WO2003085334A1

WO2003085334A1 - Improvement for multi-coupled heat pump system

Info

Publication number: WO2003085334A1
Application number: PCT/CN2003/000153
Authority: WO
Inventors: Kefang You; Xintian You
Original assignee: Kefang You; Xintian You
Priority date: 2002-02-28
Filing date: 2003-02-27
Publication date: 2003-10-16
Also published as: AU2003211676A1

Abstract

A multi-coupled heat pump system comprises a plurality of high-pressure cavity compressors with varying or unvarying frequency, improved oil supply device in parallel for the compressors and improved pre-vaporizing defrosting device. The system can ensure all compressors no lack of oil during startup, oil-richness during operation and no intermittence of oil during stop. The system does not stop heating during defrosting operation. Compared with the prior art, it has a simple constructure, and can increase its reliability and holistic capability.

Description

Improvement of multi-connected heat pump system

Technical field

The present invention relates to improvements in multi-junction heat pump systems, and in particular to improvements in system oil performance and defrosting performance. technical background

In order to improve the overall performance of multiple compressor parallel heat pump systems, especially the overall performance of multiple parallel systems of compressors belonging to the high pressure chamber, it is necessary to improve the oil supply performance and defrosting performance of the system.

On the one hand, CN 1097711C discloses the invention of "multiple refrigeration compressor oil equalization devices" to improve the oil supply performance of the system. However, the multi-refrigeration compressor oil-removing automatic control device failed to solve the problem of lack of oil after the compressor that was originally stopped working alone, and failed to prevent any one of the compressors from being shut down in the absence of oil, and the oil was shut off during the shutdown. If the compressor is started separately in the absence of oil, there will be a consequence of continued oil shortage and burning of the compressor; and because the device lacks measures to quickly establish oil pressure, oil breakage may occur when the compressor is started in a low temperature environment. The suction port of the known moving parts of the compressor is placed in the lower position of the oil pool. After the machine is stopped for a period of time, it will start, and the lean layer in the lower position will be sucked first. Since the compressor accumulates in the oil sump after shutdown in a low temperature environment, it is mutually soluble with the lubricating oil to form a higher-position rich layer and a lower-position lean layer. Excessive refrigerant contained in the lean layer is sucked into the pressure chamber by the compressor. The refrigerant is vaporized and evaporated to increase the pressure of the medium pressure chamber, which blocks the feeding of the lubricating oil to the high-pressure moving parts. The oil pressure cannot be established and reaches the high pressure. Moving parts, high-pressure moving parts are not lubricated and cooled by oil, causing the temperature to rise continuously to burn out the compressor.

On the other hand, there are also three techniques to improve the defrosting performance of heat pump systems -

1. "Heat pump with improved defrost system" published in WO 99/42768 publication, defrost by means of auxiliary electric heating for outdoor temperatures from 0 ° C to 2.2 ° C, but reverse cycle of heat pump for lower temperatures The frost scheme affects the comfort of the indoor temperature in winter.

2. The "Operation Control System for Air Conditioners" published in the publication of WO 95/12098 adopts an "indoor heat exchanger - compressor - outdoor heat exchanger - receiver" unidirectional non-recirculating recoil Defrosting scheme, It also reduces the comfort of indoor temperature in winter.

3. The "Heat Pump Air Conditioner Operation Control Method" published in the JP 312281/86 publication uses a scheme in which the compressor simultaneously decompresses the compression of the outdoor heat exchanger and the indoor heat exchanger, but the heat pump system is eliminated. The circulation circuit, the program can provide limited defrosting heat, low defrosting efficiency and system instability. Summary of the invention

In order to overcome the defects of the prior art that the individual compressor lacks oil or oil and the system has low defrosting efficiency and unstable system operation, the present invention provides a multi-joint heat pump system improvement scheme, including an improved compressor parallel oil supply device. And pre-evaporation defrosting device, which can make any compressor start without oil shortage, tend to be rich when running, and keep oil when it stops. The system does not stop heating when defrosting, and obviously improves the comfort of indoor temperature in winter.

