Hydrogen energy comprehensive utilization system using heat pump to recover heat and operation method thereof

Abstract

The application provides a hydrogen energy comprehensive utilization system adopting a heat pump to recover heat and a running method thereof, comprising a solid-state hydrogen storage unit, a heat pump unit, a hydrogen fuel cell unit and an automatic control unit, the hydrogen fuel cell unit can supply power for an electric power load and the heat pump unit, the heat pump unit can recover low-temperature heat generated by the hydrogen fuel cell unit, increase the temperature and then provide heat for hydrogen release of the solid-state hydrogen storage unit, the solid-state hydrogen storage unit supplies hydrogen for the hydrogen load and the hydrogen fuel cell unit, and through automatic adjustment of the automatic control unit, the coupling system maximizes utilization of hydrogen chemical energy and also maximizes heat utilization.

Description

Technical Field

[0001] This invention relates to the field of heat pump technology, and in particular to a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat and its operation method. Background Technology

[0002] A heat pump is a highly efficient energy-saving device that fully utilizes low-grade heat energy. Heat pump technology is a highly efficient energy conversion device that absorbs heat from a low-temperature heat source at the cost of less electricity, generating several times the return on heat energy. A hydrogen fuel cell is a device that converts the chemical energy in hydrogen and an oxidant into electrical and heat energy through an electrochemical reaction, with zero carbon emissions. It not only provides all or part of the electrical energy needed for the heat pump system, but also further heats industrial water, increasing the temperature of the industrial water when it enters the heat pump system.

[0003] Patent document 1 (CN114046615A) discloses a hydrogen fuel cell and heat pump interconnection system, including a hydrogen fuel cell, a heat pump, etc. It utilizes the electrical energy and thermal energy generated by the hydrogen fuel cell. The thermal energy is directly used to heat industrial water, and the electrical energy drives the heat pump to recover the heat from the wastewater heat source of the system and indirectly use it to heat industrial water. This achieves the goal of zero carbon emissions and economic benefits slightly higher than those of traditional natural gas, and improves the overall energy efficiency of the entire system.

[0004] Patent document 1 describes the use of a hydrogen fuel cell to drive a heat pump to recover heat from wastewater heat sources. However, for applications without low-temperature heat sources or industrial heat demand, approximately 50% of the heat generated by the operation of the hydrogen fuel cell, which accounts for the chemical energy of hydrogen, cannot be recovered and utilized. The independent operation of the hydrogen fuel cell will result in a large amount of heat loss. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by proposing a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat. This system can raise the temperature of the low-grade heat energy generated by the hydrogen fuel cell through a heat pump unit, thereby providing heat for the hydrogen release of the solid hydrogen storage unit, recovering most of the heat generated by the hydrogen fuel cell unit, and improving energy utilization efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a hydrogen energy comprehensive utilization system using a heat pump to recover heat, comprising a solid-state hydrogen storage unit, a heat pump unit, a hydrogen fuel cell unit, and an automatic control unit. The hydrogen fuel cell unit is equipped with a first heat exchanger, and the heat medium inlet and outlet of the first heat exchanger are respectively connected to the outlet and inlet of a cooling plate inside the hydrogen fuel cell unit via pipelines. The solid-state hydrogen storage unit includes one or more hydrogen storage modules, and a second heat exchanger is installed inside each solid-state hydrogen storage module. The hydrogen outlet of the solid-state hydrogen storage unit is connected to the hydrogen fuel cell unit via a pipeline. The hydrogen inlet of the battery unit is connected to an external hydrogen load. The power output of the hydrogen fuel cell unit is electrically connected to the electric heating structure of the solid-state hydrogen storage unit and the external power load. The expansion valve outlet of the heat pump unit is connected to the refrigerant inlet of the first heat exchanger via a pipeline. The refrigerant outlet of the first heat exchanger is connected to the compressor inlet of the heat pump unit. The compressor outlet of the heat pump unit is connected to the heat medium inlet of the second heat exchanger via a pipeline. The expansion valve inlet of the heat pump unit is connected to the heat medium outlet of the second heat exchanger. The power output of the hydrogen fuel cell unit is electrically connected to the heat pump unit. This invention couples a solid-state hydrogen storage device, a hydrogen fuel cell, and a heat pump unit together, enabling large-scale hydrogen storage and transportation. It can also provide electricity and hydrogen to downstream applications according to load requirements. Furthermore, the system, coupled with a heat pump unit, can elevate the low-temperature heat source released during hydrogen fuel cell operation to a high-temperature heat source, providing heat for the solid-state hydrogen storage unit when releasing hydrogen, significantly improving the utilization rate of hydrogen chemistry.

