阅读说明：本技术 太阳能发电系统 (Solar power generation system ) 是由 肖刚 庞华 杨天锋 倪明江 岑可法 于 2020-08-13 设计创作，主要内容包括：本发明公开了一种太阳能发电系统,具有容纳介质在太阳能发电系统中循环的介质流路,介质流路包括第一回路和第二回路,调压单元连通第一回路与第二回路,调压单元能够利用将第一回路中的介质向第二回路输送的方式,使第一回路中的气压稳定在规定的阈值以下。本发明所提供的太阳能发电系统,既能实现高密度储能和高效换热,又能通过太阳能化学热泵的储能方式,调节储放热过程中二氧化碳分压,将中温储能提升为应用价值高的高温储能,提高整体效率,降低系统成本。(The invention discloses a solar power generation system, which is provided with a medium flow path for accommodating a medium to circulate in the solar power generation system, wherein the medium flow path comprises a first loop and a second loop, a pressure regulating unit is communicated with the first loop and the second loop, and the pressure regulating unit can stabilize the air pressure in the first loop below a specified threshold value by utilizing a mode of conveying the medium in the first loop to the second loop. The solar power generation system provided by the invention can realize high-density energy storage and high-efficiency heat exchange, and can adjust the partial pressure of carbon dioxide in the heat storage and release process through the energy storage mode of the solar chemical heat pump, so that the medium-temperature energy storage is improved to high-temperature energy storage with high application value, the overall efficiency is improved, and the system cost is reduced.)

1. A solar power system having a medium flow path accommodating circulation of a medium in the solar power system, characterized in that the medium flow path comprises a first circuit and a second circuit, wherein,

the first loop is communicated with the solar heat absorber and the first heat storage/release unit,

the first heat storage/release unit is arranged at the downstream of the flow path of the solar heat absorber and stores energy by utilizing an endothermic reaction generated at a first temperature and a first pressure;

said medium acting as a heat transfer medium in said first circuit;

the endothermic reaction is to decompose the first solid substance to generate a second solid substance and the medium, and the generated medium is merged into the first loop;

the second loop is communicated with the Brayton cycle system and the second heat storage/release unit,

the second storage/release unit releases energy by an exothermic reaction that occurs at a second temperature higher than the first temperature and a second pressure higher than the first pressure;

the exothermic reaction is the reverse of the endothermic reaction, and the exothermic reaction combines the second solid mass with the medium in the second loop to produce the first solid mass;

a compressor of the brayton cycle system compresses the medium in the second circuit and supplies the medium to the second heat storage/release unit;

the turbine of the Brayton cycle system receives the medium flowing out of the second heat storage/release unit and takes the flowing-out medium as a working medium;

the medium flow path further comprises

And a pressure adjusting unit that communicates the first circuit and the second circuit, and that can stabilize the air pressure in the first circuit to a predetermined threshold value or less by conveying the medium in the first circuit to the second circuit.

2. The solar power generation system of claim 1, further comprising

A circuit switching device capable of switching the first heat storage/release unit to the second circuit to occupy an original position of the second heat storage/release unit, and switching the second heat storage/release unit to the first circuit to occupy an original position of the first heat storage/release unit.

3. Solar power system according to claim 1, characterized in that the voltage regulating unit comprises

A back pressure valve connected to the first circuit;

an air tank provided in the medium flow path between the back pressure valve and the second circuit;

and a pre-compressor provided in the medium flow path between the back pressure valve and the gas tank.

4. A solar power system according to claim 3, wherein an outlet of the air reservoir is connected to an inlet of the compressor of the brayton cycle system, and the medium flowing out of the air reservoir is combined with the medium from the cooler of the brayton cycle system into the compressor.

5. The solar power generation system of claim 4, further comprising

And the inlet on the heat fluid side of the heat exchanger is connected with the back pressure valve, and the inlet on the cold fluid side of the heat exchanger is connected with the outlet of the compressor.

6. The solar power generation system of claim 5, further comprising a second circuit

And the inlet of the heat regenerator heat fluid side is connected to the outlet of the turbine, and the inlet of the heat regenerator cold fluid side is connected to the outlet of the heat exchanger cold fluid side.

7. The solar power generation system of claim 1, wherein the heat transfer medium is carbon dioxide gas, the working medium is supercritical carbon dioxide, and the first solid substance is a metal carbonate or a mixture containing a metal carbonate.

8. The solar power generation system of claim 1, wherein the focusing system of the solar thermal absorber is one or more of a tower concentrator system, a dish concentrator system, a trough concentrator system, or a linear fresnel concentrator system.

