Ice storage and cold storage ice pool and transcritical and subcritical refrigeration house refrigerating system thereof

Abstract

The invention provides an ice storage and cold storage ice pool and a transcritical and subcritical refrigeration house refrigerating system thereof. A transcritical heat exchange pipe and a subcritical heat exchange pipe are arranged in the ice storage and cold storage ice pool; the transcritical refrigeration unit and the subcritical refrigeration unit exchange heat with the ice storage and cold storage ice pool through the transcritical heat exchange pipe and the subcritical heat exchange pipe respectively, and when the transcritical refrigeration unit conducts transcritical circulation refrigeration, the subcritical refrigeration unit conducts heat exchange with the ice storage and cold storage ice pool through the subcritical heat exchange pipe; the carbon dioxide refrigerant in the transcritical heat exchange tube is evaporated and vaporized, so that the cold energy is stored in an ice storage tank of the ice storage and cold storage ice pool in an ice form; when the subcritical refrigeration unit carries out subcritical circulation refrigeration, cold energy is provided for subcritical refrigeration circulation in an ice layer melting mode, and a gas-phase carbon dioxide refrigerant in the subcritical heat exchange pipe is promoted to be liquefied. The trans-critical refrigeration unit and the subcritical circulation unit can be effectively connected through the ice storage ice pool, and independent operation and multi-temperature-zone refrigeration of the trans-critical refrigeration unit and the subcritical refrigeration unit are achieved.

Description

Technical Field

[0001] The present invention relates to the field of cold storage refrigeration technology, and in particular to an ice storage pool and a transcritical and subcritical cold storage refrigeration system thereof. Background Art

[0002] At present, cold storage refrigeration systems tend to adopt two-stage compression or cascade refrigeration systems. Although the compression ratio of each stage of these two types of systems is reduced compared with the single-stage vapor compression refrigeration system, due to its relatively complex structure, the two-stage system cannot achieve single independent operation, the difficulty of system operation and control increases, and the operation of the system cannot be flexibly adjusted according to the actual refrigeration (heat) demand. For example, in a two-stage cascade system, it consists of a high-temperature stage and a low-temperature stage. The medium-temperature refrigerant is used in the high-temperature stage cycle, and the low-temperature refrigerant is used in the low-temperature stage cycle. The two-stage system is connected by an evaporative condenser. During the operation of the system, the medium-temperature refrigerant absorbs the heat of the low-temperature refrigerant in the evaporative condenser and then evaporates and vaporizes, while the low-temperature refrigerant condenses and releases heat to become a liquid refrigerant. However, when the difference in refrigeration (heat) power between the high-temperature stage and the low-temperature stage is too large, it may cause the system evaporation and condensation process to deviate from the required operating conditions, which will cause the system to fail to operate normally. At the same time, since the two-stage system needs to complete the corresponding refrigeration (heat) cycle based on the heat exchange of the refrigerant, the two-stage system needs to run synchronously, which makes it impossible to flexibly adjust the system opening and closing according to the actual required cold (heat) load. For example, in the prior art (publication number: CN115183517A), there is a cascade hot fluorine defrost type refrigeration and hot water cogeneration system, which consists of a refrigeration cycle and a heat pump cycle, and uses Freon as the refrigerant. However, this type of unit can only provide a single refrigeration (heat) temperature and the refrigeration and heating cycles need to be carried out simultaneously. In addition, compared with other refrigerants, based on the physical properties of the Freon refrigerant itself, such as the small refrigeration capacity per unit volume, the system further limits the improvement of refrigeration (heat) efficiency.

[0003] In addition, the current cold storage refrigeration system equipment tends to be selected based on the maximum load under extreme working conditions. However, this causes a lot of performance redundancy during the period when there is no cargo in and out of the cold storage or the load is relatively low; however, when the cold storage is in peak operation, the required cooling load increases significantly, the refrigeration unit will face greater working pressure, and the refrigeration efficiency decreases accordingly. In addition, the selection method based on the maximum load under extreme working conditions lacks flexibility, and it is impossible to dynamically adjust the unit according to the actual refrigeration capacity required in the daily operation of the cold storage, which significantly increases the operating cost of the refrigeration unit. For example, the ice pool ice storage and cold storage technology in the prior art, the coil-type ice pool consists of a serpentine coil, an ice storage tank, a water pump and a corresponding control system. In the coil-type ice pool, a low-temperature ethylene glycol aqueous solution flows in the coil and exchanges heat with the water in the ice storage tank outside the tube through the coil wall. In this process, the ethylene glycol solution absorbs the sensible heat of the water, causing the water temperature to gradually decrease to the freezing point. At this time, the water outside the coil gradually freezes into solid ice and is stored in the ice storage tank. During the peak period of power load, the refrigeration system stops working, the stored ice begins to melt and releases cold energy for cold storage refrigeration. In addition, in principle, flowing ice slurry can be used in cold storage systems, but the ice content of ice slurry is only 20-30%. Compared with all-solid ice, the cold energy that ice slurry can provide will also be reduced accordingly, which will lead to a decrease in the refrigeration efficiency of the cold storage. At the same time, the ice-water mixture has problems such as poor flow safety and unstable heat transfer. There is also an ice pool ice storage and cold storage technology in the prior art. The coil-type ice pool consists of a serpentine coil, an ice storage tank, a water pump and a corresponding control system. In the coil-type ice pool, a low-temperature ethylene glycol aqueous solution flows in the coil and exchanges heat with the water in the ice storage tank outside the tube through the coil wall. In this process, the ethylene glycol solution absorbs the sensible heat of the water, causing the water temperature to gradually decrease to the freezing point. At this time, the water outside the coil gradually freezes into solid ice and is stored in the ice storage tank. During the peak period of power load, the refrigeration system stops working, the stored ice begins to melt and releases cold energy for cold storage refrigeration. However, in this process, only sensible heat exchange occurs between ethylene glycol and water. Compared with phase change heat exchange, the heat exchange efficiency of sensible heat exchange is lower, which in turn affects its ice-making efficiency. Although this method can gradually reduce the water temperature to the freezing point to form a solid ice pool, the energy consumption required is also relatively high. Summary of the invention

