CN113686044B - Heat pump unit - Google Patents

Heat pump unit Download PDF

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Publication number
CN113686044B
CN113686044B CN202111007226.0A CN202111007226A CN113686044B CN 113686044 B CN113686044 B CN 113686044B CN 202111007226 A CN202111007226 A CN 202111007226A CN 113686044 B CN113686044 B CN 113686044B
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China
Prior art keywords
subcooler
economizer
heat exchanger
compressor
heat pump
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CN202111007226.0A
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Chinese (zh)
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CN113686044A (en
Inventor
张琍敏
徐亮
龙海峰
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Trane Air Conditioning Systems China Co Ltd
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Trane Air Conditioning Systems China Co Ltd
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Priority to CN202111007226.0A priority Critical patent/CN113686044B/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B13/00—Compression machines, plants or systems, with reversible cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F25B40/02—Subcoolers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems

Abstract

The embodiment of the invention provides a heat pump unit. The heat pump unit comprises a compressor, a reversing valve, a first heat exchanger, an economizer, a subcooler and a second heat exchanger which are sequentially connected through a refrigerant pipeline, wherein the compressor is provided with an air suction port, an air exhaust port and an intermediate air supplementing port, the economizer is connected with the intermediate air supplementing port of the compressor, the subcooler comprises a main path and an auxiliary path, wherein an inlet of the main path of the subcooler is connected to the economizer, an outlet of the main path of the subcooler is connected with the first heat exchanger and the second heat exchanger, an inlet of the auxiliary path of the subcooler is connected to the main path of the subcooler through a subcooler throttle valve, and an outlet of the auxiliary path of the subcooler is connected to the air suction port of the compressor. The heat pump unit provided by the embodiment of the invention can effectively ensure that the power consumption of the unit is reduced and the efficiency of the unit is improved on the premise that the refrigerating capacity of the unit is kept unchanged.

Description

Heat pump unit
Technical Field
The embodiment of the invention relates to the technical field of air conditioners, in particular to a heat pump unit.
Background
In the traditional air-cooled cold water (heat pump) unit, an intermediate air supplementing port is generally additionally arranged on a shell of a compressor for improving the refrigerating capacity or the efficiency of the unit. According to the working principle of the middle air supplementing port, the original primary compression is changed into secondary compression, so that the refrigerating capacity or efficiency of the unit is increased. At present, the compressor is widely applied to the refrigeration industry by using the air supplementing technology. However, after the air make-up technique is applied, if the unit refrigeration percentage is to be increased by 10%, the ratio of the intermediate air make-up to the main side refrigerant flow is typically higher than 10%. The result is that the efficiency of the unit (COP, coefficient of Performance) is reduced, although the unit cooling capacity is improved. If the efficiency of the unit is to be improved, the air supplementing amount needs to be reduced, and even the air can not be supplemented.
Disclosure of Invention
The embodiment of the invention aims to provide a heat pump unit, which can effectively ensure that the power consumption of the unit is reduced and the efficiency of the unit is improved on the premise that the refrigerating capacity of the unit is kept unchanged.
One aspect of the embodiments of the present invention provides a heat pump unit. The heat pump unit comprises a compressor, a reversing valve, a first heat exchanger, an economizer, a subcooler and a second heat exchanger which are connected through a refrigerant pipeline, wherein the compressor is provided with an air suction port, an air exhaust port and an intermediate air supplementing port, the economizer is connected with the intermediate air supplementing port of the compressor, the subcooler comprises a main path and an auxiliary path, an inlet of the main path of the subcooler is connected to the economizer, an outlet of the main path of the subcooler is connected with the first heat exchanger and the second heat exchanger, an inlet of the auxiliary path of the subcooler is connected to the main path of the subcooler through a subcooler throttle valve, and an outlet of the auxiliary path of the subcooler is connected to the air suction port of the compressor.
Further, an inlet of the auxiliary passage of the subcooler is connected to an inlet of the main passage of the subcooler or an outlet of the main passage of the subcooler through the subcooler throttle valve.
Further, the economizer includes a main path and an auxiliary path, an inlet of the main path of the economizer is connected to the first heat exchanger, an outlet of the main path of the economizer is connected to an inlet of the main path of the subcooler, an inlet of the auxiliary path of the economizer is connected to an inlet of the main path of the economizer or an outlet of the main path of the economizer through an economizer throttle valve, and an outlet of the auxiliary path of the economizer is connected to an intermediate make-up port of the compressor.
