A multi-system coupled heat, power and water cogeneration system and method

Abstract

The invention discloses a multi-system coupled heat, electricity and water cogeneration system and method, comprising a solar energy system, a water electrolyzer system, a fuel cell system, a heat pump system and a membrane distillation system; the solar energy system and the fuel cell system provide electric energy and heat energy for users; the water electrolyzer system utilizes the electric energy provided by the solar energy system to produce hydrogen, and provides it to the fuel cell system; the liquid treatment water of the membrane distillation system utilizes the heat of the solar energy system and the fuel cell system to produce drinkable fresh water; the heat pump system is coupled to the membrane distillation system through a condenser and an evaporator; based on the principle of energy cascade utilization, the invention integrates the solar energy system, the water electrolyzer, the fuel cell system, the heat pump system and the membrane distillation system into one, has a good temperature matching effect, and can achieve the purpose of providing electric energy, drinkable fresh water, domestic hot water and energy storage.

Description

Technical Field

[0001] The present invention relates to the technical field of renewable energy utilization and energy system, and in particular to a multi-system coupled heat, power and water cogeneration system and method. Background Art

[0002] Renewable energy such as solar energy has problems such as intermittency and discontinuity, and a suitable energy carrier is needed to provide users with continuous and reliable energy. Hydrogen energy has attracted much attention as one of the alternative energy sources to traditional fossil energy, and coupling photovoltaic power generation and water electrolysis hydrogen production technology can achieve the goal of energy conservation and emission reduction.

[0003] Traditional energy systems mainly meet people's needs for electricity, cooling and heat in a distributed manner, and their energy utilization efficiency is low, resulting in resource waste and serious environmental pollution. Distributed combined power generation system is an efficient, reliable and environmentally friendly energy system, and is an important development direction in the current field of comprehensive energy utilization technology.

[0004] With the increasing scarcity of freshwater resources and the increasing demand, freshwater production technology has achieved unprecedented development. Low-grade heat-driven membrane distillation water treatment technology is considered to be an effective water purification method, which can be widely used in the fields of seawater and brackish water desalination, especially in the treatment of high-concentration salt water. The inventors found that the existing combined supply system usually couples two systems to achieve the supply of one or two energies, which cannot meet people's needs for multiple energies at the same time. Therefore, it is urgent to study a multi-energy combined supply system that can achieve combined heat, electricity and water. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a multi-system coupled heat, power and water cogeneration system and method, which integrates solar photovoltaic / solar thermal, proton exchange membrane water electrolyzer, fuel cell, heat pump and membrane distillation into one, thereby improving the comprehensive energy utilization efficiency.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the present invention, a multi-system coupled heat, power and water cogeneration system is provided, comprising a solar energy system, a water electrolyzer system, a fuel cell system, a heat pump system and a membrane distillation system;

[0008] The solar energy system and the fuel cell system provide electricity and heat energy for users; the water electrolyzer system utilizes the electricity provided by the solar energy system to produce hydrogen, and provides it to the fuel cell system; the liquid treatment water of the membrane distillation system utilizes the heat of the solar energy system and the fuel cell system to produce drinkable fresh water; the heat pump system is coupled to the membrane distillation system through a condenser and an evaporator.

[0009] In some embodiments of the present invention, the solar energy system includes a solar photovoltaic and thermal integrated component, wherein the photovoltaic component is connected to a DC controller, and the thermal component is connected to a water pump and a hot water storage tank in sequence.

[0010] In some embodiments of the present invention, one path of the DC controller is connected to a DC / AC converter to provide power to users, and the other path is connected to a DC / DC converter to provide power to a water electrolyzer system.

[0011] In some embodiments of the present invention, the water electrolyzer system includes a PEM water electrolyzer, and a hydrogen outlet of the PEM water electrolyzer is connected to a hydrogen storage bottle.

[0012] In some embodiments of the present invention, the fuel cell system includes a PEMFC stack, the hydrogen inlet of the PEMFC stack is connected to a hydrogen storage bottle, the oxygen inlet is connected to an air compressor, and the anode and cathode wet gas outlets of the PEMFC stack are both provided with gas-liquid separators, and the liquid outlet of the gas-liquid separator is connected to a water tank.

[0013] In some embodiments of the present invention, the membrane distillation system includes a membrane distillation component, a feed liquid tank and a permeate liquid tank, and the feed liquid outlet of the feed liquid tank is connected to the high-temperature feed liquid inlet of the membrane distillation component through a heat exchanger of a fuel cell system, a hot water storage tank of a solar energy system and a condenser of a heat pump system.

