Multi-split heat pump system with good stability

Abstract

The invention relates to the technical field of heat exchange systems, and provides a multi-split heat pump system with good stability, which comprises an indoor unit heat exchanger, the output end of the indoor unit heat exchanger is communicated with an economizer, the output end of the economizer is respectively communicated with a cooling fin and a flash evaporator, the output end of the cooling fin is communicated with a filter, and the output end of the flash evaporator is communicated with a condenser. And the output end of the filter is communicated with an outdoor unit heat exchanger. The flash evaporator is arranged, so that the risk of liquid impact faults is avoided, efficient and stable operation of the system is achieved, the economizer with a micro channel is prevented from bearing large pressure, two-phase flow of the economizer is evenly distributed, and it is ensured that the purposes of enhanced vapor injection and exhaust pressure improvement can be achieved; the liquid refrigerant separated from the flash evaporator is throttled and decompressed through the second electronic expansion valve to form a low-temperature and low-pressure gaseous refrigerant, the low-temperature and low-pressure gaseous refrigerant and the refrigerant subjected to heat exchange through the outdoor unit heat exchanger are gathered and flow into the liquid storage device, the purpose of liquid spraying enthalpy increasing is achieved, and therefore the use stability of the multi-split heat pump system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchange systems, and in particular to a multi-connected heat pump system with good stability. Background Art

[0002] Heat pump technology is a technology that uses the principle of mutual conversion between refrigeration cycle and heating cycle to achieve cooling and heating functions. In a multi-split heat pump system, when cooling, the outdoor unit absorbs the hot air in the room through the refrigeration cycle system, passes through the evaporator and condenser, and releases the coolant to the outside to achieve the purpose of cooling. When heating, the outdoor unit absorbs the low-temperature air outside through the heating cycle system, passes through the evaporator and condenser, and releases the heat to the room to achieve the purpose of heating.

[0003] To this end, the patent with authorization announcement number CN109442791B discloses a heat source tower heat pump multi-split system, including a heat source tower, a heat pump host and at least two indoor units; the heat pump host includes: a four-way valve, a compressor, a host heat exchanger and a solution pump, one end of the heat source liquid pipeline in the host heat exchanger is connected to the input end of the heat source tower through the solution pump, and the other end of the heat source liquid pipeline in the host heat exchanger is connected to the output end of the heat source tower; each indoor unit includes: an indoor heat exchanger and an expansion valve, one end of the refrigerant pipeline in each indoor heat exchanger is connected to the E pipe of the four-way valve, and the other end of the refrigerant pipeline in each indoor heat exchanger is connected to the end of the expansion valve that is not connected to the host heat exchanger. The heat source tower heat pump multi-split system provided by the present invention realizes that a system can meet the needs of refrigeration and heating at the same time, and operates with high efficiency and energy saving throughout the year, while solving the problem of automatic detection of antifreeze concentration in the heat source tower heat pump system;

[0004] The above-mentioned heat source tower heat pump multi-split system adopts water-cooled heat exchange, which has better cooling effect and lower energy consumption in summer. It avoids the problem of frosting of the outdoor unit of the air-cooled unit in winter, can achieve continuous heating, and there is no need to set up defrosting modules such as auxiliary electric heating. Compared with the air-cooled multi-split unit, it has higher energy efficiency and better comfort. Each room can be adjusted independently to meet the air-conditioning load requirements of different rooms. However, during use, since the economizer of the tiny channel is under greater pressure, long-term use will lead to uneven two-phase flow distribution, and liquid hammer failure is prone to occur, making it less stable during use. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-split heat pump system with good stability, so as to solve the defects of the existing multi-split heat pump system such as uneven phase flow distribution and easy occurrence of liquid hammer failure.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a multi-split heat pump system with good stability, comprising an indoor unit heat exchanger;

[0007] The output end of the indoor unit heat exchanger is connected to an economizer, and the output end of the economizer is respectively connected to a heat sink and a flash evaporator;

[0008] The output end of the heat sink is connected to a filter, the output end of the filter is connected to an outdoor heat exchanger, and the output end of the outdoor heat exchanger is connected to a four-way reversing valve;

[0009] The first flow path of the flash evaporator is connected to a compressor, the second flow path of the flash evaporator is connected to a liquid storage device, and the output end of the compressor is connected to an oil separator.

