Solar full-spectrum utilization Rankine type reversible Carnot battery system

Abstract

The invention provides a Rankine type reversible Carnot cell system for solar full spectrum utilization, which designs and adopts a reversible system layout in which positive and negative cycle processes are coupled and integrated, can share a compression and expansion dual-purpose machine, a heat exchanger and part of flow paths in charging and discharging cycles, and can realize efficient and stable utilization of full spectrum of sunlight. The system can utilize solar energy to generate power and heat in the daytime, and the heat energy is stored in the heat tank; and electric energy can be output at night, so that the defects of volatility and intermittency of the existing photovoltaic power generation are overcome, the problems of difficulty in long-distance transmission of photo-thermal heat collection heat, strong load demand seasonality and the like are solved, and large-scale and efficient utilization of solar energy is facilitated. The system is simple in composition structure, the equipment cost can be greatly reduced, and the economical efficiency of the system is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of power storage, and in particular relates to a Rankine-type reversible Carnot battery system utilizing the full spectrum of solar energy. Background Art

[0002] At present, the common utilization methods for solar energy, a clean and renewable energy, mainly include photovoltaic power generation and solar thermal collection. These two methods use different wavelengths of sunlight and energy conversion forms. The solar energy utilization rate is not high when used alone. Therefore, it is more suitable to use these two methods in combination to convert different wavelength ranges into electrical energy or thermal energy respectively, so as to realize the full spectrum utilization of solar energy.

[0003] However, at present, photovoltaic power generation is subject to strong volatility and intermittency, the mismatch between supply and demand is more prominent, and the phenomenon of abandoned light is more common. The traditional solution to these problems is to configure batteries to balance the supply and demand relationship, but this will bring new problems such as high battery cost, short service life, short storage cycle and strong pollution of waste batteries; on the other hand, solar thermal collectors also have problems such as difficulty in transmitting heat over long distances and strong seasonality of load demand; these two aspects together limit the large-scale use of solar energy. It can be seen that this field urgently needs lower-cost, longer-life, more environmentally friendly long-term power storage technology and large-scale utilization of solar thermal heat to meet the growing demand for large-scale utilization of solar energy. Summary of the invention

[0004] In view of this, in view of the technical problems existing in the art, the present invention provides a solar energy full spectrum utilization Rankine-type reversible Carnot battery system, comprising: a Rankine-type reversible Carnot battery heat pump unit, a Rankine-type reversible Carnot battery heat storage unit, a Rankine-type reversible Carnot battery power generation unit and a solar energy full spectrum utilization unit;

[0005] The Rankine-type reversible Carnot battery heat pump unit is composed of a first heat exchanger, a compression-expansion dual-purpose machine, a second heat exchanger and a throttle valve connected in sequence to form a heat pump circulation system;

[0006] The Rankine-type reversible Carnot battery heat storage unit is composed of a second heat exchanger, a hot tank and a cold tank connected in sequence;

[0007] The Rankine-type reversible Carnot battery power generation unit is composed of a first valve, a cooling tower, a first heat exchanger, a compression-expansion dual-purpose machine, a second heat exchanger, a second valve and a working fluid pump; wherein the first valve is connected in series with the cooling tower and in parallel with the first heat exchanger to form a loop; the second valve is connected in series with the working fluid pump and in parallel with the throttle valve;

[0008] The solar energy full spectrum utilization unit is composed of a solar energy full spectrum utilization device, a heat storage tank and a third valve; wherein the heat storage tank is connected in series with the third valve, and in parallel with a branch consisting of the first valve and the cooling tower; the solar energy full spectrum utilization device is connected to the heat storage tank and the compression and expansion machine respectively, and is used to absorb solar energy and transmit heat energy to the heat storage tank, and transmit electric energy converted from solar energy to the compression and expansion machine.

[0009] Furthermore, when the throttle valve and the third valve are opened and the first valve and the second valve are closed, the system switches to a charging cycle mode; in this mode, the hot water in the heat storage tank enters the first heat exchanger, heats the circulating working fluid in the heat pump circulation system, turns it into gas and enters the compression-expansion machine; the compression-expansion machine is driven by the electric energy provided by the solar energy full-spectrum utilization device to compress the gas to a high-temperature and high-pressure state; the high-temperature and high-pressure gas enters the second heat exchanger to dissipate heat and heat the water in the cold tank; the heated water flows into the hot tank for storage, while the high-temperature and high-pressure gas cools down and reduces its pressure to become liquid, and returns to the first heat exchanger through the throttle valve to prepare for the next charging cycle.

