Stable output type photovoltaic system integrated with Rankine type Carnot cell

Abstract

According to the stable output type photovoltaic system integrated with the Rankine type Carnot battery, through the designed heat pump cycle and heat storage cycle structure, abandoned electricity or valley electricity can be fully utilized for system charging, waste heat of a photovoltaic panel can be utilized to assist in improving the photovoltaic power generation efficiency, and the system is suitable for large-scale popularization and application. Therefore, the problems of volatility, intermittency and the like in existing photovoltaic power generation are effectively solved, sunlight wide-spectrum efficient utilization is achieved, low-cost electric energy storage can be achieved by replacing a lithium battery, and large-scale grid connection of photovoltaic power generation is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of energy storage, and in particular relates to a stable output photovoltaic system integrating a Rankine-type Carnot battery. Background Art

[0002] At present, the volatility and intermittency of photovoltaic power generation cannot be eradicated, which has limited its large-scale grid connection. To address this problem, the current common solution is to configure lithium batteries that match the photovoltaic installed capacity to balance the supply and demand of the power grid. However, due to the high cost and short life of lithium batteries, the cost and scale of photovoltaic power generation have been virtually increased. In some existing technologies in the form of solar thermal power stations, although the cost and peak-valley regulation of the power grid can be solved to a certain extent, there is a disadvantage of insufficient utilization of the full spectrum of solar radiation, and it also does not have energy storage capacity, and the actual use effect is not ideal. Summary of the invention

[0003] In view of this, in view of the technical problems existing in the art, the present invention provides a stable output photovoltaic system integrating a Rankine Carnot battery, comprising: a photovoltaic power generation unit and a Rankine Carnot battery unit;

[0004] The photovoltaic power generation unit is composed of a photovoltaic panel and its connected cooling pipe and photovoltaic inverter; the photovoltaic panel is used to receive solar radiation, transfer heat through the heat pump working fluid in the cooling pipe, and generate electrical energy and supply power to the grid and the Rankine Carnot battery unit through the photovoltaic inverter;

[0005] The Rankine Carnot battery unit consists of a circulation system consisting of a heat pump device, a heat storage device and a power generation device; the heat pump device is connected to the cooling pipe and is used to receive the heat transferred by the heat pump working fluid in the cooling pipe; the heat storage device consists of a hot tank and a cold tank, which are used to store high-temperature and low-temperature heat storage media respectively; the heat storage medium circulates between the hot tank and the cold tank and exchanges heat with the heat pump working fluid and the power generation working fluid respectively; the power generation device can supply power to the power grid driven by the expansion work of the power generation cycle working fluid.

[0006] Furthermore, when the system is in charging mode, the photovoltaic panels generate electricity and supply power to the power grid through the photovoltaic inverter. The heat pump device uses the abandoned power or valley power therein to work, compresses the heat pump working fluid to a high temperature and high pressure state, and then exchanges heat with the heat storage medium flowing out of the cold tank, so that the heated heat storage medium flows into the hot tank, thereby storing the heat in the hot tank; the heat pump working fluid after the heat exchange is cooled and reduced in pressure to prepare for the next round of heat pump cycle; in the heat pump cycle, the cooling pipe is used to absorb the waste heat generated by the photovoltaic panels to improve the power generation efficiency of the photovoltaic panels and cool them down.

[0007] Furthermore, when the system is in the discharge mode, the heat storage medium flowing out of the hot tank exchanges heat with the power generation working fluid, so that the heated power generation working fluid becomes a high-temperature and high-pressure gas; the power generation working fluid expands and performs work, driving the power generation device to operate and supply power to the power grid; the power generation working fluid after performing work cools down and reduces pressure, preparing to enter the next power generation cycle.

[0008] Furthermore, the heat pump cycle of the heat pump device is specifically selected from any one of the types such as subcritical cycle, transcritical cycle, cascade cycle, multi-stage compression cycle, intermediate heat recovery cycle, etc.

[0009] Furthermore, the power generation cycle of the power generation device is specifically selected from any one of the subcritical Rankine cycle, transcritical Rankine cycle, supercritical Rankine cycle, multi-pressure evaporation Rankine cycle, intermediate heat recovery Rankine cycle and the like.

[0010] Furthermore, the heat storage form of the heat storage device is specifically selected from any one of sensible heat storage, phase change heat storage, thermochemical heat storage, etc.

[0011] The stable output photovoltaic system with integrated Rankine Carnot battery provided by the present invention can make full use of abandoned electricity or valley electricity for system charging through the designed heat pump cycle and heat storage cycle structure, and can also use the waste heat of photovoltaic panels to assist in improving the efficiency of photovoltaic power generation, thereby effectively overcoming the volatility and intermittent problems in existing photovoltaic power generation, achieving efficient utilization of a wide spectrum of sunlight, and can replace lithium batteries to achieve low-cost energy storage, which is conducive to the large-scale grid connection of photovoltaic power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a stable output photovoltaic system with an integrated Rankine Carnot cell provided by the present invention.

[0013] Explanation of the accompanying numbers: 1-photovoltaic panel, 2-cooling pipe, 3-photovoltaic inverter, 4-heat pump device, 5-hot tank, 6-cold tank, 7-power generation device. DETAILED DESCRIPTION

[0014] 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.

[0015] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 indirectly connected 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.