[0010] Preferably, the output end of the indoor unit heat exchanger is connected to an indoor unit electronic expansion valve, and the input end of the economizer is connected to a first electronic expansion valve.

[0011] Preferably, an external machine expansion valve and an external machine auxiliary expansion valve are respectively connected between the heat sink and the filter.

[0012] Preferably, the outdoor unit heat exchanger is connected to the liquid reservoir via a four-way reversing valve.

[0013] Preferably, a second electronic expansion valve is connected between the flash evaporator and the liquid storage tank.

[0014] Preferably, the output end of the liquid storage device is connected to the input end of the compressor.

[0015] Preferably, the first flow path of the oil separator is connected to the indoor unit heat exchanger through a four-way reversing valve, the four-way reversing valve and the indoor unit heat exchanger are connected through a filter, and the second flow path of the oil separator is connected to the compressor. In the process of the refrigerant from the outdoor unit heat exchanger to the indoor unit heat exchanger, it passes through the liquid storage tank, the compressor, the oil separator, and the filter in sequence, which respectively play the role of gas-liquid separation, isentropic compression, separation of gaseous refrigerant and lubricating oil, and filtering of impurities.

[0016] The invention provides a multi-connected heat pump system with good stability, which has the following advantages:

[0017] By providing a flash evaporator, the risk of liquid hammer failure is avoided, the system can be operated efficiently and stably, and the economizer with a small channel is prevented from being subjected to a large pressure, so that the two-phase flow is evenly distributed, ensuring that the purpose of increasing the exhaust pressure by jetting enthalpy can be achieved. The liquid refrigerant separated from the flash evaporator is throttled and depressurized by the second electronic expansion valve to become a low-temperature and low-pressure gaseous refrigerant, which is combined with the refrigerant after heat exchange from the outdoor unit heat exchanger and flows into the liquid storage tank, achieving the purpose of jetting enthalpy increase, thereby improving the stability of the multi-split heat pump system when in use;

[0018] By providing a heat sink, since the PCB board in the outdoor unit control box will be affected by the temperature change of the outdoor unit heat exchanger, the heat sink is exchanged with the surrounding temperature of the control box to achieve a balance of the larger temperature difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the system flow of the present invention;

[0020] Figure 2 It is a pressure enthalpy schematic diagram of the present invention.

[0021] Explanation of the reference numerals in the figure: 1. Indoor unit heat exchanger; 2. Economizer; 3. Heat sink; 4. Filter; 5. Outdoor unit heat exchanger; 6. Four-way reversing valve; 7. Flash evaporator; 8. Compressor; 9. Liquid reservoir; 10. Oil separator; a. Indoor unit electronic expansion valve; b. First electronic expansion valve; c. Outdoor unit expansion valve; d. Outdoor unit auxiliary expansion valve; e. Second electronic expansion valve. DETAILED DESCRIPTION

[0022] 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.

[0023] See also Figure 1 and Figure 2 The present invention provides a multi-split heat pump system with good stability, comprising an indoor heat exchanger 1, an output end of the indoor heat exchanger 1 is connected to an economizer 2, an output end of the indoor heat exchanger 1 is connected to an indoor electronic expansion valve a, an input end of the economizer 2 is connected to a first electronic expansion valve b, an output end of the economizer 2 is respectively connected to a heat sink 3 and a flash evaporator 7, an output end of the heat sink 3 is connected to a filter 4, an outdoor expansion valve c and an outdoor auxiliary expansion valve d are respectively connected between the heat sink 3 and the filter 4, an output end of the filter 4 is connected to an outdoor heat exchanger 5, and an output end of the outdoor heat exchanger 5 is connected to four The four-way reversing valve 6 is connected to the first flow path of the flash evaporator 7, the compressor 8 is connected to the second flow path of the flash evaporator 7, the outdoor unit heat exchanger 5 is connected to the liquid reservoir 9 through the four-way reversing valve 6, a second electronic expansion valve e is connected between the flash evaporator 7 and the liquid reservoir 9, the output end of the liquid reservoir 9 is connected to the input end of the compressor 8, the output end of the compressor 8 is connected to the oil separator 10, the first flow path of the oil separator 10 is connected to the indoor unit heat exchanger 1 through the four-way reversing valve 6, the four-way reversing valve 6 and the indoor unit heat exchanger 1 are connected through the filter 4, and the second flow path of the oil separator 10 is connected to the compressor 8.

