Refrigerant circulation method
Through the design of the refrigerant circulation method, the heat recovery of refrigerant and the integration of the multi-function refrigeration system is achieved using four-way valves and economizers, which solves the problem of defrost in winter and improves the energy efficiency ratio of the unit.
Patent Information
- Application Number
- CN202510349891.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-18
- Publication Date
- 2025-06-20
AI Technical Summary
When the outdoor temperature of existing refrigeration units is low in winter, it is difficult to effectively defrost, resulting in unstable unit operation, and low energy utilization rate of electric defrost and large cooling consumption.
A refrigerant circulation method is adopted to realize the heat recovery of refrigerant and the integration of a multifunctional refrigeration system through the design of four-way valves and economizers, including jet enthalpy and hot fluorine melting functions.
It effectively improves the energy efficiency ratio of the unit, realizes various functions such as heat collection recovery, frequency conversion, hot fluorine melting, jet flame enhancement, etc. of refrigeration compressor, heat recovery, condenser, etc., solves the problem of winter defrost and reduces energy consumption.
Smart Images
Figure CN120176333A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of refrigeration, and particularly relates to a refrigerant circulation method. Background Art
[0002] Existing refrigeration units mainly consist of a refrigeration compressor, a condenser, a filter, a liquid receiver, an expansion valve and an evaporator. Its working principle is to compress the refrigerant by the compressor. The compressed refrigerant circulates to the condenser to dissipate heat, then to the liquid receiver. The liquid refrigerant then goes to the expansion valve of each cold storage for throttling refrigeration. The cold quantity is dissipated outward through the evaporator, and the refrigerant changes from liquid to gas and then returns to the refrigeration compressor again. Due to the operation of the refrigeration compressor, the refrigerant undergoes a cyclic transformation of gas - liquid - gas to achieve the effect of external refrigeration.
[0003] In application, since the refrigeration unit operates for refrigeration in all seasons of spring, summer, autumn and winter, when the outdoor temperature is relatively low in winter in the north, the refrigeration unit needs to defrost to ensure normal operation. At this time, due to the low evaporation temperature of the machine, it is very difficult to achieve defrosting in winter. Currently, most refrigeration units use electric defrosting. The main problem of electric heating defrosting is excessive heat dissipation to the refrigeration space, large fluctuations in the cold storage temperature, and a large amount of cold quantity consumption for balancing the defrosting heat. In addition, the energy utilization rate of the electric heating method itself is relatively low, with high energy consumption. Moreover, the heat generated during the operation of the refrigeration unit is directly discharged into the atmosphere, resulting in insufficient utilization of energy. Therefore, a refrigerant circulation method for a heat recovery multi-functional refrigeration system is provided. Summary of the Invention
[0004] To achieve the above object, the present invention provides the following technical solution: A refrigerant circulation method, characterized in that the four-way valve includes an input port end and three commutation port ends. The input port end is connected to the output end of the heat recovery device, and the three commutation port ends are respectively connected to the condenser, the evaporator and the refrigeration compressor. The economizer is provided with a first flow path and a second flow path connected in parallel. The two ends of the first flow path are respectively connected to the liquid receiver and the main expansion valve, and the two ends of the second flow path are respectively connected to the main expansion valve and the supplementary gas pipeline of the refrigeration compressor. The auxiliary expansion valve is arranged at one end of the second flow path close to the main expansion valve.
[0005] The three commutation port ends are respectively an A end, a B end and a C end. During jet enthalpy-increasing, the refrigerant flows out of the refrigeration compressor, passes through the heat recovery device, the four-way valve, and flows into the inlet of the condenser from the A end of the four-way valve, flows out of the outlet of the condenser, then flows through the liquid storage device and the economizer. After flowing out of the outlet of the economizer, the refrigerant is divided into two paths. One path is throttled by the main expansion valve, then flows into the evaporator, then flows into the C end of the four-way valve, flows out of the B end of the four-way valve, and finally returns to the suction port of the refrigeration compressor; the other path is throttled by the auxiliary expansion valve, then flows into the economizer again, and finally flows into the supplementary air pipe of the refrigeration compressor.
