heat extraction unit.

[0032] Other related aspects of the invention provide a heat pump, for example, as described above, in which a working fluid exchanges heat with a radiator during operation in an exothermic cycle.

[0033] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the radiator is either a heat engine or a heat extraction unit.

[0034] Another related aspect of the invention provides a heat pump, for example, as described above, comprising a second compressor connected to a channel and disposed in a fluid loop between a second heat extraction unit and a heat storage unit.

[0035] Another related aspect of the invention provides a heat pump, for example, as described above, comprising a regenerator and a first compressor and a second compressor, wherein the regenerator is disposed on a fluid loop to extract heat from the working fluid leaving the heat storage tank during a heat storage cycle and transfer the heat to the working fluid leaving the first heat extraction unit.

[0036] Another related aspect of the invention provides a heat pump, for example, as described above, wherein a first compressor is disposed in a fluid circuit downstream of a regenerator, and a second compressor is disposed in a fluid circuit downstream of a second heat extraction unit.

[0037] Another related aspect of the invention provides a heat pump, for example, as described above, wherein the working fluid is any one of C6K perfluoroketone, propane, butane, isobutane, butene, pentane, isopentane, neopentane, D4, D5, D6, MDM, MD2M, MD3M, MD4M or other hydrocarbons, perfluorocarbons, perfluoroketones, hydrofluorocarbons, hydrofluoroolefins or siloxanes.

[0038] The foregoing and other aspects of the present invention will become apparent in the following text and the accompanying drawings. Attached Figure Description

[0039] A more comprehensive understanding of the invention can be obtained by referring to the accompanying drawings, in which:

[0040] Figure 1 This is a schematic diagram of a dual-source heat pump that uses a compressor to amplify the temperature between heat sources;

[0041] Figure 2 This is a schematic diagram of a dual-source heat pump that uses a regenerator and a compressor to amplify the temperature between the heat sources;

[0042] Figure 3 It is a schematic diagram of a dual heat source system with a regenerator that provides a temperature boost between the heat sources;

[0043] Figure 4 This is a schematic diagram showing a dual heat source, with a compressor to raise the temperature between the heat sources, and a second compressor to raise the temperature before heat storage;

[0044] Figure 5 This is a schematic diagram showing a dual heat source, where both the regenerator and the compressor raise the temperature between the heat sources, and the second compressor raises the temperature before the heat storage.

[0045] Figure 6 The working fluid has undergone a combination Figure 1 Representative pressure-enthalpy diagrams of the described heating-compression-heat cycle;

[0046] Figure 7 The working fluid has undergone a combination Figure 2 A representative pressure-enthalpy diagram describing the heating-heat exchange-compression-heat cycle;

[0047] Figure 8 It is a combination of working fluid experience Figure 3 A representative pressure-enthalpy diagram of the described heating-heat exchange-heating-compression cycle;

[0048] Figure 9 It is a combination of working fluid experience Figure 4 The representative pressure-enthalpy diagram of the described heating-compression-heating-compression cycle; and

[0049] Figure 10 It is a combination of working fluid experience Figure 5 A representative pressure-enthalpy diagram of the described heating-heat exchange-compression-heating-compression cycle. Detailed Implementation

[0050] The following description, and illustrated in the accompanying drawings, describes heat pumps and their operation methods according to the invention. These heat pumps extract heat from multiple external heat sources, for example, in different non-overlapping temperature ranges, into a single working fluid loop, which delivers the pumped heat and energy to a thermal energy storage unit. These heat pumps operate in two modes—heat charging and heat dissipation. During heat charging, thermal energy is stored in a thermal energy storage unit. During heat dissipation, thermal energy is extracted.

[0051] The heat pump according to the invention provides an economically feasible way to collect heat from different sources, such as low-temperature sources (e.g., ambient air) and high-temperature sources (e.g., solar collectors), into a single heat flow that can be easily stored for later use, such as for power generation or process heating.

