CN113686044B - Heat pump unit - Google Patents

Abstract

An embodiment of the present invention provides a heat pump unit. The heat pump unit includes a compressor, a reversing valve, a first heat exchanger, an economizer, a subcooler and a second heat exchanger connected in sequence through refrigerant pipelines. The compressor has a suction port, a discharge port and an intermediate The air supply port, the economizer is connected to the middle air supply port of the compressor. The subcooler includes a main circuit and an auxiliary circuit. The inlet of the main circuit of the subcooler is connected to the economizer, and the outlet of the main circuit of the subcooler is connected to the first exchanger. Heater and second heat exchanger, the inlet of the auxiliary circuit of the subcooler is connected to the main circuit of the subcooler through the subcooler throttle valve, and the outlet of the auxiliary circuit of the subcooler is connected to the suction port of the compressor. The heat pump unit according to the embodiment of the present invention can effectively ensure that the power consumption of the unit is reduced and the efficiency of the unit is improved while the cooling capacity of the unit remains unchanged.

Description

heat pump unit

Technical field

Embodiments of the present invention relate to the technical field of air conditioning, and in particular, to a heat pump unit.

Background technique

In traditional air-cooled chilled water (heat pump) units, in order to improve the cooling capacity or efficiency of the unit, an intermediate air supply port is usually added to the compressor casing. Based on this, the working principle of the middle air supply port is used to change the original one-stage compression into two-stage compression to expand the cooling capacity or efficiency of the unit. At present, compressor air supply technology has been widely used in the refrigeration industry. However, after applying air supplement technology, if you want to increase the cooling capacity percentage of the unit by 10%, the ratio of the intermediate air supplement volume to the main side refrigerant flow rate is usually higher than 10%. The result is that although the cooling capacity of the unit has increased, the unit's efficiency (COP, Coefficient of Performance) has decreased. To improve the efficiency of the unit, the air supply volume needs to be reduced or even eliminated.

Contents of the invention

The purpose of embodiments of the present invention is to provide a heat pump unit that can effectively ensure that the power consumption of the unit is reduced and the efficiency of the unit is improved while the cooling capacity of the unit remains unchanged.

One aspect of embodiments of the present invention provides a heat pump unit. The heat pump unit includes a compressor, a reversing valve, a first heat exchanger, an economizer, a subcooler and a second heat exchanger connected through a refrigerant pipeline. The compressor has a suction port and an exhaust port. and an intermediate air supply port, the economizer is connected to the intermediate air supply port of the compressor, the subcooler includes a main path and an auxiliary path, wherein the inlet of the main path of the subcooler is connected to the economizer, The outlet of the main circuit of the subcooler is connected to the first heat exchanger and the second heat exchanger, and the inlet of the auxiliary circuit of the subcooler is connected to the subcooler through a subcooler throttle valve. The main circuit and the outlet of the auxiliary circuit of the subcooler are connected to the suction port of the compressor.

Further, the inlet of the auxiliary circuit of the subcooler is connected to the inlet of the main circuit of the subcooler or the outlet of the main circuit of the subcooler through the subcooler throttle valve.

Further, the economizer includes a main path and an auxiliary path, the inlet of the main path of the economizer is connected to the first heat exchanger, and the outlet of the main path of the economizer is connected to the main path of the subcooler. The inlet of the auxiliary path of the economizer is connected to the inlet of the main path of the economizer or the outlet of the main path of the economizer through the economizer throttle valve, and the outlet of the auxiliary path of the economizer is connected to the The middle air supply port of the compressor.

Further, the outlet of the main circuit of the subcooler is connected to the second heat exchanger through a refrigeration throttle valve, and the outlet of the main circuit of the subcooler is connected to the first heat exchanger through a heating throttle valve. Heat Exchanger.

Further, the heat pump unit further includes an oil cooler connected to the compressor, and the outlet of the main circuit of the subcooler is also connected to the oil cooler through an oil cooling throttle.

Further, the first heat exchanger includes a plurality of cooling coils, the heat pump unit further includes a pre-distributor, and the plurality of cooling coils are connected to the pre-distributor.

