Air-cooled heat pump water chilling unit adopting deep supercooling defrosting technology

Abstract

The invention belongs to the technical field of refrigeration air conditioners and heat pumps, and particularly relates to an air-cooled heat pump water chilling unit adopting a deep supercooling defrosting technology, which comprises a compressor, a four-way valve, a condensation evaporator, a liquid storage device, a first expansion valve, a second expansion valve, an outdoor evaporative condenser, a first three-way valve and a second three-way valve, a high-temperature and high-pressure refrigerant loop is arranged for each group of evaporative condensers in a heat pump working mode of the air-cooled heat pump unit, so that the evaporative condensers can be communicated with high-temperature and high-pressure liquid from a condensation evaporator in a defrosting working mode; the high-temperature and high-pressure liquid melts frost layers on the surfaces of the evaporative condensers and is deeply supercooled at the same time, extra energy does not need to be applied to the unit, and therefore the efficiency of the unit is remarkably improved, and when the unit is in the defrosting working mode, one set of evaporative condensers enter the defrosting mode, and the other sets of evaporative condensers are kept in the normal heat pump working mode.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration, air conditioning and heat pump, and in particular to an air-cooled heat pump chiller adopting deep subcooling and defrosting technology. Background Art

[0002] The subcooling cycle is an important mode of the refrigeration cycle. In the refrigeration system, the greater the degree of subcooling in the subcooling cycle, the stronger the refrigeration capacity of the refrigerant, and the higher the efficiency of the compressor, thereby improving the cooling capacity and COP value of the system. The principle is that, first of all, the increase in the degree of subcooling will make the liquid refrigerant have a lower temperature before entering the evaporator, and more importantly, the lower the temperature of the liquid refrigerant before entering the evaporator, the smaller the loss caused by flash during the throttling process, thereby allowing more liquid refrigerant to enter the evaporator for evaporation and heat absorption.

[0003] Defrosting of heat pump units is the key to ensuring their normal operation in low temperature environments and maintaining their efficient heating performance. Current defrosting technologies mainly include: Reverse cycle defrosting: that is, the refrigeration cycle is stopped during the defrosting process. At this time, the high-temperature and high-pressure refrigerant gas discharged from the compressor no longer enters the indoor heat exchanger, but is directly discharged into the outdoor heat exchanger. The high-temperature and high-pressure refrigerant gas condenses and releases heat in the outdoor heat exchanger, and the released heat is used to melt the frost layer on the outdoor heat exchanger. At the same time, the indoor heat exchanger operates as an evaporator to absorb indoor heat (although the indoor fan may need to stop working at this time to reduce heat loss).

[0004] Hot gas bypass defrosting: that is, without changing the basic working mode of the unit, only part of the high-temperature and high-pressure refrigerant is bypassed from the compressor outlet to the outdoor heat exchanger, and the heat of this part of the refrigerant is used to melt the frost layer on the outdoor heat exchanger.

[0005] Electric heating defrosting: that is, an electric heating element is installed on the evaporator. When it is detected that frost has accumulated to a certain extent, the electric heating element is started to heat and defrost.

[0006] Hot water defrosting: using an external hot water source to heat and flush the frost layer on the outdoor heat exchanger to melt the frost.

[0007] In the above-mentioned defrosting process, the defrosting energy comes from the power consumption of the compressor or from the additional energy applied from outside the system.

[0008] From the above, it can be seen that the subcooling of the refrigerant in the subcooling cycle requires a certain amount of cold, while the defrosting of the heat pump unit requires a certain amount of heat. If the two can be linked and the cold and heat can be fed back to each other, neither of them will require additional energy from outside the system. And it can be calculated that in the defrosting mode of the heat pump unit, the heat released by the subcooling of the refrigerant is much greater than the heat required for defrosting, which provides practical feasibility for the subcooling defrosting technology.

[0009] To this end, an air-cooled heat pump chiller using deep subcooling defrosting technology is proposed to solve the above-mentioned problems. Summary of the invention

[0010] The object of the present invention is to provide an air-cooled heat pump chiller using deep subcooling defrosting technology to solve the problems raised in the above-mentioned background technology.

