阅读说明：本技术 一种基于相变储能技术的梯级蓄热控温系统及控温方法 (Stepped heat storage temperature control system and temperature control method based on phase change energy storage technology ) 是由 孙东 齐光峰 张强 刘向东 宋鑫 王强 范路 季学松 郑炜博 刘聪 于 2020-04-29 设计创作，主要内容包括：本发明提供了一种基于相变储能技术的梯级蓄热控温系统及控温方法,属于相变蓄热技术领域。其技术方案为：包括高温热源,高温热源通过废热管经蒸发器流出,蒸发器的进口和出口通过换热循环管连接,所述换热循环管上依次连接压缩机、梯级蓄热装置和储液罐；太阳能集热器的进口和出口通过集热循环管连接,集热循环管上连接梯级蓄热装置；常温水源通过供热循环管经梯级蓄热装置和待加热设备流出；控温系统包括控制器、设置在供热循环管上的温控球阀和温度传感器。本发明的有益效果为：通过不同温度梯度的换热设计,提高了热能的储放速率,大幅提高了相变储能装置的性能及效率,加快热能换热速度,提高了相变储能装置的应用性能。(The invention provides a cascade heat storage temperature control system and a temperature control method based on a phase change energy storage technology, and belongs to the technical field of phase change heat storage. The technical scheme is as follows: the device comprises a high-temperature heat source, wherein the high-temperature heat source flows out of an evaporator through a waste heat pipe, an inlet and an outlet of the evaporator are connected through a heat exchange circulating pipe, and a compressor, a step heat storage device and a liquid storage tank are sequentially connected to the heat exchange circulating pipe; the inlet and the outlet of the solar heat collector are connected through a heat collection circulating pipe, and the heat collection circulating pipe is connected with a step heat storage device; a normal temperature water source flows out through the heat supply circulating pipe through the step heat storage device and the equipment to be heated; the temperature control system comprises a controller, a temperature control ball valve and a temperature sensor, wherein the temperature control ball valve and the temperature sensor are arranged on the heat supply circulating pipe. The invention has the beneficial effects that: through the heat exchange design of different temperature gradients, the heat energy storage rate is improved, the performance and the efficiency of the phase change energy storage device are greatly improved, the heat energy exchange speed is accelerated, and the application performance of the phase change energy storage device is improved.)

1. A step heat storage temperature control system based on a phase change energy storage technology is characterized by comprising a high-temperature heat source, wherein the high-temperature heat source flows out of an evaporator through a waste heat pipe, an inlet and an outlet of the evaporator are connected through a heat exchange circulating pipe, and a compressor, a step heat storage device and a liquid storage tank are sequentially connected to the heat exchange circulating pipe;

the solar heat collector is characterized by also comprising a solar heat collector, wherein an inlet and an outlet of the solar heat collector are connected through a heat collecting circulating pipe, and the heat collecting circulating pipe is connected with the step heat storage device;

the device also comprises a normal-temperature water source, and the normal-temperature water source flows out through the step heat storage device and the equipment to be heated through a heat supply circulating pipe;

the temperature control system comprises a controller, a temperature control ball valve and a temperature sensor, wherein the temperature control ball valve and the temperature sensor are arranged on the heat supply circulating pipe and are positioned between the step heat storage device and the equipment to be heated;

and electric valves and circulating water pumps are arranged at the inlets of the waste heat pipe, the heat collection circulating pipe and the heat supply circulating pipe.

2. The stepped heat storage and temperature control system based on the phase-change energy storage technology according to claim 1, wherein the stepped heat storage device comprises a high-temperature heat storage body, a medium-temperature heat storage body and a low-temperature heat storage body which are sequentially connected through a pipeline, the high-temperature heat storage body is respectively connected with an outlet of the evaporator and an outlet of the solar heat collector, and the low-temperature heat storage body is respectively connected with an inlet of the evaporator and an inlet of the solar heat collector.

3. The cascade heat storage and temperature control system based on the phase-change energy storage technology as claimed in claim 2, wherein the high-temperature heat storage body is made of a phase-change material with a phase-change temperature of 70-90 ℃, the medium-temperature heat storage body is made of a phase-change material with a phase-change temperature of 40-60 ℃, and the low-temperature heat storage body is made of a phase-change material with a phase-change temperature of 10-30 ℃.