The technical measures adopted by the present invention to solve its technical problems include two aspects:

On the one hand, the heat pump system only has one oil separator, the oil separator is placed at the same level as each compressor, and the lowest working oil level line, the system stable oil level line and the pre-filled oil level line are determined from the bottom up, each compressor A pair of guide oil pipes are drawn at the bottom, so that each high-pressure oil pool is juxtaposed with the bottom of the oil separator through the respective oil guiding tubes. One end of the oil guiding tube is open at the lean layer at the bottom of the oil pool, and the lean oil layer is first drained through the oil guiding tube when the compressor starts. The oil separator is retained in the oil reservoir, and the oil level is reduced and maintained at the lowest working oil level line. Since there is not too much refrigerant entering the medium pressure chamber, the pressure rises to block the oil circuit, and the oil pressure is rapid. Establishing and reaching high-pressure moving parts, the high-pressure moving parts are continuously lubricated and cooled by the oil, and the compressor can work normally, avoiding the oil-breaking phenomenon that occurs in the compressor in the low-temperature environment due to the failure of the oil pressure to be established;

A return pipe is taken out from the bottom of the oil separator, and the return pipe is connected to an inlet of the oil pipe through a pressure limiter, and the ends of the oil pipes which are branched from the oil pipe are juxtaposed with the suction pipes at the near suction port of the corresponding compressor respectively. Correspondingly, the ends of the oil traps are tightly nested inside the corresponding suction pipe and provided with an oil hole. When the compressor is running, the oil at the bottom of the oil separator is transmitted to the oil hole through the pressure limiting, and the oil is self-fluiding. Drip, the high-speed airflow in the suction pipe disperses the oil droplets into a mist and is taken up by the compressor, because the amount of oil that the compressor draws from the oil hole is not less than the oil discharged from the exhaust port by the compressor. Therefore, any compressor tends to be rich in oil during operation, which avoids the phenomenon that the amount of oil returned to each compressor in the prior art is uneven and lacks oil;

The other end of the oil guiding pipe is flush with the system stable oil level line in the oil separator. The oil discharged from the compressor in operation causes the oil level of the oil separator to rise and exceed the system stable oil level line. Gravity action, through the other oil guiding pipe to actively introduce lubricating oil into the compressor in the shutdown, so that the oil level of any unstarted compressor rises after the system is turned on and tends to approach the oil level of the oil separator, so, in the operating system Any uncompressed compressor will not be short of oil, which provides the necessary conditions for the compressor to start without starting the oil, avoiding the lack of oil before the start of the prior art compressor;

The oil guiding pipe is provided with an oil guiding hole in the compressor and in the oil separator at the position of the lowest working oil level line, and each compressor and oil separator is filled with lubricating oil and reaches the pre-filling oil level line before the system is opened. When the system is turned on, the oil distribution of each part of the system tends to be stable. After the distribution of the system is stabilized, the oil level of each compressor and oil separator will drop to the system stable oil level line. The system stops again, the pressure in the compressor and the oil separator tends to be statically balanced. Due to the communication between the oil guiding pipe and the oil guiding hole, the oil level of each compressor and the oil separator tends to balance and maintain the system stable oil level line. on. In the two cases before the system is turned on and after the system is stopped, the oil level of all the compressors reaches the system stable oil level line above the minimum working oil level line without oil shortage, which is not the case when any shutdown compressor is restarted. The lack of oil provides the necessary conditions to avoid the uneven oil quantity of the prior art returning to each compressor, and there is a phenomenon of oil shortage during shutdown and oil shortage during shutdown.

On the other hand, the one end of the liquid infusion tube of the liquid pump in the heat pump circulation system is connected to the collection points of the electronic expansion valves at the rear end of the plurality of indoor heat exchangers, and the other end of the liquid storage tube is connected to an electronic expansion valve. After entering the outdoor heat exchanger, the gas pipe at the top of the liquid reservoir is connected to a solenoid valve and then connected to the outdoor heat exchanger in parallel with the aforementioned electronic expansion valve. Thus, the reservoir and its electronic expansion valve at both ends and the solenoid valve at the upper end thereof constitute a pre-evaporation defroster.

When the system needs defrosting under heating conditions, the electronic expansion valves at the rear end of several indoor heat exchangers are adjusted. Large, let each inverter compressor run at high frequency, provide more high temperature and high pressure gas, maintain the heating operation of the indoor heat exchanger, open the gas pipe and solenoid valve at the top of the liquid reservoir, and let the liquid in the liquid reservoir The refrigerant is pre-evaporated into medium-temperature and medium-pressure gas and enters the outdoor heat exchanger for defrosting. After the defrosting is finished, the gas pipe and the solenoid valve at the top of the liquid reservoir are closed, and the opening and the frequency of each electronic expansion valve at the rear end of several indoor heat exchangers The compressor frequency is restored, avoiding the drawbacks of the prior art that the heating of the room is stopped during defrosting.

The invention has the beneficial effects that the compressor can be operated under normal lubrication and cooling conditions, and can effectively defrost without affecting the comfort of the indoor temperature in winter, and has the advantages of simple structure, few components and high reliability. The overall performance of the system has been improved.