[0052] In some embodiments, heat from multiple low-temperature sources is used to provide evaporation energy to the working fluid, while heat from higher-energy sources is used to further heat the fluid to improve the overall electrical efficiency of the heat generator. In some embodiments, the heat pump according to the invention can collect additional energy from higher-temperature heat sources to further improve overall efficiency. Combining multiple heat sources enables the utilization of resources that can be optimized to improve the economic efficiency of power generation.

[0053] Some embodiments of the present invention extend the heat pump loop configuration with compression and / or recirculation stages between heat sources to increase the temperature of the working fluid between heat collection stages. After heat collection, the working fluid discharges its thermal energy to the heat storage tank before passing through a depressurization stage and re-entering the evaporation stage.

[0054] Referring to the accompanying drawings, embodiments of the invention are illustrated, wherein a working fluid flows through a fluid loop defined by channels carrying the fluid from one component to another, and (a) extracts heat from multiple heat sources, (b) raises the temperature of the collected heat, (c) transports the heat to a heat storage unit, and (d) acquires thermal energy from the storage unit at a later time. The following description depicts a flow path defined by channels in the fluid loop for a working fluid that absorbs heat at a temperature (or temperature range) corresponding to the fluid's boiling point and a second, different, and more typically substantially different, higher temperature (or temperature range). The fluid in the loop then stores the absorbed heat into an energy storage device. It will be understood that additional components may be included in the flow path of the working fluid, and these components represent different embodiments of the invention detailed in these examples.

[0055] Figures 1-5 The heat pump components shown and discussed below are connected by pipes, fittings, or other structures of the type known in the art, which are adapted to define a fluid path (or loop) and transport the working fluid along that path, as shown in the figures and described below. By convention, this path and these structures are indicated in the figures by solid lines (usually with directional arrows).

[0056] The channel may surround or pass through the components shown (and in fact, may be integral with one or more of them), and at least a portion of the channel along the loop is thermally conductive to achieve thermal coupling between the working fluid and the selected corresponding components (e.g., heat extraction units and / or their corresponding heat sources, heat storage tanks, regenerators, etc.) as the working fluid flows through or near them. The channel is fluidly connected (albeit thermally insulated from) to other components along the loop (e.g., compressors, pumps, valves, etc.) to allow the working fluid to be compressed / pressurized, expanded / depressurized, directed, and otherwise hydrodynamically manipulated by those other components without unnecessary heat loss. In light of the teachings herein, the manufacture and use of the channel in these respects are within the knowledge of those skilled in the art.

[0057] Figure 1 This is a schematic diagram illustrating the fluid circuit of a heat pump according to one embodiment of the present invention. A cryogenic heat source 100 provides thermal energy to initiate the cycle. Potential heat sources include waste heat from industrial processes, thermal energy harvested from ambient air temperature, and hot water harvested from solar thermal energy, all of which are non-limiting examples. The heat source is arranged in a conventional manner known in the art as appropriate to the teachings herein to be thermally coupled to a first heat exchanger 110.

[0058] Energy from a low-temperature heat source is exchanged with a working fluid in heat exchanger 110. In the illustrated embodiment, the working fluid is isobutane, which has a low boiling point and can therefore evaporate at low temperatures (e.g., 40°C) and pressures exceeding atmospheric pressure. In the illustrated embodiment, the heat exchanger substantially and preferably completely evaporates the working fluid and can provide additional heat to further raise the temperature of the current gaseous working fluid. Other working fluids are also possible, including low molecular weight hydrocarbons such as n-butane, propane, isobutene, and refrigerant gases such as HFC-227. In the illustrated embodiment, the heat exchanger is a shell and tubing design; however, other designs within the knowledge of those skilled in the art may be used instead or in conjunction with it. Some other possible variations of the heat exchanger include plate and frame types, as well as spiral tube heat exchangers, to name just a few. The heat exchanger is connected to compressor 120 by means of channels in a manner customary in the art to suit the teachings herein (i.e., as used herein and elsewhere in the context, “fluidly connected”).