Further, the heat pump unit also includes a filter and an oil separator, the pre-distributor is connected to the economizer through the filter, and the exhaust port of the compressor is connected to the economizer through the oil separator. The reversing valve.

Further, the second heat exchanger includes a water-side heat exchanger, and the water-side heat exchanger has a water outlet end and a water inlet end.

Further, the heat pump unit further includes a controller, which controls the simultaneous activation of the economizer and the subcooler when the compressor is running at full load.

Further, the controller controls activation of the subcooler when the compressor is operating at partial load.

The heat pump unit in the embodiment of the present invention adds another plate heat exchanger, that is, a subcooler, behind the first-stage economizer, so that the target enthalpy difference (h ₅ - h ₇ ) is not completely completed by the first-stage economizer, but by the front and rear 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 device) and are completed together after the combined action.

The heat pump unit according to the embodiment of the present invention can optimize the flow rate from the first-stage economizer to the intermediate air supply port of the compressor by optimizing the flow rate on the auxiliary side of the two plate heat exchangers of the economizer and the subcooler. Management, thereby effectively controlling the total power consumption of the entire heat pump unit, and ultimately effectively improving the operating efficiency of the heat pump unit.

Description of the drawings

Figure 1 is a schematic diagram of a heat pump unit with a compressor with an intermediate air supply port;

Figure 2 is a refrigeration cycle diagram of the two-stage compression of the compressor in Figure 1;

Figure 3 is a refrigerant flow diagram on the main and auxiliary sides of the economizer in Figure 1;

Figure 4 is a schematic diagram of a heat pump unit according to an embodiment of the present invention.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. When the following description refers to the 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 invention. Rather, they are merely examples of means consistent with aspects of the invention as detailed in the appended claims.

The terminology used in the embodiments of the present invention is only for the purpose of describing specific embodiments and is not intended to limit the present invention. Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the usual meanings understood by those with ordinary skills in the field to which the present invention belongs. "First", "second" and similar words used in the description and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Likewise, "a" or "one" and similar words do not indicate a quantitative limit, but rather indicate the presence of at least one. "Multiple" or "several" means two or more than two. Unless otherwise indicated, similar terms such as "front", "rear", "lower" and/or "upper" are for convenience of description only and are not intended to limit one position or one spatial orientation. "Including" or "including" and other similar words mean that the elements or objects appearing before "includes" or "includes" cover the elements or objects listed after "includes" or "includes" and their equivalents, and do not exclude other elements. or objects. Words such as "connected" or "connected" 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," "the" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will also be understood that the term "and/or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

FIG. 1 shows a schematic diagram of a heat pump unit 100 with a compressor 10 and an intermediate air supply port 23 . 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 that are connected in sequence through refrigerant pipelines. The compressor 10 has an air suction port 1 , an exhaust port 4 and an intermediate air supply port 23 .

The economizer 41 is connected to the intermediate air supply port 23 of the compressor 10. The economizer 41 includes a main path and an auxiliary path. The inlet of the main path of the economizer 41 is connected to the first heat exchanger 31, and the outlet of the main path of the economizer 41 is connected to the first heat exchanger 31. It is connected to the second heat exchanger 32 through the refrigeration throttle valve EXV2, the inlet of the auxiliary path of the economizer 41 is connected to the inlet of the main path of the economizer 41 through the economizer throttle valve EXV1, and the outlet of the auxiliary path of the economizer 41 is connected to the compressor The middle air supply port 23 of the machine 10. Therefore, it can be used to cool the refrigerant in the main circuit and supply air to the compressor 10 to increase the enthalpy.

Figure 2 reveals the refrigeration cycle diagram of the two-stage compression of the compressor in Figure 1. In Figure 2, EXV1 represents the economizer throttle valve EXV1, and EXV2 represents the refrigeration throttle valve EXV2. The numbers in Figure 2 represent each operating state point of the compressor 10, where 1 represents the suction port of the compressor 10, 2 represents the point where the refrigerant of the compressor 10 has just been discharged, 23 represents the middle air supply port of the compressor 10, 3 represents the outlet of the auxiliary side of the economizer 41, and 4 represents the exhaust port of the compressor 10 (that is, the refrigerant of the compressor 10 is completely discharged). discharge point), 5 represents the point coming out of the first heat exchanger 31 (i.e., the inlet of the economizer throttle valve EXV1), 6 represents the outlet of the economizer throttle valve EXV1, and 7 represents the outlet of the main path of the economizer 41 , 8 represents the point after throttling of the refrigeration throttle valve EXV2, and 9 represents the port of the second heat exchanger 32 connected to the reversing valve 20 .