[0010] Furthermore, when the throttle valve and the third valve are closed and the first valve and the second valve are opened, and the electrical connection between the solar energy full-spectrum utilization device and the compression and expansion machine is disconnected, the system switches to the discharge cycle mode; in this mode, the hot water stored in the hot tank enters the second heat exchanger to dissipate heat, causing the circulating working fluid to absorb heat and become high-temperature and high-pressure gas, and the gas enters the compression and expansion machine to output electrical energy to the outside. During the process, the gas expands and cools down and reduces its pressure; the expanded gas enters the first heat exchanger, exchanges heat with the cooling water in the cooling tower and becomes liquid; the liquid circulating working fluid enters the working fluid pump, is compressed back to a high-temperature and high-pressure state, and then enters the second heat exchanger to prepare for the next discharge cycle.

[0011] Furthermore, the heat pump cycle of the Rankine-type reversible Carnot battery heat pump unit is specifically selected from any one of the following types: subcritical cycle, transcritical cycle, supercritical cycle, multi-stage compression cycle, cascade cycle, intermediate heat recovery cycle, etc.

[0012] Furthermore, the heat storage type of the Rankine-type reversible Carnot battery heat storage unit is specifically selected from: any one of the sensible heat storage, latent heat storage or thermochemical heat storage types; the cold storage type is selected from: any one of the cold water storage, ice slurry storage, hydrated salt solution storage, low-temperature solvent storage or latent heat storage types.

[0013] Furthermore, the Rankine power generation cycle type of the Rankine-type reversible Carnot battery power generation unit is specifically selected from: any one of the water vapor Rankine cycle, organic Rankine cycle, etc.; the cycle form is selected from: any one of the subcritical Rankine cycle, transcritical Rankine cycle, supercritical Rankine cycle, multi-pressure evaporation Rankine cycle, reheat Rankine cycle, intermediate heat recovery Rankine cycle, exhaust heat recovery Rankine cycle, etc.; the circulating working fluid adopts organic working fluid.

[0014] The solar energy full spectrum provided by the present invention above utilizes the Rankine-type reversible Carnot battery system, and designs and adopts a reversible system layout that integrates the forward and reverse cycle processes. It can share the compression-expansion dual-purpose machine, heat exchanger and part of the flow path in the charging and discharging cycles, and can achieve efficient and stable utilization of the full spectrum of sunlight. The system can generate electricity and heat using solar energy during the day, and store the heat energy in a heat tank; at night, it can output electrical energy to the outside, thereby overcoming the defects of volatility and intermittency of existing photovoltaic power generation, and solving the problems of difficulty in long-distance transmission of photothermal heat collection and strong seasonality of load demand, which is conducive to large-scale and efficient utilization of solar energy. The system has a simple composition structure, which can greatly reduce equipment costs and improve the economy of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a Rankine-type reversible Carnot battery system for utilizing the full spectrum of solar energy provided by the present invention;

[0016] Figure 2 A schematic diagram of the charging cycle structure of the system provided by the present invention;

[0017] Figure 3 This is a schematic diagram of the discharge cycle structure of the system provided by the present invention.

[0018] Explanation of the accompanying symbols: 1-solar energy full spectrum utilization device, 2-heat storage tank, 3-third valve, 4-first valve, 5-cooling tower, 6-first heat exchanger, 7-compression expansion machine, 8-throttling valve, 9-working fluid pump, 10-second valve, 11-second heat exchanger, 12-hot tank, 13-cold tank. DETAILED DESCRIPTION

[0019] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms “first”, “second” and “third” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", "connected in series", "connected in parallel" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] The present invention provides a solar full spectrum utilizing a Rankine-type reversible Carnot battery system, such as Figure 1 As shown, it includes: a Rankine-type reversible Carnot battery heat pump unit, a Rankine-type reversible Carnot battery heat storage unit, a Rankine-type reversible Carnot battery power generation unit and a solar energy full spectrum utilization unit;

[0023] The Rankine-type reversible Carnot battery heat pump unit is composed of a first heat exchanger 6, a compression-expansion dual-purpose machine 7, a second heat exchanger 11 and a throttle valve 8 connected in sequence to form a heat pump circulation system;