4. The stepped heat storage and temperature control system based on the phase change energy storage technology according to claim 1, wherein the stepped heat storage device comprises at least three heat storage and heat storage bodies which are sequentially connected through a pipeline, the heat storage and heat storage bodies are divided according to temperature, the temperatures of the heat storage and heat storage bodies gradually decrease, the heat storage and heat storage body with the highest temperature is respectively connected with the outlet of the evaporator and the outlet of the solar heat collector, and the heat storage and heat storage body with the lowest temperature is respectively connected with the inlet of the evaporator and the inlet of the solar heat collector.

5. The cascade heat storage and temperature control system based on the phase change energy storage technology as claimed in claim 1, wherein the waste heat pipe, the heat exchange circulating pipe, the heat collection circulating pipe and the heat supply circulating pipe are all subjected to heat preservation and insulation treatment.

6. The system of claim 1, wherein an expansion valve and a filter are disposed on the heat exchange circulation pipe between the evaporator and the liquid storage tank.

7. The cascade heat storage and temperature control system based on the phase change energy storage technology as claimed in claim 1, wherein the refrigerant of the compressor is a high temperature working medium R245 fa.

8. The stepped heat storage and temperature control system based on the phase change energy storage technology as claimed in claim 2, wherein the heat supply circulation pipe is provided with two branch pipes through the stepped heat storage device, the two branch pipes are connected with the equipment to be heated, and the two branch pipes are respectively a high-temperature constant-temperature heating branch pipe and a medium-low-temperature stepwise preheating branch pipe.

9. The temperature control method of the cascade heat storage and temperature control system based on the phase change energy storage technology according to any one of claims 1 to 8, characterized by comprising the following steps:

heat storage process 1: the electric valves on the heat collection circulating pipe and the heat supply circulating pipe are closed, the high-temperature heat source exchanges heat with the refrigerant in the heat exchange circulating pipe through the evaporator, the gas-liquid two-phase refrigerant absorbs heat in the evaporator to become low-temperature low-pressure gas, the low-temperature low-pressure gas enters the compressor to be heated and pressurized to become high-temperature high-pressure gas, the high-temperature high-pressure refrigerant enters the step heat storage device to be condensed and release heat, the high-temperature refrigerant firstly enters the high-temperature heat storage body with the phase change temperature of 70-90 ℃ to release heat for the first time, the cooled medium-temperature refrigerant enters the medium-temperature heat storage body with the phase change temperature of 40-60 ℃ to release heat for the second time, the low-temperature refrigerant after the second temperature reduction enters the low-temperature heat storage body with the phase change temperature of 10-30 ℃ to release heat for the third time, and finally the gas-liquid two-phase refrigerant enters the liquid storage tank, then the refrigerant enters a filter, redundant gas in the refrigerant is filtered to be changed into a pure liquid phase, the pure liquid phase enters an expansion valve for throttling, and then the pure liquid phase is changed into a low-temperature low-pressure gas-liquid two phase and then enters an evaporator for next circulation;

and (3) a heat storage process 2: electric valves on the heat exchange circulating pipe and the heat supply circulating pipe are closed, high-temperature and high-pressure steam in the solar heat collector enters the step heat storage device to be condensed and release heat, the high-temperature and high-pressure steam firstly enters the high-temperature heat storage body with the phase change temperature of 70-90 ℃ to release heat for the first time, the cooled medium-temperature and wet steam enters the temperature heat storage body with the phase change temperature of 40-60 ℃ to release heat for the second time, the low-temperature water after the second cooling enters the low-temperature heat storage body with the phase change temperature of 10-30 ℃ to release heat for the third time, and finally the low-temperature water enters the solar heat collector to be circulated for the next time;

an exothermic process: the electric valve on the heat exchange circulating pipe and the heat collection circulating pipe is closed, normal-temperature water flows into the step heat storage device respectively after being pressurized by the circulating water pump on the heat supply circulating pipe to absorb heat and raise the temperature, the outlet water temperature flowing through the first heat storage body is high, the outlet water temperature flowing through the second heat storage body is medium, the outlet water temperature flowing through the third heat storage body is low, the opening degree of the temperature control ball valve is controlled by the controller according to the temperature required by equipment to be heated, and three streams of fluid are mixed into one stream of fluid to reach the water temperature required by practical engineering.