[0006] The three commutation port ends are respectively an A end, a B end and a C end. During hot gas defrosting, the refrigerant flows out of the refrigeration compressor, passes through the heat recovery device, the four-way valve, and flows into the outlet of the evaporator from the C end of the four-way valve, flows out of the inlet of the evaporator, is throttled by the main expansion valve, and then is divided into two paths and flows into the economizer. One path flows into the liquid storage device after passing through the economizer, then passes through the condenser and the four-way valve, flows into from the A end of the four-way valve, and then flows out of the B end of the four-way valve, and finally returns to the suction port of the refrigeration compressor; the other path is throttled by the auxiliary expansion valve, then flows into the economizer, and finally flows into the supplementary air pipe of the refrigeration compressor.
[0007] The refrigeration compressor is one of a piston compressor, a rotary compressor and a scroll compressor; both the main expansion valve and the auxiliary expansion valve are electronic expansion valves.
[0008] A heat exchange medium input pipe, a heat exchange medium output pipe, a delivery pump and a heat preservation box are connected to the heat recovery device, and the heat recovery device, the heat exchange medium input pipe, the heat exchange medium output pipe, the delivery pump and the heat preservation box form a heat exchange cycle.
[0009] The heat exchange medium of the heat exchange cycle is water.
[0010] The refrigeration compressor is electrically connected with a frequency converter.
[0011] A filter is further included and is arranged between the economizer and the main expansion valve.
[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0013] The present invention effectively realizes a refrigerant circulation method for a heat collection and recovery multi-functional refrigeration system. After the economizer, the refrigerant is divided into two parts. One part passes through throttling and is further cooled in a way of heat expansion to reduce the temperature of the other part and make it subcooled. The stabilized subcooled liquid then passes through the main expansion valve for throttling and temperature reduction and directly enters the evaporator for refrigeration. The uncooled gaseous refrigerant re-enters the compressor through the connecting pipe between the economizer and the refrigeration compressor to continue compression and enter the cycle. By the above expansion refrigeration method, the liquid refrigeration medium is stabilized to improve the system capacity and efficiency, which can greatly improve the energy efficiency ratio of the unit and realize the integration of functions such as heat collection and recovery, frequency conversion, hot gas defrosting, and jet enthalpy increase, including a refrigeration compressor, a heat recovery device, a four-way valve, a condenser, a liquid receiver, an economizer, a main expansion valve, a secondary expansion valve, and an evaporator. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 FIG. is a process flow schematic diagram of a heat collection and recovery multi-functional refrigeration system of the present invention;
[0016] Figure 2 FIG. is a process flow schematic diagram of hot gas defrosting of another heat collection and recovery multi-functional refrigeration system;
[0017] Figure 3 FIG. is a structural schematic diagram of a heat collection and recovery jet enthalpy increase refrigeration system;
[0018] Figure 4 is Figure 3 a side view of the refrigeration unit shown.
[0019] In the figures: 10, refrigeration compressor; 20, heat recovery device; 21, heat exchange medium input pipe; 22, heat exchange medium output pipe; 23, delivery pump; 30, four-way valve; 40, condenser; 50, liquid receiver; 60, economizer; 61, first flow path; 62, second flow path; 70, main expansion valve; 80, secondary expansion valve; 90, evaporator; 91, heat insulation board; 100, filter. DETAILED DESCRIPTION OF THE INVENTION
[0020] Next, in combination with the drawings and specific embodiments, the present invention will be further described:
[0021] There is provided a refrigerant circulation method for a heat collection and recovery multi-functional refrigeration system. Please refer to Figure 1 and Figure 2 , which integrates functions such as heat collection and recovery, frequency conversion, hot gas defrosting, and jet enthalpy increase, and can fully improve the energy efficiency ratio of the unit.
[0022] Specifically, the heat collection and recovery multi-functional refrigeration system includes a refrigeration compressor 10, a heat recovery device 20, a four-way valve 30, a condenser 40, a liquid receiver 50, an economizer 60, a main expansion valve 70, a secondary expansion valve 80, and an evaporator 90 arranged in sequence along the refrigerant flow direction. The four-way valve 30 includes an input port end and three reversing port ends. The input port end is connected to the output end of the heat recovery device 20, and the three reversing port ends are respectively connected to the condenser 40, the evaporator 90, and the refrigeration compressor 10. The economizer 60 is provided with a first flow path 61 and a second flow path 62 connected in parallel. The two ends of the first flow path 61 are respectively connected to the liquid receiver 50 and the main expansion valve 70, and the two ends of the second flow path 62 are respectively connected to the main expansion valve 70 and the supplementary gas pipeline of the refrigeration compressor 10. The secondary expansion valve 80 is arranged at one end of the second flow path 62 close to the main expansion valve 70.