[0059] In compressor 120, the pressure of the working fluid is increased. The compressor can be of any type known in the art, including centrifugal, axial, screw, scroll, and reciprocating types, as non-limiting examples. In common applications, all these techniques involve compression under nearly adiabatic conditions, where the following relationship holds:

[0060] P 1-γ T γ = constant

[0061] Where γ is the adiabatic index of the working fluid, P is the pressure, and T is the temperature. For a practically meaningful working fluid, the adiabatic index in the gas phase is greater than 1. Due to the above relationship, an increase in pressure also requires an increase in temperature. After the temperature rises, the compressor delivers the working fluid to the high-temperature heat source 130. As used elsewhere in this context and similar to this document, "delivery" refers to the guiding of the working fluid via a channel, in accordance with the conventions of the art adapted to the teachings herein.

[0062] High-temperature heat sources directly or through a second heat exchanger of a type known in the art Figure 1 A fluid (not shown) is in communication with the working fluid (i.e., as used herein and elsewhere in similar contexts, "is thermally coupled") to increase the temperature of the working fluid. Such communication (or coupling) mentioned herein and elsewhere may be performed in the similar contexts herein according to art conventions adapted to the teachings of this document. In the illustrated embodiment, the high-temperature heat source is a high-temperature solar collector. The fluid exits the high-temperature heat source (or collector) and is connected to the control valve 140 via a pipe or other structure comprising a corresponding portion of the channel.

[0063] Control valve 140 connects the high-temperature heat source to the thermal storage unit 150 and to control valve 142. Such connections (or fluid couplings) mentioned elsewhere in this context and similar to those described herein may be made in accordance with art conventions suited to the teachings herein. During thermal storage operation, valve 140 is open and introduces working fluid into the thermal storage unit, while valve 142 remains closed.

[0064] In the illustrated embodiment, the heat storage unit 150 is a container for sand with conduits through which the working fluid is delivered. As the fluid flows through the conduits in the sand, it transfers heat to the sand, and its temperature decreases. The heat storage unit is long enough to allow most of the heat collected from the unit to be released into the sand before the working fluid leaves the unit. In other embodiments, the heat storage unit may consist of a packed bed storage system in which the working fluid permeates through a porous material. In yet another embodiment, the heat storage unit may consist of a heat storage fluid that is heated in a heat exchanger by the action of the working fluid. Other configurations of the heat storage unit 150 are also within the knowledge of those skilled in the art in light of the teachings herein. The heat storage unit thus constructed is connected to control valves 140, 142, 144, and 146. During heat storage operation, control valve 144 conducts the working fluid to pressure reducing device 150, while control valve 146 remains closed.

[0065] Pressure reducing device 150 connects control valve 144 to heat exchanger 100. In the illustrated embodiment, the pressure reducing device is an energy recovery turbine, but it could also be an expansion valve or other device of a type known in the art that has a similar hydromechanical effect on the working fluid. Due to the advantage of the working fluid being cooled in storage unit 150, the working fluid will at least partially re-enter heat exchanger 110 in a fluid state, where it will be evaporated to complete the cycle.

[0066] Figure 6 Traversal of working fluid Figure 1 The angle of the middle loop describes the heat storage cycle. Figure 6 The x-axis represents the enthalpy of the working fluid. The y-axis represents the pressure. Isotherm 100 and enthalpy line 110 are also shown. The initial evaporation of the working fluid is shown as term 120. As the working fluid changes from the liquid phase to the gas phase, it absorbs heat from a low-temperature heat source at a constant temperature of 313 Kelvin (K). After evaporation, the working fluid is compressed 130. In this exemplary cycle, the temperature of the working fluid increases from 313 K to 453 K due to compression. Note that compression is almost isentropic (i.e., parallel to isentropic line 110), but the inefficiency during the compression phase introduces additional energy in the form of heat, thus increasing the enthalpy of the working fluid to slightly higher than that expected from isentropic compression. Then, as shown in 140, the working fluid absorbs additional heat. This heat is transferred by a high-temperature heat source, and in this example, it provides heat from 453 K to 513 K. After the heating cycle is complete, the heat is transferred to the storage system along trajectory 150. As shown in the figure, the temperature drops from 513 K to the initial temperature of 313 K, with a total heat transfer of 200 K. Finally, step 160 illustrates how the almost isentropic decompression in the pressure reducing device leads to the completion of the thermodynamic cycle.