10. The temperature control method of the stepped thermal storage and control system based on the phase change energy storage technology as claimed in claim 9, wherein the thermal storage process 1 and the thermal storage process 2 can be performed simultaneously.

Technical Field

The invention relates to the technical field of phase change heat storage, in particular to a cascade heat storage temperature control system and a temperature control method based on a phase change energy storage technology.

Background

The basis of the phase change heat storage technology is a phase change material which occurs under isothermal or near isothermal conditions when changing phase, so that during energy storage and release, temperature and heat flow are substantially constant, with a large amount of heat absorption/release. The phase change heat storage mainly depends on latent heat of a phase change material, has the characteristics of large latent heat quantity and high heat storage density, is larger than sensible heat by one order of magnitude, and the application of a heat energy storage technology in the fields of industrial energy conservation and new energy is gradually emphasized since the oil crisis in the 70 th 20 th century.

In industrial production, a large amount of waste heat is usually generated and is generally directly discharged into the atmosphere, and a large amount of heat is directly dissipated into the air, so that not only is the thermal efficiency of the system seriously reduced, but also the environment is thermally polluted; solar energy is a new green energy source, has the advantages of renewability, universality, huge energy and the like, but has the defects of intermittence and fluctuation. Especially in the petroleum industry, the flashing phenomenon of crude oil at the wellhead is usually generated due to the high temperature, which not only leads to the complete loss of a part of crude oil, but also leads to the waste of most heat. In addition, the high-temperature wellhead crude oil is directly stored in the oil storage tank, and a large amount of heat of the high-temperature wellhead crude oil is directly dissipated into air.

The cascade heat storage and temperature control system adopts the technology that phase-change materials with different phase-change temperatures are placed in series, is beneficial to ensuring the uniform temperature difference between the phase-change materials and heat exchange fluid, and improves the heat exchange efficiency. The temperature regulation and control technology is helpful for regulating the temperature of the required hot fluid, avoids heat waste and can achieve the effects of energy conservation and environmental protection.

Disclosure of Invention

The invention aims to provide a cascade heat storage and temperature control system and method based on a phase change energy storage technology.

The invention is realized by the following measures: a step heat storage temperature control system based on a phase change energy storage technology is characterized by comprising a high-temperature heat source, wherein the high-temperature heat source flows out of an evaporator through a waste heat pipe, an inlet and an outlet of the evaporator are connected through a heat exchange circulating pipe, and a compressor, a step heat storage device and a liquid storage tank are sequentially connected to the heat exchange circulating pipe;

the solar heat collector is characterized by also comprising a solar heat collector, wherein an inlet and an outlet of the solar heat collector are connected through a heat collecting circulating pipe, and the heat collecting circulating pipe is connected with the step heat storage device;

the device also comprises a normal-temperature water source, and the normal-temperature water source flows out through the step heat storage device and the equipment to be heated through a heat supply circulating pipe;

the temperature control system comprises a controller, a temperature control ball valve and a temperature sensor, wherein the temperature control ball valve and the temperature sensor are arranged on the heat supply circulating pipe and are positioned between the step heat storage device and the equipment to be heated; the temperature sensor can monitor the temperature in the heat supply circulating pipe in real time on line so as to control the opening of the temperature control ball valve through the controller.

And electric valves and circulating water pumps are arranged at the inlets of the waste heat pipe, the heat collection circulating pipe and the heat supply circulating pipe.

The step heat storage device comprises a high-temperature heat storage body, a medium-temperature heat storage body and a low-temperature heat storage body which are sequentially connected through pipelines, the high-temperature heat storage body is respectively connected with an outlet of the evaporator and an outlet of the solar heat collector, and the low-temperature heat storage body is respectively connected with an inlet of the evaporator and an inlet of the solar heat collector.