[0024] The Rankine-type reversible Carnot battery heat storage unit is composed of a second heat exchanger 11, a hot tank 12 and a cold tank 13 connected in sequence;

[0025] The Rankine-type reversible Carnot battery power generation unit is composed of a first valve 4, a cooling tower 5, a first heat exchanger 6, a compression-expansion dual-purpose machine 7, a second heat exchanger 11, a second valve 10 and a working fluid pump 9; wherein the first valve 4 is connected in series with the cooling tower 5 and in parallel with the first heat exchanger 6 to form a loop; the second valve 10 is connected in series with the working fluid pump 9 and in parallel with the throttle valve 8;

[0026] The solar energy full spectrum utilization unit is composed of a solar energy full spectrum utilization device 1, a heat storage tank 2 and a third valve 3; wherein the heat storage tank 2 is connected in series with the third valve 3, and is connected in parallel with a branch consisting of the first valve 4 and the cooling tower 5; the solar energy full spectrum utilization device 1 is connected to the heat storage tank 2 and the compression-expansion machine 7 respectively, and is used to transmit heat energy to the heat storage tank 2 after absorbing solar energy, and to transmit electric energy converted from solar energy to the compression-expansion machine 7.

[0027] In a preferred embodiment of the present invention, when the throttle valve and the third valve are opened and the first valve and the second valve are closed, the system switches to Figure 2The charging cycle mode shown in the figure; in this mode, the hot water in the heat storage tank enters the first heat exchanger, heats the circulating working fluid in the heat pump circulation system, turns it into gas and enters the compression expansion machine; the compression expansion machine is driven by the electric energy provided by the solar energy full spectrum utilization device to compress the gas to a high temperature and high pressure state; the high temperature and high pressure gas enters the second heat exchanger to dissipate heat and heat the water in the cold tank; the heated water flows into the hot tank for storage, and at the same time, the high temperature and high pressure gas is cooled and reduced in pressure to become liquid, and returns to the first heat exchanger through the throttle valve to prepare for the next charging cycle.

[0028] In a preferred embodiment of the present invention, when the throttle valve and the third valve are closed and the first valve and the second valve are opened, and the electrical connection between the solar full spectrum utilization device and the compression expansion machine is disconnected, the system is switched as follows: Figure 3 The discharge cycle mode shown in the figure; in this mode, the hot water stored in the hot tank enters the second heat exchanger to dissipate heat, causing the circulating working fluid to absorb heat and become high-temperature and high-pressure gas, and the gas enters the compression and expansion machine to output electrical energy to the outside. During the process, the gas expands and cools down and reduces its pressure; the expanded gas enters the first heat exchanger, exchanges heat with the cooling water in the cooling tower and becomes liquid; the liquid circulating working fluid enters the working fluid pump and is compressed back to a high-temperature and high-pressure state, and then enters the second heat exchanger to prepare for the next discharge cycle.

[0029] In a preferred embodiment of the present invention, the heat pump cycle of the Rankine-type reversible Carnot battery heat pump unit is specifically selected from any one of the following types: subcritical cycle, transcritical cycle, supercritical cycle, multi-stage compression cycle, cascade cycle, intermediate heat recovery cycle, etc.

[0030] In a preferred embodiment of the present invention, the heat storage type of the Rankine-type reversible Carnot battery heat storage unit is specifically selected from: any one of the sensible heat storage, latent heat storage or thermochemical heat storage types; the cold storage type is selected from: any one of the cold water storage, ice slurry storage, hydrated salt solution storage, low-temperature solvent storage or latent heat storage types.

[0031] In a preferred embodiment of the present invention, the Rankine power generation cycle type of the Rankine-type reversible Carnot battery power generation unit is specifically selected from: any one of the water vapor Rankine cycle, organic Rankine cycle, etc.; the cycle form is selected from: any one of the subcritical Rankine cycle, transcritical Rankine cycle, supercritical Rankine cycle, multi-pressure evaporation Rankine cycle, reheat Rankine cycle, intermediate heat recovery Rankine cycle, exhaust heat recovery Rankine cycle, etc.; the circulating working fluid adopts organic working fluid.

