Ultralow-temperature freezing crossed cascade heat pump system

Abstract

The utility model discloses an ultralow-temperature freezing cross cascade heat pump system which comprises an air type two-stage cascade heat pump which comprises a low-temperature stage part and a high-temperature stage part. The low-temperature-stage part comprises a low-temperature-stage compressor, a four-way reversing valve, a low-temperature-stage condenser, a low-temperature-stage throttling device, a low-temperature-stage evaporator, a gas-liquid separator and a low-temperature freezing heat exchanger, and the high-temperature-stage part comprises a high-temperature-stage compressor, a high-temperature-stage condenser, a high-temperature-stage throttling device, a heat supply medium outlet pipe, a heat supply medium inlet pipe and a heat supply circulating pump. A cooling tower is arranged on one side of the high-temperature-stage condenser, the low-temperature freezing heat exchanger can achieve the functions of refrigeration and quick freezing, the problems that a traditional cross cascade type heat pump system is poor in refrigeration effect and low in efficiency in summer and poor in heating effect and low in efficiency in winter are solved, and the cross cascade type heat pump system has the advantage of quick freezing.

Description

Technical Field

[0001] The utility model belongs to the technical field of heat pump heating, and in particular relates to a cross-cascade heat pump system for ultra-low temperature freezing. Background Art

[0002] In the past, coal-fired boilers were widely used for heating in life and production in major coal-producing provinces, mainly due to the living habits of local residents and the relatively low energy price of coal-fired boilers. Especially in scenarios such as heating for life in marginal urban areas, agricultural greenhouses, and animal husbandry greenhouses, coal-fired boilers have always been the main heating method. However, compared with traditional coal-fired boilers, air source heat pumps, as a clean energy heating device, use low-temperature heat sources in the air for heating, which is more in line with the requirements of modern environmental protection policies. The use of air source heat pumps can significantly reduce greenhouse gas emissions and help achieve the dual carbon goals, that is, reducing dependence on carbon emissions and promoting the clean transformation of regional energy structures.

[0003] However, in the cold winter, as the outdoor temperature drops, the heating capacity of ordinary single-stage heat pumps decays rapidly, not only greatly reducing the heating efficiency but also increasing the operating costs. Traditional refrigeration and heating systems may have problems of inefficiency. Traditional two-stage cascade heat pump systems have poor cooling effects and low efficiency in summer, and poor heating effects and low efficiency in winter. Utility Model Content

[0004] The purpose of the utility model is to solve the problems of poor cooling effect and low efficiency in summer and poor heating effect and low efficiency in winter of the traditional two-stage cascade heat pump system, and to provide a cross-cascade heat pump system for ultra-low temperature freezing.

[0005] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0006] A cross-cascade heat pump system for ultra-low temperature freezing, comprising an air-type two-stage cascade heat pump, the air-type two-stage cascade heat pump comprising a low-temperature stage part and a high-temperature stage part, the low-temperature stage part comprising a low-temperature stage compressor, a four-way reversing valve, a low-temperature stage condenser, a low-temperature stage throttling device, a low-temperature stage evaporator, a gas-liquid separator and a low-temperature refrigeration heat exchanger, one end of the low-temperature refrigeration heat exchanger is connected to one end of the low-temperature stage evaporator, the other end of the low-temperature refrigeration heat exchanger is connected to the other end of the low-temperature stage evaporator, the high-temperature stage part comprises a high-temperature stage compressor, a high-temperature stage condenser, a high-temperature stage throttling device, a heating medium outlet pipe, a heating medium inlet pipe and a heating circulation pump, a cooling tower is arranged on one side of the high-temperature stage condenser, the heating medium outlet pipe is connected to the cooling tower, the cooling tower is connected to one end of the heating circulation pump, and the other end of the heating circulation pump is connected to the heating medium inlet pipe.