FIG. 3 reveals the main and auxiliary side refrigerant flow diagram of the economizer 41 in FIG. 1 . As shown in Figure 3, 5-7 constitute the main path of the economizer 41, and 3-6 constitute the auxiliary path of the economizer 41.

When the compressor 10 is equipped with an intermediate air supply port 23, the working cycle shown in Figure 2 can be realized, in which 1-2-23-4-5-7-8-9-1 constitutes the main cycle of the heat pump unit 100, and the auxiliary side 5-6-3-23 participate in part of the cycle process.

Using the working principle of engineering thermodynamics, the cooling capacity and total power consumption of the heat pump unit 100 can be obtained, 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= _Nd + _Ng (4)

Among them, Q is the cooling capacity (kW), N is the total power consumption (kW), N _d is the power consumption of the first stage (low voltage stage) (kW), and N _g is the power consumption of the second stage (high pressure stage) ( kW), G _d is the low-pressure stage refrigerant flow, G _g is the high-pressure stage refrigerant flow, h represents the enthalpy value of the corresponding working state point of the compressor 10, and COP is the efficiency.

The working principle of the compressor 10 with the intermediate air supply port 23 will be described in detail below with reference to FIGS. 1 to 3 .

According to the law of conservation of energy, the energy released by the heat source side must be equal to the energy obtained by the cold source side. Therefore, the following formula can be derived:

G _d ×(h ₅ -h ₇ )=(G _g -G _d )×(h ₃ -h ₆ ) (6)

Among them, (G _g -G _d ) represents the refrigerant flow rate on the supply side.

Since h ₅ =h ₆ , therefore, according to formula (6), it can be deduced that the high-pressure stage refrigerant flow rate G _g is as shown in the following formula:

G _g =G _d ×(h ₃ -h ₇ )/(h ₃ -h ₆ ) (7)

Therefore, as long as the second-stage refrigerant flow rate Gg is reasonably reduced, the power consumption N of the entire unit can be effectively reduced, thereby improving the unit efficiency COP.

In view of this, embodiments of the present invention provide a technical solution for an improved heat pump unit. On the premise of ensuring that the cooling capacity Q of the heat pump unit remains unchanged, the power consumption N of the heat pump unit can be reduced and the efficiency COP of the heat pump unit can be improved.

Figure 4 reveals a schematic diagram of a heat pump unit 200 according to an embodiment of the present invention. As shown in Figure 4, a 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 third tube connected in sequence through a refrigerant pipeline. Second heat exchanger 32. The compressor 10 has an air suction 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 include, for example, but is not limited to, a water-side heat exchanger. The water-side heat exchanger has a water outlet end and an inlet port. Water end.

The economizer 41 and the subcooler 42 in the embodiment of the present invention may include, but are not limited to, a brazed plate heat exchanger (BPHE). The economizer 41 and the subcooler 42 in the embodiment of the present invention can also adopt other types.

The economizer 41 is connected to the intermediate air supply port 23 of the compressor 10. The economizer 41 includes a main path and an auxiliary path. The inlet of the main path of the economizer 41 is connected to the first heat exchanger 31, and the outlet of the main path of the economizer 41 is connected to the first heat exchanger 31. The entrance of the main circuit of the subcooler 42 is connected to the entrance of the auxiliary circuit of the economizer 41 through the economizer throttle valve EXV1. The flow valve EXV1 is connected to the outlet of the main path of the economizer 41 ), and the outlet of the auxiliary path of the economizer 41 is connected to the intermediate air supply port 23 of the compressor 10 . The auxiliary circuit of the economizer 41 branches off a stream of refrigerant from the main circuit of the economizer 41. After being throttled and depressurized by the economizer throttle valve EXV1, the temperature of the refrigerant in the auxiliary circuit is reduced, and then interacts with the refrigerant in the main circuit. After the heat exchange, the refrigerant in the auxiliary circuit absorbs the heat of the refrigerant in the main circuit. The refrigerant after absorbing the heat in the auxiliary circuit of the economizer 41 returns to the middle air supply port 23 of the compressor 10, so that the compressor 10 can be supplied with air to increase the enthalpy.