[0004] The embodiment of the present disclosure provides an ice storage pool and a transcritical and subcritical cold storage refrigeration system thereof to solve the problems existing in the related technologies. The technical solution is as follows: According to one aspect of an embodiment of the present disclosure, an ice storage and cold storage ice pool is provided, comprising: a transcritical heat exchange tube; a subcritical heat exchange tube; an ice storage tank, wherein the transcritical heat exchange tube and the subcritical heat exchange tube are arranged in the ice storage and cold storage ice pool, and a transcritical refrigeration unit and a subcritical refrigeration unit respectively realize heat exchange with the ice storage and cold storage ice pool through the transcritical heat exchange tube and the subcritical heat exchange tube, wherein when the transcritical refrigeration unit performs transcritical cycle refrigeration, the carbon dioxide refrigerant in the transcritical heat exchange tube evaporates and vaporizes to store the cold in the form of ice in the ice storage tank of the ice storage and cold storage ice pool; when the subcritical refrigeration unit performs subcritical cycle refrigeration, the ice layer is melted to provide cold for the subcritical refrigeration cycle, thereby causing the gas-phase carbon dioxide refrigerant in the subcritical heat exchange tube to liquefy, wherein the transcritical refrigeration unit and the subcritical refrigeration unit can operate independently.

[0005] Optionally, the ice storage and cold storage ice pool also includes a transcritical refrigerant liquid inlet pipe and a transcritical refrigerant gas outlet pipe, the transcritical refrigerant liquid inlet pipe is connected to the liquid inlet of the transcritical heat exchange tube, and the transcritical refrigerant gas outlet pipe is connected to the gas outlet of the transcritical heat exchange tube.

[0006] Optionally, the ice storage and cold storage ice pool also includes a subcritical refrigerant inlet pipe and a subcritical refrigerant liquid outlet pipe, the subcritical refrigerant inlet pipe is connected to the air inlet of the subcritical heat exchange tube, and the subcritical refrigerant liquid outlet pipe is connected to the liquid outlet of the subcritical heat exchange tube.

[0007] Optionally, the ice storage and cold storage ice pool further includes a water inlet pipe and a water outlet pipe connected to the ice storage tank, and the ice storage and cold storage ice pool further includes a thermal insulation layer, and the thermal insulation layer is used for thermal insulation of the ice storage and cold storage ice pool.

[0008] Optionally, the maximum ice content of the solid ice in the ice storage tank is not less than 70%.

[0009] According to another aspect of an embodiment of the present disclosure, a transcritical and subcritical cold storage refrigeration system is provided, comprising: a transcritical refrigeration unit; a subcritical refrigeration unit; the above-mentioned ice storage and cold storage ice pool, wherein the ice storage and cold storage ice pool is used to connect the transcritical refrigeration unit and the subcritical refrigeration unit, so that the transcritical refrigeration unit and the subcritical refrigeration unit operate independently, and realize ice storage and cold storage refrigeration of the ice storage and cold storage ice pool.