Further, an outlet of the main path of the subcooler is connected to the second heat exchanger through a refrigeration throttle, and an outlet of the main path of the subcooler is connected to the first heat exchanger through a heating throttle.
Further, the heat pump unit further comprises an oil cooler connected with the compressor, and an outlet of a main path of the subcooler is further connected to the oil cooler through an oil cooling restrictor.
Further, the first heat exchanger includes a plurality of cooling coils, and the heat pump unit further includes a pre-distributor to which the plurality of cooling coils are connected.
Further, the heat pump unit further includes a filter through which the pre-distributor is connected to the economizer, and an oil separator through which an exhaust port of the compressor is connected to the reversing valve.
Further, the second heat exchanger includes a water side heat exchanger having a water outlet end and a water inlet end.
Further, the heat pump unit further includes a controller that controls to simultaneously activate the economizer and the subcooler in a case where the compressor is fully loaded.
Further, the controller controls activation of the subcooler in the case of partial load operation of the compressor.
According to the heat pump unit provided by the embodiment of the invention, the other plate heat exchanger, namely the subcooler is additionally arranged behind the first-stage economizer, so that the target enthalpy difference (h) required by the heat pump unit for obtaining the target refrigerating capacity can be achieved 5 -h 7 ) This is not completely accomplished by the economizer of the first stage, but rather by the combined action of the two-stage plate heat exchangers (i.e., the first stage plate heat exchanger acting as an economizer and the second stage plate heat exchanger acting as a subcooler).
According to the heat pump unit, after the flow rates of the auxiliary sides of the two plate heat exchangers of the economizer and the subcooler are optimally configured, the flow rate of the middle air supplementing port flowing to the compressor from the first-stage economizer can be effectively managed, the total power consumption of the whole heat pump unit is effectively controlled, and the operation efficiency of the heat pump unit is finally effectively improved.
Drawings
FIG. 1 is a schematic illustration of a heat pump unit with a compressor having an intermediate air supply port;
fig. 2 is a refrigeration cycle diagram of two-stage compression of the compressor of fig. 1;
FIG. 3 is a main and auxiliary side refrigerant flow diagram of the economizer of FIG. 1;
fig. 4 is a schematic view of a heat pump unit according to an embodiment of the present invention.
Detailed Description
Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numbers in different drawings refer to the same or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus consistent with aspects of the invention as detailed in the accompanying claims.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless defined otherwise, technical or scientific terms used in the embodiments of the present invention should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present invention belongs. The terms "first," "second," and the like in the description and in the claims, are not used for any order, quantity, or importance, but are used for distinguishing between different elements. Likewise, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one. "plurality" or "plurality" means two or more. Unless otherwise indicated, the terms "front," "rear," "lower," and/or "upper" and the like are merely for convenience of description and are not limited to one location or one spatial orientation. The word "comprising" or "comprises", and the like, means that elements or items appearing before "comprising" or "comprising" are encompassed by the element or item recited after "comprising" or "comprising" and equivalents thereof, and that other elements or items are not excluded. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.
Fig. 1 discloses a schematic view of a heat pump unit 100 with an intermediate air compensating opening 23 for a compressor 10. As shown in fig. 1, the heat pump unit 100 includes a compressor 10, a reversing valve 20, a first heat exchanger 31, an economizer 41, and a second heat exchanger 32, which are sequentially connected through refrigerant lines. The compressor 10 has an intake port 1, an exhaust port 4, and an intermediate air supply port 23.
The economizer 41 is connected to the intermediate make-up port 23 of the compressor 10, the economizer 41 including a main passage and an auxiliary passage, wherein an inlet of the main passage of the economizer 41 is connected to the first heat exchanger 31, an outlet of the main passage of the economizer 41 is connected to the second heat exchanger 32 through the refrigerant throttle valve EXV2, an inlet of the auxiliary passage of the economizer 41 is connected to an inlet of the main passage of the economizer 41 through the economizer throttle valve EXV1, and an outlet of the auxiliary passage of the economizer 41 is connected to the intermediate make-up port 23 of the compressor 10. Thus, it can be used to cool the refrigerant in the main circuit and to supplement the air and increase the enthalpy of the compressor 10.