[0007] Furthermore, one end of the low-temperature compressor is connected to valve No. 1 of the four-way reversing valve, valve No. 2 of the four-way reversing valve is connected to the low-temperature condenser, valve No. 3 of the four-way reversing valve is connected to the low-temperature evaporator, valve No. 4 of the four-way reversing valve is connected to the gas-liquid separator, and an intermediate heat exchanger is provided at one end of the low-temperature condenser, and one end of the intermediate heat exchanger is connected to the low-temperature condenser.

[0008] Furthermore, one end of the high-temperature compressor is connected to the intermediate heat exchanger, the high-temperature condenser is connected to one end of the high-temperature throttling device, the other end of the high-temperature throttling device is connected to the intermediate heat exchanger, and the heat supply medium outlet pipe and the heat supply medium inlet pipe are both connected to the low-temperature condenser.

[0009] Furthermore, the heating water supply pipe can be connected to floor heating.

[0010] Furthermore, one end of the low-temperature refrigeration heat exchanger is connected to a refrigerated water outlet pipe, the other end of the low-temperature refrigeration heat exchanger is provided with a refrigerated water inlet pipe, the other end of the low-temperature stage compressor is connected to the low-temperature stage throttling device, a heat pump solenoid valve is provided between the low-temperature stage compressor and the low-temperature stage throttling device, and a refrigeration solenoid valve is provided between the other end of the low-temperature refrigeration heat exchanger and the other end of the low-temperature stage evaporator.

[0011] Furthermore, the low-temperature refrigeration heat exchanger and the low-temperature stage evaporator are connected in parallel.

[0012] Furthermore, a heating water supply pipe is provided between the cooling tower and the heat medium outlet pipe, a heating return water pipe is provided between the heating circulation pump and the cooling tower, and solenoid valves are provided between the heating water supply pipe and the heating return water pipe and the cooling tower.

[0013] Furthermore, in the normal heating mode of the heat pump, the refrigerant flows from the low-temperature stage condenser to the intermediate heat exchanger, and in the hot gas defrosting mode of the heat pump, the refrigerant flows from the intermediate heat exchanger to the low-temperature stage condenser.

[0014] Furthermore, a liquid storage device and a drying filter may be additionally provided between the intermediate heat exchanger and the low-temperature stage throttling device.

[0015] Beneficial effects: The utility model has reasonable design, simple and stable structure, strong practicality, and has the following beneficial effects:

[0016] 1. In the utility model, a low-temperature freezing heat exchanger is added to the low-temperature stage part of the two-stage cross-cascade heat pump. When the heat pump solenoid valve is closed in summer, the low-temperature medium flows into the low-temperature freezing heat exchanger through the freezing water inlet pipe, flows into the intermediate heat exchanger through the freezing solenoid valve and the low-temperature stage throttling device, flows into the low-temperature stage condenser through the intermediate heat exchanger, and then flows through one end of the low-temperature stage condenser to the four-way reversing valve No. 3 valve back to the low-temperature freezing heat exchanger, and flows out from the freezing water outlet pipe. In winter, the heat pump solenoid valve is opened and the freezing solenoid valve is closed to form a normal circuit, which solves the problem of poor cooling effect of conventional two-stage cross-cascade heat pumps in summer, and can provide a quick freezing function, which can be used for long-term refrigeration and quick freezing in supermarkets and other places.

[0017] 2. In the utility model, a cooling tower is added to the high-temperature stage of the two-stage cross-cascade heat pump. In summer, two solenoid valves are closed, and the heating medium flows into the cooling tower through the heating medium outlet pipe for cooling, and then flows out from the cooling tower to the heating circulation pump, and finally flows into the heating medium inlet pipe. In winter, the other two solenoid valves are closed, and the heating medium does not enter the cooling tower for circulation. The heating medium flows in through the heating return pipe, passes through the heating circulation pump, flows into the heating medium inlet pipe, passes through the high-temperature stage condenser, and then flows from the heating medium outlet pipe into the heating water supply pipe. By closing the solenoid valves in summer , so that the heating medium flows into the cooling tower for cooling, and the system realizes the function of summer cooling. In winter, by closing the other two solenoid valves, the system avoids the heating medium from entering the cooling tower, ensuring winter heating. Cooling down through the cooling tower in summer helps to reduce the load of equipment such as the heating circulation pump, thereby possibly extending the service life of the equipment. In winter, the heating medium is heated by the high-temperature condenser and then flows back to the heating water pipe, which helps to ensure that the heating medium is warm enough and improves the heating efficiency, solving the problem of poor heating effect and low efficiency of conventional two-stage cross-cascade heat pumps in winter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 This is a schematic structural diagram of Example 2 of the utility model.