[0007] Furthermore, the second heat exchanger comprises heat transfer channels uniformly arranged within the solid-state hydrogen storage unit. These channels have parallel upper and lower wall plates, with solid hydrogen storage material filling the space between the lower wall plate of the upper heat transfer channel and the upper wall plate of the lower heat transfer channel. Since the solid-state hydrogen storage material used in the solid-state hydrogen storage unit typically has a low heat transfer coefficient, uniformly arranging the heat transfer channels of the second heat exchanger within the solid-state hydrogen storage unit increases the heat exchange area while ensuring uniform temperature across the solid-state hydrogen storage material, thus stabilizing and uniformly increasing the hydrogen release rate throughout the solid-state hydrogen storage unit.

[0008] Furthermore, the cross-sectional shape of the heat medium channel is rectangular or circular. Rectangular and circular cross-sections allow the heat medium to pass through the channel evenly, resulting in uniform heat transfer and simple manufacturing.

[0009] Furthermore, the automatic control unit includes a first subunit controlling the solid-state hydrogen storage unit, a second subunit controlling the hydrogen fuel cell unit, and a third subunit controlling the heat pump unit. The first subunit includes components for monitoring and controlling the temperature of the hydrogen storage module in the solid-state hydrogen storage unit, the flow and temperature of the heat transfer oil, the flow and temperature of hydrogen, and the electric heating power. The second subunit includes components for detecting and controlling the anode hydrogen flow rate, hydrogen humidity, cathode air or oxygen flow rate and humidity, hydrogen fuel cell temperature, cooling water flow rate and temperature, and the output power of the hydrogen fuel cell. The third subunit includes components for monitoring the cooling temperature, heating temperature, and heat transfer oil flow rate of the heat pump unit. The automatic control unit automatically detects the operating temperature of the hydrogen fuel cell and maintains a stable operating temperature by controlling the flow and temperature of the refrigerant from the heat pump unit to the first heat exchanger. The automatic control unit automatically detects the operating temperature and hydrogen flow rate of the solid-state hydrogen storage unit and maintains a stable hydrogen release rate by controlling the flow and temperature of the heat transfer medium from the heat pump unit to the second heat exchanger.

[0010] Furthermore, the heat pump unit is either a thermoelectric heat pump or a chemical heat pump. Depending on the operating temperature of the solid-state hydrogen storage unit and the site conditions, either a thermoelectric heat pump or a chemical heat pump is selected as the heat pump unit.

[0011] Another object of the present invention discloses an operation method for a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat. The hydrogen energy comprehensive utilization system using the above-mentioned heat pump to recover heat includes the following steps:

[0012] S1. Introduce hydrogen gas from outside the boundary into the hydrogen fuel cell unit, start the hydrogen fuel cell unit, and distribute power to the electrical load and heat pump unit through the automatic control unit.

[0013] S2. Start the heat pump unit, adjust the operating power of the heat pump unit through the automatic control unit, and remove the heat released by the hydrogen fuel cell unit during operation through the refrigerant circulation of the first heat exchanger, so that the operating temperature of the hydrogen fuel cell unit is stable at T1; T1 is the stable operating temperature of the hydrogen fuel cell unit, and T1 is preferably 80-90℃.

[0014] S3. While maintaining the operating temperature of the hydrogen fuel cell unit at a stable T1, the heat pump unit raises the temperature of the heat medium in the second heat exchanger to T2 to provide heat for the solid hydrogen storage unit; T2 is the inlet temperature of the heat medium in the solid hydrogen storage unit, and T2 is preferably 300-320℃.

[0015] S4. When the temperature of the solid hydrogen storage unit reaches T3, the solid hydrogen storage unit begins to release hydrogen, and the hydrogen flow rate supplied to the hydrogen load and the hydrogen fuel cell unit is adjusted by the automatic control unit; T3 is the initial hydrogen release temperature of the solid hydrogen storage unit, and T3 is preferably 250°C.

[0016] S5. Gradually phase out hydrogen from outside the boundary area and use hydrogen produced by solid-state hydrogen storage units as fuel for hydrogen fuel cell units.

[0017] This invention discloses a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat, which has the following advantages compared with the prior art:

[0018] 1) Most of the heat generated during the operation of hydrogen fuel cells can be recovered and heated by a heat pump system to provide the heat required for hydrogen release to the solid hydrogen storage unit, which greatly improves the utilization rate of hydrogen chemical energy.

[0019] 2) This invention automatically controls the operating temperature of the hydrogen fuel cell and the solid hydrogen storage unit through an automatic control unit, and can automatically adjust the output power and hydrogen flow rate as needed. By controlling the power of the heat pump unit, the overall heat exchange efficiency is maximized. Attached Figure Description

[0020] Figure 1 A process flow diagram of a coupling system for a solid-state hydrogen storage device, a hydrogen fuel cell, and a heat pump unit;

[0021] Figure 2 This is a top-view cross-sectional view of a solid-state hydrogen storage device.