Fig. 2 discloses a refrigeration cycle diagram of two-stage compression of the compressor of fig. 1. In fig. 2, EXV1 denotes an economizer throttle valve EXV1, EXV2 denotes a refrigerant throttle valve EXV2, and numerals in fig. 2 denote respective operation state points of the compressor 10, wherein 1 denotes an intake port of the compressor 10, 2 denotes a point at which refrigerant of the compressor 10 is just discharged, 23 denotes an intermediate supply port of the compressor 10, 3 denotes an outlet on an auxiliary side of the economizer 41, 4 denotes an exhaust port of the compressor 10 (i.e., a point at which refrigerant of the compressor 10 is completely discharged), 5 denotes a point at which the refrigerant comes out of the first heat exchanger 31 (i.e., an inlet of the economizer throttle valve EXV 1), 6 denotes an outlet of the economizer throttle valve EXV1, 7 denotes an outlet of a main path of the economizer 41, 8 denotes a point after throttling of the refrigerant throttle valve EXV2, and 9 denotes a port at which the second heat exchanger 32 is connected to the reversing valve 20.
Fig. 3 discloses a main and auxiliary side refrigerant flow diagram of the economizer 41 of fig. 1. As shown in fig. 3, 5-7 constitute a main path of the economizer 41, and 3-6 constitute an auxiliary path of the economizer 41.
With the intermediate air supply opening 23, the compressor 10 can be operated in a working cycle as shown in fig. 2, wherein 1-2-23-4-5-7-8-9-1 forms the main cycle of the heat pump assembly 100, and the auxiliary side 5-6-3-23 participates in part of the cycle process.
The refrigerating capacity and the total power consumption of the heat pump unit 100 can be obtained by using the working principle of engineering thermodynamics, as shown in the following formula:
Q＝G d ×(h 9 -h 7 ) (1)
N d ＝G d ×(h 2 -h 1 ) (2)
N g ＝G g ×(h 4 -h 23 ) (3)
N＝N d +N g (4)
wherein Q is refrigerating capacity (kW), N is total power consumption (kW), N d Power consumption (kW) for the first stage (low voltage stage), N g For the power consumption (kW) of the second stage (high voltage stage), G d For low-pressure-stage refrigerant flow, G g For high pressure stage refrigerant flow, h represents the enthalpy value of the compressor 10 at the corresponding operating state point, and COP is efficiency.
The operation of the compressor 10 with the intermediate supplementary port 23 will be described in detail with reference to fig. 1 to 3.
According to the law of conservation of energy, the energy emitted from the heat source side is necessarily equal to the energy obtained from the cold source side, and therefore the following formula can be derived:
G d ×(h 5 -h 7 )＝(G g -G d )×(h 3 -h 6 ) (6)
wherein, (G) g -G d ) Indicating the flow rate of the refrigerant on the air supply side.
Due to h 5 ＝h 6 Therefore, the high-pressure stage refrigerant flow rate G can be derived from the formula (6) g As shown in the following formula:
G g ＝G d ×(h 3 -h 7 )/(h 3 -h 6 ) (7)
therefore, as long as the flow Gg of the refrigerant of the second stage is reasonably reduced, the power consumption N of the whole unit can be effectively reduced, and the unit efficiency COP is improved.
In view of the above, the embodiment of the invention provides an improved heat pump unit. On the premise of ensuring that the refrigerating capacity Q of the heat pump unit is kept unchanged, the power consumption N of the heat pump unit can be reduced, and the efficiency COP of the heat pump unit is improved.
Fig. 4 discloses a schematic view of a heat pump unit 200 according to an embodiment of the present invention. As shown in fig. 4, the heat pump unit 200 according to an embodiment of the present invention includes a compressor 10, a reversing valve 20, a first heat exchanger 31, an economizer 41, a subcooler 42, and a second heat exchanger 32, which are sequentially connected through refrigerant lines. The compressor 10 has an intake port 1, an exhaust port 4, and an intermediate air supply port 23. In one embodiment, the first heat exchanger 31 is, for example, a fin heat exchanger and the second heat exchanger 32 may, for example, include, but is not limited to, a water side heat exchanger having a water outlet end and a water inlet end.