[0020] In the figure: 1- low temperature compressor, 2- four-way reversing valve, 3- low temperature condenser, 4- low temperature throttling device, 5- low temperature evaporator, 6- gas-liquid separator, 7- low temperature refrigeration heat exchanger, 8- high temperature compressor, 9- high temperature condenser, 10- high temperature throttling device, 11- heating medium outlet pipe, 12- heating medium inlet pipe, 13- heating circulation pump, 14- cooling tower, 15- intermediate heat exchanger;

[0021] 71 - refrigerated water outlet pipe, 72 - refrigerated water inlet pipe, 73 - heat pump solenoid valve, 74 - refrigerated solenoid valve, 141 - heating water supply pipe, 142 - heating return pipe, 143 - solenoid valve, 201 - liquid reservoir, 202 - drying filter. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0023] A cross-cascade heat pump system for ultra-low temperature refrigeration, comprising an air-type two-stage cascade heat pump, the air-type two-stage cascade heat pump comprising a low-temperature stage part and a high-temperature stage part, the low-temperature stage part comprising a low-temperature stage compressor 1, a four-way reversing valve 2, a low-temperature stage condenser 3, a low-temperature stage throttling device 4, a low-temperature stage evaporator 5, a gas-liquid separator 6 and a low-temperature refrigeration heat exchanger 7, one end of the low-temperature refrigeration heat exchanger 7 is connected to one end of the low-temperature stage evaporator 5, the other end of the low-temperature refrigeration heat exchanger 7 is connected to the other end of the low-temperature stage evaporator 5, and the high-temperature stage part It includes a high-temperature compressor 8, a high-temperature condenser 9, a high-temperature throttling device 10, a heat medium outlet pipe 11, a heat medium inlet pipe 12 and a heat circulation pump 13. A cooling tower 14 is arranged on one side of the high-temperature condenser 9. The heat medium outlet pipe 11 is connected to the cooling tower 14. The cooling tower 14 is connected to one end of the heat circulation pump 13. The other end of the heat circulation pump 13 is connected to the heat medium inlet pipe 12. A low-temperature refrigeration heat exchanger 7 is added on the basis of heating, which can realize refrigeration and quick freezing functions, and has the advantage of quick freezing;

[0024] Combination Figure 1 As shown, one end of the low-temperature compressor 1 is connected to the first valve of the four-way reversing valve 2, the second valve of the four-way reversing valve 2 is connected to the low-temperature condenser 3, the third valve of the four-way reversing valve 2 is connected to the low-temperature evaporator 5, the fourth valve of the four-way reversing valve 2 is connected to the gas-liquid separator 6, and an intermediate heat exchanger 15 is provided at one end of the low-temperature condenser 3, and one end of the intermediate heat exchanger 15 is connected to the low-temperature condenser 3, which helps to ensure the smooth flow of refrigerant in the system and the coordinated operation of various components of the system, thereby contributing to the stability and efficient operation of the system, and combining the cooling and heating functions to solve the problem of poor cooling effect of the cross-cascade heat pump in summer, and has the advantage of rapid freezing;

[0025] Combination Figure 1As shown, one end of the high-temperature compressor 8 is connected to the intermediate heat exchanger 15, the high-temperature condenser 9 is connected to one end of the high-temperature throttling device 10, and the other end of the high-temperature throttling device 10 is connected to the intermediate heat exchanger 15, and the heat supply medium outlet pipe 11 and the heat supply medium inlet pipe 12 are both connected to the low-temperature condenser 3, so that the high-temperature condenser 9 is connected to the low-temperature condenser 3 through the heat supply medium outlet pipe 11, thereby enhancing the heat transfer and heat storage effect;