[0022] Figure 3 A frontal cross-sectional view of a solid-state hydrogen storage device.

[0023] 1. Solid-state hydrogen storage unit; 2. Second heat exchanger; 3. Heat pump unit; 4. First heat exchanger; 5. Hydrogen fuel cell unit; 11. Heat medium inlet; 12. Heat medium outlet; 13. Heat medium channel. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments: Example 1

[0025] This embodiment discloses a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat, such as... Figure 1-3As shown, the system includes a solid-state hydrogen storage unit 1, a heat pump unit 3, a hydrogen fuel cell unit 5, and an automatic control unit. The hydrogen fuel cell unit is equipped with a first heat exchanger 4. The heat medium inlet and outlet of the first heat exchanger 4 are connected to the cooling plate outlet and inlet inside the hydrogen fuel cell unit 5 via pipelines, respectively. The solid-state hydrogen storage unit 1 includes one or more hydrogen storage modules. A second heat exchanger 2 is installed inside each solid-state hydrogen storage module. The solid-state hydrogen storage unit 1 is connected to the hydrogen fuel cell unit via pipelines and is electrically connected to the hydrogen fuel cell unit 5. The heat pump unit 3 is connected to the refrigerant inlet and refrigerant outlet of the first heat exchanger 4 via pipelines. The compressor outlet of the heat pump unit 3 is connected to the heat medium inlet 11 of the second heat exchanger 2 via a pipeline. The expansion valve inlet of the heat pump unit 3 is connected to the heat medium outlet 12 of the second heat exchanger 2. The hydrogen fuel cell unit 5 is electrically connected to the heat pump unit 3. The second heat exchanger 2 is a heat medium channel 13 uniformly arranged inside the solid-state hydrogen storage unit 1. The heat medium channel 13 has a rectangular cross-sectional shape and is a plate structure with parallel upper and lower walls. Solid hydrogen storage material is filled between the lower wall of the upper heat medium channel and the upper wall of the lower heat medium channel. The heat pump unit is a thermoelectric heat pump.

[0026] The automatic control unit includes a first subunit for controlling the solid-state hydrogen storage unit 1, a second subunit for controlling the hydrogen fuel cell unit 5, and a third subunit for controlling the heat pump unit 3. The first subunit includes components for monitoring and controlling the temperature of the hydrogen storage module in the solid-state hydrogen storage unit 1, the flow rate and temperature of the heat transfer medium, the flow rate and temperature of hydrogen, and the electric heating power. Multiple temperature sensor probes are installed inside the hydrogen storage material of the hydrogen storage module. Flow meters and temperature sensors are respectively installed at the heat transfer medium inlet 11 and outlet 12 of the second heat exchanger. The flow rate of the heat transfer medium in the second heat exchanger is automatically adjusted based on the temperature feedback from the temperature sensors. The second subunit includes components for detecting and controlling the hydrogen flow rate at the anode, the hydrogen humidity, and the cathode air or oxygen in the hydrogen fuel cell unit 5. The components include gas flow and humidity, hydrogen fuel cell temperature, cooling water flow and temperature, and hydrogen fuel cell output power. The hydrogen inlet pipe of the fuel cell is equipped with a hydrogen flow meter and a hygrometer. A temperature sensor is installed inside the fuel cell. A flow meter is installed in the cooling water pipe of the fuel cell. Temperature sensors are installed at the cooling water inlet and outlet. The cooling water flow of the fuel cell is automatically adjusted based on the temperature feedback from the temperature sensor inside the fuel cell. The third subunit includes components for monitoring the cooling temperature, heating temperature, and heat transfer medium flow of the heat pump unit 3. Temperature sensors are installed at the compressor inlet and outlet. Temperature sensors are also installed at the expansion valve inlet and outlet. A pressure sensor and a flow meter are installed on the heat transfer medium pipe of the heat pump unit. The compressor motor is a variable frequency motor.