The high-temperature heat accumulator adopts a phase-change material with a phase-change temperature of 70-90 ℃, the medium-temperature heat accumulator adopts a phase-change material with a phase-change temperature of 40-60 ℃, and the low-temperature heat accumulator adopts a phase-change material with a phase-change temperature of 10-30 ℃. The high-temperature heat accumulator is preferably a phase-change material with the phase-change temperature of 90 ℃, the medium-temperature heat accumulator is preferably a phase-change material with the phase-change temperature of 60 ℃, and the low-temperature heat accumulator is preferably a phase-change material with the phase-change temperature of 30 ℃.

The cascade heat storage device comprises at least three heat storage and heat storage bodies which are sequentially connected through pipelines, the heat storage and heat storage bodies are divided according to temperature, the temperature of the heat storage and heat storage bodies is gradually decreased, the heat storage and heat storage body with the highest temperature is respectively connected with an outlet of the evaporator and an outlet of the solar heat collector, and the heat storage and heat storage body with the lowest temperature is respectively connected with an inlet of the evaporator and an inlet of the solar heat collector.

The waste heat pipe, the heat exchange circulating pipe, the heat collection circulating pipe and the heat supply circulating pipe are all subjected to heat preservation and heat insulation treatment.

An expansion valve and a filter are arranged on the heat exchange circulating pipe and between the evaporator and the liquid storage tank.

The refrigerant of the compressor is R245fa high-temperature working medium.

The circulating water pump can adopt a booster pump or a booster-type water pump.

The heat supply circulating pipe is provided with two branch pipes through the step heat storage device, the two branch pipes are connected with the equipment to be heated, and the two branch pipes are respectively a high-temperature constant-temperature heating branch pipe and a medium-low temperature step-by-step preheating branch pipe.

The high-temperature heat source is high-temperature wellhead crude oil or high-temperature industrial wastewater, the to-be-heated equipment is thick oil heating equipment or oil storage tank heat preservation equipment or working medium preheating equipment, thick oil heating and oil storage tank heat preservation and working medium preheating in later-stage work are achieved through the high-temperature wellhead crude oil, and resources are saved.

A temperature control method of a cascade heat storage temperature control system based on a phase change energy storage technology comprises the following steps:

heat storage process 1: the electric valves on the heat collection circulating pipe and the heat supply circulating pipe are closed, the high-temperature heat source exchanges heat with the refrigerant in the heat exchange circulating pipe through the evaporator, the gas-liquid two-phase refrigerant absorbs heat in the evaporator to become low-temperature low-pressure gas, the low-temperature low-pressure gas enters the compressor to be heated and pressurized to become high-temperature high-pressure gas, the high-temperature high-pressure refrigerant enters the step heat storage device to be condensed and release heat, the high-temperature refrigerant firstly enters the high-temperature heat storage body with the phase change temperature of 70-90 ℃ to release heat for the first time, the cooled medium-temperature refrigerant enters the medium-temperature heat storage body with the phase change temperature of 40-60 ℃ to release heat for the second time, the low-temperature refrigerant after the second temperature reduction enters the low-temperature heat storage body with the phase change temperature of 10-30 ℃ to release heat for the third time, and finally the gas-liquid two-phase refrigerant enters the liquid storage tank, then the refrigerant enters a filter, redundant gas in the refrigerant is filtered to be changed into a pure liquid phase, the pure liquid phase enters an expansion valve for throttling, and then the pure liquid phase is changed into a low-temperature low-pressure gas-liquid two phase and then enters an evaporator for next circulation;

and (3) a heat storage process 2: electric valves on the heat exchange circulating pipe and the heat supply circulating pipe are closed, high-temperature and high-pressure steam in the solar heat collector enters the step heat storage device to be condensed and release heat, the high-temperature and high-pressure steam firstly enters the high-temperature heat storage body with the phase change temperature of 70-90 ℃ to release heat for the first time, the cooled medium-temperature and wet steam enters the temperature heat storage body with the phase change temperature of 40-60 ℃ to release heat for the second time, the low-temperature water after the second cooling enters the low-temperature heat storage body with the phase change temperature of 10-30 ℃ to release heat for the third time, and finally the low-temperature water enters the solar heat collector to be circulated for the next time;

an exothermic process: the electric valve on the heat exchange circulating pipe and the heat collection circulating pipe is closed, normal-temperature water flows into the step heat storage device respectively after being pressurized by the circulating water pump on the heat supply circulating pipe to absorb heat and raise the temperature, the outlet water temperature flowing through the first heat storage body is high, the outlet water temperature flowing through the second heat storage body is medium, the outlet water temperature flowing through the third heat storage body is low, the opening degree of the temperature control ball valve is controlled by the controller according to the temperature required by equipment to be heated, and three streams of fluid are mixed into one stream of fluid to reach the water temperature required by practical engineering.