[0026] Combination Figure 1 As shown, the low temperature stage part and the high temperature stage part are coupled through the intermediate heat exchanger 15, the intermediate heat exchanger 15 is connected to the low temperature stage condenser 3 through the refrigerant, and the intermediate heat exchanger 15 is connected to the high temperature stage compressor 8 through the heating medium. This coupling and connection mode enables different temperature stage parts inside the system to effectively exchange heat energy through the setting of the intermediate heat exchanger 15, thereby improving the energy utilization efficiency of the system and facilitating the stable operation and efficient operation of the entire system.

[0027] Combination Figure 1 As shown, one end of the low-temperature refrigeration heat exchanger 7 is connected to a refrigeration water outlet pipe 71, and the other end of the low-temperature refrigeration heat exchanger 7 is provided with a refrigeration water inlet pipe 72. The other end of the low-temperature compressor 1 is connected to the low-temperature throttling device 4. A heat pump solenoid valve 73 is provided between the low-temperature compressor 1 and the low-temperature throttling device 4. A refrigeration solenoid valve 74 is provided between the other end of the low-temperature refrigeration heat exchanger 7 and the other end of the low-temperature evaporator 5. When the heat pump solenoid valve 73 is closed in summer, the low-temperature medium flows into the low-temperature refrigeration heat exchanger 7 through the refrigeration water inlet pipe 72, passes through the refrigeration solenoid valve 74 and the low-temperature throttling device 4, and flows into the low-temperature refrigeration heat exchanger 7 through the refrigeration solenoid valve 74 and the low-temperature throttling device 4. The device 4 flows into the intermediate heat exchanger 15, flows into the low-temperature condenser 3 through the intermediate heat exchanger 15, and then flows to the valve No. 3 of the four-way reversing valve 2 through one end of the low-temperature condenser 3 to return to the low-temperature refrigeration heat exchanger 7, and flows out from the refrigeration outlet pipe 71. In winter, the heat pump solenoid valve 73 is opened and the refrigeration solenoid valve 74 is closed to form a normal circuit. The system can be switched in summer and winter by controlling the state of the heat pump solenoid valve to meet different seasonal needs, and solves the problem of poor refrigeration effect of the cross-cascade heat pump in summer, and has the advantage of rapid freezing;

[0028] Combination Figure 1 As shown, the low-temperature refrigeration heat exchanger 7 and the low-temperature stage evaporator 5 are connected in parallel. The parallel connection can cause the two components to operate simultaneously, thereby increasing the efficiency of the entire system. By connecting the low-temperature refrigeration heat exchanger and the low-temperature stage evaporator in parallel, the system can make fuller use of low-temperature energy and improve energy utilization efficiency.

[0029] Combination Figure 1As shown, a heating water supply pipe 141 is arranged between the cooling tower 14 and the heat supply medium outlet pipe 11, a heating return water pipe 142 is arranged between the heat supply circulation pump 13 and the cooling tower 14, and electromagnetic valves 143 are arranged between the heating water supply pipe 141 and the heating return water pipe 142 and the cooling tower 14. When two of the electromagnetic valves 143 are closed in summer, the heat supply medium flows into the cooling tower 14 through the heat supply medium outlet pipe 11 for cooling, and then flows out from the cooling tower 14 to the heat supply circulation pump 13, and finally flows into the heat supply medium inlet pipe 12. When it is winter, the other two electromagnetic valves 143 are closed, the heat supply medium will not enter the cooling tower for circulation, and the heat supply medium will flow in through the heating return water pipe 142 and pass through the heat supply circulation pump 13 flows into the heat supply medium inlet pipe 12 through the high temperature stage condenser 9, and then flows into the heating water supply pipe 141 from the heat supply medium outlet pipe 11. By closing the solenoid valve 143 in summer, the heat supply medium flows into the cooling tower 14 for cooling. The system realizes the function of summer refrigeration. In winter, by closing the other two solenoid valves 143, the system avoids the heat supply medium from entering the cooling tower, ensuring winter heating. Cooling down through the cooling tower in summer helps to reduce the load of equipment such as the heating circulation pump, thereby possibly extending the service life of the equipment. In winter, the heat supply medium is heated through the high temperature stage condenser 9 and then flows back to the heating water supply pipe 141, which helps to ensure that the heat supply medium is warm enough and improves the heating efficiency.