The economizer 41 and subcooler 42 of an embodiment of the present invention may include, for example, but not limited to, brazed plate heat exchangers (BPHE, blazed Plate Heat Exchanger). Other types of economizers 41 and subcoolers 42 may be employed in embodiments of the invention.
The economizer 41 is connected to the intermediate gas-supply port 23 of the compressor 10, the economizer 41 includes a main passage and an auxiliary passage, wherein an inlet of the main passage of the economizer 41 is connected to the first heat exchanger 31, an outlet of the main passage of the economizer 41 is connected to an inlet of the main passage of the subcooler 42, an inlet of the auxiliary passage of the economizer 41 is connected to an inlet of the main passage of the economizer 41 through the economizer throttle valve EXV1 (or an inlet of the auxiliary passage of the economizer 41 may also be connected to an outlet of the main passage of the economizer 41 through the economizer throttle valve EXV 1), and an outlet of the auxiliary passage of the economizer 41 is connected to the intermediate gas-supply port 23 of the compressor 10. The auxiliary path of the economizer 41 branches off a refrigerant from the main path of the economizer 41, and after the refrigerant is throttled and depressurized by the economizer throttle valve EXV1, the temperature of the auxiliary path refrigerant is cooled and lowered, after heat exchange is performed with the refrigerant of the main path, the auxiliary path refrigerant absorbs heat of the main path refrigerant, and the refrigerant after the auxiliary path of the economizer 41 absorbs heat returns to the middle air-supplementing port 23 of the compressor 10, so that air-supplementing and enthalpy-increasing can be performed on the compressor 10.
The subcooler 42 includes a main path and an auxiliary path, wherein an inlet of the main path of the subcooler 42 is connected to the economizer 41, an outlet of the main path of the subcooler 42 is connected to the first heat exchanger 31 and the second heat exchanger 32, an inlet of the auxiliary path of the subcooler 42 is connected to the main path of the subcooler 42 through the subcooler throttle valve EXV5, and an outlet of the auxiliary path of the subcooler 42 is connected to the suction port 1 of the compressor 10. As shown in fig. 4, in one embodiment, the inlet of the auxiliary circuit of the subcooler 42 is connected to the inlet of the main circuit of the subcooler 42 through a subcooler throttle valve EXV 5. In another embodiment, the inlet of the auxiliary circuit of the subcooler 42 is connected to the outlet of the main circuit of the subcooler 42 through a subcooler throttle valve EXV 5. The auxiliary path of the subcooler 42 branches off a single refrigerant from the main path of the subcooler 42, and after the refrigerant is throttled and depressurized by the subcooler throttle valve EXV5, the temperature of the auxiliary path refrigerant is cooled and lowered, after heat exchange with the refrigerant in the main path is performed, the auxiliary path refrigerant absorbs heat of the main path refrigerant, and the refrigerant after the auxiliary path of the subcooler 42 absorbs heat returns to the suction port 1 of the compressor 10.
The heat pump unit 200 according to the embodiment of the present invention is not limited to the specific connection manner shown in fig. 4, and the heat pump unit 200 according to the embodiment of the present invention is intended to cover a combination mode in which the economizer 41 and the subcooler 42 are activated, and the arrangement manners of the economizer 41 and the subcooler 42 may be interchanged in position. In addition, the point of taking the auxiliary side refrigerant of the economizer 41 and the subcooler 42 according to the embodiment of the present invention is not limited to the point shown in fig. 4 taken from the upstream (meaning that the auxiliary side refrigerant is taken from the main side from the flow of the refrigerant that does not flow into the economizer or the subcooler, i.e., from the inlet of the main passage), but in other embodiments, the point of taking the auxiliary side refrigerant of the economizer 41 and the subcooler 42 according to the embodiment of the present invention may be taken from the downstream (i.e., from the outlet of the main passage).
The heat pump unit 200 according to the embodiment of the present invention adds another plate heat exchanger, namely, the subcooler 42, behind the first-stage economizer 41, so as to obtain the target enthalpy difference (h 5 -h 7 ) Not entirely by the first stage economizer 41,but is jointly completed after combined action by the front and rear two-stage plate heat exchangers, i.e. the first stage plate heat exchanger acting as economizer 41 and the second stage plate heat exchanger acting as subcooler 42.
