Cold heat electricity hydrogen combined supply system based on comprehensive utilization of carnot cell and operation method

Abstract

The application relates to a cold-heat-electricity-hydrogen combined supply system based on comprehensive utilization of Carnot cells and an operation method. The system comprises coaxial compressors and coaxial expanders connected coaxially, bypass expanders, heat storage tanks, cold storage tanks, condensers, six heat exchangers, proton exchange membrane electrolytic cells, two buffer containers, three circulating fans, three pumps and a plurality of connecting pipelines. The system is divided into five loops: a heat pump loop, a heat engine sub-loop, a heat supply sub-loop, a cold supply sub-loop and a hydrogen production sub-loop. The hydrogen production sub-loop is provided with a bypass organic Rankine cycle. Phase change devices are arranged in the heat storage tanks and the cold storage tanks. Compared with the prior art, the phase change heat storage method is adopted, and two power cycle modes are combined, so that an efficient and long-time combined storage and supply mode can be established, efficient consumption of new energy power, instant frequency modulation and peak shaving of power grids and multi-combined supply of cold, heat, electricity and hydrogen can be realized, and the application has the advantages of safety and stability, simple equipment, high efficiency, high energy storage density and the like.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to a combined cooling, heating, power and hydrogen supply system and its operation method based on the comprehensive utilization of Carnot batteries. Background Technology

[0002] Energy storage typically refers to storing electrical energy using a medium or device, and then converting the stored energy back into electricity when needed. Energy storage technology is a key technology for addressing the instability and intermittency of renewable energy sources, and also a crucial technology for peak shaving and valley filling in conventional power systems, improving the efficiency and security of regional energy systems. Currently, heat pump energy storage is a novel energy storage technology developed using thermodynamic cycles and thermal storage techniques. It effectively avoids the environmental dependence and technological limitations of traditional pumped hydro storage, compressed air storage, and flow batteries. During energy storage, electrical energy is consumed to drive a reverse power cycle, pumping some of the heat energy below ambient temperature to a higher temperature for storage, thus simultaneously obtaining both low-temperature cold energy and high-temperature heat energy relative to the environment. During energy release, the stored low-temperature cold energy and high-temperature heat energy are converted into mechanical energy through a forward power cycle to drive the power generation unit.

[0003] However, for combined cooling, heating, electricity, and hydrogen systems, which integrate multiple energy sources, it is crucial to efficiently and accurately manage the energy matching between electricity and the cooling and heating components. Existing heat pump energy storage cannot meet the demands of combined cooling, heating, electricity, and hydrogen supply, making it difficult to establish an efficient and long-term combined storage and supply mode. When renewable energy sources are extensively integrated into the system, problems such as low operating efficiency and instability can easily occur, leading to inefficient absorption of renewable energy and hindering the grid's real-time frequency regulation and peak shaving, as well as the combined cooling, heating, electricity, and hydrogen supply. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a combined cooling, heating, power and hydrogen supply system based on the comprehensive utilization of Carnot batteries and its operation method, which can establish an efficient and long-term combined storage and supply mode and ensure the efficient, safe and stable operation of the system.

[0005] The objective of this invention can be achieved through the following technical solution: a combined cooling, heating, power and hydrogen supply system based on the comprehensive utilization of Carnot batteries, comprising a coaxial compressor and a coaxial expander connected coaxially. When the coaxial expander is connected to an electric motor / generator, the coaxial expander is connected to a cold storage tank. The cold storage tank is connected to the coaxial compressor through a second heat exchanger. The coaxial compressor is connected to a heat storage tank. The heat storage tank is connected to the coaxial expander through a first heat exchanger. A first buffer container is connected between the first heat exchanger and the second heat exchanger, thereby forming a heat pump circuit.

[0006] When a coaxial compressor is connected to an electric motor / generator, the coaxial compressor is connected to a heat storage tank, the heat storage tank is connected to a coaxial expander, the coaxial expander is connected to a second heat exchanger, the second heat exchanger is connected to a cold storage tank, the cold storage tank is connected to the coaxial compressor, a sixth heat exchanger is connected in parallel to both ends of the cold storage tank, a second buffer container is connected between the cold storage tank and the heat storage tank, a third heat exchanger and a fourth heat exchanger are connected in parallel to both ends of the heat storage tank, the third heat exchanger is connected to a fifth heat exchanger through a bypass expander, the bypass expander is connected to a proton exchange membrane electrolyzer to form a bypass organic Rankine cycle, and a condenser is connected in parallel to both ends of the fifth heat exchanger, thus forming a combined cooling, heating, power, and hydrogen production circuit;

[0007] Both the thermal storage tank and the cold storage tank are equipped with phase change devices. The combined cooling, heating, power and hydrogen production circuit includes a heat engine sub-circuit, a heating sub-circuit, a cooling sub-circuit, and a hydrogen production sub-circuit.