The heat accumulation process 1 and the heat accumulation process 2 may be performed simultaneously.

Compared with the prior art, the invention has the beneficial effects that: firstly, the phase change heat storage devices are arranged in a cascade manner to carry out cascade heat storage, which is beneficial to improving the heat storage capacity and the heat storage efficiency; under the condition of the same mass of heat storage materials, the heat storage capacity of the cascade heat accumulator is larger than that of the single heat accumulator; thirdly, heat pump circulation is adopted to convert low-quality heat energy into high-quality heat energy, so that the heat energy is stored more easily; fourthly, the hot water temperature of the stepped phase change heat storage device is controlled through the ball valve, the actual engineering requirements are met, and the effects of energy conservation and environmental protection are achieved.

The invention can realize the purpose of high-efficiency energy storage, realizes the high-efficiency utilization of the phase-change material through the structural optimization, and improves the effective storage capacity of heat energy; through the heat exchange design of different temperature gradients, the storage rate of heat energy is improved, and the performance and efficiency of the phase change energy storage device are greatly improved; theoretical analysis and field tests prove that the cascade heat storage and temperature control system of the phase-change energy storage technology is safe and reliable, saves cost, improves effective storage capacity of heat energy, accelerates heat exchange of the heat energy, and improves application performance of the phase-change energy storage device.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

Wherein the reference numerals are: 1. a high temperature heat source; 2. a first booster pump; 3. a first electric valve; 4. an evaporator; 5. low-temperature waste heat; 6. a compressor; 7. a high temperature heat accumulator; 8. a medium-temperature heat accumulator; 9. a low temperature heat accumulator; 10. a liquid storage tank; 11. a filter; 12. an expansion valve; 13. a solar heat collector; 14. a normal temperature water source; 15. a second booster pump; 16. a second electric valve; 17. a water circulating pump; 18. electrically operated valve III; 19. a temperature control ball valve; 20. a temperature sensor; 21. a controller; 22. electrically operated valve IV; 23. electrically operated valve V; 24. preheating branch pipes step by step at a medium and low temperature; 25. heating the branch pipe at a high temperature and a constant temperature; 26. a waste heat pipe; 27. a heat exchange circulating pipe; 28. a heat collection circulation pipeline; 29. a heat supply circulation pipe; 30. and (4) conducting wires.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

The first embodiment is as follows:

referring to fig. 1: a step heat storage temperature control system based on a phase change energy storage technology comprises a high-temperature heat source 1, wherein the high-temperature heat source 1 flows out of an evaporator 4 through a waste heat pipe 26, an inlet and an outlet of the evaporator 4 are connected through a heat exchange circulating pipe 27, and a compressor 6, a step heat storage device and a liquid storage tank 10 are sequentially connected to the heat exchange circulating pipe 27;

the solar heat collector 13 is also included, the inlet and the outlet of the solar heat collector 13 are connected through a heat collecting circulating pipe 28, and the heat collecting circulating pipe 28 is connected with a step heat storage device;

the device also comprises a normal-temperature water source 14, wherein the normal-temperature water source 14 flows out through the stepped heat storage device and the equipment to be heated through a heat supply circulating pipe 29;

the device also comprises a temperature control system, wherein the temperature control system comprises a controller 21, a temperature control ball valve 19 and a temperature sensor 20, the temperature control ball valve 19 and the temperature sensor 20 are arranged on the heat supply circulating pipe 29 and are positioned between the step heat storage device and the equipment to be heated, the temperature control ball valve 19 and the temperature sensor 20 are respectively and electrically connected with the controller 21 through leads 30, and the temperature sensor 20 is positioned between the temperature control ball valve 19 and the equipment to be heated; the temperature sensor 20 can monitor the temperature in the heat supply circulating pipe 29 in real time on line so as to control the opening of the temperature control ball valve 19 through the controller 21.