[0067] Once the thermal storage system stores heat... Figure 1 Valves 140 and 144 are closed. Valves 142 and 146 are opened to connect the heat storage tank 150 to the pump 170 and the radiator 180.

[0068] As described above and elsewhere in this document, the heat pump according to the present invention (e.g., such as...) Figures 1-5 The operation of pumps, valves and other moving parts (shown) in the heat storage cycle can be performed "manually" by an operator (not shown), by a machine (e.g., by a digital data processor, PLC or other control device or a combination thereof (not shown)), or by a combination of humans and machines, all in accordance with the art conventions adapted to the teachings herein.

[0069] Fluid pump 170 is connected to radiator 180 and valve 146. When discharging heat, the pump delivers working fluid through valve 146. Valve 146 connects the fluid pump to heat storage unit 150 and valve 144. When discharging heat, valve 146 remains open, delivering working fluid to heat storage unit 150. In heat storage unit 150, the flow direction of the working fluid is opposite to that during heat storage. The working fluid enters at a low temperature and exits the storage unit at a high temperature. The storage unit is connected to valves 140 and 142. During heat dissipation, valve 142 remains open, while valve 140 remains closed. Valve 142 is connected to radiator 180. After leaving valve 142, the fluid enters radiator 180. The heat energy gained from the heat storage unit is consumed by the radiator. In the illustrated embodiment, the radiator is a heat engine using a turbine, as is common in the art in the Rankine cycle. In other embodiments, a heat exchanger can be used to extract heat from the working fluid. The radiator is connected to pump 170. The circulation continues when the working fluid re-enters the pump.

[0070] As described above and elsewhere in this document, note the operation of the pumps, valves, and other moving parts of the heat pump (e.g., as indicated above) in relation to the heat storage cycle according to the invention. Figures 1-5 During the exothermic cycle (as shown), it can be performed "manually" by an operator (not shown), by a machine (e.g., by a digital data processor, PLC or other control device or a combination thereof (not shown)), or by a combination of humans and machines, all in accordance with the conventions of the art adapted to the teachings herein.

[0071] Figure 2 An embodiment of the invention is described where the temperature difference between the two heat sources is maintained by the combined action of a regenerator and a compressor. In the illustrated embodiment of this configuration, the working fluid is Novec 649 heat transfer fluid manufactured by 3M, also known as C6K perfluoroketone. In other embodiments, different working fluids may be used; for example, as a non-limiting example, low molecular weight hydrocarbons, siloxanes, and hydrofluorocarbons may be used.

[0072] Figure 2 The system operates in a manner similar to Figure 1 The low-temperature heat source 100, pump 105, high-temperature heat source 130, valve 140, valve 142, valve 144, valve 146, heat storage unit 150, pressure reducer 160, pump 170 and radiator 180 perform the same functions as described above and are connected in the same manner.

[0073] The newly illustrated element in this configuration is the regenerator 190. It is positioned across two flow paths: a first flow path from valve 144 to pressure reducer 150, and a second flow path from heat exchanger 110 to compressor 120. The function of the regenerator is to transfer heat from the first flow path to the second flow path. In the illustrated embodiment, the regenerator is a counter-current finned tube regenerator, although in other embodiments, other types of devices known in the art that have similar hydromechanical effects on the working fluid may be used instead or supplemented. The working fluid from valve 144 is conveyed counter-currently through the conduit of the regenerator, thereby ensuring that the working fluid delivered to pressure reducer 160 is at a relatively low temperature. The working fluid from heat exchanger 110 passes through the finned tubes in regenerator 190. When the working fluid is delivered to compressor 120, the heat raises the temperature of the working fluid.

[0074] Heat exchanger 110 is connected to pump 105 and cryogenic heat source 100 on one side. The other side of the heat exchanger is connected to pressure reducer 160 and regenerator 190. It transfers heat from the cryogenic heat source to evaporate the working fluid.

[0075] The compressor 120 is connected to the regenerator 190 and a high-temperature heat source. In the above configuration, the compressor in the illustrated embodiment is a centrifuge, but other suitable compression technologies known to those skilled in the art can be used instead or supplemented.