[0011] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an air-cooled heat pump chiller adopting deep subcooling defrosting technology, comprising a compressor, a four-way valve, a condenser evaporator, a liquid storage device, a first expansion valve, a second expansion valve, an outdoor evaporative condenser, a first three-way valve and a second three-way valve, the exhaust end of the compressor is connected to the four-way valve through a fifth pipeline, the intake end of the compressor is connected to the four-way valve through a first pipeline, the four-way valve is connected to a first input end of the condenser evaporator through a second pipeline, the second input end and the second output end of the condenser evaporator are connected to a user side, and the first output end of the condenser evaporator is connected to a user side. The first control valve is connected to the first expansion valve, the fourth pipeline and the first control valve respectively through the third pipeline, and is connected to the liquid reservoir through the fourth pipeline and the second control valve. The first control valve is connected to the first three-way valves of multiple groups of outdoor evaporative condensers through high-pressure and high-temperature liquid pipelines. The second three-way valves of the multiple groups of outdoor evaporative condensers are connected to the input end of the liquid reservoir through high-pressure and low-temperature liquid pipelines and the third control valve. The output end of the liquid reservoir is connected to the other end of the second three-way valve of the multiple groups of outdoor evaporative condensers through the second expansion valve and the low-pressure and low-temperature liquid pipeline. The first three-way valves of the multiple groups of outdoor evaporative condensers are connected to the four-way valve through a gas pipeline.

[0012] Preferably, the two ends of the multiple groups of outdoor evaporative condensers are respectively connected to one end of the first three-way valve and the second three-way valve, and the other two ends of the first three-way valve and the second three-way valve are respectively connected to the gas pipeline and the high-pressure and high-temperature liquid pipeline and the high-pressure and low-temperature liquid pipeline.

[0013] Preferably, the input end of the liquid reservoir is connected to the second control valve and the third control valve respectively, and the output end of the liquid reservoir is connected to the first expansion valve and the second expansion valve respectively.

[0014] Preferably, a second expansion valve is provided on the low-pressure and low-temperature liquid pipeline of the second three-way valve leading from the liquid storage device to the outdoor evaporative condenser; and a first expansion valve is provided on the third pipeline leading to the condensing evaporator.

[0015] Preferably, a second control valve is provided between the fourth pipeline and the liquid reservoir.

[0016] Preferably, a third control valve is provided between the high-pressure and low-temperature liquid pipeline and the liquid reservoir.

[0017] Preferably, a first control valve is provided between the condenser evaporator and the high-pressure and high-temperature liquid pipeline.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a high-temperature and high-pressure refrigerant circuit for each group of evaporative condensers in the heat pump working mode of the air-cooled heat pump unit, so that they can all be connected to the high-temperature and high-pressure liquid from the condensing evaporator in the defrosting working mode, so that the high-temperature and high-pressure liquid can melt the frost layer on the surface of the evaporative condenser and deeply supercool itself without applying additional energy to the unit, thereby significantly improving the efficiency of the unit. In the defrosting working mode of the unit, one group of evaporative condensers enters the defrosting mode, and the other groups maintain the normal heat pump working mode. In this way, each group of evaporators of the unit enters the defrosting mode in turn to ensure the supercooling of the high-temperature and high-pressure liquid and the continuation of the heat pump working mode of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention.