The inlet of the waste heat pipe 26 is provided with a booster pump 2 and an electric valve 3, the inlet of the heat collecting circulating pipe 28 is provided with a circulating water pump 17 and an electric valve III 18, and the inlet of the heat supplying circulating pipe 29 is provided with a booster pump 15 and an electric valve II 16.

The step heat storage device comprises a high-temperature heat storage body 7, a medium-temperature heat storage body 8 and a low-temperature heat storage body 9 which are sequentially connected through pipelines, the high-temperature heat storage body 7 is respectively connected with an outlet of the evaporator 4 and an outlet of the solar heat collector 13, and the low-temperature heat storage body 9 is respectively connected with an inlet of the evaporator 4 and an inlet of the solar heat collector 13.

The high-temperature heat accumulator 7 is made of a phase-change material with the phase-change temperature of 90 ℃, the medium-temperature heat accumulator 8 is made of a phase-change material with the phase-change temperature of 60 ℃, and the low-temperature heat accumulator 9 is made of a phase-change material with the phase-change temperature of 30 ℃.

The step heat storage device comprises at least three heat storage and accumulation bodies which are sequentially connected through pipelines, the heat storage and accumulation bodies are divided according to the temperature, the temperature of the heat storage and accumulation bodies is gradually decreased, the heat storage and accumulation body with the highest temperature is respectively connected with the outlet of the evaporator 4 and the outlet of the solar heat collector 13, and the heat storage and accumulation body with the lowest temperature is respectively connected with the inlet of the evaporator 4 and the inlet of the solar heat collector 13.

The waste heat pipe 26, the heat exchange circulating pipe 27, the heat collection circulating pipe 28 and the heat supply circulating pipe 29 are all subjected to heat preservation and heat insulation treatment.

An expansion valve 12 and a filter 11 are arranged on the heat exchange circulating pipe 27 and between the evaporator 4 and the liquid storage tank 10.

The refrigerant of the compressor 6 is R245fa high-temperature working medium.

The circulating water pump can adopt a booster pump or a booster-type water pump.

The heat supply circulating pipe 29 is provided with two branch pipes through the step heat storage device, the two branch pipes are connected with equipment to be heated, the two branch pipes are respectively a high-temperature constant-temperature heating branch pipe 24 and a medium-low temperature step-by-step preheating branch pipe 25, an electric valve 22 is arranged on the high-temperature constant-temperature heating branch pipe 24, and an electric valve 23 is arranged on the medium-low temperature step-by-step preheating branch pipe 25.

The high-temperature heat source 1 is high-temperature wellhead crude oil or high-temperature industrial wastewater, the to-be-heated equipment is thick oil heating equipment or oil storage tank heat preservation equipment or working medium preheating equipment, thick oil heating, oil storage tank heat preservation and working medium preheating in later-stage work are achieved through the high-temperature wellhead crude oil, and resources are saved.

A temperature control method of a cascade heat storage temperature control system based on a phase change energy storage technology comprises the following steps:

heat storage process 1: the booster pump II 15, the electric valve II 16, the circulating water pump 17, the electric valve III 18, the electric valve IV 22 and the electric valve V23 are closed, the booster pump I2 and the electric valve I3 are opened, the high-temperature heat source 1 exchanges heat with the refrigerant in the evaporator 4, the heat of the high-temperature heat source 1 is released to become low-temperature waste heat 5, the gas-liquid two-phase refrigerant absorbs heat in the evaporator to become low-temperature low-pressure gas, the gas enters the compressor 6 and then is heated and pressurized to become high-temperature high-pressure gas, the high-temperature high-pressure refrigerant gas enters the step heat storage device to be condensed and released, the high-temperature refrigerant enters the high-temperature heat storage body 7 with the phase change temperature of 90 ℃ to release heat for the first time, the cooled medium-temperature refrigerant enters the medium-temperature heat storage body 8 with the phase change temperature of 60 ℃ to release heat for the second time, the low-temperature refrigerant after the second temperature cooling enters the low-temperature heat storage body 9 with the phase change temperature of 30 ℃ to release heat for the third time, and finally the gas-liquid storage tank 10, and then the refrigerant enters a filter 11, redundant gas in the refrigerant is filtered to be changed into a pure liquid phase, the pure liquid phase enters an expansion valve 12 for throttling, and then the pure liquid phase is changed into a low-temperature low-pressure gas-liquid two-phase and enters the evaporator 4 for next circulation.

