CO2 cold carrier energy storage cooling system externally connected with high-pressure gas tank

Abstract

The utility model relates to a CO2 cold carrier energy storage cooling system of external high-pressure gas tank, and relates to a cooling system. Compressor, condenser, refrigerant storage tank and electronic expansion valve are sequentially connected, compressor is connected with condensation evaporator, electronic expansion valve is connected with condensation evaporator, the liquid pipe export of CO2 storage tank is connected with the gas pipe entrance of CO2 storage tank through main road and bypass after liquid pump, main road is arranged with cold evaporator, bypass is arranged with electromagnetic regulating valve, the liquid pipe entrance of CO2 storage tank is connected with condensation evaporator, the gas pipe export of CO2 storage tank is connected with condensation evaporator, air compressor connects the gas pipe export of CO2 storage tank with the gas pipe entrance of CO2 high-pressure gas tank, and the gas pipe export of CO2 high-pressure gas tank is sequentially connected with condensation evaporator through electromagnetic regulating valve and pressure reducing valve. External CO2 high-pressure gas tank realizes pressure stability, guarantees system safety and stability, stores cold capacity simultaneously using CO2 storage tank, and improves economy.

Description

TECHNICAL FIELD

[0001] The application relates to a cooling supply system, in particular a CO2 cooling agent energy storage cooling supply system externally connected with a high-pressure gas tank, and belongs to the technical field of economic cooling supply system research and development. BACKGROUND

[0002] In the field of cooling supply systems, there are common problems of peak-valley electricity price, day-night operation efficiency and cooling demand difference: in the daytime, the refrigeration cycle efficiency is low, the electricity price is high, but the cooling demand is large; in the night, the refrigeration cycle efficiency is high, the electricity price is low, but the cooling demand is small. Therefore, energy storage technology is usually used to solve the mismatch of supply and demand capacity and the large gap of operation cost and benefit, that is, in the night, the operation efficiency is high, the operation cost is low, and the cooling demand is small, so that more cold is produced and stored, and the cold stored in the night is used in the daytime to reduce the daytime refrigeration demand and reduce the cost.

[0003] In the cooling supply system taking CO2 as the cooling agent, the effect of energy storage can be achieved by increasing the amount of CO2 in the cooling agent system, but if the volume of the CO2 storage tank and the content of CO2 in the cooling agent system are simply increased, the content of CO2 gas will change greatly at the peak and valley time, and the peak and valley change value of the pressure of the CO2 storage tank will be huge: in the night, there is more liquid CO2 in the tank, and there is less gaseous CO2, and the system pressure is extremely low, on the contrary, in the daytime, there is more liquid CO2 in the tank, and there is more gaseous CO2, and the system pressure is extremely high. Since the CO2 storage tank is directly connected with the cooling agent conveying and distribution system, the huge pressure change in the tank will seriously affect the safety and stability of the whole system, therefore, it is urgent to optimize and improve this problem, solve the adverse pressure change of the CO2 storage tank, and realize the safe and stable and economic operation of the system. SUMMARY