[0020] In the figure: 1 compressor, 2 four-way valve, 3 condenser evaporator, 4 liquid storage device, 5-1 first expansion valve, 5-2 second expansion valve, 6 outdoor evaporative heat exchanger, 7 first pipeline, 8 gas pipeline, 9 second pipeline, 10 first three-way valve, 11 second three-way valve, 12 third pipeline, 13 low-pressure low-temperature liquid pipeline, 14 high-pressure high-temperature liquid pipeline, 15 fourth pipeline, 16 high-pressure low-temperature liquid pipeline, 17 fifth pipeline, 18 second control valve, 19 third solenoid valve, 20 first control valve. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] Example: See also Figure 1 , the present invention provides a technical solution: A wind-cooled heat pump chiller adopting deep subcooling defrosting technology comprises a compressor 1, a four-way valve 2, a condenser evaporator 3, a liquid storage 4, a first expansion valve 5-1, a second expansion valve 5-2, an outdoor evaporative condenser 6, a first three-way valve 10 and a second three-way valve 11, the exhaust end of the compressor 1 is connected to the four-way valve 2 through a fifth pipeline 17, the air intake end of the compressor 1 is connected to the four-way valve 2 through a first pipeline 7, the four-way valve 2 is connected to the first input end of the condenser evaporator 3 through a second pipeline 9, the second input end and the second output end of the condenser evaporator 3 are connected to the user side, and the first output end of the condenser evaporator 3 is connected to the first expansion valve 5-1 and the second expansion valve 5-2 through a third pipeline 12. The fourth pipeline 15 is connected to the first control valve 20, and is connected to the liquid reservoir 4 through the fourth pipeline 15 and the second control valve 18. The first control valve 20 is connected to the first three-way valve 10 of multiple groups of outdoor evaporative condensers 6 through the high-pressure and high-temperature liquid pipeline 14. The second three-way valve 11 of multiple groups of outdoor evaporative condensers 6 is connected to the input end of the liquid reservoir 4 through the high-pressure and low-temperature liquid pipeline 16 and the third control valve 19. The output end of the liquid reservoir 4 is connected to the other end of the second three-way valve 11 of multiple groups of outdoor evaporative condensers 6 through the second expansion valve 5-2 and the low-pressure and low-temperature liquid pipeline 13. The first three-way valve 10 of multiple groups of outdoor evaporative condensers 6 is connected to the four-way valve 2 through the gas pipeline 8.

[0024] The two ends of multiple groups of outdoor evaporative condensers 6 are respectively connected to one end of their respective first three-way valves 10 and second three-way valves 11, and the other two ends of the first three-way valves 10 and second three-way valves 11 are respectively connected to the gas pipeline 8 and the high-pressure and high-temperature liquid pipeline 14 and the high-pressure and low-temperature liquid pipeline 16 and the low-pressure and low-temperature liquid pipeline 13.

[0025] The input end of the liquid storage device 4 is connected to the second control valve 18 and the third control valve 19 respectively, and the output end of the liquid storage device 4 is connected to the first expansion valve 5-1 and the second expansion valve 5-2 respectively.

[0026] A second expansion valve 5 - 2 is provided on the low-pressure and low-temperature liquid pipeline 13 of the second three-way valve 11 leading from the liquid storage device 4 to the outdoor evaporative condenser 6 ; a first expansion valve 5 - 1 is provided on the third pipeline 12 leading to the condensing evaporator 3 .

[0027] A second control valve 18 is provided between the fourth pipeline 15 and the liquid reservoir 4 .

[0028] A third control valve 19 is provided between the high-pressure and low-temperature liquid pipeline 16 and the liquid storage tank 4 .

[0029] A first control valve 20 is provided between the condenser evaporator 3 and the high-pressure and high-temperature liquid pipeline 14 .

[0030] The deep subcooling defrosting technology is to use the high-temperature and high-pressure liquid behind the condenser evaporator 3 to melt and remove the frost layer on the surface of the outdoor evaporative condenser 6 while deeply subcooling the unit under the defrosting working mode of the heat pump (cold water) unit; in the defrosting mode of the heat pump working condition, only one group of outdoor evaporative condensers 6 enters the defrosting mode, and the other groups still maintain the normal heat pump circulation mode, and rotate to enter the defrosting mode under the control of the automatic control program to maintain the subcooling and defrosting and the continuous operation of the entire heat pump system; each group of outdoor evaporative condensers 6 is equipped with a first three-way valve 10 and a second three-way valve 11 to realize the functional conversion of the subcooler and the evaporator under the heat pump working condition.