[0008] Furthermore, in the combined cooling, heating, power, and hydrogen production circuit, a first circulating fan is connected between the fourth heat exchanger and the heat storage tank to stabilize the pressure balance between the fourth heat exchanger and the heat storage tank and ensure smooth heat exchange.

[0009] Furthermore, the input end of the fourth heat exchanger is connected to a first pump for controlling the flow rate of the heating return water.

[0010] Furthermore, the fourth heat exchanger is specifically a shell-and-tube heat exchanger, in which heat return water is introduced into the tube side and the working fluid circulates into the heat storage tank on the shell side for heat exchange.

[0011] Furthermore, in the combined cooling, heating, power, and hydrogen production circuit, a second circulating fan is connected between the sixth heat exchanger and the cold storage tank to stabilize the pressure balance between the sixth heat exchanger and the cold storage tank and ensure smooth heat exchange.

[0012] Furthermore, the input end of the sixth heat exchanger is connected to a second pump for controlling the flow rate of the cooling return water.

[0013] Furthermore, the sixth heat exchanger is specifically a shell-and-tube heat exchanger, in which cooling return water is introduced through the tube side and the working fluid circulates into the cold storage tank through the shell side for heat exchange.

[0014] Furthermore, in the combined cooling, heating, power, and hydrogen production circuit, a third pump is connected between the fifth heat exchanger and the condenser to control the flow rate of the working fluid in the bypass organic Rankine cycle.

[0015] Furthermore, the internal structure of both the heat storage tank and the cold storage tank is a phase change bed or a bed-type stepped phase change device structure. The heat storage tank is equipped with a phase change heat storage medium, and the cold storage tank is equipped with a phase change cold storage medium.

[0016] A method for operating a combined cooling, heating, power and hydrogen supply system based on the comprehensive utilization of Carnot batteries includes the charging process of the heat pump circuit, the discharging process of the heat engine sub-circuit, the heating process of the heating sub-circuit, the cooling process of the cooling sub-circuit, and the hydrogen production process of the hydrogen production sub-circuit.

[0017] The charging process specifically involves using renewable energy or off-peak and surplus power supplied by the power grid to drive an electric motor, compressing the working fluid from a normal temperature and pressure state to a high temperature and pressure state, thus converting electrical energy into the internal energy of the working fluid.

[0018] The working fluid flows through the heat storage tank, transferring heat to the phase change device inside the tank. The thermocline inside the tank moves from the top to the bottom, and the temperature of the working fluid returns to normal.

[0019] The phase change device absorbs heat in the form of sensible heat and latent heat to store thermal energy. Then, the working fluid at high pressure and normal temperature enters the coaxial expander, expands and cools to a state of normal pressure and low temperature.

[0020] The working fluid flows in from the bottom of the cold storage tank, releases cold energy to the phase change device, and then returns to its initial state, completing one energy storage cycle.

[0021] The charging process is complete when all electrical energy is converted into heat energy and stored in the system or heat storage tank to reach its maximum rechargeable capacity.

[0022] The first heat exchanger and the second heat exchanger are used to stabilize the inlet gas temperature of the coaxial expander and the coaxial compressor, respectively. This heat and cold energy can be recovered and reused through the first heat exchanger and the second heat exchanger, respectively. The first buffer container is used to stabilize the pressure state during the charging process and ensure cycle stability.

[0023] The discharge process is as follows: the working fluid flows in the opposite direction, and the thermocline layer in the heat storage tank and the cold storage tank also moves in the opposite direction, transferring the heat / cold energy stored in the tank to the working fluid. The expansion of the working fluid drives the expander to drive the generator, thus completing the discharge process.

[0024] The second heat exchanger is used to recover irreversible losses during the discharge process, provide hot water for the hydrogen production process, and improve the overall efficiency of the system. The second buffer container is used to stabilize the pressure state during the discharge process.

[0025] The heating process is as follows: the fourth heat exchanger is connected to the heat storage tank and the third heat exchanger. It is determined whether to activate the bypass organic Rankine cycle based on the user's heating demand. When the bypass organic Rankine cycle is working, the fourth heat exchanger is used to further recover heat and improve the overall utilization efficiency of the system. When the bypass organic Rankine cycle is not working, the fourth heat exchanger is used to absorb the medium and low temperature heat in the heat storage tank and directly supply heat to the user.

[0026] In addition, the first heat exchanger is used to recover the heat lost irreversibly during the charging process, and the second heat exchanger is used to recover the heat lost irreversibly during the discharging process.

[0027] The cooling process is as follows: the sixth heat exchanger is connected to the cold storage tank. The sixth heat exchanger is used to release the cold energy stored in the energy storage tank for cooling. In addition, the second heat exchanger is used to recover the cold energy lost irreversibly during the charging process.

