CN110285398A - A new cogeneration system of concentrated photovoltaics and vapor compression cycle - Google Patents

Abstract

The invention provides a novel heat and power cogeneration system of concentrating photovoltaics and a vapor compression cycle, which belongs to the technical field of hydrogen energy preparation devices. The combined heat and power system of the present invention includes a concentrating photovoltaic CPV power generation system and a vapor compression cycle system. The CPV uses solar energy to convert electric energy and part of heat energy. The electric energy is output to an external water electrolyzer for electrolysis to prepare hydrogen, and the heat energy is transferred to the vapor compression cycle system. The water is heated to increase the temperature of the water in the external water electrolysis cell to increase the electrolysis efficiency. The combined heat and power system of the present invention utilizes solar energy and can be used to combine with external water electrolysis devices to form a complete system that can be recycled to prepare hydrogen, avoiding the defect that the introduction of fossil fuels or other electric energy can electrolyze water to prepare hydrogen, and the whole process is seamless. Produce tail gas pollution, especially to lay the foundation for the realization of efficient and environmentally friendly hydrogen fuel cells.

Description

A new cogeneration system of concentrated photovoltaics and vapor compression cycle

technical field

The invention belongs to the technical field of hydrogen energy production equipment, and in particular relates to a novel cogeneration system of heat and power.

Background technique

At present, as an environmentally friendly fuel, the penetration rate of hydrogen production and application in the civilian field is still low. The main problem is that the efficiency and cost of hydrogen production are difficult to balance, and it is difficult to achieve the ideal balance between commercial application and environmental protection. Hydrogen energy has been commercialized in the field of fuel cells (Fuel cell "FC"). As a commercial product, FC technology is currently mainly used in electric vehicles and micro combined heat and power (m-CHP) systems in residential and industrial sites.

Existing technologies for hydrogen production include reforming of fossil fuels or natural gas, which has been adopted in many FC-based m-CHP products. However, reforming of fossil fuels or natural gas will still consume fossil fuels and emit harmful pollutants, which cannot fundamentally solve the fossil energy crisis and protect the environment.

Another existing route to hydrogen production is the electrolysis of water or simple hydrocarbons such as methanol. The electrolysis of water is preferred because it does not involve emitting harmful pollution such as carbon dioxide. Achieving electrolysis requires an input of energy in the form of pure electricity, pure heat, or a combination of both. Situations that require pure heat are often referred to as pyrolysis, however, this is rarely used in practice because the temperatures required to achieve this effect typically exceed 2300K. There are relatively many existing applications that require pure electricity, and high voltage electricity is usually used for electrolysis. However, the main issue preventing the widespread commercialization of existing electrolytic hydrogen production methods on hydrogen fuel cells is the need for electrolyzer power supply, and the input power must be provided by another form of power generation, so that it is impossible to form a set that can be used efficiently. The system of recycling hydrogen energy is still required to convert fossil fuels to provide power for electrolysis of water when applied to hydrogen fuel cells, which cannot achieve the environmental protection goal of zero tail gas emissions.

Contents of the invention

In order to solve the deficiencies of the prior art mentioned in the aforementioned background technology, the present invention provides a new type of combined heat and power system, which can generate electricity by itself and heat water, and can be used to process water with an external electrolyzer. Electrolysis is used to obtain hydrogen, which has the advantages of self-circulation power generation and heat generation, high efficiency, environmental protection and no tail gas pollution.

The technical scheme provided by the invention is as follows:

A new cogeneration system of concentrated photovoltaics and vapor compression cycle, including a concentrated photovoltaic power generation device and a vapor compression cycle device; the concentrated photovoltaic power generation device includes a concentrated photovoltaic panel; the vapor compression cycle device includes a steam cycle path and hot water There is coolant inside the steam circulation path; the steam circulation path includes a heat-absorbing end and a heat-dissipating end, the heat-absorbing end of the steam circulation path is connected to the concentrating photovoltaic panel for heat exchange, and the heat-releasing end is connected to the hot water tank for heat exchange; The hot water tank includes a water inlet and a water outlet.

The energy transfer process in this system is: the concentrated photovoltaic panel receives solar energy, outputs electric energy to the outside of the concentrated photovoltaic power generation device, and outputs heat energy to the vapor compression cycle device; the vapor compression cycle device is connected to the outside of the concentrated photovoltaic panel facing the sun Position; the cooling liquid in the steam circulation path receives heat energy from the concentrated photovoltaic panel, then conducts the heat energy to the connection with the hot water tank for exchange and release, and then returns to the heat-absorbing end of the steam circulation path to continue to receive heat energy.