[0023] The three reversing port ends are respectively an A end, a B end, and a C end.
[0024] As Figure 1 shown, during jet enthalpy-increasing, the refrigerant flows out from the refrigeration compressor 10, passes through the heat recovery device 20 and the four-way valve 30, and flows into the inlet of the condenser 40 from the A end of the four-way valve 30, flows out from the outlet of the condenser 40, then flows through the liquid receiver 50 and the economizer 60. After flowing out from the outlet of the economizer 60, the refrigerant is divided into two paths. One path is throttled by the main expansion valve 70, then flows into the evaporator 90, then flows into the C end of the four-way valve 30, flows out from the B end of the four-way valve 30, and finally returns to the suction port of the refrigeration compressor 10; the other path is throttled by the secondary expansion valve 80, then flows into the economizer 60 again, and finally flows into the supplementary gas pipeline of the refrigeration compressor 10.
[0025] In the above jet enthalpy-increasing refrigeration system, after the refrigerant passes through the economizer 60, it is divided into two flow directions. One part is throttled and further cooled in the way of heat expansion to reduce the temperature of the other part and make it subcooled. The stabilized subcooled liquid is then throttled and cooled down by the main expansion valve 70 and directly enters the evaporator 90 for refrigeration. The uncooled gaseous refrigerant enters the compressor through the connecting pipeline between the economizer 60 and the refrigeration compressor 10 to continue compression and enter the cycle. By the above expansion refrigeration method, the liquid refrigeration medium is stabilized to improve the system capacity and efficiency, and the energy efficiency ratio of the unit can be greatly improved.
[0026] As Figure 2As shown in the figure, during hot-gas defrosting, the refrigerant flows out of the refrigeration compressor 10, passes through the heat recovery unit 20 and the four-way valve 30, and enters the outlet of the evaporator 90 from the C port of the four-way valve 30, flows out from the inlet of the evaporator 90, is throttled by the main expansion valve 70, and then divides into two paths to flow into the economizer 60. One path flows into the liquid receiver 50 after passing through the economizer 60, then passes through the condenser 40 and the four-way valve 30, enters from the A port of the four-way valve 30, and flows out from the B port of the four-way valve 30, and finally returns to the suction port of the refrigeration compressor 10; the other path is throttled by the auxiliary expansion valve 80, then flows into the economizer 60, and finally flows into the supplementary gas pipe of the refrigeration compressor 10.
[0027] In the above-mentioned hot-gas defrosting refrigeration system, when it is judged that the cold storage or the evaporator 90 has enough frost, by controlling the flow path reversal of the four-way valve 30, the high-temperature refrigerant first flows to the evaporator 90, the temperature of the evaporator 90 rises, and the frost on the surface of the evaporator 90 melts, that is, the evaporator 90 is transformed into the condenser 40, so that low-temperature defrosting can be realized to ensure the normal operation of the unit.
[0028] When the outdoor temperature is very low, the heat exchange capacity with the ambient temperature decreases, the return air volume of the normal return air port of the refrigeration compressor 10 decreases, the power of the refrigeration compressor 10 decreases, and the best effect cannot be exerted. However, through the other return air path of the economizer 60, the refrigerating gas is supplemented, so as to increase the exhaust volume of the refrigeration compressor 10, increase the circulating refrigerant amount, and increase the heating capacity.