[0010] Optionally, the transcritical refrigeration unit includes a transcritical compressor, an ice storage pool, a gas cooler, a first expansion valve and a first gas-liquid separator. The transcritical refrigeration unit is used to realize ice storage and cold storage in the ice storage pool. The transcritical compressor compresses low-temperature and low-pressure carbon dioxide refrigerant to make it reach a supercritical state. The carbon dioxide refrigerant flows through the gas cooler and performs sensible heat exchange with an ambient cold source to release heat. After releasing the heat, the carbon dioxide refrigerant is throttled and depressurized by the first expansion valve and enters the transcritical heat exchange tube in the ice storage pool in the form of gas-liquid two-phase state to absorb heat and gradually vaporize, and causes the water on the outer surface of the transcritical heat exchange tube to freeze. Subsequently, the carbon dioxide refrigerant returns to the transcritical compressor through the first gas-liquid separator to realize cyclic refrigeration. The subcritical refrigeration unit includes a subcritical compressor, an ice storage pool, a second expansion valve, an air cooler, a cold storage, and a second gas-liquid separator. The air cooler is arranged in the cold storage. The hot and humid air formed by absorbing the heat of the goods in the cold storage flows into the return air port of the air cooler and exchanges heat with the heat exchange pipe of the air cooler. The carbon dioxide refrigerant in the heat exchange pipe of the air cooler vaporizes and absorbs heat to realize cooling and cooling of the hot and humid air into humid and cold air. The humid and cold air flows into the cold storage again through the air supply port of the air cooler to ensure the constant temperature in the cold storage. After the carbon dioxide refrigerant is vaporized, it passes through the second gas-liquid separator to realize gas-liquid separation. The gas phase carbon dioxide refrigerant flows through the subcritical compressor and is compressed to a high temperature and high pressure state. Subsequently, the gas phase carbon dioxide refrigerant exchanges heat with the solid ice layer formed by the transcritical refrigeration unit through the subcritical heat exchange pipe. The solid ice layer gradually melts and provides cooling capacity for the subcritical refrigeration cycle. After condensation and heat dissipation, the carbon dioxide refrigerant flows into the second expansion valve to throttle and reduce the pressure and returns to the heat exchange pipe in the air cooler to evaporate and vaporize to realize cyclic refrigeration.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: by using an ice storage and cold storage ice pool as a link, the transcritical refrigeration unit and the subcritical refrigeration unit can be effectively connected to meet the needs of ice storage in the ice storage and cold storage ice pool and refrigeration of a low-temperature cold storage (minus 18-40°C); and based on the cold storage characteristics of the ice storage and cold storage ice pool, the independent operation of the transcritical refrigeration unit and the subcritical refrigeration unit can be further realized, and then the opening and closing of the ice storage and cold storage ice pool and the low-temperature cold storage can be independently controlled according to the actual ice storage amount and refrigeration load requirements, thereby reducing the complexity of system control while improving its operational flexibility, thereby reducing the energy consumption required for system operation; in addition, by adding a hot water storage tank and a high-temperature cold storage to the transcritical refrigeration unit, the transcritical refrigeration cycle can be used to meet the refrigeration of the high-temperature cold storage (0-15°C), and the waste heat of the compressor can be used to realize hot water supply. During this process, the transcritical refrigeration unit and the subcritical refrigeration unit do not need to operate synchronously. The opening and closing states of the ice storage pool, high-temperature cold storage refrigeration and low-temperature cold storage refrigeration can be independently controlled according to the actual refrigeration load demand, which will further achieve the purpose of multi-temperature zone refrigeration.

[0012] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present disclosure will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments according to the present disclosure and should not be regarded as limiting the scope of the present disclosure.

[0014] Figure 1 It is a schematic diagram of a carbon dioxide transcritical refrigeration cycle system in the prior art; Figure 2 A schematic diagram of an ice storage and cold storage ice pool in an embodiment of the present disclosure; Figure 3 It is a schematic diagram of the transcritical and subcritical cold storage refrigeration system in the embodiment of the present disclosure; Figure 4 This is another implementation schematic diagram of the transcritical and subcritical cold storage refrigeration system in the embodiment of the present disclosure. DETAILED DESCRIPTION

[0015] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0016] like Figure 1 FIG. 1 is a schematic diagram of a carbon dioxide transcritical refrigeration cycle system in the prior art, including a compressor, a gas cooler, an expansion valve, an evaporator, etc. Figure 1 In stages 1-2, the low-temperature and low-pressure carbon dioxide refrigerant evaporates and vaporizes after heat exchange with the surrounding environment in the evaporator, thereby lowering the temperature of the surrounding environment; in stages 2-3, the carbon dioxide refrigerant after absorbing heat enters the compressor for compression. The temperature and pressure of the compressed refrigerant increase, and its pressure exceeds the critical pressure (7.38Mpa); the high-temperature and high-pressure carbon dioxide refrigerant enters the gas cooler for cooling in stages 3-4. In this stage, the carbon dioxide refrigerant releases heat at a constant pressure in a supercritical state, and the refrigerant does not undergo a phase change, becoming a high-pressure and medium-temperature carbon dioxide refrigerant; stage 4-1 is an adiabatic throttling process, in which the temperature and pressure of the carbon dioxide refrigerant decrease in the expansion valve, and returns to the evaporator again to complete the refrigeration cycle.

[0017] A transcritical refrigeration cycle refers to a vapor compression refrigeration cycle in which the suction pressure is below the critical pressure (7.38Mpa) and the exhaust pressure is above the critical pressure (7.38Mpa); a subcritical refrigeration cycle refers to a vapor compression refrigeration cycle in which the evaporation pressure and condensing pressure of the system are always kept below the critical pressure (7.38Mpa).

[0018] See also Figure 2 The present disclosure provides an ice storage and cold storage ice pool 100, comprising: Transcritical heat exchange tube 1; Subcritical heat exchange tube 2; The ice storage tank 3, the transcritical heat exchange tube 1 and the subcritical heat exchange tube 2 are arranged in the ice storage and cold storage ice pool 100, and the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300 respectively realize heat exchange with the ice storage and cold storage ice pool 100 through the transcritical heat exchange tube 1 and the subcritical heat exchange tube 2, wherein, when the transcritical refrigeration unit 200 performs transcritical cycle refrigeration, the carbon dioxide refrigerant in the transcritical heat exchange tube 1 evaporates and vaporizes to store the cold energy in the form of ice in the ice storage tank 3 of the ice storage and cold storage ice pool 100; when the subcritical refrigeration unit 300 performs subcritical cycle refrigeration, the ice layer is melted to provide cold energy for the subcritical refrigeration cycle, so as to liquefy the gas-phase carbon dioxide refrigerant in the subcritical heat exchange tube 2, wherein the transcritical refrigeration unit and the subcritical refrigeration unit can operate independently.

[0019] The above-mentioned ice storage and cold storage ice pool 100 in the embodiment of the present disclosure can effectively connect the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300, and can realize the independent operation of the transcritical refrigeration unit and the subcritical refrigeration unit; it can also meet the demand of simultaneously supplying multiple refrigeration temperatures (not less than 3) within the wide temperature range of -18-40°C by configuring multiple subcritical refrigeration units, which is different from other single refrigeration systems that can only meet 1-2 refrigeration temperature requirements.