The subcooler 42 includes a main circuit and an auxiliary circuit, wherein the inlet of the main circuit of the subcooler 42 is connected to the economizer 41 , and the outlet of the main circuit of the subcooler 42 is connected to the first heat exchanger 31 and the second heat exchanger 32 , the inlet of the auxiliary circuit of the subcooler 42 is connected to the main circuit of the subcooler 42 through the subcooler throttle valve EXV5, and the outlet of the auxiliary circuit 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 the subcooler throttle valve EXV5. 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 the subcooler throttle valve EXV5. The auxiliary circuit of the subcooler 42 branches off a stream of refrigerant from the main circuit of the subcooler 42. After being throttled and depressurized by the subcooler throttle valve EXV5, the temperature of the refrigerant in the auxiliary circuit is reduced. After the refrigerant exchanges heat, the auxiliary circuit refrigerant absorbs the heat of the main circuit refrigerant, and the refrigerant after the auxiliary circuit absorbs the heat in the subcooler 42 returns to the suction port 1 of the compressor 10 .

The heat pump unit 200 of the embodiment of the present invention is not limited to the specific connection method shown in Figure 4. The heat pump unit 200 of the embodiment of the present invention is intended to cover the combined mode of enabling the economizer 41 and the subcooler 42. The economizer 41 and the supercooler are The arrangement of the cooler 42 can also be interchanged in terms of position. In addition, the point of taking the auxiliary side refrigerant of the economizer 41 and the subcooler 42 in the embodiment of the present invention is not limited to taking it from the upstream as shown in Figure 4 (meaning that neither the auxiliary side refrigerant flows into the economizer from the main side or The refrigerant flow of the subcooler is sampled (that is, from the entrance of the main circuit). In other embodiments, the sampling point of the auxiliary side refrigerant of the economizer 41 and the subcooler 42 in the embodiment of the present invention can also be sampled from the downstream. Take it (that is, take it from the exit of the main road).

The heat pump unit 200 in the embodiment of the present invention adds another plate heat exchanger, that is, the subcooler 42, behind the first-stage economizer 41, so that the heat pump unit 200 can obtain the target enthalpy difference required to obtain the target cooling capacity. (h ₅ -h ₇ ) is not completely completed by the first-stage economizer 41, but by the front and rear two-stage plate heat exchangers (i.e., the first-stage plate heat exchanger acting as the economizer 41 and the subcooler 42 The second stage plate heat exchanger) is completed together after the combined action.

The heat pump unit 200 in the embodiment of the present invention can optimize the flow of the two plate heat exchangers auxiliary side of the economizer 41 and the subcooler 42, so that the intermediate supplementary flow from the first-stage economizer 41 to the compressor 10 can be optimized. The flow rate of the air port 23 is effectively managed, thereby effectively controlling the total power consumption of the entire heat pump unit 200, and ultimately effectively improving the operating efficiency of the heat pump unit 200.

Continuing to refer to FIG. 4 , the outlet of the main circuit of the subcooler 42 is connected to the second heat exchanger 32 through the cooling throttle valve EXV2, and the outlet of the main circuit of the subcooler 42 is connected to the second heat exchanger 32 through the heating throttle valve EXV4. A heat exchanger 31.

The heat pump unit 200 in the embodiment of the present invention also 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 the oil cooling throttle valve EXV3.

In some embodiments, first heat exchanger 31 includes multiple cooling coils. The heat pump unit 200 of the embodiment of the present invention also includes a pre-distributor 80 . A plurality of cooling coils are connected to the predistributor 80 . In some embodiments, the heat pump unit 200 of the embodiment of the present invention further includes a filter 70 , and the predistributor 80 is connected to the economizer 41 through the filter 70 .