[0029] In one embodiment, an inlet temperature detector and an outlet temperature detector (not shown in the figure) are installed on the evaporator 90. The severity of the frost on the evaporator 90 is judged by the temperature difference between the inlet temperature detector and the outlet temperature detector. The method for judging the frost on the evaporator 90 is as follows: Set a measured value of the cold storage temperature. When the absolute value of the difference between the measured value of the cold storage temperature and the absolute value of the outlet temperature of the evaporator 90 ≤ 5 - 10 °C, the evaporator 90 is not frosted; when the absolute value of the difference between the threshold value of the cold storage temperature control valve and the absolute value of the outlet temperature of the evaporator 90 is greater than 11 - 20 °C, and the absolute value of the difference between the outlet temperature and the inlet temperature of the evaporator 90 is in the range of 5 - 10 °C, the evaporator 90 has partial frosting; when the absolute value of the difference between the measured value of the cold storage temperature and the absolute value of the outlet temperature of the evaporator 90 is greater than 21 - 30 °C, and the absolute value of the difference between the outlet temperature and the inlet temperature of the evaporator 90 is in the range of 10 - 20 °C, the evaporator 90 is severely frosted. When the evaporator 90 is severely frosted, the hot-gas defrosting refrigeration system is started for defrosting work.
[0030] Optionally, the refrigeration compressor 10 is, but not limited to, one of a piston compressor, a rotary compressor, and a scroll compressor; the main expansion valve 70 and the auxiliary expansion valve 80 are, but not limited to, electronic expansion valves; the refrigerant is, but not limited to, R404a; the refrigeration compressor 10 is electrically connected to a frequency converter, and the output power of the refrigeration compressor 10 is controlled by the frequency converter. The control method for frequency conversion of the refrigeration compressor 10 is as follows: Set an operating temperature target value. When the measured value of the cold storage temperature > the operating temperature target value + 3°C, the output power of the refrigeration compressor 10 is increased through the frequency converter, so that the refrigeration compressor 10 outputs at a high frequency; when the measured value of the cold storage temperature ≤ the operating temperature target value, the output power of the refrigeration compressor 10 is decreased through the frequency converter, so that the refrigeration compressor 10 outputs at a low frequency, thereby greatly reducing the operating energy consumption of the entire system.
[0031] In one embodiment, the heat recovery device 20 is, but not limited to, one of a plate heat exchanger, a heat pipe heat exchanger, and a corrugated plate heat exchanger; the condenser 40 is, but not limited to, an air-cooled condenser with forced air flow, which is composed of one or several groups of serpentine tubes with fins and a fan. The high-temperature refrigerant enters the serpentine tubes from the upper inner header, and the fan is used to strengthen heat transfer on the air side to compensate for the defect of too low convective heat transfer coefficient on the air surface. After heat transfer, the low-temperature refrigerant flows out from the upper outer header. Among them, to improve the utilization rate of the heat transfer area, the number of tube rows of the condenser 40 in the air flow direction is 4 - 6 rows. The evaporator 90 is, but not limited to, a horizontal evaporator 90, which is composed of tube rows and a cooling fan. The tube rows are, but not limited to, one of cooling tube rows, serpentine tube rows, and U-shaped tube rows. The heat recovery device 20 is connected with a heat transfer medium input pipe 21, a heat transfer medium output pipe 22, a delivery pump 23, and a heat preservation box (not shown in the figure). The heat recovery device 20, the heat transfer medium input pipe 21, the heat transfer medium output pipe 22, the delivery pump 23, and the heat preservation box form a heat transfer cycle. Heat is stored and utilized through the heat preservation box. Among them, the heat transfer medium of the heat transfer cycle is water. Among them, the heat preservation box can be installed separately later, or the heat transfer medium input pipe 21 is directly connected to the water supply pipe, and the heat transfer medium output pipe 22 is connected to the faucet for direct use.
[0032] In another embodiment, the heat collection and recovery multifunctional refrigeration system further includes a filter 100 disposed between the economizer 60 and the main expansion valve 70 to filter impurities in the liquid refrigerant to avoid clogging the evaporator 90. In this embodiment, the filter 100 is located in front of the input port of the auxiliary expansion valve 80.