According to the heat pump unit 200 provided by the embodiment of the invention, after the flow rates of the auxiliary sides of the two plate heat exchangers of the economizer 41 and the subcooler 42 are optimally configured, the flow rate of the first-stage economizer 41 flowing to the middle air supplementing port 23 of the compressor 10 can be effectively managed, so that the total power consumption of the whole heat pump unit 200 is effectively controlled, and the operation efficiency of the heat pump unit 200 is finally effectively improved.
With continued reference to fig. 4, the outlet of the main path of the subcooler 42 is connected to the second heat exchanger 32 through a refrigeration throttle EXV2, and the outlet of the main path of the subcooler 42 is connected to the first heat exchanger 31 through a heating throttle EXV 4.
The heat pump unit 200 of the embodiment of the present invention further includes an oil cooler 60 connected to the compressor 10. The outlet of the main circuit of the subcooler 42 is also connected to the oil cooler 60 through an oil-cooled throttle valve EXV 3.
In some embodiments, the first heat exchanger 31 comprises a plurality of cooling coils. The heat pump assembly 200 of the embodiment of the present invention further includes a pre-distributor 80. A plurality of cooling coils are connected to the pre-distributor 80. In some embodiments, the heat pump assembly 200 of the present embodiment further includes a filter 70, and the pre-distributor 80 is connected to the economizer 41 through the filter 70.
The pre-distributor 80 may initially distribute the amount of refrigerant to a plurality of cooling coils. According to the embodiment of the invention, the subcooler 42 is additionally arranged behind the economizer 41, so that the refrigerant components at the inlet of the pre-distributor 80 can be effectively controlled, the liquid components in the refrigerant are more, and the more the liquid is, the more uniform the distribution of the refrigerant can be. Thus, embodiments of the present invention may provide for a more even distribution of refrigerant from the plurality of cooling coils in the first heat exchanger 31.
The heat pump unit 200 of the embodiment of the present invention further includes an oil separator 50 and a reservoir 90, and the discharge port 4 of the compressor 10 is connected to the reversing valve 20 through the oil separator 50.
The heat pump unit 200 according to the embodiment of the present invention further includes a controller (not shown). Wherein, in case of full-load operation of the compressor 10, the controller may control to simultaneously enable the economizer 41 and the subcooler 42; and in the case of partial load operation of the compressor 10, the controller may control the activation of the subcooler 42.
According to the heat pump unit 200 provided by the embodiment of the invention, the subcooler 42 is additionally arranged behind the economizer 41, so that the subcooler 42 can be started when the compressor 10 is in partial load, the supercooling degree can be still obtained when the compressor is in partial load operation, and the heat transfer of the evaporator is facilitated, thereby solving the problem that the utilization rate of the economizer 41 is lower because the compressor 10 with the middle air supplementing port 23 can be started only when the economizer 41 is fully used. The subcooler 42 is turned on at the time of partial load, which is advantageous in heat distribution and facilitates improvement of heating capacity.
When the heat pump unit 200 of the embodiment of the present invention is operated in the cooling mode, as indicated by the arrow in fig. 4As shown, the refrigerant is compressed in the compressor 10, the original low-temperature low-pressure refrigerant gas is compressed into high-temperature high-pressure superheated steam, and the superheated steam is discharged from the discharge port 4 of the compressor 10, passes through the oil separator 50, enters the reversing valve 20, and the flow direction of the refrigerant is controlled by the reversing valve 20. Superheated steam at high temperature and high pressure enters from the inlet of the reversing valve 20. Since the discharge port 4 of the compressor 10 is connected to the first heat exchanger 31 through the reversing valve 20 in the cooling mode, high-temperature and high-pressure superheated steam is introduced into the first heat exchanger 31 through the reversing valve 20. At this time, the first heat exchanger 31 corresponds to the condenser. The superheated steam at high temperature and high pressure is cooled in the first heat exchanger 31, and the superheated refrigerant is converted from a gaseous state to a liquid state. After passing through the pre-distributor 80, the refrigerant passes through the check valve CV1, flows through the filter 70 and enters the inlet of the main path of the economizer 41, then enters the inlet of the main path of the subcooler 42 from the outlet of the main path of the economizer 41, and enters the second heat exchanger 32 through the throttling and depressurization of the refrigeration throttle valve EXV2 from the outlet of the main path of the subcooler 42. At this time, the second heat exchanger 32 functions as an evaporator, and the refrigerant liquid is in the second heat exchanger 32The heat absorbs and vaporizes, and then the refrigerant is vaporized into a low-temperature and low-pressure gaseous refrigerant. The low-temperature low-pressure gaseous refrigerant passes through the reversing valve 20, is sucked into the compressor 10 through the suction port 1 of the compressor 10, and enters the next refrigeration cycle.