The predistributor 80 can initially distribute the amount of refrigerant among the plurality of cooling coils. In the embodiment of the present invention, by adding a subcooler 42 after the economizer 41, the refrigerant composition at the inlet of the predistributor 80 can be effectively controlled so that there is more liquid in the refrigerant. The more liquid, the better the cooling efficiency. The more evenly the agent is distributed. Therefore, the embodiment of the present invention can make the refrigerant of the multiple cooling coils in the first heat exchanger 31 more evenly distributed.

The heat pump unit 200 in the embodiment of the present invention also includes an oil separator 50 and a liquid reservoir 90 . The exhaust 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 also includes a controller (not shown). Wherein, when the compressor 10 is running at full load, the controller can control the economizer 41 and the subcooler 42 to be activated at the same time; and when the compressor 10 is running at part load, the controller can control the activation of the subcooler 42 .

The heat pump unit 200 in the embodiment of the present invention adds a subcooler 42 after the economizer 41. The subcooler 42 can be activated when the compressor 10 is partially loaded. The subcooling degree can still be obtained during partial load operation, which is beneficial to the evaporator. heat transfer, thereby solving the problem that the compressor 10 with the intermediate air supply port 23 simply uses the economizer 41 and can only be activated when it is fully loaded, resulting in low utilization of the economizer 41. Moreover, the subcooler 42 is opened during partial load, which is also beneficial to heating distribution and can easily improve the heating capacity.

When the heat pump unit 200 according to the embodiment of the present invention is running in the cooling mode, as shown by the arrow in Figure 4 As shown, the refrigerant is compressed in the compressor 10, and the original low-temperature and low-pressure refrigerant gas is compressed into high-temperature and high-pressure superheated steam, and is discharged from the exhaust port 4 of the compressor 10, and then enters the commutation after passing through the oil separator 50. The valve 20 controls the flow direction of the refrigerant through the reversing valve 20 . High-temperature and high-pressure superheated steam enters from the inlet of the reversing valve 20 . Since the exhaust port 4 of the compressor 10 is connected to the first heat exchanger 31 through the reversing valve 20 in the cooling mode, the superheated steam with high temperature and high pressure is introduced into the first heat exchanger 31 through the reversing valve 20 . At this time, the first heat exchanger 31 functions as a condenser. The high-temperature and high-pressure superheated steam is cooled in the first heat exchanger 31, and the superheated refrigerant changes from gaseous state to liquid state. After passing through the pre-distributor 80, it passes through the one-way valve CV1, flows through the filter 70, enters the main path inlet of the economizer 41, and then enters the main path inlet of the subcooler 42 from the outlet of the economizer 41. The outlet of the main path of the cooler 42 is throttled and depressurized by the refrigeration throttle valve EXV2, and the low-temperature and low-pressure refrigerant liquid enters the second heat exchanger 32 . At this time, the second heat exchanger 32 functions as an evaporator, and the refrigerant liquid absorbs heat and vaporizes in the second heat exchanger 32, and then vaporizes into a low-temperature and low-pressure gaseous refrigerant. After the low-temperature and low-pressure gaseous refrigerant passes through the reversing valve 20, it is sucked into the compressor 10 from the suction port 1 of the compressor 10 and enters the next refrigeration cycle.

When the heat pump unit 200 according to the embodiment of the present invention is running in the heating mode, as shown by the arrow in Figure 4 As shown, the refrigerant is compressed in the compressor 10, and the originally low-temperature and low-pressure refrigerant gas is compressed into high-temperature and high-pressure superheated steam. The high-temperature and high-pressure superheated steam compressed by the compressor 10 is discharged from the exhaust port 4 of the compressor 10. After passing through the oil separator 50, the high-temperature and high-pressure superheated steam is directly sent to the second heat exchanger 32 through the reversing valve 20. At this time, the second heat exchanger 32 functions as a condenser. The superheated steam dissipates heat through the second heat exchanger 32 . After the superheated steam is cooled, it forms a low-temperature and high-pressure liquid and enters the liquid reservoir 90 . The low-temperature and high-pressure refrigerant liquid in the accumulator 90 then passes through the one-way valve CV2, flows through the filter 70, enters the inlet of the main path of the economizer 41, and then enters the outlet of the main path of the economizer 41 into the subcooler 42. After the inlet of the main circuit and the outlet of the main circuit of the subcooler 42 are throttled and depressurized by the heating throttle valve EXV4, the low-temperature and low-pressure refrigerant is sent to the first heat exchanger 31 through the pre-distributor 80 middle. At this time, the first heat exchanger 31 functions as 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 becomes dry saturated steam again. The dry saturated steam finally passes through the reversing valve 20 and then returns to the suction port 1 of the compressor 10 to continue the next heating cycle.