And (3) a heat storage process 2: the booster pump I2, the electric valve I3, the booster pump II 15, the electric valve II 16, the electric valve IV 22 and the electric valve V23 are closed, the circulating water pump 17 and the electric valve III 18 are opened, high-temperature high-pressure steam in the solar heat collector 13 enters the step heat storage device for condensation and heat release, the high-temperature high-pressure steam firstly enters the high-temperature heat storage body 7 with the phase change temperature of 90 ℃ for first heat release, the cooled middle-temperature wet steam enters the middle-temperature heat storage body 8 with the phase change temperature of 60 ℃ for second heat release, the low-temperature water after second temperature reduction enters the low-temperature heat storage body 9 with the phase change temperature of 30 ℃ for third heat release, and finally enters the solar heat collector (13) for next circulation.

An exothermic process: the first booster pump 2, the first electric valve 3, the circulating water pump 17, the third electric valve 18 and the fifth electric valve 23 are closed, the second booster pump 15, the second electric valve 16 and the fourth electric valve 22 are opened, the normal-temperature water source 14 enters the cascade heat storage device and flows into the cascade heat storage device for heat absorption and temperature rise respectively after being boosted by the booster pump, the outlet water temperature flowing through the high-temperature heat storage body 7 is 90 ℃, the outlet water temperature flowing through the medium-temperature heat storage body 8 is 60 ℃, the outlet water temperature flowing through the low-temperature heat storage body 9 is 30 ℃, the opening degree of the ball valve is adjusted according to the temperature required by the medium-low-temperature stepwise preheating branch pipe 24, and three streams of fluids are mixed into one stream of fluid to reach the water temperature required by the actual engineering.

Example two:

the heat accumulation process 1 and the heat accumulation process 2 may be performed simultaneously. The method specifically comprises the following steps:

closing the second booster pump 15, the second electric valve 16, the circulating water pump 17, the third electric valve 18, the fourth electric valve 22 and the fifth electric valve 23, opening the first booster pump 2 and the first electric valve 3, opening the circulating water pump 17 and the third electric valve 18,

the high-temperature heat source 1 and the refrigerant exchange heat in the evaporator 4, the heat released by the high-temperature heat source 1 is changed into low-temperature waste heat 5, the gas-liquid two-phase refrigerant absorbs heat in the evaporator and is changed into low-temperature low-pressure gas, the gas enters the compressor 6 and then is heated and pressurized to be changed into high-temperature high-pressure gas, the high-temperature high-pressure refrigerant gas enters the step heat storage device to be condensed and release heat, simultaneously, the high-temperature high-pressure steam in the solar heat collector 13 enters the step heat storage device to be condensed and release heat, the high-temperature refrigerant and the high-temperature high-pressure steam firstly enter the high-temperature heat storage body 7 with the phase change temperature of 90 ℃ to release heat for the first time, the cooled medium-temperature refrigerant and the medium-temperature wet steam enter the medium-temperature heat storage body 8 with the phase change temperature of 60 ℃ to release heat for the second time, and the low-temperature refrigerant and the low-temperature water after the second temperature cooling enter the low-temperature heat storage body 9 with the phase change temperature of 30 ℃ to release heat for the third time, the low-temperature refrigerant is changed into a gas-liquid two-phase refrigerant, enters the liquid storage tank 10, then enters the filter 11, filters redundant gas in the refrigerant to be changed into a pure liquid phase, enters the expansion valve 12 for throttling, is changed into a low-temperature low-pressure gas-liquid two-phase refrigerant, then enters the evaporator 4 for next circulation, and finally enters the solar heat collector (13) for next circulation.