[0030] Combination Figure 1 As shown, the heating water supply pipe 141 can be connected to the floor heating, and the heating water supply pipe 141 can recover and reuse the waste heat generated in the heating system, thereby improving the overall efficiency of the system, using energy more effectively, and reducing energy waste;

[0031] Combination Figure 2 As shown, a liquid storage tank 201 and a drying filter 202 may be provided between the intermediate heat exchanger 15 and the low-temperature stage throttling device 4 to facilitate temporary storage of the medium solution, reduce the difficulty of coupling through the intermediate heat exchanger 4, and enhance the stability of the system.

[0032] Working principle: In the scheme of the utility model, in the low-temperature loop, the fan drives the low-temperature evaporator 5 to perform rapid heat exchange. The low-temperature evaporator 5 is connected to the No. 3 valve of the four-way reversing valve 2. The working medium flows in from the No. 3 valve and flows out from the No. 1 valve of the four-way reversing valve 2. After being compressed by the low-temperature compressor 1, it flows into the four-way reversing valve 2 from the No. 4 valve, and flows into the low-temperature condenser 3 through the No. 2 valve of the four-way reversing valve 2. The low-temperature condenser 3 is connected to the intermediate heat exchanger 15, and the intermediate heat exchanger 15 is connected to the low-temperature throttling device 4. The low-temperature throttling device 4 is connected to the low-temperature evaporator 5. The working medium flows into the intermediate heat exchanger 15. 15, connected to the low-temperature throttling device 4, and finally flows into the low-temperature evaporator 5. At the same time, when the heat pump solenoid valve 73 is closed in summer, the low-temperature medium flows into the low-temperature refrigeration heat exchanger 7 through the refrigeration water inlet pipe 72, flows into the intermediate heat exchanger 15 through the refrigeration solenoid valve 74 and the low-temperature throttling device 4, and then flows into the low-temperature condenser 3 through the intermediate heat exchanger 15, and then flows through one end of the low-temperature condenser 3 to the three valves of the four-way reversing valve 2 to return to the low-temperature refrigeration heat exchanger 7, and flows out from the refrigeration water outlet pipe 71. In winter, the heat pump solenoid valve 73 is opened and the refrigeration solenoid valve 74 is closed to form a normal circuit;

[0033] The working medium in the high-temperature loop absorbs heat from the intermediate heat exchanger 15, flows out of the intermediate heat exchanger 15, is compressed by the high-temperature compressor 8, and flows into the high-temperature condenser 9. The heating medium is heated from the high-temperature condenser 9, and then flows out through the high-temperature throttling device 10 and flows into the intermediate heat exchanger 15 to form a reflux. When two of the solenoid valves 143 are closed in summer, the heating medium flows into the cooling tower 14 through the heating medium outlet pipe 11 for cooling, and then flows out from the cooling tower 14 to the heating circulation pump 13, and finally flows into the heating medium inlet pipe 12. When it is winter, the other two solenoid valves 143 are closed, and the heating medium will not enter the cooling tower to enter the circulation. The heating medium flows in through the heating return water pipe 142, flows into the heating medium inlet pipe 12 through the heating circulation pump 13, passes through the high-temperature condenser 9, and then flows into the heating water supply pipe 141 from the heating medium outlet pipe 11.