The heat pump unit 200 in the embodiment of the present invention adds a subcooler 42, and the subcooler 42 can be linked with the economizer 41, thereby reducing the intermediate air supply amount of the compressor 10. Since the intermediate air supply amount of the compressor 10 is reduced, Therefore, the power consumption of the compressor 10 can be reduced, and the heat pump unit 200 according to the embodiment of the present invention can improve both the rated cooling efficiency and the rated heating efficiency.

In the heat pump unit 200 according to the embodiment of the present invention, after the air supply volume of the middle air supply port 23 of the compressor 10 is reduced, the vibration of the auxiliary side of the economizer 41 connected to the middle air supply port 23 of the compressor 10 can also be reduced. Since the size of the middle air supply port 23 of the compressor 10 is fixed, after the auxiliary side flow rate of the economizer 41 is reduced, the refrigerant pipeline flow rate can be effectively reduced.

In the heat pump unit 200 according to the embodiment of the present invention, by adding the subcooler 42, the refrigerant flow rate of the low-pressure stage through the reversing valve 20 is also reduced. Therefore, the pressure on the suction side (the suction side corresponding to cooling and heating) of the reversing valve 20 is reduced. It can be lowered. As the system resistance decreases, the exhaust pressure at 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 conducted a test comparison of two schemes of heat pump units under rated refrigeration conditions in the laboratory, that is, the first scheme is a heat pump unit scheme in which the economizer 41 is enabled but the subcooler 42 is bypassed, and the second scheme is It is a heat pump unit scheme that jointly activates the economizer 41 and the subcooler 42. The performance data collected from the system after the working conditions are stable can be found. The second scheme (that is, the heat pump unit scheme that jointly activates the economizer 41 and the subcooler 42 ) Compared with the first solution (that is, the heat pump unit solution with only economizer 41 enabled), the efficiency COP of the heat pump unit has increased by nearly 1.77%. In addition, it was found that the main reason is that the heat pump unit solution in which the economizer 41 and the subcooler 42 are jointly enabled reduces the refrigerant flow rate on the supply side compared to the heat pump unit solution in which only the economizer 41 is enabled, thereby reducing the power consumption of the compressor. In this way, the total power consumption of the heat pump unit is reduced, and the efficiency COP of the heat pump unit is improved. Therefore, it is verified that the solution of adding a subcooler 42 to the heat pump unit according to the embodiment of the present invention is very effective.

By comparing the data of the heat pump unit with a new subcooler 42 in the embodiment of the present invention during rated cooling and heating operations, the applicant can find that the heat pump unit with a new subcooler 42 in the embodiment of the present invention not only operates in the cooling mode is valid and is still valid when the heating is running.

In addition, by comparing the data of the heat pump unit with the subcooler 42 enabled and without the subcooler 42 when the compressor is running at partial load, the applicant can find that after the subcooler 42 is added to the heat pump unit according to the embodiment of the present invention, the heat pump The corresponding efficiency COP of the unit when operating at part load is better than the efficiency under the same load. Therefore, adding a subcooler 42 is also an effective means to improve the IPLV value of the comprehensive part load performance of the heat pump unit.

The heat pump unit provided by the embodiment of the present invention has been introduced in detail above. This article uses specific examples to illustrate the heat pump unit according to the embodiments of the present invention. The description of the above embodiments is only used to help understand the core idea of the present invention and is not intended to limit the present invention. It should be pointed out that for those of ordinary skill in the art, several improvements and modifications can be made to the present invention without departing from the spirit and principles of the present invention, and these improvements and modifications should also fall within the scope of the present invention. within the scope of protection of the 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.