[0004] To solve the problems in the background art, the application provides a CO2 cooling agent energy storage cooling supply system externally connected with a high-pressure gas tank, which realizes the pressure stability of the CO2 storage tank by externally connecting a CO2 high-pressure gas tank in the CO2 loop, guarantees the safety and stability of the system, and at the same time, stores the cold of the liquid CO2 in the CO2 storage tank to improve the economy.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a CO2 refrigerant energy storage and cooling system with an external high-pressure gas storage tank, comprising a refrigerant loop and a CO2 loop. Besides a shared condenser-evaporator, the refrigerant loop further includes a compressor, a condenser, a refrigerant liquid storage tank, and an electronic expansion valve (EEV). The compressor outlet, condenser, refrigerant liquid storage tank, and electronic expansion valve (EEV) are connected sequentially. The compressor inlet is connected to the refrigerant outlet of the condenser-evaporator, and the electronic expansion valve (EEV) is connected to the refrigerant inlet of the condenser-evaporator. The CO2 loop further includes a CO2 liquid pump, a refrigerant evaporator, a CO2 liquid storage tank, an air compressor, and a CO2 high-pressure gas storage tank. The liquid outlet of the CO2 storage tank is connected to a CO2 liquid pump. The CO2 liquid pump is ultimately connected to the gas inlet of the CO2 storage tank via a main line and a bypass. The main line includes multiple parallel branches, each of which is sequentially equipped with an electromagnetic regulating valve, a shut-off valve, and the refrigerated evaporator. The bypass is equipped with an electromagnetic regulating valve. The liquid inlet of the CO2 storage tank is connected to the CO2 condenser outlet of the condenser evaporator. The gas outlet of the CO2 storage tank is connected to the CO2 condenser inlet of the condenser evaporator. The air compressor connects the gas outlet of the CO2 storage tank to the gas inlet of the high-pressure CO2 storage tank. The gas outlet of the high-pressure CO2 storage tank is sequentially connected to the CO2 condenser inlet of the condenser evaporator via an electromagnetic regulating valve and a pressure reducing valve.

[0006] Compared with the prior art, the beneficial effects of the present invention are:

[0007] 1. Safety and stability: When the amount of gas in the CO2 liquid storage tank increases, the excess gaseous CO2 can be compressed into the high-pressure CO2 storage tank through an air compressor for storage, preventing the pressure in the CO2 liquid storage tank and CO2 loop from becoming too high. When the amount of gas in the CO2 liquid storage tank decreases, the excess gaseous CO2 in the high-pressure CO2 storage tank can be released into the condenser-evaporator through an electromagnetic regulating valve and a pressure reducing valve, preventing the pressure in the CO2 liquid storage tank and CO2 loop from becoming too low, ensuring the safety of the system. The external high-pressure CO2 storage tank's excellent storage function for gaseous CO2 allows the system to buffer changes in cooling demand or cooling capacity in a timely manner by storing CO2, ensuring stable operation.

[0008] 2. Energy storage function: When the cooling capacity exceeds the cooling demand, the condenser liquefies the CO2 gas released from the high-pressure CO2 storage tank, increasing the liquid CO2 in the CO2 storage tank. This allows the liquid CO2 to store the cooling capacity and achieve the function of energy storage. The stored cooling capacity can still ensure the operation of the system when the refrigerant loop fails and the system shuts down.

[0009] 3. Economy and operation efficiency, the load required to be borne by the refrigerant loop in the daytime can be reduced by the way of night storage, the power consumption is reduced, the problem of peak-valley electricity price is effectively alleviated, the economy is improved, the compressor can be maintained in the operation condition near the higher operation efficiency, and the system operation efficiency is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic diagram of the CO2 cold carrier energy storage cooling system of the external high-pressure gas tank of the present application. DETAILED DESCRIPTION