[0020] Among them, Figure 2 As shown, the transcritical heat exchange tube 1 and the subcritical heat exchange tube 2 are distributed in the ice storage and cold storage ice pool 100, for example, they can be distributed in a serpentine cross shape to optimize the heat exchange effect; as an optional embodiment, the ice storage and cold storage ice pool 100 also includes a transcritical refrigerant liquid inlet pipe 101 and a transcritical refrigerant gas outlet pipe 102, which serve as interfaces connected to the transcritical refrigeration unit 200, the transcritical refrigerant liquid inlet pipe 101 is connected to the liquid inlet of the transcritical heat exchange tube 1, and the transcritical refrigerant gas outlet pipe 102 is connected to the gas outlet of the transcritical heat exchange tube 1.

[0021] As an optional embodiment, the ice storage pool 100 also includes a subcritical refrigerant inlet pipe 201 and a subcritical refrigerant liquid outlet pipe 202, which serve as interfaces for connecting to the subcritical refrigeration unit 300. The subcritical refrigerant inlet pipe 201 is connected to the air inlet of the subcritical heat exchange tube 2, and the subcritical refrigerant liquid outlet pipe 202 is connected to the liquid outlet of the subcritical heat exchange tube 2.

[0022] As an optional embodiment, the ice storage and cold storage ice pool 100 also includes a water inlet pipe 4 and a water outlet pipe 5 connected to the ice storage tank 3, and the ice storage and cold storage ice pool also includes a thermal insulation layer 6, and the thermal insulation layer 6 is used for thermal insulation of the ice storage and cold storage ice pool 100.

[0023] As an optional implementation manner, the maximum ice content of the solid ice in the ice storage tank 3 is not less than 70%.

[0024] See attached Figure 3 The disclosed embodiment also provides a transcritical and subcritical cold storage refrigeration system, including: a transcritical refrigeration unit 200; a subcritical refrigeration unit 300; the ice storage and cold storage ice pool 100 in the above embodiment, wherein the ice storage and cold storage ice pool 100 is used to connect the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300, so that the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300 can refrigerate separately while realizing ice storage and cold storage refrigeration of the ice storage and cold storage ice pool 100.

[0025] As a preferred embodiment, the transcritical refrigeration unit 200 also includes a transcritical compressor 21, an ice storage pool 100, a gas cooler 22, a first expansion valve 23 and a first gas-liquid separator 24. The transcritical refrigeration unit 200 is used to realize ice storage and cold storage in the ice storage pool 100. The transcritical compressor 21 compresses the low-temperature and low-pressure carbon dioxide refrigerant to make it reach a supercritical state. The carbon dioxide refrigerant flows through the gas cooler 22 and performs sensible heat exchange with the ambient cold source to release heat. After releasing the heat, the carbon dioxide refrigerant is throttled and depressurized by the first expansion valve 23 and enters the transcritical heat exchange tube 1 in the ice storage pool 100 in the form of gas-liquid two-phase state to absorb heat and gradually vaporize, and causes the water on the outer surface of the transcritical heat exchange tube 1 to freeze. Subsequently, the carbon dioxide refrigerant returns to the transcritical compressor 21 through the first gas-liquid separator 24 to realize circulating refrigeration.

[0026] As a preferred embodiment, the subcritical refrigeration unit 300 includes a subcritical compressor 31, an ice storage pool 100, a second expansion valve 32, a second air cooler 33, a low-temperature cold storage 34, and a second gas-liquid separator 35. The second air cooler 33 is arranged in the low-temperature cold storage 34. The hot and humid air formed by absorbing the heat of the cold storage goods in the low-temperature cold storage 34 flows into the return air port of the second air cooler 33 and exchanges heat with the heat exchange pipe of the second air cooler 33; wherein the carbon dioxide refrigerant in the heat exchange pipe of the second air cooler 33 vaporizes and absorbs heat to cool the hot and humid air into humid cold air, and the humid cold air passes through The air supply port of the second air cooler 33 flows into the low-temperature cold storage 34 again to ensure the constant temperature in the cold storage; the carbon dioxide refrigerant is vaporized and passes through the second gas-liquid separator 35 to achieve gas-liquid separation, wherein the gas phase carbon dioxide refrigerant flows through the subcritical compressor 31 and is compressed to a high temperature and high pressure state, and then exchanges heat with the solid ice layer formed by the transcritical refrigeration unit 200 through the subcritical heat exchange tube 2, the solid ice layer gradually melts and provides cooling capacity for the subcritical refrigeration cycle, and after completing condensation and heat dissipation, the carbon dioxide refrigerant flows into the second expansion valve 32 to throttle and reduce the pressure and returns to the heat exchange tube in the second air cooler 33 to evaporate and vaporize to achieve cyclic refrigeration.

