Air conditioning system with compressors connected in parallel

Abstract

The utility model relates to the technical field of air conditioning, and specifically to a compressor parallel air conditioning system, including an indoor heat exchanger, a throttle valve, an outdoor heat exchanger, and a plurality of mutually parallel compression parallel branches; each compression parallel branch includes a compressor, an oil separator, and a one-way valve; the oil separator includes a suction port, a discharge port, and a recovery port. The utility model is provided with an oil separator and a one-way valve in each compression parallel branch, so that the compressor can balance its suction and exhaust pressure difference to complete unloading in the shortest downtime, and ensure the safe start of the compressor when loading next time.

Description

Technical Field

[0001] The utility model relates to the technical field of air conditioning, in particular to an air conditioning system with compressors connected in parallel. Background Art

[0002] For the current parallel compressor air conditioning system, generally speaking, all compressors will be started and stopped at the same time. When a compressor fails, only the faulty compressor is shut down, and the compressor is turned on directly after the fault is restored. Some parallel systems can support the operation of single-open compressors and double-open compressors, but the original system solution operation mode switching has certain operation risks and limitations. For the same start and stop solution, the refrigeration limit adjustment range is small. For the single-open, double-open and multi-open compressor solutions, the refrigeration limit adjustment range is wide, but it is inevitable to encounter problems such as load starting, cross-flow or oil shortage.

[0003] Load starting (pressure differential starting) refers to the phenomenon that the compressor starts with a high pressure differential when the pressure on the suction and exhaust sides of the compressor is unbalanced. When starting with load, the starting current will be very large, and it may approach or even exceed the demagnetization current of the compressor, and the compressor will vibrate and make loud noises. When the pressure differential is large, there may also be a phenomenon of starting failure. Long-term load starting will cause the compressor structure and motor to be damaged. The above problems are more significant for low-voltage compressors (such as 48V compressors). Because the compressor must start with load, it must have a large starting torque. The torque is positively correlated with the current, while the current is negatively correlated with the voltage. When the compressor starts with load, the starting current is very large, the compressor is at risk of demagnetization, and it will also cause impact on the power grid; in the parallel system, if the compressor is to be switched from single-open to double-open, the closed compressor will inevitably have the problem of load starting when it is turned on. This problem needs to be solved to ensure the safe and reliable operation of the parallel compressor system.

[0004] Currently, there are two known solutions to solve the problem of on-load startup:

[0005] The first is that when switching from single-start to double-start, the single-start compressor is first reduced to the lowest frequency to reduce the high and low pressure difference to unload, and then the other compressor is turned on. This method can alleviate the problem of starting with high pressure difference to a certain extent, but when the external ambient temperature is high, the condensing pressure will still maintain a high value even after the frequency is reduced. At this time, the pressure difference is still large, and the start-up may fail.

[0006] The second method is to achieve unloading between the compressor suction and exhaust pipes through a combination of a solenoid valve and a one-way valve. When the second compressor needs to be started, the solenoid valve is opened to balance the suction and exhaust pressures to achieve unloading and starting; however, unloading through a solenoid valve will increase costs. Utility Model Content

[0007] The utility model aims to provide an air conditioning system with compressors connected in parallel in view of the above-mentioned deficiencies in the prior art.

[0008] The purpose of the utility model is achieved through the following technical solutions: A compressor parallel air conditioning system, comprising an indoor heat exchanger, a throttle valve, an outdoor heat exchanger and a plurality of mutually parallel compression parallel branches;

[0009] Each compression parallel branch includes a compressor, an oil separator and a one-way valve; the oil separator includes a suction port, a discharge port and a recovery port;

[0010] One end of the indoor heat exchanger is connected to one end of the throttle valve; the other end of the throttle valve is connected to one end of the outdoor heat exchanger; the other end of the outdoor heat exchanger is connected to one end of the one-way valve; the other end of the one-way valve is connected to the discharge port; the suction port is connected to one end of the compressor; the other end of the compressor is connected to the other end of the indoor heat exchanger; the recovery port is connected to the other end of the compressor.

[0011] The utility model is further configured that an oil return capillary is provided between the recovery port and the other end of the compressor.

[0012] The utility model is further configured that the compression parallel branch includes a first compression parallel branch and a second compression parallel branch;

[0013] The first compression parallel branch includes a first compressor, a first oil separator and a first one-way valve; the second compression parallel branch includes a second compressor, a second oil separator and a second one-way valve; one end of the first one-way valve is connected to one end of the second one-way valve; the other end of the first compressor is connected to the other end of the second compressor.

[0014] The utility model is further configured to include a liquid return solenoid valve and a third one-way valve; the other end of the indoor heat exchanger is connected to one end of the liquid return solenoid valve; the other end of the liquid return solenoid valve is connected to the other end of the compressor; the third one-way valve is arranged between the other end of the indoor heat exchanger and the other end of the outdoor heat exchanger.

[0015] The utility model is further configured that a drying filter is provided between the throttle valve and one end of the outdoor heat exchanger.