[0076] Valve 144 connects storage unit 150 to regenerator 190. During heat charging, valve 144 transfers working fluid from storage unit to regenerator.

[0077] Pressure reducer 160 connects regenerator 190 to heat exchanger 110. In the illustrated embodiment, pressure reducer is a turbine. As mentioned above, other techniques are also possible.

[0078] The working fluid returns to heat exchanger 110, completing the heat storage cycle. The heat absorbed in the storage system can be used as follows: Figure 1 The mechanism is to recycle, that is, to reconstruct valves 140, 142, 144, and 146 so that pump 170 can circulate the working fluid through heat storage tank 150 and into radiator 180.

[0079] Figure 7 Described from the perspective of working fluid Figure 2 The heat storage cycle in an embodiment. For example... Figure 6 This is a graph showing the pressure versus enthalpy of a representative working fluid, with isotherms 100 and isentropic lines 110. Note that... Figure 6Unlike other compressors, the isentropic line 110, starting from low pressure, crosses the phase boundary of the working fluid 210. This poses a problem for many types of compressor technology, especially for centrifugal and axial turbine mechanisms, because the miscible material impacts and rapidly erodes the rotor blades. It is precisely this characteristic of the working fluid that necessitates a regenerator 140 in the cycle. The regenerator preheats the working fluid from 353 K to 393 K before the compression stage 150, thus preventing near-isentropic compression from crossing the phase boundary. Figure 6 The working fluid absorbs additional heat from the high-temperature source 160 in the range of 473K to 513K, and then passes through the storage unit 170 to release heat from 513K to 413K. Figure 7 Item 180 defines the point from which the heat exchanger exits and enters the regenerator. The regenerator transfers heat from the high-pressure fluid to the low-pressure fluid at 190. Upon exiting the regenerator, the high-pressure fluid enters the pressure reducer at 200 and returns to a cryogenic and low-pressure state, where it absorbs heat during the evaporation of the cryogenic heat source at 120. The gaseous phase of the working fluid then re-enters the regenerator at 130 to complete the cycle.

[0080] Figure 3 Embodiments of the invention are described, in which the temperature difference between the two heat sources is maintained by the action of a regenerator, while additional temperature rise is achieved by a compressor located after the high-temperature heat source. In the illustrated embodiment of this configuration, the working fluid is Novec 649 heat transfer fluid manufactured by 3M, also known as C6K perfluoroketone. In other embodiments, different working fluids may be used; for example, by way of non-limiting example, low molecular weight hydrocarbons, siloxanes, and hydrofluorocarbons may be used.

[0081] Figure 3 The system operates in a manner similar to Figure 2 The following are described in the manner described: Low-temperature heat source 100, pump 105, heat exchanger 110, valve 142, valve 144, valve 146, heat storage tank 150, pressure reducer 160, pump 170, and radiator 180 perform the same functions as described above and are connected in exactly the same manner.

[0082] Figure 3 The structure and Figure 2 The difference is Figure 2 The compressor 120 has been removed, and Figure 3 A new compressor 200 was added between the high-temperature heat source 130 and the valve 140.

[0083] The regenerator 120 is connected to valve 144 and pressure regulator 160 in the first flow path. Its second flow path is connected to heat exchanger 110 and high-temperature heat source 130. (As...) Figure 2 As shown, the regenerator transfers heat from the first flow path to the second flow path.

[0084] A high-temperature heat source is connected to the regenerator 120 and the compressor 200. The heated fluid leaving the regenerator receives additional heat from the high-temperature heat source, directly or indirectly, through a heat exchanger. This increases the temperature of the working fluid as it leaves the high-temperature heat source and enters the compressor 200.

[0085] Compressor 200 is connected to high-temperature heat source 130 and valve 140, as described above. Figure 1 The compressor 120 in the middle will increase the pressure and temperature of the working fluid by acting on it.

[0086] Valve 140 is connected to compressor 200, heat storage unit 150, and valve 142. During heat charging operation, valve 140 remains open, allowing working fluid to circulate through the heat storage unit. Upon exiting valve 140, the fluid passes through in the same sequence as during heat charging. Figure 2 The same components are cycled.