Furthermore, the concentrated photovoltaic power generation device further includes a hub, which is a component that collects optical fibers and is connected to the sunny side of the concentrated photovoltaic panel. The hub is used to concentrate external sunlight input to the concentrated photovoltaic panel.

Furthermore, the steam cycle path includes a fluid heat exchanger, a compressor, a heat exchanger, an air radiator, an expander, a first three-way valve, and a second three-way valve; the fluid heat exchanger is connected to the concentrated photovoltaic panel, Receive the thermal energy of the concentrated photovoltaic panel; one end of the compressor is connected to the fluid heat exchanger, and the other end is connected to the first port of the second three-way valve; the second port and the third port of the second three-way valve are respectively connected to the heat exchanger, air Radiator; the heat exchanger is connected with the hot water tank, and outputs heat energy to the hot water tank; the second port and the third port of the first three-way valve are respectively connected with the heat exchanger and the air radiator, and the third port is connected with one of the expanders one end; the other end of the expander connects to the fluid heat exchanger.

Preferably, the vapor compression cycle device also includes a thermal management controller, which is an electronic device with a temperature sensor, a control switch and a microprocessor, the temperature sensor is arranged at the hot water tank, and the control switch is respectively arranged at the second and second At the second three-way valve; the microprocessor is electrically connected with the temperature sensor and the control switch respectively.

Preferably, the air radiator is an air-cooled radiator.

Further, the specific circulation path of the cooling liquid in the steam circulation path is the fluid heat exchanger, the compressor, the second three-way valve, the air radiator or heat exchanger, the first three-way valve, the expander, and the fluid heat exchange device.

Further, the hot water tank is made of heat insulating material, and the hot water tank also includes a hot water outlet.

Compared with the prior art, the new cogeneration system of concentrating photovoltaics and vapor compression cycle of the present invention has the beneficial effect that: the concentrating photovoltaic panel CPV is an existing high-efficiency power generation technology, and it adopts low-cost The hub can capture multiple different spectral ranges, effectively utilize the entire spectrum of sunlight, and increase the number of photovoltaic cells that can be placed per unit area, thereby bringing the possibility of device miniaturization. As an active cooling system, the steam circulation path conducts the heat energy generated during the power generation process of the concentrated photovoltaic power generation device to other places, avoiding the problem of a sharp drop in the power generation efficiency of the CPV battery caused by the excessive temperature of the CPV panel, and also protecting the CPV panel due to high temperature. resulting irreversible damage. Existing active cooling systems are either too simple and have low efficiency and poor precision, or the device structure is too complicated to achieve miniaturization. The steam circulation path conducts the heat energy generated by the concentrated photovoltaic power generation device to the hot water tank through the cooling liquid in the circulation path, and heats the water in the hot water tank. After the water in the hot water tank is heated up, it flows to the external electrolysis The tank can be used to improve the electrolysis efficiency of hydrogen generated in the water electrolysis process, and the cooling liquid returns to the concentrating photovoltaic panel after exothermic expansion for the next round of compression and refrigeration cycle. At the same time, due to the simple structure of the device and the compressor, expander, heat exchanger, etc. are all small components, combined with the concentrated photovoltaic power generation CPV device and the external water electrolyzer, driven by sunlight, a renewable self-circulation can be realized And other small cogeneration systems CHP such as hydrogen fuel cells with zero exhaust emissions.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of one of the embodiments of the present invention;

Fig. 2 is the schematic diagram of energy conversion of electricity, heat and chemical energy of the embodiment in Fig. 1;

FIG. 3 is a flow chart of the control algorithm of the thermal management controller in the embodiment shown in FIG. 1 .

Detailed ways

In order to further illustrate the principle, system structure and working process of the present invention, one implementation mode will be described in detail in combination with the contents of the accompanying drawings.

One of the implementations of a novel cogeneration system of concentrated photovoltaics and a vapor compression cycle is shown in Figures 1 to 3 .