[0014] In some embodiments of the present invention, the permeate outlet of the membrane distillation module is connected to the permeate tank via an evaporator of a heat pump system.

[0015] In some embodiments of the present invention, the heat pump system includes a compressor, a condenser, a throttle valve and an evaporator connected in sequence.

[0016] In some embodiments of the present invention, the heat pump system further includes a regenerator for exchanging heat between the high-temperature heat pump working fluid from the evaporator and the low-temperature heat pump working fluid from the condenser.

[0017] In a second aspect of the present invention, a multi-system coupled heat, power and water cogeneration method is provided, comprising:

[0018] When solar radiation is sufficient, the solar system provides electricity and hot water to users, and the membrane distillation system provides drinkable fresh water to users;

[0019] When solar radiation is insufficient, the solar energy system provides partial electricity and hot water for users, the fuel cell system provides electricity for users, and the membrane distillation system provides drinkable fresh water for users;

[0020] When there is no solar radiation, the hot water storage tank provides hot water for users, the fuel cell system provides electricity for users, and the membrane distillation system provides drinkable fresh water for users.

[0021] One or more technical solutions of the present invention have the following beneficial effects:

[0022] (1) The present invention introduces a membrane distillation system to recover the medium and low temperature waste heat of the fuel cell system and the solar energy system to produce drinkable fresh water, thereby improving energy utilization efficiency; and organically combines the heat pump system with the membrane distillation system to further improve the heat exchange efficiency in the membrane distillation process.

[0023] (2) The present invention is based on the principle of energy cascade utilization, integrating a solar energy system, a water electrolyzer, a fuel cell system, a heat pump system and a membrane distillation system into one, having a good temperature matching effect, and can achieve the purpose of providing electricity, drinkable fresh water, domestic hot water and energy storage.

[0024] (3) The multi-system coupled cogeneration system proposed in the present invention can continuously provide electricity, potable fresh water and domestic hot water to users according to different operating conditions, and the entire system will not be affected by the discontinuity of solar energy.

[0025] (4) The multi-system coupled cogeneration system of the present invention is provided with a plurality of heat exchangers and heat regenerators, which can recycle the heat generated by each system, thereby maximizing energy utilization and improving energy utilization rate.

[0026] (5) The multi-system coupled heat, power and water cogeneration system proposed in the present invention has a short construction period, convenient maintenance and can be "unmanned". It can be used in military fields, border areas, islands and remote areas that are difficult to cover by public power grids, to meet users' heat, power and water needs, and achieve the goals of energy conservation, emission reduction and improving energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of a multi-system coupled cogeneration system according to Example 1 of the present invention.

[0028] In the figure, 1, solar photovoltaic and thermal integrated component, 2, DC controller, 3, first DC / AC converter, 4, DC / DC converter, 5, PEM water electrolyzer, 6, first electricity user, 7, hydrogen storage bottle, 8, air compressor, 9, pressure reducing valve, 10, first confluence valve, 11, air humidifier, 12, hydrogen humidifier, 13, hydrogen compressor, 14, PEMFC stack, 15, first gas-liquid separator, 16, second gas-liquid separator, 17, second DC / AC converter, 18, second electricity user, 19, second confluence valve, 20, water storage tank, 21, first water pump, 22, first heat exchanger, 23, liquid tank, 24, second water pump, 25, second heat exchanger, 26, fresh water user, 27, permeate tank, 28, third water pump, 29, membrane distillation component, 30, evaporator, 31. Throttle valve, 32. Regenerator, 33. Heat pump working fluid compressor, 34. Condenser, 35. First valve, 36. Second valve, 37. Third valve, 38. Fourth valve, 39. Heat storage tank, 40. Fourth water pump, 41. Hot water user. DETAILED DESCRIPTION

[0029] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] For the convenience of description, if the words "up", "down", "left" and "right" appear in the present invention, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0032] Example 1

[0033] In a typical embodiment of the present invention, a multi-system coupled heat, power and water cogeneration system is proposed, such as Figure 1As shown, it includes a solar energy system, a water electrolyzer system, a fuel cell system, a heat pump system and a membrane distillation system; the solar energy system and the fuel cell system provide electric energy and thermal energy to users; the water electrolyzer system utilizes the electric energy provided by the solar energy system to produce hydrogen, and provides it to the fuel cell system; the liquid treatment water of the membrane distillation system utilizes the heat of the solar energy system and the fuel cell system to produce drinkable fresh water; the heat pump system is coupled to the membrane distillation system through a condenser and an evaporator.