When the heat pump unit 200 of the embodiment of the present invention is operated in the heating mode, as indicated by the arrow in fig. 4As shown, the refrigerant is compressed in the compressor 10, the refrigerant gas having a low temperature and a low pressure is compressed into the superheated steam having a high temperature and a high pressure, the superheated steam having a high temperature and a high pressure compressed by the compressor 10 is discharged from the discharge port 4 of the compressor 10, passes through the oil separator 50, and then directly passes through the reversing valve 20 to be sent to the second heat exchanger 32. At this time, the second heat exchanger 32 acts as a condenser, and the superheated steam radiates heat by the second heat exchanger 32, and the superheated steam cools to form a low-temperature high-pressure liquid, which is introduced into the accumulator 90. The low-temperature high-pressure refrigerant liquid in the accumulator 90 then passes through the check valve CV2, flows through the filter 70, enters the inlet of the main passage of the economizer 41, enters the inlet of the main passage of the subcooler 42 from the outlet of the main passage of the economizer 41, passes through the throttle and the pressure reduction of the heating throttle valve EXV4 from the outlet of the main passage of the subcooler 42, and is fed into the first heat exchanger 31 through the pre-distributor 80. At this time, the first heat exchanger 31 corresponds to the function of an evaporator. The low temperature and low pressure refrigerant completes the vaporization process in the first heat exchanger 31, and the refrigerant liquid releases a large amount of heat to the outside and turns into dry saturated vapor. The dry saturated steam finally returns to the suction port 1 of the compressor 10 through the reversing valve 20, and the next heating cycle is continued.
According to the heat pump unit 200 provided by the embodiment of the invention, the subcooler 42 is additionally arranged, so that the subcooler 42 can be linked with the economizer 41, the intermediate air supplementing quantity of the compressor 10 can be reduced, and the power consumption of the compressor 10 can be reduced due to the reduction of the intermediate air supplementing quantity of the compressor 10.
In the heat pump unit 200 according to the embodiment of the present invention, after the air supply amount of the air supply port 23 in the middle of the compressor 10 is reduced, the vibration of the auxiliary side of the economizer 41 connected to the air supply port 23 in the middle of the compressor 10 can be reduced. Since the size of the intermediate make-up port 23 of the compressor 10 is constant, the refrigerant line flow rate can be effectively reduced after the auxiliary side stream of the economizer 41 is reduced.
In the heat pump unit 200 according to the embodiment of the present invention, the subcooler 42 is added, so that the refrigerant flow rate of the low-pressure stage passing through the reversing valve 20 is also reduced, and therefore, the pressure drop on the suction side (the suction side corresponding to cooling and heating) of the reversing valve 20 can be reduced. Because the system resistance decreases, the exhaust pressure of the exhaust port 4 of the compressor 10 can also decrease, thereby reducing the power consumption of the heat pump unit 200 and helping to improve the efficiency of the heat pump unit 200.
The applicant has carried out a test comparison of two schemes in a laboratory under a rated refrigeration condition, namely, the first scheme is a scheme of a heat pump unit which enables the economizer 41 and the subcooler 42 but bypasses, the second scheme is a scheme of a heat pump unit which jointly enables the economizer 41 and the subcooler 42, and after the working condition is stabilized, the performance data obtained by the acquisition system can be found, and the second scheme (namely, the scheme of a heat pump unit which jointly enables the economizer 41 and the subcooler 42) is improved by nearly 1.77% compared with the first scheme (namely, the scheme of a heat pump unit which only enables the economizer 41). In addition, it was found that the heat pump unit solution, in which the economizer 41 and the subcooler 42 are thus jointly activated, reduces the flow of the make-up side refrigerant relative to the heat pump unit solution in which only the economizer 41 is activated, thereby reducing the power consumption of the compressor and thus the overall power consumption of the heat pump unit, and achieving an improvement in the efficiency COP of the heat pump unit. Therefore, the scheme of adding the subcooler 42 to the heat pump unit according to the embodiment of the present invention is proved to be very effective.