As shown in FIG. 1 , the cogeneration system of this embodiment includes a concentrated photovoltaic power generation device and a vapor compression cycle device. The concentrating photovoltaic power generation device includes a concentrating photovoltaic CPV panel and a hub for collecting optical fibers. The vapor compression cycle device includes a fluid heat exchanger, a compressor, a three-way valve V2, an air-cooled air radiator, a heat exchanger, a three-way valve V1, an expander, a heat exchanger with a thermometer and a control switch, and a microprocessor. Management controller, hot water tank made of thermal insulation. The fluid heat exchanger, compressor, three-way valve V2, air-cooled air radiator, heat exchanger, three-way valve V1, and expander constitute the steam cycle path of the vapor compression cycle device, and the entire steam cycle path relies on cooling Liquid to conduct heat energy; among them, the air radiator, heat exchanger, three-way valve V1, and expander constitute the exothermic end of the steam circulation path, and the fluid heat exchanger, compressor, and three-way valve V2 constitute the suction end of the steam circulation path. The hot end; the thermal management controller constitutes the console for the thermal energy transfer path within the steam cycle path. The hot water tank also has a water inlet, a hot water outlet and an electrolyzed water outlet.

The structural principle of this embodiment shown in Figure 1, the energy transfer path shown in Figure 2, and the thermal energy control algorithm flow shown in Figure 3, wherein the power converter in Figure 2 refers to the aforementioned CPV panel and steam cycle device Various heat exchange components.

The sun-facing side of the concentrated photovoltaic CPV panel is connected to a hub, and the sunlight is concentrated and irradiated to the battery in the concentrated photovoltaic _{CPV panel} through the hub. device, external water electrolyzer, and at the same time, excess electric energy can be exported to the external power grid, and the heat energy generated is conducted to the vapor compression cycle device. The concentrating photovoltaic CPV panel is connected to a fluid heat exchanger at a position other than the sunny side, where the heat energy generated by the CPV panel enters the cooling liquid in the vapor compression cycle device. One end of the fluid heat exchanger is connected to the compressor, and the coolant enters the compressor after the fluid heat exchanger obtains heat energy conducted from the CPV panel. The compressor works by receiving the power W _c of the electric energy of the CPV panel. The compressor is also connected to the first port of the three-way valve V2. After the coolant is further compressed in the compressor to increase heat energy, it passes through the three-way valve V2. Under control, select flow to air radiator or heat exchanger. The second and third ports of the three-way valve V2 are respectively connected to the air radiator and the heat exchanger. The air radiator radiates excess thermal energy Q _amb into the air. The heat exchanger is connected to the hot water tank to exchange the heat energy carried in the coolant into the hot water tank, the water input from the water inlet of the hot water tank is heated up through heat exchange, and the hot water tank then outputs hot water from the electrolyzed water outlet The hydrogen is electrolyzed to the external water electrolyzer, and the hot water is output from the hot water outlet to the external user hot water terminal. The second and third ports of the three-way valve V1 are respectively connected to the air radiator or heat exchanger, and the first port is connected to the expander. After the coolant passes through the heat exchanger and the three-way valve V1, the pressure is further reduced in the expander to release heat energy. . The other end of the expander is connected with the fluid heat exchanger, and the coolant is transported by the expander to the fluid heat exchanger for the next cycle.

The thermometer of the thermal management controller is designed at the hot water tank. The control switches are arranged at the three-way valves V1 and V2 respectively, and can control the respective opening and closing states of the three ports of the three-way valves V1 and V2. The microprocessor of the thermal management controller is programmed with a control algorithm. As shown in Figure 3, the temperature at the hot water tank is denoted as T _w , an upper temperature threshold value T _h is set in the control algorithm, and a temperature lower limit threshold value T _l is also set. At the beginning, the thermometer reads the water temperature Tw in the hot water tank, and compares it with the set temperature threshold _Th and _Tl through the microprocessor _. When _Tw is lower than _Tl , the control switch makes the three-way valve V1 and V2 closes the channel through which the coolant flows through the air radiator, and the coolant takes all the heat to the heat exchanger to exchange the water in the hot water tank; continue to heat the water in the hot water tank so that T _w is greater than T _l and is less than T _h , the control switch makes the three-way valves V1 and V2 maintain the current channel; when T _w is higher than T _h , the control switch makes the three-way valves V1 and V2 close the path of the coolant flowing through the heat exchanger, so that The coolant radiates too much heat energy into the air at the air radiator; finally when the value of T _w returns to be greater than T _l and less than T _h , continue to close the path of the coolant flowing through the heat exchanger and only pass through the air Channels for radiators.