[0028] The hydrogen production process is as follows: During the discharge process, when the temperature of the heat storage tank is lower than the working temperature of the coaxial expander, the coaxial expander cannot work. At this time, the heat in the 120-200℃ temperature range in the heat storage tank is used to absorb heat through the third heat exchanger in the bypass organic Rankine cycle, drive the bypass organic Rankine cycle to generate electricity, and then use the hot water from the heating process in the proton exchange membrane electrolyzer to electrolyze water to produce hydrogen.

[0029] In addition, the working medium is preheated by the fifth heat exchanger and then reaches the third heat exchanger. After gaining heat, it is then used to generate electricity through the coaxial expander and recover waste heat through the fifth heat exchanger. After condensing in the condenser, it enters the next cycle.

[0030] Compared with existing technologies, this invention proposes a combined cooling, heating, electricity, and hydrogen supply system based on the comprehensive utilization of Carnot batteries. By constructing a heat pump circuit and a combined cooling, heating, electricity, and hydrogen production circuit including a heat engine sub-circuit, a heating sub-circuit, a cooling sub-circuit, and a hydrogen production sub-circuit, and utilizing heat storage tanks and cold storage tanks equipped with phase change devices, it can efficiently recover and utilize irreversible heat loss during the process. By utilizing thermal cycle electricity storage, heat and cold are stored in the system, and cooling and heating needs can be met flexibly and efficiently. This enables the establishment of an efficient and long-term combined storage and supply mode, thereby realizing the efficient consumption of new energy power, real-time frequency regulation and peak shaving of the power grid, and combined cooling, heating, electricity, and hydrogen supply, ensuring the efficient, safe, and stable operation of the system.

[0031] This invention fully integrates the Carnot battery and, by setting up a bypass organic Rankine cycle, can efficiently utilize the heat in the thermal storage tank to drive the bypass system to generate electricity, and use a proton exchange membrane electrolyzer to electrolyze water to produce hydrogen, thereby achieving the purpose of long-term energy storage and hydrogen supply, and improving energy utilization efficiency.

[0032] In the heating sub-circuit and cooling sub-circuit of the present invention, the corresponding fourth and sixth heat exchangers are both shell-and-tube heat exchangers, that is, they are connected to the user side through shell-and-tube heat exchangers, which can intelligently adjust the energy supply strategy of the system according to the user's heating and cooling load requirements.

[0033] In this invention, the internal structure of the thermal storage tank and the cold storage tank adopts a phase change bed or a bed-type stepped phase change device structure, which can achieve better heat exchange characteristics and a larger heat storage density. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the heat pump circuit charging process in this invention;

[0035] Figure 2 This is a schematic diagram of the combined cooling, heating, power, and hydrogen production circuit in this invention;

[0036] Figure 3 This is a schematic diagram of the system power supply structure of the present invention;

[0037] Figure 4 This is a schematic diagram illustrating a specific application strategy of the present invention;

[0038] Figure 5 This is a schematic diagram illustrating the system operation results analysis in the embodiment;

[0039] Figure 6 The figure shows the characteristic curves of the system performance parameters under different compression / expansion ratios in the embodiment.

[0040] The markings in the diagram are as follows: M, electric motor; G, generator; C, coaxial compressor; E, coaxial expander; E1, bypass expander; HR, thermal storage tank; CR, cold storage tank; CON, condenser; BV1, first buffer container; BV2, second buffer container; CF1, first circulating fan; CF2, second circulating fan; H2, proton exchange membrane electrolyzer; P1, first pump; P2, second pump; P3, third pump; HX1, first heat exchanger; HX2, second heat exchanger; HX3, third heat exchanger; HX4, fourth heat exchanger; HX5, fifth heat exchanger; HX6, sixth heat exchanger. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0042] Example

[0043] like Figure 1 and Figure 2 As shown, a combined cooling, heating, electricity, and hydrogen supply system based on the comprehensive utilization of Carnot batteries is described. The system includes a pair of coaxial compressors C / expander E, a bypass expander E1, a heat storage tank HR, a cold storage tank CR, a condenser CON, six heat exchangers HX1-HX6, a proton exchange membrane electrolyzer H2, two buffer containers BV1 and BV2, two circulating fans CF1 and CF2, three centrifugal pumps P1-P3, and several connecting pipes. The system is divided into five loops, namely the heat pump loop (e.g., Figure 1 As shown), a combined cooling, heating, power, and hydrogen production circuit (such as...) Figure 2 As shown, it includes a heat engine sub-circuit, a heating sub-circuit, a cooling sub-circuit, and a hydrogen production sub-circuit.