[0016] The invention provides a stable output photovoltaic system with integrated Rankine Carnot cell, such as Figure 1 As shown, it includes: a photovoltaic power generation unit and a Rankine-type Carnot battery unit;

[0017] The photovoltaic power generation unit is composed of a photovoltaic panel 1 and a cooling pipe 2 and a photovoltaic inverter 3 connected thereto; the photovoltaic panel 1 is used to receive solar radiation, transfer heat through the heat pump working fluid in the cooling pipe 2, and generate electrical energy and supply power to the grid and the Rankine Carnot battery unit through the photovoltaic inverter 3;

[0018] The Rankine Carnot battery unit is composed of a circulation system consisting of a heat pump device 4, a heat storage device and a power generation device 7; the heat pump device 4 is connected to the cooling pipe 2, and is used to receive the heat transferred by the heat pump working fluid in the cooling pipe 2; the heat storage device is composed of a hot tank 5 and a cold tank 6, which are used to store high-temperature and low-temperature heat storage media respectively; the heat storage medium circulates between the hot tank 5 and the cold tank 6, and exchanges heat with the heat pump working fluid and the power generation working fluid respectively; the power generation device 7 can supply power to the power grid driven by the expansion work of the power generation cycle working fluid.

[0019] In a preferred embodiment of the present invention, when the system is in charging mode, the photovoltaic panels generate electricity to supply power to the power grid through the photovoltaic inverter, and the heat pump device uses the abandoned power or valley power therein to work, compresses the heat pump working fluid to a high temperature and high pressure state, and then exchanges heat with the heat storage medium flowing out of the cold tank, so that the heated heat storage medium flows into the hot tank, thereby storing the heat in the hot tank; the heat pump working fluid after the heat exchange is cooled and reduced in pressure to prepare for the next round of heat pump cycle; in the heat pump cycle, the cooling pipe is used to absorb the waste heat generated by the photovoltaic panels to improve the power generation efficiency of the photovoltaic panels and cool them down.

[0020] In a preferred embodiment of the present invention, the heat storage medium flowing out of the hot tank exchanges heat with the power generation working fluid, so that the heated power generation working fluid becomes a high-temperature and high-pressure gas; the power generation working fluid expands and performs work, driving the power generation device to operate and supply power to the power grid; the power generation working fluid after performing work cools down and reduces pressure, preparing to enter the next power generation cycle.

[0021] In a preferred embodiment of the present invention, the heat pump cycle of the heat pump device is specifically selected from any one of the types such as subcritical cycle, transcritical cycle, cascade cycle, multi-stage compression cycle, intermediate heat recovery cycle, etc.

[0022] In a preferred embodiment of the present invention, the power generation cycle of the power generation device is specifically selected from any one of the subcritical Rankine cycle, transcritical Rankine cycle, supercritical Rankine cycle, multi-pressure evaporation Rankine cycle, intermediate heat recovery Rankine cycle and the like.

[0023] In a preferred embodiment of the present invention, the heat storage form of the heat storage device is specifically selected from any one of sensible heat storage, phase change heat storage, thermochemical heat storage, etc.

[0024] 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.

[0025] 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. A stable output photovoltaic system integrating a Rankine Carnot cell, characterized in that: It includes photovoltaic power generation units and Rankine-type Carnot battery units; The photovoltaic power generation unit is composed of a photovoltaic panel and its connected cooling pipe and photovoltaic inverter; the photovoltaic panel is used to receive solar radiation, transfer heat through the heat pump working fluid in the cooling pipe, and generate electrical energy and supply power to the grid and the Rankine Carnot battery unit through the photovoltaic inverter; The Rankine Carnot battery unit consists of a circulation system consisting of a heat pump device, a heat storage device and a power generation device; the heat pump device is connected to the cooling pipe and is used to receive the heat transferred by the heat pump working fluid in the cooling pipe; the heat storage device consists of a hot tank and a cold tank, which are used to store high-temperature and low-temperature heat storage media respectively; the heat storage medium circulates between the hot tank and the cold tank and exchanges heat with the heat pump working fluid and the power generation working fluid respectively; the power generation device can supply power to the power grid driven by the expansion work of the power generation cycle working fluid.

2. The system according to claim 1, characterized in that: When the system is in charging mode, the photovoltaic panels generate electricity to supply power to the power grid through the photovoltaic inverter. The heat pump device uses the abandoned power or valley power therein to work, compresses the heat pump working fluid to a high temperature and high pressure state, and then exchanges heat with the heat storage medium flowing out of the cold tank, so that the heated heat storage medium flows into the hot tank, thereby storing the heat in the hot tank; the heat pump working fluid after the heat exchange is cooled and reduced in pressure to prepare for the next round of heat pump cycle; during the heat pump cycle, the cooling pipe is used to absorb the waste heat generated by the photovoltaic panels to improve the power generation efficiency of the photovoltaic panels and cool them down.

3. The system according to claim 1, characterized in that: When the system is in the discharge mode, the heat storage medium flowing out of the hot tank exchanges heat with the power generation working fluid, so that the heated power generation working fluid becomes a high-temperature and high-pressure gas; the power generation working fluid expands and performs work, driving the power generation device to operate and supply power to the power grid; after performing work, the power generation working fluid cools down and reduces pressure, preparing to enter the next power generation cycle.

4. The system according to claim 1, characterized in that: The heat pump cycle of the heat pump device is specifically selected from any one of the subcritical cycle, transcritical cycle, cascade cycle, multi-stage compression cycle, and intermediate heat recovery cycle types.

5. The system according to claim 1, characterized in that: The power generation cycle of the power generation device is specifically selected from any one of the subcritical Rankine cycle, transcritical Rankine cycle, supercritical Rankine cycle, multi-pressure evaporation Rankine cycle, and intermediate heat recovery Rankine cycle.

6. The system according to claim 1, characterized in that: The heat storage form of the heat storage device is specifically selected from any one of sensible heat storage, phase change heat storage, and thermochemical heat storage.

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