[0027] In addition, based on the cold storage characteristics of the ice storage pool 100, the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300 can be further operated independently, and then the opening and closing of the ice storage pool 100 and the low-temperature cold storage 34 can be independently controlled according to the actual ice storage amount and the refrigeration load demand. In this process, when the ice storage amount of the ice storage pool 100 is sufficient and there is a refrigeration demand in the low-temperature cold storage 34, the transcritical refrigeration unit 200 can stop running, the subcritical refrigeration unit 300 is turned on, and the ice storage pool 100 temporarily stops the carbon dioxide refrigerant from making ice through the transcritical refrigeration unit 200. At this time, the high-temperature and high-pressure carbon dioxide refrigerant compressed by the subcritical compressor 31 exchanges heat with the solid ice stored in the ice storage pool 100, and the solid ice inside the ice storage pool 100 gradually melts to provide cold for the subcritical refrigeration unit 300 cycle. However, when there is no goods stored in the low-temperature cold storage 34 and it does not need refrigeration, the subcritical refrigeration unit 300 can be stopped, and the opening and closing of the transcritical refrigeration unit 200 is determined according to the ice storage capacity of the ice storage pool 100. When the ice storage pool 100 has sufficient ice storage or it is in the peak power period, the transcritical refrigeration unit 200 can also be stopped. Otherwise, the refrigeration cycle of the transcritical refrigeration unit 200 can be turned on to achieve ice storage in the ice storage pool 100. In short, based on the actual ice storage and refrigeration needs, the complexity of system control can be reduced while improving its operation flexibility, thereby reducing the energy consumption required for system operation.

[0028] See attached Figure 4The disclosed embodiment also provides a transcritical and subcritical cold storage refrigeration system, including: a transcritical refrigeration unit 200; a subcritical refrigeration unit 300; the ice storage and cold storage ice pool 100 in the above embodiment, wherein the ice storage and cold storage ice pool 100 is used to connect the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300, so that the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300 can refrigerate separately while realizing ice storage and cold storage refrigeration of the ice storage and cold storage ice pool 100. The transcritical refrigeration unit 200 also includes a transcritical compressor 21, an ice storage tank 100, a gas cooler 22, a first expansion valve 23, a first gas-liquid separator 24, a three-way valve 25, a liquid storage tank 26, a bypass constant pressure valve 27 and a hot water recovery device 29. The transcritical compressor 21 compresses the low-temperature and low-pressure carbon dioxide refrigerant to make it reach a supercritical state. When there is a demand for hot water supply, the gaseous refrigerant passes through the three-way valve 25 and enters the hot water recovery device 29 to fully exchange heat with municipal cold water and is stored in the hot water storage tank 500, thereby meeting industrial or domestic needs. The supply demand of hot water is met to realize the efficient recycling of waste heat; the carbon dioxide refrigerant after sufficient heat exchange with municipal cold water exchanges sensible heat with the ambient cold source through the gas cooler 22 to release heat; when there is no demand for hot water supply, the gaseous refrigerant directly enters the gas cooler through the three-way valve 25 to complete the heat exchange; then, after the carbon dioxide refrigerant flows through the liquid storage tank 26, the gaseous refrigerant is directly sucked into the transcritical compressor 21 through the circuit where the bypass constant pressure valve 27 is located to complete the compression again; the liquid refrigerant flows through the first expansion valve 23 to complete the throttling and pressure reduction process. Then, based on the opening and closing control of the second solenoid valve 211, part of the carbon dioxide refrigerant is transported to the heat exchange coil of the first cold air machine 401 inside the high-temperature cold storage 400. The axial flow fan in the first cold air machine 401 promotes the heat exchange between the hot and humid air and the heat exchange coil by forced convection, and the refrigerant vaporizes and absorbs heat to remove the heat of the humid air, thereby realizing the cooling and cooling of the humid air. Subsequently, the wet cold air is evenly delivered to every corner of the high-temperature cold storage 400 through the air supply port on the side of the first cold air machine. After the wet cold air flows through the surface of the cargo and completes the cooling process to become wet hot air, it flows into the first cold air machine 401 again through the return air port at the bottom of the first cold air machine 401 for circulation treatment. At the same time, another part of the refrigerant flows into the transcritical heat exchange tube 1 of the ice storage pool 100 after passing through the first solenoid valve 210 to absorb heat and gradually vaporize, and causes the water on the outer surface of the transcritical heat exchange tube 1 to freeze to meet the cooling load demand in the heat dissipation process of the subcritical unit. Subsequently, the carbon dioxide refrigerant that has completed the refrigeration of the high-temperature cold storage 400 and the ice storage pool 100 is separated into gas and liquid by the first gas-liquid separator 24, and the gaseous refrigerant returns to the transcritical compressor 21 again to realize circulation refrigeration.

[0029] The transcritical refrigeration unit 200 further includes a first oil separator 28 connected after the transcritical compressor 21 , which is used to separate the lubricating oil in the high-pressure steam discharged from the transcritical compressor 21 and return it to the transcritical compressor 21 .

[0030] The subcritical refrigeration unit 300 includes a subcritical compressor 31, an ice storage pool 100, a second expansion valve 32, a second air cooler 33, a low-temperature cold storage 34, and a second gas-liquid separator 35. The second air cooler 33 is arranged in the low-temperature cold storage 34. The hot and humid air formed by absorbing the heat of the cold storage goods in the low-temperature cold storage 34 flows into the return air port of the second air cooler 33 and exchanges heat with the heat exchange pipe of the second air cooler 33; wherein the carbon dioxide refrigerant in the heat exchange pipe of the second air cooler 33 vaporizes and absorbs heat to realize the cooling of the hot and humid air into humid cold air, and the humid cold air passes through the second cold air The air outlet of the machine 33 flows into the low-temperature cold storage 34 again to ensure the constant temperature in the cold storage; the carbon dioxide refrigerant is vaporized and passes through the second gas-liquid separator 35 to achieve gas-liquid separation; wherein, the gas phase carbon dioxide refrigerant flows through the subcritical compressor 31 and is compressed to a high temperature and high pressure state, and then, through the subcritical heat exchange tube 2, it exchanges heat with the solid ice layer formed by the transcritical refrigeration unit 200, and the solid ice layer gradually melts and provides cold for the subcritical refrigeration cycle. After condensation and heat dissipation, the carbon dioxide refrigerant flows into the second expansion valve 32 to throttle and reduce the pressure and returns to the heat exchange tube in the second air cooler 33 to evaporate and vaporize to achieve cyclic refrigeration. The subcritical refrigeration unit 300 also includes a drying filter 36, which is arranged before the second expansion valve to remove moisture and impurities in the carbon dioxide refrigerant.