[0044] Specifically, the heat pump circuit is the charging cycle, such as... Figure 1 As shown, during the charging process, the motor M is driven by renewable energy or off-peak and surplus electricity supplied by the grid. Air is compressed from ambient temperature and pressure (25°C, 1 bar) to high temperature and pressure (500°C, 10 bar) by compressor C, converting electrical energy into the air's internal energy. The air flows through the thermal storage tank HR, transferring heat to the phase change capsule inside the tank. The thermocline layer inside the tank moves from the top to the bottom, restoring the air temperature to ambient temperature. The phase change capsule absorbs heat in the form of sensible and latent heat, achieving thermal energy storage. After being cooled by circulating cooling water in the first heat exchanger HX1, the air temperature returns to a high-pressure ambient temperature state (25°C, 10 bar). Then, the high-pressure ambient temperature air enters the expander E, expanding and cooling to an ambient pressure low temperature state (-150°C, 1 bar). The air flows in from the bottom of the cold storage tank CR, releasing cold energy to the phase change capsule. After absorbing heat through circulating water in the second heat exchanger HX2, it returns to its initial state, completing one energy storage cycle. The charging process is considered complete when all electrical energy is converted into heat energy and stored in the system, or when the energy storage tank reaches its maximum rechargeable capacity. During the process, the two heat exchangers (HX1 and HX2) stabilize the inlet gas temperature of the compressor C and expander E, and this heat and cold energy can be recovered and reused through the heat exchangers. The first buffer container BV1 stabilizes the pressure state during the process, ensuring cycle stability.

[0045] like Figure 2 As shown, the heat engine sub-loop, or discharge cycle, involves air flowing in the opposite direction during discharge. The thermocline within the heat storage tank HR also moves in the opposite direction, transferring the stored heat / cold energy to the air. The air expansion drives the expander E, which in turn drives the generator G, completing the discharge process. The second heat exchanger HX2 recovers irreversible losses during the process, providing hot water for the hydrogen production system and improving the overall system efficiency. The second buffer vessel BV2 aims to stabilize the pressure state during the process.

[0046] In the discharge process, air flows in the opposite direction. The working fluid, initially at ambient temperature and pressure, enters the cold storage tank CR, releasing heat to the phase change energy storage medium inside the tank, absorbing the cold energy of the storage medium, and transforming into a low-temperature state before flowing out of the cold storage tank. It then enters the compressor C, where it is compressed to a high-pressure, room-temperature state, and then enters the heat storage tank HR, absorbing heat from the heat storage medium before flowing out of the heat storage tank, where the working fluid becomes a high-temperature, high-pressure state. The working fluid then enters the expander E to perform work, which is ultimately converted into electrical energy by the generator G. After the working medium flows out of the expander, it enters the second heat exchanger HX2, releasing heat and returning to its initial state, completing one discharge cycle.

[0047] The heating sub-loop, or heating process, connects the fourth heat exchanger HX4 to the thermal storage tank HR and the third heat exchanger HX3. The activation of the bypass organic Rankine cycle is determined based on the user's heating demand. When the bypass system is operational, the fourth heat exchanger HX4 further recovers heat, improving the overall system efficiency. When the bypass system is not operational, the fourth heat exchanger HX4 directly absorbs most of the medium- and low-temperature heat from the thermal storage tank HR, directly supplying heat to the user. The fourth heat exchanger HX4 is a shell-and-tube heat exchanger; the return water from the heating system flows through the tube side, while air circulates into the thermal storage tank HR from the shell side for heat exchange, meeting the heating requirements. The flow rate of the return water from the heating system is controlled by the first pump P1, and the first circulating fan CF1 stabilizes the pressure balance between the fourth heat exchanger HX4 and the thermal storage tank HR, ensuring smooth heat exchange. The heat not only provides water to the user but also provides 70–80°C hot water to the proton exchange membrane hydrogen production system, fully utilizing the stored heat in the thermal storage tank HR and mitigating irreversible heat losses during the process.

[0048] That is, the heating process is divided into three heat outputs: the heat lost due to irreversible heat loss recovered by the first heat exchanger HX1 during the charging process, the heat lost due to irreversible heat loss recovered by the second heat exchanger HX2 during the discharging process, the heat stored in the heat storage tank HR, and the heat recovered from the bypass system, which is then supplied through the fourth heat exchanger HX4.

[0049] The cooling sub-loop is the cooling process. During the cooling process, the sixth heat exchanger HX6 is connected to the cold storage tank CR. Similar to the heating process, the sixth heat exchanger HX6 is a shell-and-tube heat exchanger. The return water from the cooling system flows into the tube side, while the air circulating into the cold storage tank CR on the shell side undergoes heat exchange to meet the cooling requirements. The flow rate of the return water from the cooling system is controlled by the second pump P2, and the second circulating fan CF2 stabilizes the pressure balance between the sixth heat exchanger HX6 and the cold storage tank CR, ensuring smooth heat exchange during the process.