[0034] The solar energy system includes a solar photovoltaic and thermal integrated component (PVT) 1, the photovoltaic component in the solar photovoltaic and thermal integrated component is connected to a DC controller 2, the thermal component is connected to a fourth water pump 40 and a hot water storage tank 39 in sequence, one of the paths of the DC controller 2 is connected to a first DC / AC converter 3 to provide electric energy to users, and the other path is connected to a DC / DC converter 4 to provide electric energy to a water electrolyzer system, the photovoltaic component converts solar energy into electric energy, the DC controller 2 is used to control the direct current generated by the photovoltaic component, the first DC / AC converter 3 converts direct current into alternating current for a first electric user 6, the DC / DC converter 4 converts direct current into direct current matching the operation of a PEM water electrolyzer 5 to produce hydrogen; the thermal component converts solar energy into thermal energy to heat water, the hot water is stored in a hot water storage tank 39, and is used to heat the feed liquid and provide domestic hot water.

[0035] The water electrolyzer system includes a PEM water electrolyzer 5. The PEM water electrolyzer uses a solid proton exchange membrane as an electrolyte and pure water as a reactant. It uses electrical energy to ionize water to produce hydrogen. The hydrogen outlet of the PEM water electrolyzer is connected to a hydrogen storage bottle 7, which stores hydrogen.

[0036] The fuel cell system is a proton exchange membrane fuel cell (PEMFC) system, including a PEMFC stack 14, wherein the hydrogen inlet of the PEMFC stack 14 is connected to a hydrogen storage bottle 7 through a pressure reducing valve 9, and the oxygen inlet is connected to an air compressor 8. The anode and cathode wet gas outlets of the PEMFC stack are provided with a first gas-liquid separator 15 and a second gas-liquid separator 16 for recovering moisture in the wet gas at the anode and cathode outlets of the PEMFC stack. The liquid outlets of the first gas-liquid separator 15 and the second gas-liquid separator 16 are connected to a second confluence. The valve 19 is connected to the water tank 20, which stores the recovered water. The gas outlet of the first gas-liquid separator 15 enters the hydrogen pipeline through the hydrogen compressor 13 and the first confluence valve 10. A hydrogen humidifier 12 is arranged between the hydrogen inlet of the PEMFC stack and the hydrogen storage bottle, and an air humidifier 11 is arranged between the oxygen inlet and the air compressor 8. The water in the hydrogen humidifier and the air humidifier comes from the water tank 20. The electric energy generated by the PEMFC stack is converted into alternating current through the second DC / AC converter 17 and provided to the second electricity user 18.

[0037] Since the fuel cell system generates a large amount of heat, a first heat exchanger 22 is also provided in the fuel system. The first water pump 21 pumps water into the PEMFC stack to take away the heat generated by it, and then enters the first heat exchanger to exchange the heat with the feed liquid of the membrane distillation system. The cooled water enters the PEMFC stack again for cooling, and this process is repeated continuously.

[0038] The membrane distillation system includes a membrane distillation component 29, a feed liquid tank 23 and a permeate liquid tank 27. The feed liquid outlet of the feed liquid tank 23 is connected to the high-temperature feed liquid inlet of the membrane distillation component 29 through the first heat exchanger 22 of the fuel cell system, the hot water storage tank 39 of the solar energy system and the condenser 34 of the heat pump system; the permeate liquid outlet of the membrane distillation component is connected to the permeate liquid tank 27 through the evaporator 30 of the heat pump system to provide fresh water for the fresh water user 26, and part of the fresh water in the permeate liquid tank re-enters the membrane distillation component 29 for circulation under the action of the third water pump.

[0039] Furthermore, the high-temperature liquid outlet of the membrane distillation component 29 returns to the liquid tank 23 again through the second heat exchanger 25. The liquid in the liquid tank enters the second heat exchanger 25 under the action of the second water pump 24 to exchange heat with the high-temperature liquid from the membrane distillation component, thereby realizing the recovery and utilization of the heat of the high-temperature liquid.

[0040] The heat pump system comprises a heat pump working medium compressor 33, a condenser 34, a throttle valve 31 and an evaporator 30 which are connected in sequence, forming a closed circulation loop of the heat working medium.

[0041] Furthermore, the heat pump system also includes a regenerator 32 for exchanging heat between the high-temperature heat pump working fluid from the evaporator 30 and the low-temperature heat pump working fluid from the condenser 34, thereby improving energy utilization efficiency and reducing power consumption of the compressor.

[0042] In the multi-system coupled cogeneration system of the present embodiment, a plurality of valves are provided, including a first valve 35, a second valve 36, a third valve 37, and a fourth valve 38, and different operating conditions can be achieved by changing the opening of the valves.