[0031] The subcritical refrigeration unit 300 further includes a second oil separator 37 connected after the subcritical compressor 31 , which is used to separate the lubricating oil in the high-pressure steam discharged from the subcritical compressor 31 and return it to the subcritical compressor 31 .

[0032] When the transcritical and subcritical cold storage refrigeration system in the embodiment of the present disclosure is applied to the refrigeration of the high-temperature cold storage 400, the ice storage and cold storage of the ice storage pool 100, and the hot water supply, the system operation process is as follows: When the exhaust waste heat in the transcritical compressor 21 is recovered and used for industrial or domestic hot water supply, the low-temperature and low-pressure carbon dioxide refrigerant is first compressed by the transcritical compressor 21 to reach a supercritical state, and then transported to the first oil separator 28. In the first oil separator 28, the lubricating oil is efficiently separated from the high-pressure steam and reflowed back into the transcritical compressor 21 to ensure the normal and continuous operation of the transcritical compressor 21 unit. Subsequently, the high-temperature and high-pressure exhaust gas of the transcritical compressor 21 is bypassed to the hot water recovery device 29 through the three-way valve 25. After the high-temperature and high-pressure exhaust gas is fully heat-exchanged with the municipal water supply in the hot water recovery device 29, it enters the gas cooler to continue to dissipate heat. And according to the actual needs of life or industrial life, the flow rate of the carbon dioxide refrigerant entering the hot water storage tank 500 is adjusted in real time through the opening and closing control of the solenoid valve. At the same time, if there is no demand for hot water supply, the high-temperature and high-pressure carbon dioxide refrigerant compressed by the transcritical compressor directly flows into the gas cooler 22 after passing through the three-way valve 25 to complete the cooling process.

[0033] When the transcritical refrigeration unit 200 is used for refrigeration of the high-temperature cold storage 400 and ice storage and cold storage of the ice storage pool 100, the opening and closing of the subcritical refrigeration unit 300 can be controlled according to the actual refrigeration demand of the low-temperature cold storage 34. During the transcritical refrigeration cycle, the carbon dioxide refrigerant flowing through the gas cooler 22 exchanges sensible heat with the ambient cold source by air cooling. In this process, the carbon dioxide refrigerant releases a large amount of heat and its temperature is significantly reduced. Subsequently, after the carbon dioxide refrigerant enters the liquid storage tank 26, the gaseous carbon dioxide refrigerant is directly sucked into the transcritical compressor 21 through the circuit where the bypass constant pressure valve 27 is located to complete the compression again; the liquid carbon dioxide refrigerant flows through the first expansion valve 23 for throttling and pressure reduction; subsequently, based on the opening and closing control of the second solenoid valve 211, when there is a refrigeration demand in the high-temperature cold storage 400, part of the refrigerant is transported to the heat exchange coil of the first cold air blower 401 inside the high-temperature cold storage 400. In the first air cooler 401, the axial flow fan promotes the heat exchange between the hot and humid air and the heat exchange coil by forced convection, and the refrigerant vaporizes and absorbs heat to remove the heat of the humid air, thereby realizing the cooling and cooling of the humid air. Subsequently, the humid and cold air is evenly transported to every corner of the high-temperature cold storage through the air supply port on the side of the first air cooler 401. After the humid and cold air flows through the surface of the goods and completes the cooling process to become humid and hot air, it flows into the first air cooler 401 again through the return air port at the bottom of the first air cooler 401 for circulation. At the same time, another part of the refrigerant flows into the ice storage tank 100 after passing through the first solenoid valve 210 to meet the cooling load demand of the subcritical refrigeration unit 300 during the heat dissipation process. In this process, the carbon dioxide refrigerant in a low-temperature and low-pressure state enters the transcritical heat exchange tube 1 through the transcritical refrigerant inlet pipe 101 on the side of the ice storage tank 100, and after absorbing the heat of the water inside the ice storage tank 100 and gradually vaporizing, it flows out through the transcritical refrigerant outlet pipe 102. As the refrigerant continuously absorbs heat, water continues to flow on the outer surface of the transcritical heat exchange tube 1 and gradually forms an ice layer, storing the cold in the form of ice. As time goes by, the ice layer continues to thicken, eventually forming a solid ice storage pool 100 with a maximum ice content of more than 70%. After completing the refrigeration of the high-temperature cold storage 400 and the ice storage pool 100, the low-temperature and low-pressure carbon dioxide refrigerant is separated from the gas and liquid by the first gas-liquid separator 24 and then returns to the transcritical compressor 21, starting a new cycle. In this transcritical refrigeration cycle, based on the opening and closing control of the first solenoid valve 210 and the second solenoid valve 211, the refrigerant flow to the high-temperature cold storage 400 and the ice storage pool 100 can be independently adjusted, so as to further control the refrigeration output of the first air cooler 401 in the high-temperature cold storage 400 and the ice making efficiency of the ice storage pool 100 according to the actual cooling load demand of the high-temperature cold storage 400 and the ice storage amount of the ice storage pool 100. At the same time, the ice storage pool 100 can also be used to store ice and store cold during the off-peak period, and the operating cost will be further reduced.