[0011] The technical solutions in the present application will be described clearly and completely in the embodiments of the present application combined with the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0012] As Figure 1As shown, a CO2 cold carrier energy storage cooling system outside a high-pressure gas tank includes a refrigerant loop and a CO2 loop, in addition to the shared condenser evaporator 5, the refrigerant loop further includes a compressor 1, a condenser 2, a refrigerant storage tank 3 and an electronic expansion valve EEV 4, the outlet of the compressor 1, the condenser 2, the refrigerant storage tank 3 and the electronic expansion valve EEV 4 are connected in sequence through the pipeline, the inlet of the compressor 1 is connected with the refrigerant outlet of the condenser evaporator 5 through the pipeline, the electronic expansion valve EEV 4 is connected with the refrigerant inlet of the condenser evaporator 5 through the pipeline, the CO2 loop further includes a CO2 liquid pump 6, a cold evaporator 7, a CO2 storage tank 8, an air compressor 9 and a CO2 high-pressure gas tank 10, the liquid pipe outlet of the CO2 storage tank 8 is connected with the CO2 liquid pump 6 through the pipeline, the CO2 liquid pump 6 is finally connected with the gas pipe inlet of the CO2 storage tank 8 through the main path and the bypass, the main path includes multiple branches connected in parallel and each branch is sequentially arranged with an electromagnetic regulating valve 12, a stop valve 13 and the cold evaporator 7, the bypass is arranged with an electromagnetic regulating valve 12, the liquid pipe inlet of the CO2 storage tank 8 is connected with the CO2 condensing pipe outlet of the condenser evaporator 5 through the pipeline, the gas pipe outlet of the CO2 storage tank 8 is connected with the CO2 condensing pipe inlet of the condenser evaporator 5 through the pipeline, the air compressor 9 connects the gas pipe outlet of the CO2 storage tank 8 with the gas pipe inlet of the CO2 high-pressure gas tank 10 through the pipeline, the gas pipe outlet of the CO2 high-pressure gas tank 10 is connected with the CO2 condensing pipe inlet of the condenser evaporator 5 through the pipeline in sequence through the electromagnetic regulating valve 12 and the pressure reducing valve 11, further, the air compressor 9 and the electromagnetic regulating valve 12 are connected with a control circuit, the control circuit is connected with a pressure sensor, the pressure sensor is arranged in the CO2 storage tank 8, the internal pressure of the CO2 storage tank 8 is detected by the pressure sensor and compared with the set value, if the pressure is lower than the set value, the air compressor 9 is closed and the electromagnetic regulating valve 12 is opened, if the pressure is higher than the set value, the air compressor 9 is opened and the electromagnetic regulating valve 12 is closed.

[0013] The specific operation process of the cooling system of the present application is as follows:

[0014] I. The operation process of the refrigerant loop

[0015] The high-temperature and high-pressure refrigerant gas discharged from the compressor 1 becomes low-temperature and high-pressure refrigerant gas-liquid mixed fluid after heat exchange in the condenser 2 and flows into the refrigerant storage tank 3, the refrigerant liquid in the refrigerant storage tank 3 becomes low-temperature and low-pressure refrigerant liquid after passing through the electronic expansion valve EEV 4, enters the condenser evaporator 5 and exchanges heat with CO2 to absorb heat and become refrigerant gas, and finally flows into and does work in the compressor 1 to become high-temperature and high-pressure refrigerant gas.

[0016] II. The user cooling process of the CO2 loop

[0017] The CO2 liquid in the CO2 storage tank 8 is pumped by the CO2 liquid pump 6 and divided into a main path and a bypass path. The main path is divided into multiple branches, sequentially passes through the electromagnetic regulating valve 12 and the stop valve 13, enters the cold evaporator 7 to absorb heat and gasify, and then the CO2 gas-liquid mixed fluid at the outlet of the cold evaporator 7 flows into the CO2 storage tank 8. The bypass path passes through the electromagnetic regulating valve 12 and then flows into the CO2 storage tank 8.

[0018] III. CO2 loop CO2 condensation liquefaction process

[0019] When storing cold energy, the high-pressure CO2 gas in the CO2 high-pressure storage tank 10 flows through the electromagnetic regulating valve 12 and becomes low-pressure CO2 gas through the pressure reducing valve 11, and is mixed with the low-pressure CO2 gas directly from the CO2 storage tank 8 to enter the condensation evaporator 5 to absorb cold energy and liquefy into CO2 liquid, and finally flows into the CO2 storage tank 8. When releasing the stored cold energy, the CO2 gas in the CO2 storage tank 8 is pressurized by the air compressor 9 and sent into the CO2 high-pressure storage tank 10.