[0043] The multi-system coupled heat, power and water cogeneration system of the present invention includes the following operating conditions:

[0044] (1) When the solar radiation is sufficient

[0045] The solar energy system provides the electricity required by users and the heat required for the membrane distillation process.

[0046] Part of the direct current generated by the PVT components of the solar system is converted into alternating current through the DC / AC converter 3 to provide electric energy for users, and the other part is converted into direct current matching the operation of the PEM water electrolyzer 5 through the DC / DC converter 4 to produce hydrogen, which is stored in the hydrogen storage bottle 7 to realize the energy storage process. In addition, the heat energy generated by the solar PVT components is stored in the hot water storage tank 39, part of which is used to heat the feed liquid, and the other part is used to provide domestic hot water for users.

[0047] The low-temperature feed liquid from the feed liquid tank 23 is preheated by the high-temperature feed liquid from the membrane distillation component 29 through the second heat exchanger 25 to improve energy utilization efficiency; at this time, the second valve 36 and the third valve 37 are closed, and the first valve 35 and the fourth valve 38 are opened. The preheated feed liquid first flows through the hot water storage tank 39 to absorb heat, then enters the condenser 34 to absorb the heat of the heat pump working fluid, and then enters the membrane distillation component 29 to complete a cycle; at the same time, the low-temperature permeate in the permeate tank 27 is pumped into the membrane distillation component 29 by the third water pump 28 to complete the membrane distillation process; the high-temperature permeate from the membrane distillation component 29 enters the evaporator 30 of the heat pump system to exchange heat with the heat pump working fluid, releases heat, and then flows back to the permeate tank 27 to complete a cycle, providing users with drinkable fresh water.

[0048] The high-temperature and high-pressure gaseous heat pump working fluid in the heat pump system enters the condenser 34 to release heat, then enters the regenerator 32 to further release heat, then enters the throttle valve 31 to become a low-temperature and low-pressure liquid working fluid, then enters the evaporator 30 to absorb the heat of the permeate, then enters the regenerator 32 to further absorb heat to become a gaseous working fluid, and then enters the heat pump working fluid compressor 33 to complete a cycle; by setting the regenerator 32, energy utilization efficiency is improved and compressor power consumption is reduced.

[0049] (2) When solar radiation is insufficient

[0050] The solar energy system and the fuel cell system together provide the electricity required by users and the heat energy required for the membrane distillation process.

[0051] The direct current generated by the PVT components of the solar system is completely converted into alternating current through the DC / AC converter 3 to provide electric energy for users; the heat energy generated by the PVT components is stored in the hot water storage tank 39, part of which is used to heat the feed liquid and the other part is used to provide domestic hot water for users.

[0052] The fuel cell system uses the hydrogen stored in the hydrogen storage bottle to generate electricity, heat and water; the direct current generated by the PEMFC stack is converted into alternating current through the second DC / AC converter 17 to provide electricity for users; the first water pump 21 and the first heat exchanger 22 are connected by a pipeline to form a thermal management cycle, the coolant takes away the waste heat generated by the PEMFC stack, and heats the feed liquid through the first heat exchanger 22 to release heat; the first gas-liquid separator 15 and the second gas-liquid separator 16 respectively collect moisture in the wet gas at the anode and cathode outlets, and store them in the water storage tank 20 to replenish moisture for the air humidifier 11 and the hydrogen humidifier 12, forming a water management cycle.

[0053] At this time, the second valve 36 and the fourth valve 38 are opened, the first valve 35 and the third valve 37 are closed, and the feed liquid preheated by the second heat exchanger 25 first enters the first heat exchanger 22 to absorb the heat of the coolant, then flows through the hot water storage tank 39 to absorb heat, and then enters the condenser 34 to absorb the heat of the heat pump working fluid, and finally enters the membrane distillation component 29 to complete a cycle; the circulation method of the permeate and the circulation method of the heat pump are the same as those under the condition of sufficient solar energy.

[0054] (3) When there is no solar radiation (at night or in bad weather)

[0055] The fuel cell system provides the electrical energy required by the user and the thermal energy required for the membrane distillation process.

[0056] The hot water stored in the hot water storage tank 39 can provide domestic hot water for users, and the fuel cell system uses the hydrogen stored in the hydrogen storage bottle to generate electricity, heat and water.

[0057] At this time, the second valve 36 and the third valve 37 are opened, the first valve 35 and the fourth valve 38 are closed, and the feed liquid preheated by the second heat exchanger 25 first enters the first heat exchanger 22 to absorb the heat of the coolant, then enters the condenser 34 to absorb the heat of the heat pump working fluid, and then enters the membrane distillation component 29 to complete a cycle; the rest of the system is the same as the cycle of the above two working conditions.