[0034] When the subcritical cycle is applied to the refrigeration of the low-temperature cold storage 34, in the low-temperature cold storage 34, after the humid cold air flows through the surface of the goods and completes the cooling of the goods, it absorbs heat and converts it into humid hot air, and further cooling treatment is required. At this time, the humid hot air flows in through the return air port at the bottom of the second cold air machine 33, and the axial flow fan promotes the heat exchange between the hot and humid air and the heat exchange tube in the second cold air machine 33 by forced convection. In this process, the refrigerant inside the heat exchange tube in the second cold air machine 33 vaporizes and absorbs heat, taking away the heat in the hot and humid air, thereby achieving the cooling and cooling of the humid air. Subsequently, the humid cold air flows into the low-temperature cold storage 34 again through the air supply port on the side of the second cold air machine 33, and is evenly transported to every corner of the low-temperature cold storage 34, ensuring that the temperature in the low-temperature cold storage 34 is maintained in a stable and uniform state, thereby completing a new round of cargo cooling.

[0035] During the refrigeration cycle of the subcritical unit, when the ice storage tank 100 has sufficient ice storage capacity, the first solenoid valve 210 connected to the ice storage tank 100 is closed, and the ice storage tank 100 temporarily stops the carbon dioxide refrigerant from making ice through the transcritical cycle. Subsequently, the low-temperature and low-pressure carbon dioxide refrigerant absorbs the heat of the hot and humid air in the low-temperature cold storage 34 in the heat exchange tube inside the second air cooler 33 and evaporates and vaporizes, and then flows through the second gas-liquid separator 35, the subcritical compressor 31, the second oil separator 37, the ice storage tank 100, the drying filter 36 and the second expansion valve 32 in sequence, thereby completing the entire refrigeration cycle. Specifically, after the evaporated and vaporized low-temperature and low-pressure carbon dioxide refrigerant passes through the second gas-liquid separator 35, the gaseous refrigerant flows through the subcritical compressor 31 and is compressed to a high-temperature and high-pressure state, and then flows into the second oil separator 37. During this process, the separated lubricating oil will flow back to the subcritical compressor 31 to ensure the normal operation of the subcritical compressor 31. Next, the high-temperature and high-pressure carbon dioxide refrigerant enters the subcritical heat exchange tube 2 in the ice storage tank 100 through the subcritical refrigerant inlet pipe 201, and performs efficient heat exchange with the solid ice formed by the transcritical refrigeration unit to complete the condensation and heat dissipation process. At this time, based on the ice-water phase change principle, the solid ice inside the ice storage tank 100 gradually melts, creating a stable low-temperature environment, so that the operating pressure of the subcritical unit is always lower than its critical pressure (7.38Mpa). After completing the condensation and heat dissipation, the carbon dioxide refrigerant flows through the drying filter 36, removes the internal moisture and impurities, and then flows into the second expansion valve 32 to throttle and reduce the pressure and evaporates in the heat exchange tube in the second air cooler 33, and the cycle is repeated to meet the cargo refrigeration needs. In addition, in the process of using the ice storage and cold storage ice pool 100 to complete condensation heat dissipation, when the cold storage capacity of the ice storage and cold storage ice pool 100 is not enough to offset the condensation heat dissipation during the refrigeration process of the low-temperature cold storage 34, the first solenoid valve 210 of the refrigerant circuit where the ice storage and cold storage ice pool 100 is located is opened, so that the carbon dioxide refrigerant continues to make ice through a transcritical cycle, thereby achieving the purpose of storing cold in the ice storage and cold storage ice pool 100.

[0036] During the subcritical refrigeration cycle, the opening of the second expansion valve 32 in the subcritical refrigeration cycle can be appropriately adjusted according to the design requirements of the low-temperature cold storage 34 and the actual cooling load demand of the low-temperature cold storage 34, so as to control the refrigerant flow through the ice storage pool 100, and further optimize the condensation heat dissipation of the carbon dioxide refrigerant when it flows through the ice storage pool 100, thereby adjusting the cooling capacity change of the subcritical unit. During this operation, the fluctuation of the load of the low-temperature cold storage 34 is balanced by the cold capacity transfer of the ice storage pool 100.

[0037] In addition, the transcritical refrigeration unit 200 and the subcritical refrigeration unit 300 do not need to operate synchronously, and the opening and closing states of the ice storage pool 100, the high temperature cold storage 400 and the low temperature cold storage 34 can be independently controlled according to the actual refrigeration demand, thereby achieving the purpose of multi-temperature zone refrigeration. When there is no goods stored in the low temperature cold storage 34 and there is no refrigeration demand, the subcritical refrigeration unit 300 can be stopped; at the same time, the opening and closing of the transcritical refrigeration unit 200 is determined according to the ice storage amount of the ice storage pool 100 and the refrigeration demand of the high temperature cold storage 400. When the ice storage amount of the ice storage pool 100 is insufficient or there is a refrigeration demand of the high temperature cold storage 400, the transcritical refrigeration unit 200 is turned on and operated, and by controlling the opening and closing of the first solenoid valve 210 and the second solenoid valve 211, the independent operation and control of the ice storage pool 100 and the high temperature cold storage 400 can be further achieved.