[0034] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0035] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A cross-cascade heat pump system for ultra-low temperature refrigeration, comprising an air-type two-stage cascade heat pump, characterized in that: The air-type two-stage cascade heat pump comprises a low-temperature stage part and a high-temperature stage part, wherein the low-temperature stage part comprises a low-temperature stage compressor (1), a four-way reversing valve (2), a low-temperature stage condenser (3), a low-temperature stage throttling device (4), a low-temperature stage evaporator (5), a gas-liquid separator (6) and a low-temperature refrigeration heat exchanger (7), wherein one end of the low-temperature refrigeration heat exchanger (7) is connected to one end of the low-temperature stage evaporator (5), the other end of the low-temperature refrigeration heat exchanger (7) is connected to the other end of the low-temperature stage evaporator (5), and the high-temperature The stage part comprises a high-temperature stage compressor (8), a high-temperature stage condenser (9), a high-temperature stage throttling device (10), a heat supply medium outlet pipe (11), a heat supply medium inlet pipe (12) and a heat supply circulation pump (13); a cooling tower (14) is arranged on one side of the high-temperature stage condenser (9); the heat supply medium outlet pipe (11) is connected to the cooling tower (14); the cooling tower (14) is connected to one end of the heat supply circulation pump (13); and the other end of the heat supply circulation pump (13) is connected to the heat supply medium inlet pipe (12).

2. A cross-cascade heat pump system for ultra-low temperature refrigeration according to claim 1, characterized in that: One end of the low-temperature compressor (1) is connected to valve No. 1 of the four-way reversing valve (2), valve No. 2 of the four-way reversing valve (2) is connected to the low-temperature condenser (3), valve No. 3 of the four-way reversing valve (2) is connected to the low-temperature evaporator (5), valve No. 4 of the four-way reversing valve (2) is connected to the gas-liquid separator (6), and an intermediate heat exchanger (15) is provided at one end of the low-temperature condenser (3), and one end of the intermediate heat exchanger (15) is connected to the low-temperature condenser (3).

3. A cross-cascade heat pump system for ultra-low temperature refrigeration according to claim 2, characterized in that: One end of the high-temperature compressor (8) is connected to the intermediate heat exchanger (15), the high-temperature condenser (9) is connected to one end of the high-temperature throttling device (10), the other end of the high-temperature throttling device (10) is connected to the intermediate heat exchanger (15), and the heat supply medium outlet pipe (11) and the heat supply medium inlet pipe (12) are both connected to the low-temperature condenser (3).

4. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 2, characterized in that: The low-temperature stage part and the high-temperature stage part are coupled via an intermediate heat exchanger (15), the intermediate heat exchanger (15) and the low-temperature stage condenser (3) are connected via a refrigerant, and the intermediate heat exchanger (15) and the high-temperature stage compressor (8) are connected via a heating medium.

5. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 1, characterized in that: One end of the low-temperature refrigeration heat exchanger (7) is connected to a refrigeration water outlet pipe (71), and the other end of the low-temperature refrigeration heat exchanger (7) is provided with a refrigeration water inlet pipe (72). The other end of the low-temperature stage compressor (1) is connected to the low-temperature stage throttling device (4), a heat pump solenoid valve (73) is provided between the low-temperature stage compressor (1) and the low-temperature stage throttling device (4), and a refrigeration solenoid valve (74) is provided between the other end of the low-temperature refrigeration heat exchanger (7) and the other end of the low-temperature stage evaporator (5).

6. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 1, characterized in that: The low-temperature refrigeration heat exchanger (7) and the low-temperature stage evaporator (5) are connected in parallel.

7. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 1, characterized in that: A heating water supply pipe (141) is provided between the cooling tower (14) and the heat medium outlet pipe (11), a heating water return pipe (142) is provided between the heating circulation pump (13) and the cooling tower (14), and solenoid valves (143) are provided between the heating water supply pipe (141) and the heating water return pipe (142) and the cooling tower (14).

8. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 7, characterized in that: The heating water supply pipe (141) can be connected to floor heating.

9. The ultra-low temperature refrigeration cross-cascade heat pump system according to claim 2, characterized in that: A liquid storage device (201) and a drying filter (202) may be additionally provided between the intermediate heat exchanger (15) and the low-temperature stage throttling device (4).

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