[0031] The present invention provides a high-temperature and high-pressure refrigerant liquid circuit for each of the multiple groups of air-cooled evaporative condensers (i.e., evaporators under heat pump working conditions, the same below) of the air-cooled heat pump chiller, so that the evaporator can realize the evaporator function under the heat pump working state after being connected with the low-temperature and low-pressure refrigerant liquid from the throttle valve, and can also play the role of a subcooler after being connected with the high-temperature and high-pressure refrigerant liquid from the condenser (evaporator). When the refrigerant is connected with the high-temperature and high-pressure refrigerant liquid from the condenser (evaporator) as a subcooler, the refrigerant not only supercools the high-temperature and high-pressure refrigerant liquid, but also removes the frost layer formed on the refrigerant during the period of being an evaporator under the heat pump working condition, so that the dual effects of supercooling and defrosting can be obtained. At the same time, the high-temperature and high-pressure refrigerant liquid is deeply supercooled, thereby reducing its throttling loss, so that the efficiency of the unit is greatly improved. In the defrost working mode, only one set of evaporators (condensers) enters the defrost mode, and the other sets still maintain the heat pump working mode and play the role of evaporators normally. In this way, multiple sets of evaporators (condensers) enter the defrost mode in rotation to maintain supercooling and defrosting and the continuous operation of the entire heat pump system.

[0032] Working principle: (1) Refrigeration cycle In the refrigeration cycle mode, the high-pressure and high-temperature gas discharged from the compressor 1 is connected to the outdoor evaporator condensers 6 via the fifth pipeline 17 and the four-way valve 2 and the subsequent high-pressure and high-temperature gas pipe 14 and the first three-way valve 10. The high-pressure and high-temperature gas is condensed into high-temperature and high-pressure liquid therein and then sent to the liquid reservoir 4 via its three-way valve 11, the high-pressure and high-temperature liquid pipe 14 and the third control valve 19. At this time, the second control valve 18 and the first control valve 20 are closed, and the high-pressure liquid sent to the liquid reservoir 4 is throttled by the first expansion valve 5-1 and then sent to the condenser evaporator 3 via the third pipeline 12. The low-temperature and low-pressure gas evaporated in the condenser evaporator 3 is then connected to the suction port of the compressor 1 via the second pipeline 9, the four-way valve 2 and its first pipeline 7, and is discharged after being compressed by the compressor 1 to complete its refrigeration cycle.

[0033] (2) Heat pump cycle In the heat pump cycle mode, the high-pressure and high-temperature gas discharged from the compressor 1 is connected to the user-side heat exchanger through the four-way valve 2 and the high-pressure and high-temperature gas pipe 14 thereafter, and is condensed into high-temperature and high-pressure liquid therein and then sent to the liquid reservoir 4 through the second control valve 18. At this time, the second control valve 19 and the first control valve 20 are closed, and the high-temperature and high-pressure liquid output from the liquid reservoir 4 is throttled by the second expansion valve 5-2 and sent to the outdoor evaporative condenser 6 through the low-pressure and low-temperature liquid pipe 13. At this time, the second three-way valve 11 of each group of outdoor evaporative condensers 6 is connected to the low-pressure and low-temperature liquid pipe 13 after throttling. After the low-pressure and low-temperature liquid evaporates in the outdoor evaporative condenser 6, its low-temperature and low-pressure gas is then sent to the four-way valve 2 through the gas pipeline 8 through the first three-way valve 10 and connected to the suction port of the compressor 1 through its first pipeline 7. The low-temperature and low-pressure gas sent to the compressor 1 is compressed by the compressor 1 and then discharged to complete its heat pump cycle.