[0024] When the indoor heat exchanger 1 is in cooling mode, the low-temperature, low-pressure liquid refrigerant enters the indoor heat exchanger 1 after throttling and decompression. At this time, the indoor air temperature is higher than the refrigerant temperature. The heavy copper tube of the heat exchanger serves as a passage for the refrigerant. The liquid refrigerant flows in the copper tube. Due to the temperature difference, heat is transferred from the indoor air to the copper tube through the aluminum fins. The aluminum fins increase the heat exchange area and play a key role in enhancing heat transfer. Driven by the indoor unit fan, the air continuously flows through the aluminum fins and the surface of the copper tube. After the heat is transferred to the refrigerant, the liquid refrigerant begins to absorb heat and gradually vaporizes. As the vaporization process proceeds, the temperature of the refrigerant will also rise. However, as long as its temperature is still lower than the indoor air temperature, heat will continue to be absorbed. Finally, the gaseous refrigerant leaves the indoor unit heat exchanger 1 and is compressed for the next cycle. In the heating mode, the flow direction of the refrigerant is changed by the four-way reversing valve 6. At this time, the high-temperature and high-pressure gaseous refrigerant enters the indoor unit heat exchanger 1. The indoor fan blows the heated air into the room to increase the indoor temperature. As the refrigerant continuously releases heat, its own state will gradually change from gas to liquid, and then flow to the outdoor unit heat exchanger 5 through the pipeline for subsequent circulation.

[0025] When the outdoor unit heat exchanger 5 is in cooling mode, the high-temperature, high-pressure gaseous refrigerant flowing out of the indoor unit evaporator enters the outdoor unit heat exchanger 5. At this time, the outdoor unit heat exchanger 5 acts as a condenser. The gaseous refrigerant flows in the copper tube. Since its temperature is higher than the outdoor air temperature, the heat will be transferred from the refrigerant to the copper tube. The aluminum fins quickly dissipate the heat of the copper tube to the surrounding air. The fan of the outdoor unit forces the air to flow through the aluminum fins and the copper tube surface to accelerate the heat dissipation. In this process, the gaseous refrigerant gradually cools and liquefies, completing the process. The heat released from the transition from gas to liquid is taken away by the outdoor air. In the heating mode, the outdoor unit heat exchanger 5 acts as an evaporator, and the liquid refrigerant from the indoor unit condenser (at this time, the indoor unit heat exchanger 1 acts as a condenser) enters the outdoor unit heat exchanger 5 under the action of pressure difference. Since the temperature of the liquid refrigerant is lower than the outdoor air temperature, the heat of the outdoor air will be transferred to the refrigerant through the aluminum fins and copper tubes. After absorbing the heat, the refrigerant gradually vaporizes, and then returns to the indoor unit heat exchanger 1 for the next round of heating cycle.

[0026] Economizer 2 absorbs heat through the throttling evaporation of the refrigerant itself, thereby supercooling another part of the refrigerant to improve the efficiency of the refrigeration cycle. The refrigerant entering economizer 2 is further cooled in economizer 2. In this process, a part of the refrigerant is throttled by the throttling device and evaporates, absorbing the heat of the surrounding high-pressure liquid refrigerant and evaporating into medium-pressure gas, which is then sucked into the middle air supply port of compressor 8 to participate in the subsequent compression process. At the same time, the heat absorbed by the evaporated refrigerant causes another part of the refrigerant to be supercooled, that is, its temperature is further reduced and the enthalpy value is correspondingly reduced.

[0027] When the flash evaporator 7 allows the high-pressure saturated liquid to enter the low-pressure space in the flash evaporator 7 through a throttling device such as a pressure reducing valve, the pressure of the liquid decreases rapidly, causing its boiling point to drop below the current temperature. Part of the liquid will rapidly vaporize into steam, while the remaining liquid will become a saturated liquid under the low pressure until both the liquid and the steam reach a saturated state under the pressure.