[0050] That is, the cooling process consists of two cooling outputs: the cooling capacity recovered from irreversible heat loss during the charging process using the second heat exchanger HX2 and the cooling capacity stored in the cold storage tank CR, which are then supplied for cooling through the sixth heat exchanger HX6.

[0051] The hydrogen production sub-loop, or hydrogen production process, requires the expander E to operate when the temperature of the thermal storage tank HR is lower than the operating temperature of the expander E during discharge. The hydrogen production loop efficiently utilizes the heat within the 120–200°C temperature range of the thermal storage tank HR. The bypass organic Rankine cycle absorbs heat through the fifth heat exchanger HX5, causing the working fluid to evaporate. The flow rate of the working fluid in the bypass system is controlled by the third pump P3, efficiently utilizing the heat in the thermal storage tank HR in a cascade manner. The organic Rankine cycle achieves high operating efficiency between 120°C and 150°C. The working medium is pressurized under the drive of the third pump P3, preheated by the fifth heat exchanger HX5, and then passes through the bypass third heat exchanger HX3. After gaining heat, it generates electricity through the expander E, recovers some waste heat through the fifth heat exchanger HX5, and enters the condenser CON for condensation before entering the next cycle. The additional electricity generated in this process is used to produce hydrogen through water electrolysis. The proton exchange membrane electrolyzer H2 operates at a temperature between 70 and 80°C, and can be pre-adjusted to fully utilize the hot water in the heating circuit, providing a longer-term energy storage mechanism and energy utilization strategy.

[0052] In the hydrogen production process, the heat absorbed by the third heat exchanger HX3 in the heat storage tank HR during the discharge cycle drives the bypass system to generate electricity through an organic Rankine cycle. The hydrogen is then produced by electrolyzing water in the proton exchange membrane electrolyzer H2, using the hot water from the heating process.

[0053] In this embodiment, the inlets of the coaxial compressor C and the coaxial expander E are connected to buffer containers (BV1 and BV2) via valves and pipes. These buffer containers control the temporary storage of the working fluid, providing stable pressure and flow rate for the working fluid to flow smoothly through the energy storage tanks (HR and CR). Simultaneously, the working fluid experiences a certain pressure loss after passing through the heat exchanger and energy storage tanks. By regulating the pressure in the buffer containers and valves, the flow rate of the working fluid in the cold storage tank CR and the heat storage tank HR is stabilized, maintaining stable inlet pressure and operation of the expander E and compressor C. This reduces the impact of instability caused by changes in inlet parameters, thus affecting the equipment's service life and the overall system efficiency.

[0054] The heating sub-loop and cooling sub-loop are connected to the user side through shell-and-tube heat exchangers, which can feed back to the system based on the user's heating and cooling load requirements and intelligently adjust the system's energy supply strategy.

[0055] The hydrogen production sub-loop can efficiently utilize the heat in the thermal storage tank HR and the hot water in the heating circuit to produce hydrogen by electrolyzing water using a proton exchange membrane electrolyzer H2. The produced hydrogen can be supplied to nearby enterprises or combined with new energy hydrogen production systems.

[0056] In addition, the working fluid in the system, the working medium running throughout the system, includes, but is not limited to, air, argon, and helium;

[0057] The working pressure of the thermal storage tank HR does not exceed 1 MPa, and the working pressure of the cold storage tank CR is at atmospheric pressure.

[0058] Both the thermal storage tank HR and the cold storage tank CR have internal structures of phase change bed or stacked bed type cascade phase change device structures, which have good heat exchange characteristics and large heat storage density. The phase change heat storage medium of the thermal storage tank HR includes: NaOH solid powder with a phase change temperature of 318℃, KNO3 molten salt with a phase change temperature of 333℃, or Mg-Zn (49:51) alloy with a phase change temperature of 342℃. In this embodiment, NaOH solid powder with a phase change temperature of 318℃ is used. The phase change cold storage medium of the cold storage tank CR includes: CaCl2 (29.8wt.%) aqueous solution with a phase change temperature of -55℃, HCl (24.8wt.%) aqueous solution with a phase change temperature of -86℃, or LiCl (24wt.%) aqueous solution with a phase change temperature of -67℃. In this embodiment, CaCl2 (29.8wt.%) aqueous solution with a phase change temperature of -55℃ is used.

[0059] The operating temperature of the thermal storage tank HR is 25℃~500℃ (maximum temperature not exceeding 550℃), and the operating temperature of the cold storage tank CR is -150℃~25℃ (minimum operating temperature not lower than -160℃).

[0060] Butene is selected as the working fluid for the bypass organic Rankine cycle.

[0061] The coaxial compressor C and expander E have a compression / expansion ratio of 5-15.