[0034] (3) Heat pump defrost cycle In the heat pump defrost mode, the high-pressure and high-temperature gas discharged from the compressor 1 is connected to the condenser evaporator 3 through the four-way valve 2 and the second pipe 9 thereafter, and is condensed into high-temperature and high-pressure liquid therein, and then directly sent to one group of outdoor evaporative condensers 6 through the high-pressure and high-temperature liquid pipe 14 through the first control valve 20. At this time, the first three-way valve 10 of the group of evaporative condensers 6 is connected with the high-pressure and high-temperature gas pipe 14, and the second control valve 18 is closed; after the high-temperature and high-pressure liquid is defrosted and supercooled in the group of heat exchangers, it is sent to the liquid reservoir 4 through the second three-way valve 11 and the high-pressure and low-temperature liquid pipe 16 and the third control valve 19. At this time, the second three-way valve 11 of the group of outdoor evaporative condensers 6 is connected with the high-pressure and low-temperature liquid pipe 16, and the high-pressure and low-temperature liquid entering the liquid reservoir 4 is then sent to the remaining groups of outdoor evaporative condensers 6 outdoors through the low-pressure and low-pressure liquid pipe 13 after being throttled by the second expansion valve 5-2. At this time, the remaining groups of outdoor evaporative condensers 6 maintain a normal heat pump circulation mode. After evaporation, the low-temperature and low-pressure liquid is connected to the air intake of the compressor 1 through the gas pipeline 8 through the first three-way valve 10, the four-way valve 2 and the first pipeline 7, and then discharged after being compressed by the compressor 1, thus completing the heat pump cycle under the defrosting condition. The outdoor heat exchangers of each group of the unit rotate into the defrosting mode under the control of the system centralized control system, thereby maintaining the continuous operation of supercooling and defrosting and the entire heat pump system.

[0035] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An air-cooled heat pump chiller using deep subcooling defrosting technology, comprising a compressor (1), a four-way valve (2), a condenser evaporator (3), a liquid storage device (4), a first expansion valve (5-1), a second expansion valve (5-2), an outdoor evaporative condenser (6), a first three-way valve (10) and a second three-way valve (11), characterized in that: The exhaust end of the compressor (1) is connected to the four-way valve (2) via a fifth pipeline (17); the intake end of the compressor (1) is connected to the four-way valve (2) via a first pipeline (7); the four-way valve (2) is connected to the first input end of the condenser evaporator (3) via a second pipeline (9); the second input end and the second output end of the condenser evaporator (3) are connected to the user side; the first output end of the condenser evaporator (3) is respectively connected to the first expansion valve (5-1), the fourth pipeline (15) and the first control valve (20) via a third pipeline (12); and is connected to the liquid storage device (4) via a fourth pipeline (15) and the second control valve (18); The first control valve (20) is connected to the first three-way valve (10) of the plurality of outdoor evaporative condensers (6) via a high-pressure and high-temperature liquid pipeline (14); the second three-way valve (11) of the plurality of outdoor evaporative condensers (6) is connected to the input end of the liquid reservoir (4) via a high-pressure and low-temperature liquid pipeline (16) and a third control valve (19); the output end of the liquid reservoir (4) is connected to the other end of the second three-way valve (11) of the plurality of outdoor evaporative condensers (6) via a second expansion valve (5-2) and a low-pressure and low-temperature liquid pipeline (13); and the first three-way valve (10) of the plurality of outdoor evaporative condensers (6) is connected to the four-way valve (2) via a gas pipeline (8).

2. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: The two ends of the plurality of outdoor evaporative condensers (6) are respectively connected to one end of the first three-way valve (10) and the second three-way valve (11), and the other two ends of the first three-way valve (10) and the second three-way valve (11) are respectively connected to the gas pipeline (8) and the high-pressure high-temperature liquid pipeline (14) and the high-pressure low-temperature liquid pipeline (16) and the low-pressure low-temperature liquid pipeline (13).

3. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: The input end of the liquid storage device (4) is respectively connected to the second control valve (18) and the third control valve (19), and the output end of the liquid storage device (4) is respectively connected to the first expansion valve (5-1) and the second expansion valve (5-2).

4. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: A second expansion valve (5-2) is provided on the low-pressure and low-temperature liquid pipeline (13) of the second three-way valve (11) leading from the liquid storage device (4) to the outdoor evaporative condenser (6); and a first expansion valve (5-1) is provided on the third pipeline (12) leading to the condensing evaporator (3).

5. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: A second control valve (18) is provided between the fourth pipeline (15) and the liquid storage tank (4).

6. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: A third control valve (19) is provided between the high-pressure low-temperature liquid pipeline (16) and the liquid storage tank (4).

7. The air-cooled heat pump chiller using deep subcooling defrosting technology according to claim 1, characterized in that: A first control valve (20) is provided between the condenser evaporator (3) and the high-pressure and high-temperature liquid pipeline (14).

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