[0020] The specific operation mode of the system energy storage is as follows:

[0021] At night, the refrigeration capacity of the refrigerant loop is greater than the cold consumption of the user, that is, the liquefied CO2 produced by the condensation evaporator 5 is more than the gaseous CO2 produced by the cold evaporator 7, so that the gaseous CO2 in the CO2 storage tank 8 decreases and the pressure drops. After the pressure sensor arranged in the CO2 storage tank 8 detects that the pressure is lower than the set value, the air compressor 9 is turned off, the opening degree of the electromagnetic regulating valve 12 is adjusted, the high-pressure CO2 gas in the CO2 high-pressure storage tank 10 is reduced in pressure through the pressure reducing valve 11 and enters the condensation evaporator 5, the gaseous CO2 absorbs the cold energy of the refrigerant loop and becomes liquefied CO2 flowing into the CO2 storage tank 8, and the gaseous CO2 that is not completely liquefied enters the CO2 storage tank 8 together to ensure the stability of the pressure, and the liquid CO2 in the CO2 storage tank 8 is used for storing cold energy;

[0022] During the day, the refrigeration capacity of the refrigerant loop is less than the cold consumption of the user, that is, the liquefied CO2 produced by the condensation evaporator 5 is less than the gaseous CO2 produced by the cold evaporator 7, so that the gaseous CO2 in the CO2 storage tank 8 increases and the pressure rises. After the pressure sensor arranged in the CO2 storage tank 8 detects that the pressure is higher than the set value, the electromagnetic regulating valve 12 is closed to prevent the high-pressure CO2 in the CO2 high-pressure storage tank 10 from flowing out, and the air compressor 9 is turned on to compress the gaseous CO2 in the CO2 storage tank 8 and input into the CO2 high-pressure storage tank 10, thereby ensuring the stability of the pressure of the CO2 storage tank 8. At the same time, the liquid CO2 in the CO2 storage tank 8 is continuously gasified during the operation of the entire cooling system, and the cold energy stored at night is released.

[0023] It is apparent to a person skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but that it can be implemented in other embodiments without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than by the above description, and all changes coming within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the features to which the reference signs are attached.

[0024] Furthermore, it should be understood that although the description is made on embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and a person skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be combined appropriately to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A CO2 secondary refrigerant energy storage cooling system for an external high pressure gas storage tank, characterized by: The refrigerant loop and CO2 loop, two loops in addition to the common condensation evaporator (5), the refrigerant loop also includes compressor (1), condenser (2), refrigerant storage tank (3) and electronic expansion valve EEV (4), the outlet of the compressor (1), condenser (2), refrigerant storage tank (3) and electronic expansion valve EEV (4) are connected in turn, the inlet of the compressor (1) is connected with the refrigerant outlet of the condensation evaporator (5), the electronic expansion valve EEV (4) is connected with the refrigerant inlet of the condensation evaporator (5), the CO2 loop also includes CO2 liquid pump (6), cold evaporator (7), CO2 storage tank (8), air compressor (9) and CO2 high pressure gas tank (10), the liquid pipe outlet of the CO2 storage tank (8) is connected with the CO2 liquid pump (6), the CO2 liquid pump (6) is finally connected with the gas pipe inlet of the CO2 storage tank (8) through the main path and the bypass, the main path includes multiple branches in parallel and each branch is arranged with electromagnetic regulating valve (12), stop valve (13) and the cold evaporator (7) in turn, the bypass is arranged with electromagnetic regulating valve (12), the liquid pipe inlet of the CO2 storage tank (8) is connected with the CO2 condensing pipe outlet of the condensation evaporator (5), the gas pipe outlet of the CO2 storage tank (8) is connected with the CO2 condensing pipe inlet of the condensation evaporator (5), the air compressor (9) connects the gas pipe outlet of the CO2 storage tank (8) with the gas pipe inlet of the CO2 high pressure gas tank (10), the gas pipe outlet of the CO2 high pressure gas tank (10) is connected with the CO2 condensing pipe inlet of the condensation evaporator (5) through electromagnetic regulating valve (12) and pressure reducing valve (11) in turn.

2. The CO2 secondary refrigerant energy storage cooling system for high pressure gas tank according to claim 1, characterized in that: The electromagnetic regulating valve (12) connected between the air compressor (9) and the condensation evaporator (5) and the CO2 high pressure gas tank (10) is connected with a control circuit, the control circuit is connected with a pressure sensor, and the pressure sensor is arranged in the CO2 storage tank (8).

Images