[0062] like Figure 3 As shown, in practical applications, the sixth heat exchanger HX6 and the second heat exchanger HX2 provide cooling to the user side, while the fourth heat exchanger HX4, the second heat exchanger HX2, and the first heat exchanger HX1 provide heating to the user side and hot water to the proton exchange membrane electrolyzer H2. Furthermore, the process of powering electricity and producing hydrogen can be achieved by converting renewable energy power and off-peak electricity from the grid through a Carnot battery.

[0063] Applying the above technical solutions to practice, such as Figure 4 As shown, the energy supply strategy of the southern region is analyzed based on the seasonal characteristics of different seasons. In spring and autumn, the demand for heating and cooling is relatively low, and the main focus is on power supply. During this process, the heat in the thermal storage tank is efficiently utilized to electrolyze water and produce hydrogen. In summer, the main focus is on supplying cooling, with a small portion supplied for hot water and electricity. If most of the heat in the thermal storage tank is not utilized, it can be used to drive the bypass system to generate electricity, thereby producing hydrogen. In winter, the main focus is on supplying heating, with most of the heat used for heating and maintaining the basic demand for cooling.

[0064] This embodiment provides a theoretical analysis of the system charging process and a specific implementation case of combined cooling, heating, power, and hydrogen production. First, based on the user's energy consumption habits, heating and cooling strategies are pre-determined, utilizing energy in a tiered manner to achieve maximum efficiency. After determining the user's heating and cooling needs, intelligent control and utilization of high-temperature heat and low-temperature cold energy are used for power supply, with the remaining heat used to bypass the organic Rankine cycle system. During the heat absorption process of the organic Rankine cycle system, some heat is also recovered by the fourth heat exchanger HX4 and integrated with other excess heat and cold energy, distributing it to the user's heating and cooling supply. Figure 5 As shown, after determining the user's heating and cooling needs, calculations show that the thermal storage tank HR can be controlled to supply power when its temperature is between 300 and 500°C; when the thermal storage tank HR temperature is between 120 and 300°C, it can exchange heat with the bypass organic Rankine cycle system to drive water electrolysis for hydrogen production, and further recover heat to the user side through the fourth heat exchanger HX4; when the thermal storage tank HR temperature is below 120°C, the bypass organic Rankine cycle system is shut down, and the remaining heat in the thermal storage tank HR is directly recovered using the fourth heat exchanger HX4; the cold storage tank CR can supply power when its temperature is between -150 and 100°C; and the cold storage tank CR can supply cooling to cold storage facilities or refrigeration equipment when its temperature is between -100 and 0°C.

[0065] like Figure 6 As shown, based on different compression / expansion ratios, the optimal COP value, maximum temperature, and minimum temperature can be obtained for this system, thus facilitating equipment selection for different applications and efficient energy utilization. COP represents the system's performance parameter and is defined as:

[0066]

[0067] In the formula, E output E represents the output power. heat E represents the output heat. cold This indicates the output cooling capacity. E represents the calorific value of the output hydrogen gas. input E represents the amount of electricity input from renewable energy sources or during off-peak hours. pump This indicates the amount of electricity consumed by the pump during the cycle. For example, in this system, with a compression ratio and expansion ratio of 10, an isentropic efficiency of 0.95, a charging time of 5 hours, and simultaneous supply of cold, hot, electric, and hydrogen, Efficiency reached over 65%, and COP reached over 170%.

[0068] In summary, this technical solution addresses the shortcomings of existing technologies by proposing a combined cooling, heating, electricity, and hydrogen power supply system and its operation method based on the comprehensive utilization of Carnot batteries. It employs phase change thermal storage and combines two power cycle modes to establish an efficient and long-term combined storage and power supply system. This enables efficient consumption of new energy power, real-time frequency and peak regulation of the power grid, and combined cooling, heating, electricity, and hydrogen power supply. It features safety, stability, simple equipment, and high efficiency; under stable operating conditions, the system's coefficient of performance (COP) exceeds 100%.

[0069] Compared to traditional distributed systems, this technical solution utilizes thermodynamic cycle energy storage, storing heat and cold within the system and enabling flexible heating and cooling. Energy losses due to irreversible energy loss during system operation can be recovered and reused by the distributed system or hydrogen production system. The system can efficiently utilize electricity generated from renewable energy sources and off-peak electricity, exhibiting high conversion efficiency and COPS. The hydrogen production system can be fully integrated with Carnot batteries to improve energy utilization efficiency. This technical solution explores different operating modes for the system, addressing issues such as large-scale renewable energy integration and efficient utilization of distributed energy supply. It also boasts advantages such as high efficiency, safety, stability, lack of geographical limitations, and high energy storage density.