[0032] It should be understood that the size of the serial numbers of the steps in the embodiment of the present invention does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. Full spectrum solar energy using Rankine-type reversible Carnot battery system, characterized by: include: Rankine-type reversible Carnot battery heat pump unit, Rankine-type reversible Carnot battery heat storage unit, Rankine-type reversible Carnot battery power generation unit and solar energy full spectrum utilization unit; The Rankine-type reversible Carnot battery heat pump unit is composed of a first heat exchanger, a compression-expansion dual-purpose machine, a second heat exchanger and a throttle valve connected in sequence to form a heat pump circulation system; The Rankine-type reversible Carnot battery heat storage unit is composed of a second heat exchanger, a hot tank and a cold tank connected in sequence; The Rankine-type reversible Carnot battery power generation unit is composed of a first valve, a cooling tower, a first heat exchanger, a compression-expansion dual-purpose machine, a second heat exchanger, a second valve and a working fluid pump; wherein the first valve is connected in series with the cooling tower and in parallel with the first heat exchanger to form a loop; the second valve is connected in series with the working fluid pump and in parallel with the throttle valve; The solar energy full spectrum utilization unit is composed of a solar energy full spectrum utilization device, a heat storage tank and a third valve; wherein the heat storage tank is connected in series with the third valve, and in parallel with a branch consisting of the first valve and the cooling tower; the solar energy full spectrum utilization device is connected to the heat storage tank and the compression and expansion machine respectively, and is used to absorb solar energy and transmit heat energy to the heat storage tank, and transmit electric energy converted from solar energy to the compression and expansion machine.

2. The system according to claim 1, characterized in that: When the throttle valve and the third valve are opened and the first valve and the second valve are closed, the system switches to the charging cycle mode; in this mode, the hot water in the heat storage tank enters the first heat exchanger, heats the circulating working fluid in the heat pump circulation system, turns it into gas and enters the compression expansion machine; the compression expansion machine is driven by the electric energy provided by the solar energy full spectrum utilization device to compress the gas to a high temperature and high pressure state; the high temperature and high pressure gas enters the second heat exchanger to dissipate heat and heat the water in the cold tank; the heated water flows into the hot tank for storage, and at the same time the high temperature and high pressure gas is cooled and reduced in pressure to become liquid, and returns to the first heat exchanger through the throttle valve to prepare for the next charging cycle.

3. The system according to claim 1, characterized in that: When the throttle valve and the third valve are closed and the first valve and the second valve are opened, and the electrical connection between the solar energy full-spectrum utilization device and the compression and expansion machine is disconnected, the system switches to the discharge cycle mode; in this mode, the hot water stored in the hot tank enters the second heat exchanger to dissipate heat, so that the circulating working fluid absorbs heat and becomes high-temperature and high-pressure gas, and the gas enters the compression and expansion machine to output electrical energy to the outside. During the process, the gas expands and cools down and reduces its pressure; the expanded gas enters the first heat exchanger, exchanges heat with the cooling water in the cooling tower and becomes liquid; the liquid circulating working fluid enters the working fluid pump and is compressed back to a high-temperature and high-pressure state, and then enters the second heat exchanger to prepare for the next discharge cycle.

4. The system according to claim 1, characterized in that: The specific selection of the heat pump cycle of the Rankine-type reversible Carnot battery heat pump unit is any one of a subcritical cycle, a transcritical cycle, a supercritical cycle, a multi-stage compression cycle, a cascade cycle, and an intermediate heat recovery cycle.

5. The system according to claim 1, characterized in that: The specific selection of heat storage type of the Rankine-type reversible Carnot battery heat storage unit is: any one of sensible heat storage, latent heat storage or thermochemical heat storage; the selection of cold storage type is: any one of cold water storage, ice slurry storage, hydrated salt solution storage, low-temperature solvent storage or latent heat storage.

6. The system according to claim 1, characterized in that: The specific selection of the Rankine power generation cycle type of the Rankine-type reversible Carnot battery power generation unit: any one of the water vapor Rankine cycle and the organic Rankine cycle; the cycle form selection: any one of the subcritical Rankine cycle, the transcritical Rankine cycle, the supercritical Rankine cycle, the multi-pressure evaporation Rankine cycle, the reheat Rankine cycle, the intermediate heat recovery Rankine cycle, and the exhaust heat recovery Rankine cycle; the circulating working fluid adopts an organic working fluid.

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