[0016] The utility model is further configured that a liquid storage tank is provided between the drying filter and one end of the outdoor heat exchanger.

[0017] The utility model is further configured to further include a heat pipe solenoid valve; a branch of the heat pipe solenoid valve is connected in parallel with a branch of the throttle valve and a drying filter.

[0018] The utility model is further configured that a first temperature sensor is provided at one end of the compressor; a second temperature sensor is provided at the other end of the compressor; and a pressure sensor is provided at the other end of the outdoor heat exchanger.

[0019] The utility model is further configured such that an indoor fan is provided at the indoor heat exchanger; and an outdoor fan is provided at the outdoor heat exchanger.

[0020] Beneficial effects of the utility model: the utility model provides an oil separator and a one-way valve in each compression parallel branch, so that the compressor can balance its suction and exhaust pressure difference to complete unloading within the shortest downtime, ensuring the safe start-up of the compressor when loading next time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The utility model is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the utility model. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0022] Figure 1 It is the system principle diagram of the utility model;

[0023] Among them: 11, indoor heat exchanger; 12, outdoor heat exchanger; 13, throttle valve; 14, indoor fan; 15, outdoor fan; 21, first compressor; 22, first oil separator; 23, first one-way valve; 31, second compressor; 32, second oil separator; 33, second one-way valve; 4, oil return capillary; 51, suction port; 52, discharge port; 53, recovery port; 61, liquid return solenoid valve; 62, third one-way valve; 71, drying filter; 72, liquid storage tank; 8, heat pipe solenoid valve; 91, first temperature sensor; 92, second temperature sensor; 93, pressure sensor. DETAILED DESCRIPTION

[0024] The utility model is further described in conjunction with the following embodiments.

[0025] Depend on Figure 1 It can be seen that the compressor parallel air conditioning system described in this embodiment includes an indoor heat exchanger 11, a throttle valve 13, an outdoor heat exchanger 12 and a plurality of mutually parallel compression parallel branches;

[0026] Each compression parallel branch includes a compressor, an oil separator and a one-way valve; the oil separator includes a suction port 51, a discharge port 52 and a recovery port 53;

[0027] One end of the indoor heat exchanger 11 is connected to one end of the throttle valve 13; the other end of the throttle valve 13 is connected to one end of the outdoor heat exchanger 12; the other end of the outdoor heat exchanger 12 is connected to one end of the one-way valve; the other end of the one-way valve is connected to the discharge port 52; the suction port 51 is connected to one end of the compressor; the other end of the compressor is connected to the other end of the indoor heat exchanger 11; the recovery port 53 is connected to the other end of the compressor.

[0028] Specifically, the air-conditioning system with parallel compressors described in this embodiment can achieve pressure balance on both sides of the compressors by providing an oil separator and connecting the high-pressure and low-pressure sides of the compressors. In addition, the oil separator can separate the oil in the exhaust gas to avoid the accumulation of exhaust oil in the outdoor heat exchanger 12. In addition, by providing a one-way valve, a pressure-relieving environment can be provided for the high-pressure side of the stopped compressor. One side of the one-way valve is the high pressure of the compressor in the open state, and the other side is the exhaust gas of the compressor in the stopped state. The exhaust side of the stopped compressor is not affected by the high pressure of the opened compressor. If there is no one-way valve, the exhaust branch pipes of all compressors are directly connected to the exhaust main pipe, and they are all at the same high pressure, and independent pressure relief of the stopped compressor cannot be achieved. In addition, the one-way valve can prevent the oil discharged from the opened compressor from accumulating in the exhaust branch pipe of the stopped compressor, thereby causing the opened compressor to lack oil. Secondly, the one-way valve can prevent the exhaust gas of the opened compressor from flowing back to the suction side through the stopped compressor, resulting in reduced system energy efficiency.

[0029] In the air conditioning system with parallel compressors described in this embodiment, an oil return capillary 4 is provided between the recovery port 53 and the other end of the compressor. The oil return capillary 4 is respectively connected to the rising section of the connection between the suction branch pipe and the suction main pipe of each compressor.

[0030] In the air conditioning system with compressors connected in parallel described in this embodiment, the compression parallel branch includes a first compression parallel branch and a second compression parallel branch;

[0031] The first compression parallel branch includes a first compressor 21, a first oil separator 22 and a first one-way valve 23; the second compression parallel branch includes a second compressor 31, a second oil separator 32 and a second one-way valve 33; one end of the first one-way valve 23 is connected to one end of the second one-way valve 33; the other end of the first compressor 21 is connected to the other end of the second compressor 31.

[0032] This embodiment takes two compression parallel branches as an example. When the first compressor 21 and the second compressor 31 are both turned on and switched to the first compressor 21 being turned off and the second compressor 31 being turned on, the high-pressure exhaust gas from the second one-way valve 33 can be isolated by the first one-way valve 23, and the first compressor 21 can directly balance its suction and exhaust pressure difference through the oil return capillary 4 to complete unloading within the shortest downtime, thereby ensuring the safe start-up of the first compressor 21 during the next loading; the other two independent oil separators can also ensure the oil return of the two compressors.