9. A method of solar power generation, comprising the steps of:

providing a medium flow path for accommodating circulation of a medium in the solar power generation system, the medium flow path comprising a first loop and a second loop, wherein the first loop communicates the solar heat absorber and the first heat storage/release unit, the second loop communicates the brayton cycle system and the second heat storage/release unit, and the first heat storage/release unit is disposed downstream of the flow path of the solar heat absorber;

storing energy using an endothermic reaction occurring at a first temperature and a first pressure, the medium acting as a heat transfer medium in the first circuit, the endothermic reaction decomposing a first solid material to produce a second solid material and the medium;

merging the generated medium into the first circuit;

releasing energy using an exothermic reaction that occurs at a second temperature higher than the first temperature and a second pressure higher than the first pressure, the exothermic reaction being a reverse of the endothermic reaction, and the exothermic reaction combining the second solid mass with the medium in the second circuit to produce the first solid mass;

compressing the medium in the second circuit by a compressor of the brayton cycle system and supplying the compressed medium to the second heat storage/release unit;

receiving the medium flowing out of the second heat storage/release unit by using a turbine of the Brayton cycle system, and taking the flowing-out medium as a working medium;

and stabilizing the gas pressure in the first circuit below a predetermined threshold value by a pressure regulating means that communicates the first circuit and the second circuit so as to convey the medium in the first circuit to the second circuit.

10. A method of solar energy power generation as claimed in claim 9, further comprising the steps of:

and switching the first heat storage/release unit to the second loop to occupy the original position of the second heat storage/release unit, and switching the second heat storage/release unit to the first loop to occupy the original position of the first heat storage/release unit.

Technical Field

The invention relates to the technical field of energy, in particular to a solar power generation system.

Background

With the large consumption of traditional fossil energy and increasingly outstanding environmental problems, the development of renewable energy is widely concerned, and solar energy is the most abundant clean energy and the development focus of renewable energy in the future.

Solar power generation technologies mainly include photovoltaic power generation and photo-thermal power generation, and compared with photovoltaic power generation, solar photo-thermal power generation utilizes a low-cost energy storage technology, has the advantages of stable and continuous power generation power output, can be used as both basic charge power supply and peak regulation power supply, and has great development potential.

The solar thermal power generation technology mainly comprises a tower type thermal power station, a trough type thermal power station, a disc type thermal power station and a linear Fresnel type thermal power station, wherein the light gathering ratio of the tower type thermal power station is high, the operation temperature of a system is high, the heat collection efficiency is high, and the research is hot at present.

The supercritical carbon dioxide Brayton cycle takes carbon dioxide in a supercritical state (the critical pressure is 7.38MPa, and the critical temperature is 30.98 ℃) as a working medium, and the Brayton cycle is adopted to realize energy conversion. Compared with a vapor Rankine cycle, the supercritical carbon dioxide Brayton cycle performs single-phase work, the system design is simple, and the complexity of operation is reduced; the supercritical carbon dioxide keeps high density in the whole power cycle, the required compression work is less, the sizes of a turbine and a heat exchanger are smaller, the occupied area is small, and the heat efficiency is higher; in addition, the cooling mode of the supercritical carbon dioxide Brayton cycle can adopt air cooling, is not limited by water resources, and can be used in arid areas with sufficient sunlight and water resource shortage. Therefore, the high-efficiency and compact supercritical carbon dioxide Brayton cycle is an ideal choice for solar thermal power generation.

The coupling mode of the supercritical carbon dioxide Brayton cycle and the solar thermal power station is divided into a direct coupling mode and an indirect coupling mode. In the direct coupling mode, supercritical carbon dioxide is simultaneously used as a heat transfer medium and a working medium, firstly passes through a solar heat absorber, absorbs high-temperature solar energy, and then enters a power cycle system to work, the heat transfer medium and the working medium do not need heat exchange, a heat exchanger is omitted, the device is simplified, the heat exchange loss is reduced, the temperature of the working medium is higher, the heat efficiency is higher, but the requirements on the heat absorber are more strict, and the control process under high temperature and high pressure is more difficult to realize; in the indirect coupling mode, the supercritical carbon dioxide is only used as a working medium, other substances are used as heat transfer media, the heat transfer media pass through the solar heat absorber, the heated high-temperature heat transfer media transfer heat to the working medium supercritical carbon dioxide through the heat exchanger, the formed high-temperature supercritical carbon dioxide enters the power circulation system to work, and compared with the direct coupling mode, the indirect coupling mode is easier to realize the combination with the heat storage system.