[0087] During heat dissipation, the fluid flow is related to... Figure 2 The same as described in the text. Fluid flows through valve 142, heat storage unit 150, valve 144, pump 170, and radiator 180 before returning valve 142. Valves 140 and 144 remain closed during discharge.

[0088] Figure 8 Described from the perspective of working fluid Figure 3 The heat storage cycle is shown. Similarly, this is a pressure-enthalpy diagram, with isotherms 100 and isentropic lines 110. The working fluid evaporates at a temperature of 353 K in step 120. Item 130 indicates entry into the regenerator, which, as shown in item 140, heats the fluid from 353 K to 393 K. The fluid then exits the regenerator at point 150 and passes through a high-temperature heat source 160 to raise the temperature to 453 K. The compression stage 170 raises the temperature to 513 K. The fluid then enters the storage unit 180, where it releases heat as it cools from 513 K to 413 K. At 190, the fluid re-enters the regenerator, transferring heat to the low-pressure stage of cycle 200. Once the fluid cools, it enters the pressure recovery unit 210, which returns it to the heat exchanger and completes the cycle.

[0089] Figure 4 Embodiments of the present invention have been described, wherein the temperature difference between two heat sources is achieved through, as... Figure 1 The working fluid is maintained by the action of the compressor 120, while the additional compressor 200 further increases its temperature and pressure before it enters the heat storage unit. In the illustrated embodiment, the working fluid is isobutane. In other embodiments, different working fluids may be used, such as low molecular weight hydrocarbons, siloxanes, and hydrofluorocarbons.

[0090] The low-temperature heat source 100, pump 105, heat exchanger 110, compressor 120, valve 142, valve 144, valve 146, storage unit 150, pressure reducer 160, pump 170, and radiator 180 all perform the same function and are in harmony with... Figure 1 Connect in the same way.

[0091] exist Figure 4 In the configuration, a high-temperature heat source 130 is connected to compressors 120 and 200. When fluid passes through the high-temperature heat source from compressor 120 to compressor 200, the temperature increases with the increase of heat.

[0092] Compressor 200 is connected to a high-temperature heat source 130 and to valve 140. When the working fluid is compressed by the compressor, both temperature and pressure increase, as described above. Figure 1 Description of compressor 120.

[0093] Valve 140 is connected to compressor 200, heat storage unit 150, and valve 142. During heat charging operation, valve 140 remains open.

[0094] Heat dissipation operation to cooperate with Figure 1 The process proceeds in the same manner as described in [the original text]. Valves 140 and 144 are closed, while valves 142 and 146 are open. Pump 180 circulates the working fluid through radiator 180 to valve 144, into storage unit 150, and returns the fluid to the pump through valve 146.

[0095] Figure 9 Described from the perspective of working fluid Figure 4 The cycle is as follows. Similar to other examples, this is a pressure-enthalpy diagram with isotherm 100 and isentropic line 110. The working fluid absorbs heat from a low-temperature heat source at 313 K and becomes gas. This gas is compressed along segment 130 to raise the temperature to 373 K. A high-temperature heat source, as shown by segment 140, supplies heat from 373 K to 453 K. The compressor further raises the temperature from 453 K to 513 K along segment 150. Then, as the temperature drops from 513 K to 313 K, the heat is transferred to storage unit 160. The fluid returns to the evaporator via pressure reducing device 170, thus completing the cycle.

[0096] Figure 5 Embodiments of the invention are described, in which the temperature difference between the two heat sources is maintained by the combined action of a regenerator and a compressor, and a second compressor is used to raise the temperature of the working fluid before it stores its thermal energy in the heat storage unit. In the illustrated embodiment of this configuration, the working fluid is Novec 649 thermally conductive fluid manufactured by 3M, also known as C6K perfluoroketone. In other embodiments, different working fluids may be used, such as low molecular weight hydrocarbons, siloxanes, and hydrofluorocarbons.