[0070] Therefore, this technical solution effectively solves the problems of consuming renewable energy power, utilizing off-peak electricity for energy storage, and combining cooling, heating, and power (CHP). It innovatively proposes a Carnot battery system for CHP, featuring low cost, high efficiency, and stable system operation, suitable for large-scale energy storage and discharging, as well as the construction of distributed energy resources. During charging, cold and heat are stored in the system, flexibly and efficiently meeting cooling and heating needs. The system utilizes renewable energy power and off-peak electricity, exhibiting high conversion efficiency and COP. By applying phase change energy storage technology within the storage tank and improving the system structure, irreversible heat loss during the process is efficiently recovered and utilized. This energy can be recovered and reused by the hydrogen production system and distributed systems. By combining Carnot batteries, the heat in the hot tank is fully and efficiently utilized to drive the bypass system for power generation, thereby producing hydrogen through water electrolysis, achieving long-term energy storage and hydrogen supply. This technical solution fully and efficiently utilizes energy, adjusting the ratio of cold, heat, electricity, and hydrogen according to user needs to maximize the efficiency of stored and utilized energy, improving energy conversion efficiency.

Claims

1. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of Carnot batteries, characterized in that, The system includes a coaxial compressor (C) and a coaxial expander (E) connected coaxially. When the coaxial expander (E) is connected to an electric motor / generator, the coaxial expander (E) is connected to a cold storage tank (CR). The cold storage tank (CR) is connected to the coaxial compressor (C) through a second heat exchanger (HX2). The coaxial compressor (C) is connected to a heat storage tank (HR). The heat storage tank (HR) is connected to the coaxial expander (E) through a first heat exchanger (HX1). A first buffer container (BV1) is connected between the first heat exchanger (HX1) and the second heat exchanger (HX2), thereby forming a heat pump circuit. When a coaxial compressor (C) is connected to an electric motor / generator, the coaxial compressor (C) is connected to a heat storage tank (HR), the heat storage tank (HR) is connected to a coaxial expander (E), the coaxial expander (E) is connected to a second heat exchanger (HX2), the second heat exchanger (HX2) is connected to a cold storage tank (CR), the cold storage tank (CR) is connected to the coaxial compressor (C), and a sixth heat exchanger (HX6) is connected in parallel across both ends of the cold storage tank (CR). The cold storage tank (CR) and the heat storage tank (HR)... A second buffer container (BV2) is connected between the two ends of the heat storage tank (HR). The third heat exchanger (HX3) and the fourth heat exchanger (HX4) are connected in parallel at both ends. The third heat exchanger (HX3) is connected to the fifth heat exchanger (HX5) through a bypass expander (E1). The bypass expander (E1) is connected to the proton exchange membrane electrolyzer (H2) to form a bypass organic Rankine cycle. The fifth heat exchanger (HX5) is connected in parallel at both ends to a condenser (CON), thereby forming a combined cooling, heating, electricity and hydrogen production circuit. Both the heat storage tank (HR) and the cold storage tank (CR) are equipped with phase change devices. The combined cooling, heating, power and hydrogen production circuit includes a heat engine sub-circuit, a heating sub-circuit, a cooling sub-circuit, and a hydrogen production sub-circuit.

2. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of Carnot batteries according to claim 1, characterized in that, In the combined cooling, heating, power and hydrogen production circuit, a first circulating fan (CF1) is connected between the fourth heat exchanger (HX4) and the heat storage tank (HR) to stabilize the pressure balance between the fourth heat exchanger (HX4) and the heat storage tank (HR) and ensure the smooth operation of heat exchange.

3. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of a Carnot battery according to claim 2, characterized in that, The input end of the fourth heat exchanger (HX4) is connected to the first pump (P1) for controlling the flow rate of the heating return water.

4. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of a Carnot battery, as described in claim 2 or 3, characterized in that... The fourth heat exchanger (HX4) is specifically a shell-and-tube heat exchanger, in which heat return water is introduced into the tube side and the working fluid is circulated into the heat storage tank (HR) on the shell side for heat exchange.

5. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of a Carnot battery according to claim 1, characterized in that, In the combined cooling, heating, power and hydrogen production loop, a second circulating fan (CF2) is connected between the sixth heat exchanger (HX6) and the cold storage tank (CR) to stabilize the pressure balance between the sixth heat exchanger (HX6) and the cold storage tank (CR) and ensure the smooth operation of heat exchange.

6. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of Carnot batteries according to claim 5, characterized in that, The input end of the sixth heat exchanger (HX6) is connected to a second pump (P2) for controlling the flow rate of the cooling return water.

7. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of a Carnot battery, as described in claim 5 or 6, characterized in that... The sixth heat exchanger (HX6) is specifically a shell-and-tube heat exchanger, in which cooling return water is introduced through the tube side and the working fluid is circulated into the cold storage tank (CR) through the shell side for heat exchange.

8. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of Carnot batteries according to claim 1, characterized in that, In the combined cooling, heating, power and hydrogen production circuit, a third pump (P3) is connected between the fifth heat exchanger (HX5) and the condenser (CON) to control the flow rate of the working fluid in the bypass organic Rankine cycle.

9. A combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of a Carnot battery according to claim 1, characterized in that, The internal structure of both the thermal storage tank (HR) and the cold storage tank (CR) is a phase change bed or a bed-type stepped phase change device structure. The thermal storage tank (HR) is equipped with a phase change thermal storage medium, and the cold storage tank (CR) is equipped with a phase change cold storage medium.

10. A method for operating a combined cooling, heating, power, and hydrogen supply system based on the comprehensive utilization of Carnot batteries, characterized in that, This includes the charging process of the heat pump circuit, the discharging process of the heat engine sub-circuit, the heating process of the heating sub-circuit, the cooling process of the cooling sub-circuit, and the hydrogen production process of the hydrogen production sub-circuit. The charging process specifically involves using renewable energy or off-peak and surplus power supplied by the power grid to drive an electric motor, compressing the working fluid from a normal temperature and pressure state to a high temperature and pressure state, thus converting electrical energy into the internal energy of the working fluid. The working fluid flows through the thermal storage tank (HR) and transfers heat to the phase change device inside the thermal storage tank (HR). The thermocline inside the thermal storage tank (HR) moves from the top to the bottom, and the temperature of the working fluid returns to normal. The phase change device absorbs heat in the form of sensible heat and latent heat to store thermal energy. Then, the working fluid at high pressure and normal temperature enters the coaxial expander (E) and expands and cools to a state of normal pressure and low temperature. The working fluid flows in from the bottom of the cold storage tank (CR), releases cold energy to the phase change device, and then returns to its initial state, completing one energy storage cycle. The charging process is complete when all electrical energy is converted into heat energy and stored in the system or when the thermal storage tank (HR) reaches its maximum rechargeable capacity. The first heat exchanger (HX1) and the second heat exchanger (HX2) are used to stabilize the inlet gas temperature of the coaxial expander (E) and the coaxial compressor (C) respectively. This heat and cold can be recovered and reused through the first heat exchanger (HX1) and the second heat exchanger (HX2) respectively. The first buffer container (BV1) is used to stabilize the pressure state during the charging process and ensure cycle stability. The discharge process is as follows: the working fluid flows in the opposite direction, and the thermocline in the thermal storage tank (HR) and the cold storage tank (CR) also moves in the opposite direction, transferring the heat / cold energy stored in the tank to the working fluid. The expansion of the working fluid drives the expander to drive the generator, thus completing the discharge process. The second heat exchanger (HX2) is used to recover irreversible losses during the discharge process, provide hot water for the hydrogen production process, and improve the overall efficiency of the system. The second buffer vessel (BV2) is used to stabilize the pressure state during the discharge process. The heating process is as follows: the fourth heat exchanger (HX4) is connected to the heat storage tank (HR) and the third heat exchanger (HX3). It determines whether to activate the bypass organic Rankine cycle based on the user's heating demand. When the bypass organic Rankine cycle is working, the fourth heat exchanger (HX4) is used to further recover heat and improve the overall utilization efficiency of the system. When the bypass organic Rankine cycle is not working, the fourth heat exchanger (HX4) is used to absorb the low-temperature heat in the heat storage tank (HR) and directly supply heat to the user. In addition, the first heat exchanger (HX1) is used to recover the heat lost irreversibly during the charging process, and the second heat exchanger (HX2) is used to recover the heat lost irreversibly during the discharging process. The cooling process is as follows: the sixth heat exchanger (HX6) is connected to the cold storage tank (CR). The sixth heat exchanger (HX6) is used to release the cold energy stored in the energy storage tank for cooling. In addition, the second heat exchanger (HX2) is used to recover the cold energy lost due to irreversible heat during the charging process. The hydrogen production process is as follows: During the discharge process, when the temperature of the thermal storage tank (HR) is lower than the operating temperature of the coaxial expander (E), the coaxial expander (E) cannot work. At this time, the heat in the 120-200℃ temperature range inside the thermal storage tank (HR) is used to absorb heat through the third heat exchanger (HX3) in the bypass organic Rankine cycle to drive the bypass organic Rankine cycle to generate electricity. Then, hydrogen is produced by electrolyzing water in the proton exchange membrane electrolyzer (H2) using the hot water from the heating process. In addition, the working medium is preheated by the fifth heat exchanger (HX5) and then reaches the third heat exchanger (HX3). After obtaining heat, it is then used to generate electricity by the coaxial expander (E), and the waste heat is recovered by the fifth heat exchanger (HX5). It then enters the condenser (CON) for condensation and enters the next cycle.

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