[0058] Example 2

[0059] In a typical embodiment of the present invention, a multi-system coupled heat, power and water cogeneration method is proposed, comprising:

[0060] When solar radiation is sufficient, the solar system provides electricity and hot water to users, the membrane distillation system provides drinkable fresh water to users, and the heat pump system provides heat / cooling to users;

[0061] When solar radiation is insufficient, the solar energy system provides partial electricity and hot water for users, the fuel cell system provides electricity for users, the membrane distillation system provides drinkable fresh water for users, and the heat pump system provides heat / cooling for users;

[0062] When there is no solar radiation, the hot water storage tank provides hot water for users, the fuel cell system provides electricity for users, the membrane distillation system provides drinkable fresh water for users, and the heat pump system provides heat / cooling for users.

[0063] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-system coupled heat, power and water cogeneration system, characterized in that: These include solar energy systems, water electrolyzer systems, fuel cell systems, heat pump systems, and membrane distillation systems; The solar energy system and the fuel cell system provide electricity and heat energy for users; the water electrolyzer system uses the electricity provided by the solar energy system to produce hydrogen and provides it to the fuel cell system; the liquid treatment water of the membrane distillation system uses the heat of the solar energy system and the fuel cell system to produce drinkable fresh water; the heat pump system is coupled to the membrane distillation system through a condenser and an evaporator; The water electrolyzer system comprises a PEM water electrolyzer, and the hydrogen outlet of the PEM water electrolyzer is connected to a hydrogen storage bottle; The PEM water electrolyzer uses a solid proton exchange membrane as an electrolyte and pure water as a reactant, using electrical energy to ionize water to produce hydrogen; The fuel cell system comprises a PEMFC stack, wherein the hydrogen inlet of the PEMFC stack is connected to a hydrogen storage bottle, the oxygen inlet is connected to an air compressor, the positive and negative electrode wet gas outlets of the PEMFC stack are both provided with gas-liquid separators, and the liquid outlet of the gas-liquid separator is connected to a water storage tank; the water of the hydrogen humidifier and the air humidifier comes from the water storage tank, and the electric energy generated by the PEMFC stack is converted into alternating current by a second DC / AC converter and provided to a second electricity user; A first heat exchanger is also provided in the fuel cell system. The first water pump pumps water into the PEMFC stack to take away the heat generated by the water. The water then enters the first heat exchanger to exchange the heat with the feed liquid of the membrane distillation system. The cooled water enters the PEMFC stack again for cooling. This process is continuously circulated. The solar energy system includes a solar photovoltaic and thermal integrated component, wherein the photovoltaic component is connected to a DC controller, and the thermal component is connected to a fourth water pump and a hot water storage tank in sequence. The membrane distillation system includes a membrane distillation component, a feed liquid tank and a permeate tank. The feed liquid outlet of the feed liquid tank is connected to the high-temperature feed liquid inlet of the membrane distillation component through the first heat exchanger of the fuel cell system, the hot water storage tank of the solar system and the condenser of the heat pump system.

2. The multi-system coupled heat, power and water cogeneration system according to claim 1, characterized in that: One of the paths of the DC controller is connected to the DC / AC converter to provide electric energy for the user, and the other path is connected to the DC / DC converter to provide electric energy for the water electrolyzer system.

3. The multi-system coupled heat, power and water cogeneration system according to claim 1, characterized in that: The permeate outlet of the membrane distillation assembly is connected to the permeate tank through the evaporator of the heat pump system.

4. The multi-system coupled heat, power and water cogeneration system according to claim 1, characterized in that: The heat pump system comprises a compressor, a condenser, a throttle valve and an evaporator which are connected in sequence.

5. The multi-system coupled heat, power and water cogeneration system according to claim 4, characterized in that: The heat pump system further comprises a regenerator for exchanging heat between the high-temperature heat pump working fluid from the evaporator and the low-temperature heat pump working fluid from the condenser.

6. A multi-system coupled heat, power and water cogeneration method, using the multi-system coupled heat, power and water cogeneration system according to any one of claims 1 to 5, characterized in that: include: When solar radiation is sufficient, the solar system provides electricity and hot water to users, and the membrane distillation system provides drinkable fresh water to users; When solar radiation is insufficient, the solar energy system provides partial electricity and hot water for users, the fuel cell system provides electricity for users, and the membrane distillation system provides drinkable fresh water for users; When there is no solar radiation, the hot water storage tank provides hot water for users, the fuel cell system provides electricity for users, and the membrane distillation system provides drinkable fresh water for users.

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