DRAWINGS

The invention will now be further described with reference to the drawings and embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a configuration diagram of a first embodiment of an improved multi-junction heat pump system.

Figure 2 is a cross-sectional view of the oil hole.

Figure 1. Compressor, 2. Lubricating oil pool, 3. Oil guiding hole, 4. Double-guide oil pipe, 5. Oil separator, 6. Exhaust pipe, 7. Oil return hole, 8. Oil return pipe, 9. Pressure limiter, 10. Oil pipe inlet, 11. Oil pipe end, 12. Oil hole, 13. Check valve, 14. Suction pipe, 15. Oil suction hole, 16. Intake pipe, 17. Outlet pipe, 18 Pre-filled oil level line, 19. System stable oil level line, 20. Minimum working oil level line, 21. Four-way valve, 22. Outdoor heat exchanger, 23. Solenoid valve, 24. Outdoor electronic expansion valve, 25. Storage Liquid, 26. Indoor electronic expansion valve, 27. Indoor heat exchanger

Detailed ways

On the one hand, in the first embodiment shown in FIG. 1, a plurality of double-guide oil pipes 4 are taken out from the bottom of the oil separator 5, in order to realize the oil pool of each compressor 1 through the double-guide oil pipe 4 and the bottom of the oil separator 5 In connection, the opening of the oil guiding pipe 4 at one end of the compressor 1 is set at the bottom of the oil pool 2 below the lowest working oil level line 20, and the other end of the oil guiding pipe 4 is extended from the bottom of the oil separator 5 to the system stable oil level line 19. The wall of the arm is bent and opened. When the compressor 1 is started, the oil guiding pipe 4 first drains the lean layer at the bottom of the oil pool 2 into the oil separator 5 to retain the rich layer in the oil pool 2 Inside, the pressure difference causes the oil pressure to quickly build up and reach the high-pressure moving parts, and the high-pressure moving parts are continuously lubricated and cooled by the oil. The oil discharged from the compressor 1 causes the oil level of the oil separator 5 to rise, and the oil guiding tube 4 in turn causes the oil in the oil separator 5 higher than the system stabilizing oil line 19 to be actively introduced into the oil pool 2 of the compressor 1 that is stopped. in.

The oil guiding pipe 4 opens the oil guiding hole 3 in the compressor 1 and in the oil separator 5 according to the lowest working oil line 20, and the communication between the oil guiding pipe 4 and the oil guiding hole 3 makes the compressor 1 when the system is static. And the oil level of the oil separator 5 is balanced on the system stabilizing oil line 19;

A return oil pipe 8 is drawn from the bottom of the oil separator 5, and the oil return pipe 8 is connected to an inlet of an adjustable or fixed pressure limiter 9. The outlet of the pressure limiter 9 is connected with the oil inlet pipe inlet 10 to supply oil to the oil collecting pipe after pressure limiting. . The oil return pipe 8-end is opened below the lowest working oil line 20 at the bottom of the oil separator 5. In order to preferentially supply the oil-rich layer portion to the oil pipeline, the opening may also be extended upwards slightly below the system stable oil level line 19 and separated from the oil. The oil return hole 7 is disposed below the lowest working oil level line 20 at the bottom of the device 5, and the other end of the oil return pipe 8 distributes the oil through the oil collecting pipe inlet 10 to the end 11 of each oil collecting pipe, and the end portions 11 of the oil collecting pipes are tightly fitted into the vicinity of the suction port of the corresponding compressor 1. The inside of the suction pipe 14 is provided with an oil hole 12, and FIG. 2 is a cross-sectional view of the oil hole 12, and the end of the oil pipe end 11 is inserted into the suction pipe 14 to reduce the cross-sectional area of the corresponding portion in the suction pipe 14, The speed of the local air flow is increased, and the oil from the oil hole 12 is atomized by the speed-up airflow and sent to the compressor 1 to supply oil to the compressor 1.

The oil guiding pipe 4 opens the oil guiding hole 3 in the compressor 1 and in the oil separator 5 according to the lowest working oil line 20, and the communication between the oil guiding pipe 4 and the oil guiding hole 3 makes the compressor 1 when the system is static. The oil level of the oil separator 5 is balanced on the system stabilizing oil line 19. This ensures the reliability of the oil supply to each compressor 1 of the system, that is, there is no shortage of oil when any compressor is started, it tends to be rich when it is running, and it is constantly oiled when it is stopped.