[0097] Figure 5 The system operates in a manner similar to Figure 2 The process is carried out in the manner described above. The low-temperature heat source 100, pump 105, heat exchanger 110, regenerator 190, compressor 120, valve 142, valve 144, valve 146, heat storage unit 150, pressure reducer 160, pump 170, and radiator 180 all perform the same operation as described above. Figure 2 They have the same functionality and are connected in exactly the same way.

[0098] exist Figure 5 In the configuration, a high-temperature heat source 130 is connected to compressors 120 and 200. When fluid passes through the high-temperature heat source from compressor 120 to compressor 200, the temperature increases with the increase of heat.

[0099] Compressor 200 is connected to a high-temperature heat source 130 and to valve 140. When the working fluid is compressed by the compressor, both temperature and pressure increase, as described above. Figure 1 Description of compressor 120.

[0100] Valve 140 is connected to compressor 200, heat storage unit 150, and valve 142. During heat charging operation, valve 140 remains open.

[0101] Heat dissipation operation to cooperate with Figure 1 The process proceeds in the same manner as described in [the original text]. Valves 140 and 144 are closed, while valves 142 and 146 are opened. Pump 180 circulates the working fluid through radiator 180, to valve 144, into storage unit 150, and through valve 146, which returns the fluid to the pump.

[0102] Figure 10 Described from the perspective of working fluid Figure 5 The cycle is as follows. Similar to other examples, this is a pressure-enthalpy diagram with isotherms 100 and isentropic lines 110. The working fluid absorbs heat from a low-temperature heat source at 353 K and becomes gas. The gas enters the regenerator at 130 and absorbs heat 140 to raise its temperature to 393 K. Compressor 150 further raises the temperature from 393 K to 433 K. The fluid then passes through a high-temperature heat source 160, which supplies heat from 433 K to 483 K. A second compressor 170 raises the temperature again to 513 K. The heat in the working fluid from 513 K to 413 K is transferred to the storage system 180. It re-enters the regenerator at 190 and transfers heat 200 to the low-pressure gas. After leaving the regenerator, the working fluid passes through a pressure reducing device 210 and returns to the evaporator to complete the cycle.

[0103] The above description and figures illustrate heat pumps and operating methods consistent with the previously mentioned purposes. It will be understood that the illustrated embodiments are merely examples of the invention, and other embodiments different from those described and shown herein are also included in the invention. Therefore, for example, while the foregoing embodiments describe certain selected components of the heat pump according to the invention, those skilled in the art will understand that other components may be included in the fluid paths of these systems in place of or supplement to those shown in the figures and discussed above, including, for example, pressure and temperature sensors, safety valves, piping and adapters, filters, oil separators, and other apparatus necessary to support the operation of specific selected components in the system. Those skilled in the art will further understand that components such as “compressor,” “regenerator,” “heat exchanger,” “pressure reducer,” “pump,” “storage unit,” and “radiator” can be implemented by alternative devices that provide similar functionality.

[0104] Finally, practitioners in this field will understand that, although Figures 1-5 The construction described herein describes a system that supplies only two independent temperature ranges from an external source, but these descriptions can be extended within the scope of the invention to include three or more heat sources by introducing additional heat exchangers and / or compressors in the flow path between these additional heat sources.

Claims

1. A heat pump, comprising A. A first heat extraction unit that provides thermal coupling between a working fluid and a first heat source to extract heat from the first heat source within a first temperature range. B. A second heat extraction unit that achieves thermal coupling between the working fluid and the second heat source to extract heat from the second heat source within a second temperature range that is on average higher than the first temperature range. C. Thermal storage unit, D. A channel connecting the first heat-collecting unit, the second heat-collecting unit, and the heat storage unit, the channel defining a fluid circuit through which the working fluid flows sequentially, directly or indirectly, from the outlet of the first heat-collecting unit to the inlet of the second heat-collecting unit and finally to the heat storage unit. E. A pressure-reducing stage, which is connected to the channel and arranged in series in the fluid loop between the heat storage unit and the first heat extraction unit. F. At least one of a first compressor and a regenerator, which is connected to the channel and disposed in a fluid loop between the outlet of the first heat extraction unit and the inlet of the second heat extraction unit.

2. The heat pump according to claim 1, wherein, The first temperature range and the second temperature range do not overlap.