At present, the research on an energy storage system of a solar supercritical carbon dioxide brayton cycle thermal power station is mainly based on an indirect coupling mode, generally, molten salt or solid particles are used as a heat transfer medium and a heat storage medium, the molten salt or the solid particles pass through a solar heat absorber to absorb high-temperature solar energy, the heat transfer medium after heat absorption is divided into two parts, one part is used as the heat storage medium and enters a storage tank to store heat, the other part enters a heat exchanger to transfer the heat to a working medium, namely supercritical carbon dioxide, and the heated supercritical carbon dioxide enters a power circulation system to apply work externally. The mode of carrying out the energy storage through the promotion of fused salt or solid particle temperature belongs to the sensible heat energy storage, energy storage density is lower, heat transfer medium adopts indirect heat transfer with the acting medium mostly, heat exchange efficiency is low, and the heat transfer process can't avoid there being the temperature drop, energy quality reduces, the transportation of fused salt and solid particle needs to consume the merit, simultaneously, high temperature heat absorber heat dissipation loss is big, influence overall efficiency, furthermore, thermochemical energy storage technique that combines with solar energy supercritical carbon dioxide thermal power station lacks, system cost is higher, therefore, develop a high heat-retaining density, high use temperature, low cost, high efficiency, the thermochemical energy storage technique that the environment is friendly is crucial to solar energy supercritical carbon dioxide brayton cycle thermal power station.

Disclosure of Invention

Aiming at the problems, the invention provides a solar power generation system, which realizes medium-temperature heat storage and high-temperature heat release by adjusting the partial pressure of carbon dioxide in the heat storage and release process, and the operating pressure and temperature of a heat transfer medium are lower, so that the requirements on the material strength of a heat absorber and a pipeline are greatly reduced, the manufacturing cost of the heat absorber and the pipeline is reduced, the operating safety of the system is improved, the heat absorber absorbs heat under the medium-temperature condition while the power generation system does work under the high-temperature condition, the large heat loss of the high-temperature heat absorber is avoided, the overall efficiency is favorably improved, and the problems in the background technology can be effectively solved.

The invention provides a solar power generation system, which is provided with a medium flow path for accommodating a medium to circulate in the solar power generation system, wherein the medium flow path comprises a first loop and a second loop,

the first loop is communicated with the solar heat absorber and the first heat storage/release unit,

the first heat storage/release unit is arranged at the downstream of the flow path of the solar heat absorber and stores energy by utilizing endothermic reaction generated under a first temperature and a first pressure;

in the endothermic reaction, the first solid substance is decomposed to generate a second solid substance and a medium, and the generated medium is merged into the first loop;

the second loop is communicated with the Brayton cycle system and the second heat storage/release unit,

a second storage/release unit that releases energy by an exothermic reaction that occurs at a second temperature higher than the first temperature and a second pressure higher than the first pressure;

the exothermic reaction is the reverse of the endothermic reaction, and the exothermic reaction combines the second solid substance with the medium in the second loop to produce the first solid substance;

the compressor of the Brayton cycle system compresses the medium in the second circuit and supplies the compressed medium to the second heat storage/release unit;

the turbine of the Brayton cycle system receives the medium flowing out of the second heat storage/release unit and takes the flowing-out medium as a working medium;

the medium flow path further includes a pressure regulating means for communicating the first circuit and the second circuit, and the pressure regulating means can stabilize the air pressure in the first circuit to a predetermined threshold value or less by conveying the medium in the first circuit to the second circuit.

By adopting the technical scheme, when the first heat storage/release unit is used as a heat storage module, an endothermic reaction occurs in the first heat storage/release unit, and when the second heat storage/release unit is used as a heat release module, an exothermic reaction occurs in the second heat storage/release unit; the solar heat absorber is communicated with the first heat storage/release unit in the first loop, and the first heat storage/release unit is arranged at the downstream of the flow path of the solar heat absorber, so that the solar heat absorber heats the medium flowing through the solar heat absorber, the medium carrying solar energy flows into the first heat storage/release unit, the medium is generated due to the endothermic reaction in the first heat storage/release unit, and the air pressure of the first loop is increased along with the increase of the amount of the medium in the first heat storage/release unit. The pressure regulating unit is communicated with the first loop and the second loop, reactions generated by the first heat storing/releasing unit and the second heat storing/releasing unit are mutually inverse reactions, when a medium generated by an endothermic reaction exceeds a pressure set value of the first loop, the medium is led into the second loop through the pressure regulating unit to be consumed as a gas reactant of the heat releasing reaction, and because the total material quantity of the medium in the first loop and the second loop is conserved, the respective pressure of the first loop and the second loop can be stabilized. Because the Brayton cycle system and the second heat storage/release unit are communicated in the second loop, the medium which is compressed to high pressure by the compressor of the Brayton cycle system and then heated can flow into the second heat storage/release unit through the medium flow path to meet the high-temperature heat release reaction condition in the second heat storage/release unit, because the other part of the medium is heated by the heat released by the reaction in the second heat storage/release unit, the medium flowing into the turbine from the outlet of the second heat storage/release unit reaches the temperature capable of driving the turbine to do work, because the medium flowing into the inlet of the second heat storage/release unit is compressed to the pressure capable of driving the turbine to do work by the compressor of the Brayton cycle system, the temperature and the pressure of the working medium flowing into the turbine from the outlet of the second heat storage/release unit both meet the condition for driving the turbine to do work, the turbine works and further drives a generator connected to the downstream of the turbine to generate electricity; the medium-temperature heat storage and high-temperature heat release of the power generation system are realized, the requirements on the strength of heat absorbers and pipeline materials are reduced, the manufacturing cost is reduced, the condition that a working medium of a turbine needs high temperature and high pressure is met, the large heat loss of the high-temperature heat absorber is avoided, and the overall efficiency is improved.