[0027] Upon system startup, hydrogen from outside the boundary is first introduced into the hydrogen fuel cell unit, activating it. Power is then distributed to the electrical load and heat pump unit via the automatic control unit. The heat pump unit is then activated, and its operating power is adjusted by the automatic control unit. The heat released by the hydrogen fuel cell unit during operation is removed through the refrigerant circulation in the first heat exchanger, stabilizing the unit's operating temperature at 90°C. To maintain this stable temperature, the heat pump unit raises the refrigerant temperature in the second heat exchanger to 320°C, providing heat to the solid-state hydrogen storage unit. When the solid-state hydrogen storage unit reaches 250°C, it begins releasing hydrogen. The automatic control unit maintains the solid-state hydrogen storage unit temperature between 250°C and 300°C, ensuring a stable hydrogen flow to the hydrogen load and fuel cell unit. The hydrogen from outside the boundary is gradually phased out, and the hydrogen produced by the solid-state hydrogen storage unit is used exclusively as fuel for the fuel cell unit.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An operation method for a hydrogen energy comprehensive utilization system that uses a heat pump to recover heat, characterized in that: Specifically, the following steps are included: S1. Introduce hydrogen gas from outside the boundary into the hydrogen fuel cell unit (5), start the hydrogen fuel cell unit (5), and distribute power to the external power load and heat pump unit (3) through the automatic control unit; S2. Start the heat pump unit, adjust the operating power of the heat pump unit (3) through the automatic control unit, and remove the heat released by the hydrogen fuel cell unit (5) during operation through the refrigerant circulation of the first heat exchanger (4), so that the operating temperature of the hydrogen fuel cell unit (5) is stable at T1, where T1 is 80-90℃; S3. While maintaining the operating temperature of the hydrogen fuel cell unit (5) at a stable T1, the heat pump unit (3) raises the temperature of the heat medium of the second heat exchanger (2) to T2 to provide heat for the solid hydrogen storage unit (1). T2 is 300-320℃. S4. When the temperature of the solid hydrogen storage unit (1) reaches T3, the solid hydrogen storage unit (1) starts to release hydrogen. The flow rate of hydrogen supplied to the external hydrogen load and the hydrogen fuel cell unit (5) is adjusted by the automatic control unit. T3 is 250°C. S5. Gradually phase out hydrogen outside the boundary area and use hydrogen generated by the solid hydrogen storage unit (1) as fuel for the hydrogen fuel cell unit (5); The hydrogen energy comprehensive utilization system using a heat pump to recover heat includes a solid hydrogen storage unit (1), a heat pump unit (3), a hydrogen fuel cell unit (5), and an automatic control unit. The hydrogen fuel cell unit (5) is equipped with a first heat exchanger (4). The heat medium inlet and outlet of the first heat exchanger (4) are respectively connected to the cooling plate outlet and inlet inside the hydrogen fuel cell unit (5) through pipelines. The solid hydrogen storage unit (1) includes one or more hydrogen storage modules. The solid hydrogen storage unit (1) is equipped with a second heat exchanger (2). The hydrogen outlet of the solid hydrogen storage unit (1) is connected to the hydrogen inlet and external hydrogen storage tank of the hydrogen fuel cell unit (5) through pipelines. The hydrogen fuel cell unit (5) is connected to the power output terminal of the hydrogen fuel cell unit (5) and the electric heating structure and external power load of the solid hydrogen storage unit (1). The expansion valve outlet of the heat pump unit (3) is connected to the refrigerant inlet of the first heat exchanger (4) through a pipeline. The refrigerant outlet of the first heat exchanger (4) is connected to the compressor inlet of the heat pump unit (3). The compressor outlet of the heat pump unit (3) is connected to the heat medium inlet (11) of the second heat exchanger (2) through a pipeline. The expansion valve inlet of the heat pump unit is connected to the heat medium outlet (12) of the second heat exchanger (2). The power output terminal of the hydrogen fuel cell unit (5) is connected to the heat pump unit (3). The second heat exchanger (2) is a heat medium channel (13) uniformly arranged inside the solid hydrogen storage unit (1).

2. The operation method of a hydrogen energy comprehensive utilization system using a heat pump to recover heat according to claim 1, characterized in that: The cross-sectional shape of the heat medium channel (13) is rectangular or circular.

3. The operation method of a hydrogen energy comprehensive utilization system using a heat pump to recover heat according to claim 1, characterized in that: The automatic control unit includes a main control unit, a first sub-unit for controlling the solid hydrogen storage unit (1), a second sub-unit for controlling the hydrogen fuel cell unit (5), and a third sub-unit for controlling the heat pump unit (3). The main control unit is communicatively connected to the first sub-unit, the second sub-unit, and the third sub-unit, respectively. The first subunit includes components for monitoring and controlling the temperature, heat transfer oil flow rate and temperature, hydrogen flow rate and temperature, and electric heating power of the solid hydrogen storage unit (1) hydrogen storage module; The second subunit includes components for detecting and controlling the hydrogen fuel cell unit (5) anode hydrogen flow rate, hydrogen humidity, cathode air or oxygen flow rate and humidity, hydrogen fuel cell temperature, cooling water flow rate and temperature, and hydrogen fuel cell output power. The third subunit includes components that monitor the cooling temperature, heating temperature and heat transfer oil flow rate of the heat pump unit (3).

4. The operation method of a hydrogen energy comprehensive utilization system using a heat pump to recover heat according to claim 1, characterized in that: The heat pump unit (3) is a thermoelectric heat pump or a chemical heat pump.

Images