3. The heat pump according to claim 1, comprising both the regenerator and the first compressor, wherein the regenerator is disposed in the fluid circuit to extract heat from the working fluid leaving the heat storage tank and transfer the heat to the working fluid leaving the first heat extraction unit.

4. The heat pump according to claim 3, wherein the first compressor is disposed in the fluid circuit downstream of the second heat extraction unit.

5. The heat pump according to any one of claims 3 and 4, wherein the working fluid is any one of C6K perfluoroketone, propane, butane, isobutane, butene, pentane, isopentane, neopentane, D4, D5, D6, MDM, MD2M, MD3M, MD4M perfluorocarbon, perfluoroketone, hydrofluorocarbon, hydrofluoroolefin and siloxane.

6. The heat pump according to claim 3, wherein the regenerator is a counter-current finned tube heat exchanger.

7. The heat pump of claim 1, wherein the thermal coupling in the first heat extraction unit provides energy for evaporation to the working fluid.

8. The heat pump of claim 1, comprising one or more additional heat extraction units coupled to the channel, wherein the working fluid flows through the additional heat extraction units between the second heat extraction unit and the heat storage unit.

9. The heat pump according to claim 1, which is capable of operating in a heat storage cycle to store heat energy in the heat storage tank and in a heat release cycle to remove heat energy from the heat storage tank.

10. The heat pump of claim 1, wherein the first heat extraction unit comprises a heat exchanger that transfers heat from a low-temperature heat source to the working fluid.

11. The heat pump of claim 10, wherein the low-temperature heat source provides sufficient thermal energy to evaporate the working fluid.

12. The heat pump of claim 11, wherein the low-temperature heat source is any one of waste heat from an industrial process, thermal energy from the environment, and hot water collected from solar thermal energy.

13. The heat pump of claim 10, wherein the working fluid is any one of C6K perfluoroketone, propane, butane, isobutane, butene, pentane, isopentane, neopentane, D4, D5, D6, MDM, MD2M, MD3M, MD4M, perfluorocarbon, perfluoroketone, hydrofluorocarbon, hydrofluoroolefin, and siloxane.

14. The heat pump of claim 1, wherein the second heat extraction unit realizes any one of direct and indirect heating of the working fluid by the second heat source.

15. The heat pump of claim 14, wherein the second heat extraction unit comprises a heat exchanger that transfers heat from the second heat source to the working fluid.

16. The heat pump according to claim 15, wherein the second heat source is a high-temperature solar collector.

17. The heat pump of claim 1, wherein the heat storage unit contains sand.

18. The heat pump according to claim 1, wherein it operates in a heat storage cycle, wherein A. When the working fluid absorbs heat from the first heat source at the temperature of the first heat extraction unit, it changes from a liquid phase to a gas phase. B. The working fluid experiences a temperature increase in either the first compressor or the regenerator. C. The working fluid absorbs additional heat from the second heat source in the second heat extraction unit. D. The working fluid transfers heat to the heat storage tank, and E. The working fluid undergoes a pressure drop in the depressurization stage before re-entering the first heat extraction unit.

19. The heat pump of claim 1, which operates in a heat-exhausting cycle, wherein the working fluid exchanges heat with a radiator.

20. The heat pump of claim 19, wherein the radiator is either a heat engine or a heat extraction unit.

21. The heat pump of claim 1, further comprising a second compressor connected to the channel and disposed in a fluid loop between the second heat extraction unit and the heat storage unit.

22. The heat pump of claim 21, comprising the regenerator and the first compressor and the second compressor, wherein the regenerator is disposed in the fluid circuit to extract heat from the working fluid leaving the heat storage tank during a heat storage cycle and transfer the heat to the working fluid leaving the first heat extraction unit.

23. The heat pump of claim 22, wherein the first compressor is disposed in a fluid circuit downstream of the regenerator, and the second compressor is disposed in a fluid circuit downstream of the second heat extraction unit.

24. The heat pump of claim 21, wherein the working fluid is any one of a low molecular weight hydrocarbon, a siloxane, and a hydrofluorocarbon.

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