[0028] The oil separator 10 separates the mixed gas of high-temperature, high-pressure refrigerant and lubricating oil discharged from the compressor 8, thereby avoiding waste of resources and pollution to subsequent equipment.

[0029] In the heating mode, the refrigerant in the indoor unit heat exchanger 1 passes through the indoor unit electronic expansion valve a, economizer 2, heat sink 3, outdoor unit expansion valve c, outdoor unit auxiliary expansion valve d, and filter 4 in turn during the process of reaching the outdoor unit heat exchanger 5. The indoor unit electronic expansion valve a and the outdoor unit expansion valve c are set to adapt to more complex working conditions and keep the unit running at high speed. According to the actual working conditions, the system automatically adjusts the opening of the indoor unit electronic expansion valve a and the outdoor unit expansion valve c to achieve the target working condition. The refrigerant in the outdoor unit heat exchanger 5 passes through the liquid storage tank 9, compressor 8, oil separator 10, and filter 4 in turn during the process of reaching the indoor unit heat exchanger 1, which respectively play the role of gas-liquid separation, isentropic compression, separation of gaseous refrigerant and lubricating oil, and filtering impurities.

[0030] The system oil return is set in two modes: rapid oil return and continuous oil return, to avoid oil shortage in the compressor 8, which leads to reduced energy efficiency and life, and to reduce the lubricating oil retained in the heat exchanger to affect the heat exchange capacity.

[0031] Since the PCB board in the outdoor unit control box will be affected by the temperature change of the outdoor unit heat exchanger 5, the refrigerant liquid pipe of the heat sink 3 is heat-exchanged with the ambient temperature of the control box to achieve a large temperature difference.

[0032] Since the refrigerant in the multi-split system flows through a long pipeline, it is throttled and reduced in pressure before entering the indoor unit to minimize the heat loss of the refrigerant before it enters the indoor unit heat exchanger and to achieve the user's different requirements for the heat and humidity load of the indoor unit in each room.

[0033] The liquid refrigerant separated from the flash evaporator 7 is throttled and reduced in pressure by the second electronic expansion valve e to become a low-temperature and low-pressure gaseous refrigerant, which is combined with the refrigerant after heat exchange from the outdoor unit heat exchanger 5 and flows into the liquid storage tank 9 to achieve the purpose of liquid injection and enthalpy increase.

[0034] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-split heat pump system with good stability, comprising an indoor unit heat exchanger (1); Features: The output end of the indoor unit heat exchanger (1) is connected to an economizer (2), and the output end of the economizer (2) is respectively connected to a heat sink (3) and a flash evaporator (7); The output end of the heat sink (3) is connected to a filter (4), the output end of the filter (4) is connected to an outdoor heat exchanger (5), and the output end of the outdoor heat exchanger (5) is connected to a four-way reversing valve (6); The first flow path of the flash evaporator (7) is connected to a compressor (8), the second flow path of the flash evaporator (7) is connected to a liquid storage device (9), and the output end of the compressor (8) is connected to an oil separator (10).

2. A multi-split heat pump system with good stability according to claim 1, characterized in that: The output end of the indoor unit heat exchanger (1) is connected to an indoor unit electronic expansion valve (a), and the input end of the economizer (2) is connected to a first electronic expansion valve (b).

3. A multi-split heat pump system with good stability according to claim 1, characterized in that: An external machine expansion valve (c) and an external machine auxiliary expansion valve (d) are respectively connected between the heat sink (3) and the filter (4).

4. A multi-connected heat pump system with good stability according to claim 1, characterized in that: The outdoor unit heat exchanger (5) is connected to the liquid storage tank (9) via a four-way reversing valve (6).

5. A multi-connected heat pump system with good stability according to claim 1, characterized in that: A second electronic expansion valve (e) is connected between the flash evaporator (7) and the liquid storage tank (9).

6. A multi-split heat pump system with good stability according to claim 1, characterized in that: The output end of the liquid storage device (9) is connected to the input end of the compressor (8).

7. A multi-split heat pump system with good stability according to claim 1, characterized in that: The first flow path of the oil separator (10) is connected to the indoor unit heat exchanger (1) via a four-way reversing valve (6), the four-way reversing valve (6) and the indoor unit heat exchanger (1) are connected via a filter (4), and the second flow path of the oil separator (10) is connected to the compressor (8).

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