On the other hand, in the first embodiment shown in Fig. 1, the one-end infusion tube of the accumulator 25 in the system is connected to the collection point of each of the indoor electronic expansion valves 26, and the other end of the accumulator 25 is passed through the infusion tube. After being connected to the outdoor electronic expansion valve 24, the outdoor heat exchanger 22 is connected, and the gas pipe at the top end of the accumulator 25 is connected to the electromagnetic valve 23, and then connected to the outdoor heat exchanger 22 in parallel with the outdoor electronic expansion. Thus, the reservoir 25 and the electronic expansion valves 24, 26 at both ends thereof The upper solenoid valves 23 together form a pre-evaporation defroster.

When the system needs defrosting in the heating cycle, the indoor electronic expansion valve 26 at the rear end of the plurality of indoor heat exchangers 27 is turned on, and each of the inverter compressors 1 operates at a high frequency to provide more high-temperature and high-pressure gas to maintain the indoors. The heat supply function of the heat exchanger 27 is such that the gas pipe at the top end of the accumulator 25 is opened to the solenoid valve 23, and the liquid refrigerant in the accumulator 25 is pre-evaporated into a medium-temperature medium-pressure gas and enters the outdoor heat exchanger 22 for defrosting. After the defrosting is completed, the gas pipe and the electromagnetic valve 23 at the top of the accumulator 25 are closed, and if the indoor electronic expansion at the rear end of the thousand indoor heat exchanger 27 is restored to 26 degrees, the synchronization in the system heating cycle is realized. Defrost.

Claims

Claim

1. A multi-connected heat pump system, comprising a plurality of variable frequency or fixed frequency high pressure cavity compressors, a parallel oil supply device of the compressor, and a pre-evaporation defrost device, wherein: the parallel oil supply device is provided with only one oil separator. The oil separator is connected in parallel with the high pressure oil pool of the corresponding compressor through a plurality of double-guide oil pipes at the bottom, the oil separator is placed at the same level as each compressor, and the lowest working oil level line and the system stable oil are determined from the bottom upward. Bit line and pre-filled oil level line.

2. The multi-connected heat pump system according to claim 1, wherein: the oil guiding pipe of the parallel oil feeding device is flush with the lowest working oil level line in the opening position of the oil separator, and can also work at a minimum. After the oil level line is flushed, the oil guiding hole is opened, and then the system is stabilized to the system and the wall is bent and opened. The opening position of the oil guiding tube in the compressor oil pool can be flush with the lowest working oil level line. The oil guide hole can be opened flush with the lowest working oil level line and then extended to the bottom of the oil pool and opened.

3. The multi-unit heat pump system according to claim 1, wherein: the oil separator of the parallel oil supply device has a return pipe at the bottom, and the opening position of the oil return pipe in the oil separator can be lower than the minimum working oil level. The line may also be opened between the rising to the lowest working oil level line and the system stable oil level line after the oil return hole is set below the minimum working oil level line, and the return oil pipe is connected to the inlet of the oil collecting pipe through the pressure limiter, The ends of the oil pipes that are divergent from the oil pipeline can be connected to the suction pipe near the suction port of each compressor, or can be tightly fitted into the air intake pipe and bent in the direction of the airflow to form a parallel segment rear opening, or in a parallel segment. An oil hole is provided in the middle portion to supply oil to the respective compressors.

4. The multi-connected heat pump system according to claim 1, wherein: the pre-evaporation defrost device is composed of a liquid reservoir and an electronic expansion valve at both ends thereof and an electromagnetic valve at an upper end thereof, and an infusion tube at one end of the reservoir It is connected with the collection points of the electronic expansion valves at the rear end of the plurality of indoor heat exchangers, and the other end of the liquid storage tube is connected to an electronic expansion valve and then connected to the outdoor heat exchanger, and the gas supply pipe at the top of the liquid storage device is connected to the electromagnetic tube. After connecting, it is connected to the outdoor heat exchanger in parallel with the aforementioned one electronic expansion valve.

5. The multi-connected heat pump system according to claim 4, wherein: the pre-evaporation defroster device can open the electronic expansion valves at the rear end of the plurality of indoor heat exchangers when defrosting is required under system heating conditions. Large adjustment, will store liquid The gas pipe at the top of the device is opened with a solenoid valve, so that the liquid in the liquid reservoir is pre-evaporated into a medium-temperature medium-pressure gas and enters the outdoor heat exchanger for defrosting. After the defrosting is completed, the gas pipe and the solenoid valve at the top of the liquid reservoir can be Shutdown, restore the electronic expansion valve opening and the frequency of each inverter compressor at the rear end of several indoor heat exchangers.