[0033] The compressor parallel air conditioning system described in this embodiment also includes a liquid return solenoid valve 61 and a third one-way valve 62; the other end of the indoor heat exchanger 11 is connected to one end of the liquid return solenoid valve 61; the other end of the liquid return solenoid valve 61 is connected to the other end of the compressor; the third one-way valve 62 is arranged between the other end of the indoor heat exchanger 11 and the other end of the outdoor heat exchanger 12. Specifically, through the above arrangement, the pressure, flow rate and flow direction of the system can be controlled.

[0034] In the air conditioning system with compressors in parallel described in this embodiment, a drying filter 71 is provided between the throttle valve 13 and one end of the outdoor heat exchanger 12. The above arrangement facilitates filtering impurities in the system.

[0035] In the air conditioning system with compressors in parallel described in this embodiment, a liquid storage tank 72 is provided between the drying filter 71 and one end of the outdoor heat exchanger 12. The above arrangement facilitates the storage of refrigerant.

[0036] The air conditioning system with compressors in parallel described in this embodiment further includes a heat pipe solenoid valve 8, the branch of which is connected in parallel with the throttle valve 13 and the dry filter 71. The system has a compressor mode and a heat pipe mode.

[0037] In the air conditioning system with compressors in parallel described in this embodiment, a first temperature sensor 91 is provided at one end of the compressor; a second temperature sensor 92 is provided at the other end of the compressor; and a pressure sensor 93 is provided at the other end of the outdoor heat exchanger 12. The above arrangement facilitates the measurement of the temperature and pressure at various positions of the system.

[0038] In the air conditioning system with compressors in parallel described in this embodiment, the indoor heat exchanger 11 is provided with an indoor fan 14, and the outdoor heat exchanger 12 is provided with an outdoor fan 15. The above arrangement facilitates the indoor heat exchanger 11 and the outdoor heat exchanger 12 to exchange heat with the environment respectively.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. An air conditioning system with compressors connected in parallel, characterized in that: It comprises an indoor heat exchanger (11), a throttle valve (13), an outdoor heat exchanger (12) and a plurality of compression parallel branches connected in parallel with each other; Each compression parallel branch comprises a compressor, an oil separator and a one-way valve; the oil separator comprises a suction port (51), a discharge port (52) and a recovery port (53); One end of the indoor heat exchanger (11) is connected to one end of the throttle valve (13); the other end of the throttle valve (13) is connected to one end of the outdoor heat exchanger (12); the other end of the outdoor heat exchanger (12) is connected to one end of the one-way valve; the other end of the one-way valve is connected to the discharge port (52); the suction port (51) is connected to one end of the compressor; the other end of the compressor is connected to the other end of the indoor heat exchanger (11); and the recovery port (53) is connected to the other end of the compressor.

2. The air conditioning system with compressors in parallel according to claim 1, characterized in that: An oil return capillary tube (4) is provided between the recovery port (53) and the other end of the compressor.

3. The air conditioning system with compressors in parallel according to claim 1, characterized in that: The compression parallel branch includes a first compression parallel branch and a second compression parallel branch; The first compression parallel branch comprises a first compressor (21), a first oil separator (22) and a first non-return valve (23); the second compression parallel branch comprises a second compressor (31), a second oil separator (32) and a second non-return valve (33); one end of the first non-return valve (23) is connected to one end of the second non-return valve (33); and the other end of the first compressor (21) is connected to the other end of the second compressor (31).

4. The air conditioning system with compressors in parallel according to claim 1, characterized in that: It also includes a liquid return solenoid valve (61) and a third one-way valve (62); the other end of the indoor heat exchanger (11) is connected to one end of the liquid return solenoid valve (61); the other end of the liquid return solenoid valve (61) is connected to the other end of the compressor; the third one-way valve (62) is arranged between the other end of the indoor heat exchanger (11) and the other end of the outdoor heat exchanger (12).

5. The air conditioning system with compressors in parallel according to claim 1, characterized in that: A drying filter (71) is provided between the throttle valve (13) and one end of the outdoor heat exchanger (12).

6. An air conditioning system with compressors in parallel according to claim 5, characterized in that: A liquid storage tank (72) is provided between the drying filter (71) and one end of the outdoor heat exchanger (12).

7. The air conditioning system with compressors in parallel according to claim 5, characterized in that: It also includes a heat pipe solenoid valve (8); a branch of the heat pipe solenoid valve (8) is connected in parallel with a branch of a throttle valve (13) and a drying filter (71).

8. The air conditioning system with compressors in parallel according to claim 1, characterized in that: A first temperature sensor (91) is provided at one end of the compressor; a second temperature sensor (92) is provided at the other end of the compressor; and a pressure sensor (93) is provided at the other end of the outdoor heat exchanger (12).

9. The air conditioning system with compressors in parallel according to claim 1, characterized in that: The indoor heat exchanger (11) is provided with an indoor fan (14); and the outdoor heat exchanger (12) is provided with an outdoor fan (15).

Images