Compared with the existing combined heat and power generation system, this embodiment abandons the traditional fossil fuel power generation to provide power for the water electrolyzer, and uses the high-efficiency concentrating photovoltaic CPV panel for power generation and heating, namely It avoids tail gas pollution and also constitutes a self-circulating combined heat and power system. The hub is applied to the CPV panel, which can capture multiple different spectral ranges, effectively utilize the entire spectrum of sunlight, increase the number of photovoltaic cells that can be placed per unit area, and further contribute to the miniaturization of power generation and heat generation devices. Bring the base. The vapor compression cycle device makes full use of the large amount of waste heat generated by the CPV panel, which not only heats the water in the water phase, but also provides better reaction conditions for the external electrolysis of water to produce hydrogen, and also realizes the cooling of the CPV panel to avoid CPV Excessive panel temperature will greatly reduce the power generation efficiency and even damage the photovoltaic cells. The vapor compression cycle is superior to other typical technologies, such as thermoelectric coolers, because it can provide a higher coefficient of performance, which means lower energy consumption. Furthermore, to further increase the power efficiency of the system, the employed vapor compression cycle also involves an alternate path consisting of an air radiator, and a set of on-off valves to decide whether to use this component or the hot water path. Two different vapor compression circulation paths, combined with the thermal management controller to select the cooling liquid circulation path, enable the entire combined heat and power system to maintain a dynamic balance process of energy input and output. Since both the vapor compression cycle device and the concentrated photoelectric power generation device can be miniaturized, the combined heat and power system of this embodiment can be combined with an external water electrolyzer to form a small hydrogen fuel system that relies on solar energy for renewable power generation. The miniaturization of fuel cells and heat generating equipment brings good prospects.

The above implementation is only one of the schemes of the present invention, and is used to explain the technical principle of the present invention, but not all the embodiments of the present invention. It should be clear to those skilled in the art that, on the basis of the above-mentioned embodiments, any equivalent replacement scheme without outstanding substantive specificity and significant progress falls within the scope of the present invention. The protection scope of the technical solution of the present invention is defined by the claims.

Claims (7)

1. A novel cogeneration system of concentrated photovoltaic and vapor compression cycle, comprising a concentrated photovoltaic power generation device and a vapor compression cycle device, characterized in that: the concentrated photovoltaic power generation device comprises a concentrated photovoltaic panel; The compression cycle device includes a steam circulation path and a hot water tank; the steam circulation path has a coolant inside; the steam circulation path includes a heat-absorbing end and a heat-dissipating end, and the heat-absorbing end of the steam circulation path is connected to a concentrated photovoltaic panel for heat exchange, The heat release end is connected to a hot water tank for heat exchange; the hot water tank includes a water inlet and a water outlet. 2. The combined heat and power system according to claim 1, wherein the concentrated photovoltaic power generation device also includes a hub, the hub is a component that collects optical fibers, and is connected to the sunny side of the concentrated photovoltaic panel, Concentrate external sunlight input into concentrated photovoltaic panels. 3. The combined heat and power system according to claim 2, characterized in that: the steam circulation path includes a fluid heat exchanger, a compressor, a heat exchanger, an air radiator, an expander, a first three-way valve and a second Two and three-way valves; the fluid heat exchanger is connected to the concentrating photovoltaic panel to receive heat energy from the concentrating photovoltaic panel; one end of the compressor is connected to the fluid heat exchanger, and the other end is connected to the first port of the second three-way valve; The second port and the third port of the second three-way valve are respectively connected to a heat exchanger and an air radiator; the heat exchanger is connected to a hot water tank, and outputs heat energy to the hot water tank; the first three-way valve The second port and the third port are respectively connected to the heat exchanger and the air radiator, and the third port is connected to one end of the expander; the other end of the expander is connected to the fluid heat exchanger. 4. The combined heat and power system according to claim 3, wherein the vapor compression cycle device further comprises a thermal management controller, and the thermal management controller is an electronic device with a temperature sensor, a control switch and a microprocessor. equipment, the temperature sensor is arranged at the hot water tank, and the control switches are respectively arranged at the second and second three-way valves; the microprocessor is electrically connected with the temperature sensor and the control switch respectively. 5. The combined heat and power system according to claim 3, wherein the air radiator is an air-cooled radiator. 6. The combined heat and power system according to claim 4 or 5, wherein the specific circulation path of the coolant in the steam circulation path is a fluid heat exchanger, a compressor, a second three-way valve, an air Radiator or heat exchanger, first three-way valve, expander, fluid heat exchanger. 7. The combined heat and power system according to claim 6, wherein the hot water tank is made of heat insulating material, and the hot water tank further comprises a hot water outlet.