One technical solution of the present invention is further configured to further include a circuit switching device, where the circuit switching device is capable of switching the first heat storage/release unit to the second circuit to occupy an original position of the second heat storage/release unit, and switching the second heat storage/release unit to the first circuit to occupy an original position of the first heat storage/release unit.

By adopting the technical scheme, the first heat storage/release unit and the second heat storage/release unit can be exchanged by the loop switching device at the connecting device of the power generation system, and the reactions generated in the first heat storage/release unit and the second heat storage/release unit are mutually inverse reactions, so that the reactant of the first heat storage/release unit is a product in the second heat storage/release unit, the respective connecting device of the first heat storage/release unit and the second heat storage/release unit is switched, the switching is equivalent to the switching of the heat storage/release states of the first heat storage/release unit and the second heat storage/release unit, the cyclic switching is realized, and the stability and the continuity of the output power of the power cycle system are ensured.

According to one technical scheme, the pressure regulating unit comprises a backpressure valve and is connected with the first loop; a gas tank disposed in a medium flow path between the back pressure valve and the second circuit; and a precompressor disposed in the medium flow path between the back pressure valve and the gas tank.

By adopting the technical scheme, because the backpressure valve is connected with the first loop, the backpressure valve guides a medium which is generated in the first loop and exceeds the air pressure threshold of the first loop into the second loop, and the stability of the air pressure of the first loop is maintained; because the pre-compressor and the air storage tank are sequentially arranged in the medium flow path of the back pressure valve and the second loop, the medium flows into the pre-compressor through the back pressure valve firstly and is compressed, and then enters the air storage tank to be stored; because the pressure regulating unit is communicated with the first loop and the second loop, the medium flowing out of the outlet of the air storage tank can flow into the compressor of the Brayton cycle system, and the air storage tank, the precompressor and the compressor are matched, so that the efficiency of the whole power generation system is improved; the reservoir is capable of replenishing the second circuit with medium so as to maintain the gas pressure in the second circuit at a high value.

In one aspect of the present invention, it is further configured that an outlet of the gas tank is connected to an inlet of a compressor of the brayton cycle system, and the medium flowing out of the gas tank is merged into the compressor together with the medium from a cooler of the brayton cycle system.

By adopting the technical scheme, because the outlet of the air storage tank is connected with the inlet of the compressor of the Brayton cycle system, the outlet of the cooler is also connected with the inlet of the compressor of the Brayton cycle system, and the inlet of the air storage tank is connected with the outlet of the pre-compressor, the media of different medium flow paths are pre-compressed and cooled at the same time and are gathered to the compressor, and then are compressed to high pressure, and the high efficiency of the system is ensured.

According to one technical scheme, the heat exchanger further comprises a heat exchanger, an inlet on the heat fluid side of the heat exchanger is connected with a back pressure valve, and an inlet on the cold fluid side of the heat exchanger is connected with an outlet of the compressor.

Through adopting above-mentioned technical scheme, because the back pressure valve is connected to the entry of the hot fluid side of heat exchanger, so from the medium heat transfer of the medium after the first return circuit is absorbed heat and the medium heat transfer of the heat exchanger cold fluid side, because the entry of the cold fluid side of heat exchanger and the exit linkage of compressor, so the medium after the compressor compression and the medium heat transfer from the first return circuit outflow have improved the utilization efficiency of medium heat energy.

According to one technical scheme, the second loop further comprises a heat regenerator, an inlet on the side of a heat fluid of the heat regenerator is connected with an outlet of a turbine, and an inlet on the side of a cold fluid of the heat regenerator is connected with an outlet on the side of a cold fluid of the heat exchanger.