[0038] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. An ice storage pool, characterized in that: include: Transcritical heat exchange tubes; Subcritical heat exchange tubes; An ice storage tank, wherein the transcritical heat exchange tube and the subcritical heat exchange tube are arranged in the ice storage pool, and the transcritical refrigeration unit and the subcritical refrigeration unit respectively realize heat exchange with the ice storage pool through the transcritical heat exchange tube and the subcritical heat exchange tube, wherein when the transcritical refrigeration unit performs transcritical cycle refrigeration, the carbon dioxide refrigerant in the transcritical heat exchange tube evaporates and vaporizes to store the cold energy in the form of ice in the ice storage tank of the ice storage pool; when the subcritical refrigeration unit performs subcritical cycle refrigeration, the ice layer is melted to provide cold energy for the subcritical refrigeration cycle, thereby causing the gas phase carbon dioxide refrigerant in the subcritical heat exchange tube to liquefy, wherein the transcritical refrigeration unit and the subcritical refrigeration unit can operate independently.

2. The ice storage and cold storage ice pool according to claim 1, characterized in that: The ice storage and cold storage ice pool also includes a transcritical refrigerant liquid inlet pipe and a transcritical refrigerant gas outlet pipe, the transcritical refrigerant liquid inlet pipe is connected to the liquid inlet of the transcritical heat exchange tube, and the transcritical refrigerant gas outlet pipe is connected to the gas outlet of the transcritical heat exchange tube.

3. The ice storage and cold storage ice pool according to claim 1 or 2, characterized in that: The ice storage and cold storage ice pool also includes a subcritical refrigerant air inlet pipe and a subcritical refrigerant liquid outlet pipe, wherein the subcritical refrigerant air inlet pipe is connected to the air inlet of the subcritical heat exchange tube, and the subcritical refrigerant liquid outlet pipe is connected to the liquid outlet of the subcritical heat exchange tube.

4. The ice storage and cold storage ice pool according to claim 1 or 2, characterized in that: The ice storage and cold storage ice pool also includes a water inlet pipe and a water outlet pipe connected to the ice storage tank, and the ice storage and cold storage ice pool also includes a heat preservation layer, and the heat preservation layer is used for heat preservation and heat insulation of the ice storage and cold storage ice pool.

5. The ice storage and cold storage ice pool according to claim 1 or 2, characterized in that: The maximum ice content of the solid ice in the ice storage tank is not less than 70%.

6. Transcritical and subcritical cold storage refrigeration system, characterized in that: include: Transcritical refrigeration unit; Subcritical refrigeration unit; The ice storage and cold storage ice pool according to any one of claims 1 to 5, wherein the ice storage and cold storage ice pool is used to connect the transcritical refrigeration unit and the subcritical refrigeration unit to achieve ice storage and cold storage refrigeration of the ice storage and cold storage ice pool.

7. The transcritical and subcritical cold storage refrigeration system according to claim 6, characterized in that: The transcritical refrigeration unit comprises a transcritical compressor, an ice storage pool, a gas cooler, a first expansion valve and a first gas-liquid separator. The transcritical refrigeration unit is used to realize ice storage and cold storage in the ice storage pool. The transcritical compressor compresses low-temperature and low-pressure carbon dioxide refrigerant to make it reach a supercritical state. The carbon dioxide refrigerant flows through the gas cooler and performs sensible heat exchange with an ambient cold source to release heat. After releasing heat, the carbon dioxide refrigerant enters the transcritical heat exchange tube in the ice storage pool in the form of gas-liquid two-phase state after throttling and reducing pressure by the first expansion valve to absorb heat and gradually vaporize, and promotes the freezing of water on the outer surface of the transcritical heat exchange tube. Subsequently, the carbon dioxide refrigerant returns to the transcritical compressor again through the first gas-liquid separator to realize cyclic refrigeration. The subcritical refrigeration unit includes a subcritical compressor, an ice storage pool, a second expansion valve, an air cooler, a cold storage, and a second gas-liquid separator. The air cooler is arranged in the cold storage. The hot and humid air formed by absorbing the heat of the goods in the cold storage flows into the return air port of the air cooler and exchanges heat with the heat exchange pipe of the air cooler. The carbon dioxide refrigerant in the heat exchange pipe of the air cooler vaporizes and absorbs heat to realize cooling and cooling of the hot and humid air into humid and cold air. The humid and cold air flows into the cold storage again through the air supply port of the air cooler to ensure the constant temperature in the cold storage. After the carbon dioxide refrigerant is vaporized, it passes through the second gas-liquid separator to realize gas-liquid separation. The gas phase carbon dioxide refrigerant flows through the subcritical compressor and is compressed to a high temperature and high pressure state. Subsequently, the gas phase carbon dioxide refrigerant exchanges heat with the solid ice layer formed by the transcritical refrigeration unit through the subcritical heat exchange pipe. The solid ice layer gradually melts and provides cooling capacity for the subcritical refrigeration cycle. After condensation and heat dissipation, the carbon dioxide refrigerant flows into the second expansion valve to throttle and reduce the pressure and returns to the heat exchange pipe in the air cooler to evaporate and vaporize to realize cyclic refrigeration.

Images