Example three:

the invention provides a step heat storage and temperature control system based on a phase change energy storage technology, which is different from the first embodiment in that:

the step heat storage device is divided into four heat storage bodies, and phase-change materials with the phase-change temperature of 90 ℃, 70 ℃, 50 ℃ and 30 ℃ are respectively adopted in the four heat storage bodies.

Compared with the embodiment 1, the step heat storage device is additionally provided with the heat accumulator, and the technology that the phase-change materials with different phase-change temperatures are placed in series is adopted, so that the temperature difference between the phase-change materials and the heat exchange fluid is ensured to be more uniform, and the heat exchange efficiency is improved.

The invention provides a step heat storage and temperature control method based on a phase change energy storage technology, which comprises the following steps:

heat storage process 1: the booster pump II 15, the electric valve II 16, the circulating water pump 17, the electric valve III 18, the electric valve IV 22 and the electric valve V23 are closed, the booster pump I2 and the electric valve I3 are opened, the high-temperature heat source 1 exchanges heat with the refrigerant in the evaporator 4, the heat released by the high-temperature heat source 1 is changed into low-temperature waste heat 5, the gas-liquid two-phase refrigerant absorbs heat in the evaporator to be changed into low-temperature low-pressure gas, the low-temperature low-pressure gas enters the compressor 6 and is heated and pressurized to be changed into high-temperature high-pressure gas, the high-temperature high-pressure refrigerant enters the heat storage body with the phase change temperature of 90 ℃ for first heat release, the refrigerant after primary temperature reduction enters the heat storage body with the phase change temperature of 70 ℃ for second heat release, the refrigerant after secondary temperature reduction enters the heat storage body with the phase change temperature of 50 ℃ for third heat release, the refrigerant after tertiary temperature reduction enters the heat storage body with the phase change temperature of 30 ℃ for fourth heat release, finally, the refrigerant which is changed into gas-liquid two-phase refrigerant enters the liquid storage tank 10, then enters the filter 11, filters redundant gas in the refrigerant to be changed into pure liquid phase, enters the expansion valve 12 for throttling, is changed into low-temperature and low-pressure gas-liquid two-phase refrigerant, and then enters the evaporator 4 for next circulation.

And (3) a heat storage process 2: the first booster pump 2, the first electric valve 3, the second booster pump 15, the second electric valve 16, the fourth electric valve 22 and the fifth electric valve 23 are closed, the circulating water pump 17 and the third electric valve 18 are opened, high-temperature high-pressure steam in the solar heat collector 13 enters the step heat storage device to be condensed and release heat, the high-temperature high-pressure steam firstly enters the heat storage body with the phase change temperature of 90 ℃ to release heat for the first time, wet steam after primary cooling enters the heat storage body with the phase change temperature of 70 ℃ to release heat for the second time, water after secondary cooling enters the heat storage body with the phase change temperature of 50 ℃ to release heat for the third time, water after tertiary cooling enters the heat storage body with the phase change temperature of 30 ℃ to release heat for the fourth time, and finally enters the solar heat collector (13) to perform next circulation.

An exothermic process: the first booster pump 2, the first electric valve 3, the circulating water pump 17, the third electric valve 18 and the fifth electric valve 23 are closed, the second booster pump 15, the second electric valve 16 and the fourth electric valve 22 are opened, the normal-temperature water source 14 enters the cascade heat storage device, the normal-temperature water enters the cascade heat storage device after being boosted by the booster pump, the cascade heat storage device absorbs heat and heats the cascade heat storage device, the outlet water temperature of the four heat storage bodies flows through the cascade heat storage device is 90 ℃, 70 ℃, 50 ℃ and 30 ℃, the opening degree of the ball valve is adjusted according to the temperature required by the medium-low-temperature stepwise preheating branch pipe 24, and the three streams of fluid are mixed into one stream of fluid to reach the water temperature required by the actual engineering.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings, which are merely for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be construed as limiting the invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "disposed" are to be construed broadly, e.g. as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the creation of the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical features of the present invention which are not described in the above embodiments may be implemented by or using the prior art, and are not described herein again, of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and variations, modifications, additions or substitutions which may be made by those skilled in the art within the spirit and scope of the present invention should also fall within the protection scope of the present invention.