By adopting the technical scheme, because the inlet on the heat fluid side of the heat regenerator is connected with the outlet of the turbine, after the working medium drives the turbine to work, the residual heat of the working medium exchanges heat with the medium on the cold fluid side of the heat regenerator, because the inlet on the cold fluid side of the heat regenerator is connected to the outlet on the cold fluid side of the heat exchanger, the medium flowing out of the cold fluid side of the heat exchanger is preheated by the medium flowing out of the first loop, then the working medium after the driving turbine works is reheated, and because the Brayton cycle system of the second loop is communicated with the second heat storage/release unit, the medium flows into the second heat storage/release unit after being heated for the second time by the heat regenerator, at the moment, the medium reaches the temperature condition of reaction in the second heat storage/release unit, and the energy utilization rate and the efficiency of the system.

According to one technical scheme, the heat transfer medium is carbon dioxide, the working medium is supercritical carbon dioxide, and the first solid substance is metal carbonate or a mixture containing the metal carbonate.

By adopting the technical scheme, because the heat transfer medium, the working medium and the metal carbonate or the gas product/reactant of the mixture containing the metal carbonate are all carbon dioxide, a direct contact heat exchange mode can be adopted in the heat storage/release process, and the heat exchange efficiency is higher than that of indirect heat exchange; in addition, the reciprocal reaction of decomposition and combination of the metal carbonate or the mixture containing the metal carbonate only generates solid substances or carbon dioxide, but does not generate other products, so that the construction of a circulating system is facilitated, and the adaptability of the supercritical carbon dioxide and the Brayton cycle is good, so that the carbon dioxide-carbon composite material is an ideal choice for solar thermal power generation.

According to one technical scheme, the focusing system of the solar heat absorber is one or more of a tower type light condensing system, a disc type light condensing system, a groove type light condensing system or a linear Fresnel type light condensing system.

By adopting the technical scheme, the solar heat absorber can be selected and matched with different light-gathering systems, so that the applicability of the power generation system is improved.

The invention provides a solar power generation method, which comprises the following steps:

providing a medium flow path for accommodating a medium to circulate in the solar power generation system, wherein the medium flow path comprises a first loop and a second loop, the first loop is communicated with the solar heat absorber and the first heat storage/release unit, and the second loop is communicated with the Brayton cycle system and the second heat storage/release unit;

providing a first heat storage/release unit disposed downstream of the flow path of the solar heat absorber;

storing energy by utilizing endothermic reaction which occurs at a first temperature and a first pressure, wherein the medium is used as a heat transfer medium in the first loop, and the endothermic reaction is used for decomposing the first solid substance into a second solid substance and a medium;

merging the generated medium into a first loop;

releasing energy by an exothermic reaction occurring at a second temperature higher than the first temperature and a second pressure higher than the first pressure, the exothermic reaction being the reverse of the endothermic reaction, and the exothermic reaction combining the second solid substance with the medium in the second circuit to produce a first solid substance;

compressing the medium in the second circuit by using a compressor of the Brayton cycle system and supplying the compressed medium to the second heat storage/release unit;

receiving the medium flowing out of the second heat storage/release unit by using a turbine of the Brayton cycle system, and taking the flowing-out medium as a working medium;

the pressure in the first circuit is stabilized to be equal to or lower than a predetermined threshold value by a pressure regulating means that communicates the first circuit and the second circuit so as to convey the medium in the first circuit to the second circuit.

One technical scheme of the invention is further configured to further comprise the following steps:

and switching the first heat storage/release unit to the second loop to occupy the original position of the second heat storage/release unit, and switching the second heat storage/release unit to the first loop to occupy the original position of the first heat storage/release unit.

Drawings

Fig. 1 is a schematic structural diagram of a solar power generation system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a solar power system including a recompression Brayton cycle system according to a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a solar power system including a recompression partial cooling Brayton cycle system according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of a solar power generation system including a recompression intercooling brayton cycle system according to a second embodiment of the present invention.

Description of reference numerals: 1-a solar heat absorber; 2-a first storage/release unit; 3-a second storage/release unit; 4-a heat exchanger; 5-a precompressor; 6-air storage tank; 7-turbine; 8-a generator; 9-a compressor; 91-a main compressor; 92-a recompressor; 10-a cooler; 11-a heat regenerator; 111-high temperature regenerator; 112-a low temperature regenerator; 12-back pressure valve; 13-a first compressor; 14-an intercooler; 15-medium flow path; 151-first loop; 152-a second loop; 16-a voltage regulating unit; 17-brayton cycle system; 18-loop switching device.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.