[0033] Please refer to again Figure 2 and Figure 3, is a schematic structural diagram of an integrated refrigeration unit of the present invention. The integrated refrigeration unit includes the above-mentioned heat collection and recovery multi-functional refrigeration system. The heat collection and recovery multi-functional refrigeration system includes a refrigeration compressor 10, a heat recovery device 20, a four-way valve 30, a condenser 40, a liquid receiver 50, an economizer 60, a main expansion valve 70, a sub-expansion valve 80, and an evaporator 90 arranged in sequence along the refrigerant flow direction. The refrigeration compressor 10, the heat recovery device 20, the four-way valve 30, the condenser 40, the liquid receiver 50, the economizer 60, the main expansion valve 70, and the sub-expansion valve 80 are all installed on the top of the evaporator 90. The condenser 40 is located on one side of the top of the evaporator 90, and the heat dissipation air outlet of the condenser 40 is arranged outward.
[0034] A heat insulation board 91 is arranged on the top of the evaporator 90. The evaporator 90 is separated from other devices by the heat insulation board 91 to prevent the heat dissipated by other devices from exchanging heat with the evaporator 90 and affecting the refrigeration efficiency.
[0035] The heat insulation board 91 comprises the following components in parts by weight: 25-40 parts of polystyrene foam particles, 10-15 parts of linear low-density polyethylene, 5-8 parts of aluminum hydroxide, 5-8 parts of ceramic fiber, 5-8 parts of graphene oxide, 1-3 parts of maleic anhydride grafted POE, and 1-3 parts of silane coupling agent. Graphene oxide is added to the heat insulation board 91, which can more effectively block heat transfer. At high temperatures, the carbon layers formed by graphene oxide are dense and continuous, which will block the surface and prevent oxygen from entering the deep part of the material. The formed carbon layer has good wrapping property for polystyrene foam particles, making the material have good fire resistance; in addition, graphene oxide also has a very high surface area, which can adsorb flammable organic volatiles and toxic gases and prevent their release and diffusion during the combustion process. Ceramic fiber is also added. Ceramic fiber not only has a flame retardant effect, and its main components are aluminum oxide and zirconium oxide, but also has the characteristics of light weight and high temperature resistance.
Claims
1. A refrigerant cycle method, characterized in that, The four-way valve includes an input port end and three reversing port ends, namely the A end, the B end and the C end. When jet enthalpy-increasing is carried out, the refrigerant flows out from the refrigeration compressor, passes through the heat recovery device and the four-way valve, and flows into the inlet of the condenser from the A end of the four-way valve, flows out from the outlet of the condenser, then flows through the liquid storage device and the economizer. After flowing out from the outlet of the economizer, the refrigerant is divided into two paths. One path is throttled by the main expansion valve, then flows into the evaporator, then flows into the C end of the four-way valve, flows out from the B end of the four-way valve, and finally returns to the suction port of the refrigeration compressor; the other path is throttled by the sub-expansion valve, then flows into the economizer again, and finally flows into the supplementary air pipe of the refrigeration compressor. When hot gas defrosting is carried out, the refrigerant flows out from the refrigeration compressor, passes through the heat recovery device and the four-way valve, and flows into the outlet of the evaporator from the C end of the four-way valve, flows out from the inlet of the evaporator, is throttled by the main expansion valve, and then is divided into two paths and flows into the economizer. One path flows into the liquid storage device after passing through the economizer, then passes through the condenser and the four-way valve, flows in from the A end of the four-way valve, and then flows out from the B end of the four-way valve, and finally returns to the suction port of the refrigeration compressor; the other path is throttled by the sub-expansion valve, then flows into the economizer, and finally flows into the supplementary air pipe of the refrigeration compressor.
2. The refrigerant cycle method according to claim 1, characterized in that, The refrigeration compressor is one of a piston compressor, a rotary compressor and a scroll compressor; both the main expansion valve and the sub-expansion valve are electronic expansion valves.
3. The refrigerant cycle method according to claim 1, characterized in that, A heat exchange medium input pipe, a heat exchange medium output pipe, a delivery pump and a heat preservation box are connected to the heat recovery device, and the heat recovery device, the heat exchange medium input pipe, the heat exchange medium output pipe, the delivery pump and the heat preservation box form a heat exchange cycle.
4. The refrigerant cycle method according to claim 1, characterized in that, The heat exchange medium of the heat exchange cycle is water.
5. The refrigerant cycle method according to claim 1, characterized in that, The refrigeration compressor is electrically connected with a frequency converter.
6. The refrigerant cycle method according to claim 1, characterized in that, It further includes a filter arranged between the economizer and the main expansion valve.