The applicant can find that the heat pump unit of the newly added subcooler 42 of the embodiment of the present invention is effective not only in the cooling mode but also in the heating operation by comparing the data of the heat pump unit of the newly added subcooler 42 in the rated cooling and heating operations.
In addition, the applicant can find that, by comparing the data of the heat pump unit with the subcooler 42 and the heat pump unit without the subcooler 42 in the partial load operation of the compressor, after the subcooler 42 is additionally arranged, the efficiency COP of the heat pump unit in the partial load operation is better than that in the same load. Therefore, the addition of the subcooler 42 is also an effective means for improving the comprehensive part load performance IPLV of the heat pump unit.
The heat pump unit provided by the embodiment of the invention is described in detail above. The heat pump unit according to the embodiments of the present invention is described herein by applying specific examples, and the description of the above embodiments is only for helping to understand the core idea of the present invention, and is not intended to limit the present invention. It should be noted that it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the spirit and principles of the invention, which should also fall within the scope of the appended claims.

Claims (8)

1. A heat pump unit comprising a compressor, a reversing valve, a first heat exchanger, an economizer, a subcooler and a second heat exchanger connected by refrigerant lines, the compressor having an intake, an exhaust and an intermediate make-up, the economizer being connected to the intermediate make-up of the compressor, the subcooler comprising a main and an auxiliary, the heat pump unit further comprising a reservoir, a solenoid valve disposed at the bottom of the reservoir, a first check valve and a second check valve, the reservoir being connected to the first heat exchanger by the solenoid valve and the first check valve, the reservoir being connected to the second heat exchanger by the solenoid valve and the second check valve, wherein an inlet of the main of the subcooler is connected to the economizer, an outlet of the main of the subcooler is connected to the first heat exchanger and the second heat exchanger, an inlet of the auxiliary of the subcooler is connected to the main of the subcooler by a subcooler throttle valve, an outlet of the auxiliary of the subcooler is connected to the first heat exchanger, the heat pump unit is further controlled to operate while the compressor is activated by the controller; the controller controls activation of the subcooler with the compressor part load operation.
2. The heat pump assembly of claim 1, wherein: the inlet of the auxiliary path of the subcooler is connected to the inlet of the main path of the subcooler or the outlet of the main path of the subcooler through the subcooler throttle valve.
3. The heat pump assembly of claim 1, wherein: the economizer comprises a main path and an auxiliary path, wherein an inlet of the main path of the economizer is connected to the first heat exchanger, an outlet of the main path of the economizer is connected to an inlet of the main path of the subcooler, an inlet of the auxiliary path of the economizer is connected to the inlet of the main path of the economizer or an outlet of the main path of the economizer through an economizer throttle valve, and an outlet of the auxiliary path of the economizer is connected to an intermediate air supplementing port of the compressor.
4. The heat pump assembly of claim 1, wherein: the outlet of the main path of the subcooler is connected to the second heat exchanger through a refrigeration throttle valve, and the outlet of the main path of the subcooler is connected to the first heat exchanger through a heating throttle valve.
5. The heat pump assembly of claim 1, wherein: and an oil cooler connected with the compressor, wherein an outlet of a main path of the subcooler is also connected with the oil cooler through an oil cooling restrictor.
6. The heat pump assembly of claim 1, wherein: the first heat exchanger includes a plurality of cooling coils, and the heat pump unit further includes a pre-distributor to which the plurality of cooling coils are connected.
7. The heat pump assembly of claim 6, wherein: also included is a filter through which the pre-distributor is connected to the economizer and an oil separator through which the compressor discharge is connected to the reversing valve.
8. The heat pump assembly of claim 1, wherein: the second heat exchanger includes a water side heat exchanger having a water outlet end and a water inlet end.
CN202111007226.0A 2021-08-30 2021-08-30 Heat pump unit Active CN113686044B (en)

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CN114111110A (en) * 2021-12-02 2022-03-01 广东日出东方空气能有限公司 Heat pump system with plate for exchanging supercooling

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