An air conditioning unit with a low dew point that can operate continuously

Abstract

The present invention discloses an air-conditioning unit capable of continuous operation with a low dew point. The double-evaporator parallel mode is adopted to achieve continuous operation under low dew point conditions. When one of the evaporators needs to be defrosted, the unit enters the defrosting mode. The refrigerant vapor uses reverse flow compared with the refrigeration mode for defrosting liquid collection, and then uses the same-direction flow of the refrigeration mode for defrosting. Cooperating with the opening and closing of the air valve, continuous refrigeration can be achieved while the unit is defrosting. Compared with the traditional defrosting method, the present invention can achieve rapid heating of the upper and lower parts of the evaporator together. The frost layer can be quickly and synchronously melted and separated from the evaporator wall surface, and the whole realizes block-like falling, greatly improving the defrosting efficiency and reducing the heat consumption and duration of defrosting. At the same time, through the parallel connection of the double evaporators, single-evaporator defrosting and single-evaporator refrigeration are realized, ensuring continuous operation under low dew point conditions.

Description

Technical Field

[0001] The present invention belongs to the fields of refrigeration, air conditioning and heat pumps, and particularly relates to an air conditioning unit with a low dew point and capable of continuous operation. Background Art

[0002] Under the low dew point refrigeration and dehumidification condition, the evaporator of the refrigeration and air conditioning unit will have a frosting phenomenon, and relevant defrosting methods need to be adopted for treatment. At present, the common defrosting methods in this design are heat pump defrosting or hot gas bypass, and these methods will all result in phenomena such as unstable air supply temperature of the unit and unstable system operation.

[0003] In addition, in the current heat pump defrosting methods, the reverse flow mode of refrigerant vapor is adopted, that is, the flow direction of refrigerant vapor is opposite to that during refrigeration during the defrosting process. Generally, the refrigerant vapor enters from the upper part of the evaporator and flows out from the lower part, while the frost layer on the evaporator is generally thinner at the upper part and thicker at the lower part. Therefore, the frost layers on the upper and lower parts of the evaporator do not melt synchronously. The thin frost layer at the upper part quickly melts into water and accumulates on the lower frost layer without falling off, increasing the heat demand and time for unit defrosting and reducing the operating efficiency of the unit. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide an air conditioning unit with a low dew point and capable of continuous operation, and its advantages are that compared with the traditional defrosting method, it can realize rapid heating of the upper and lower parts of the evaporator together, the frost layer can quickly melt synchronously and detach from the evaporator wall surface, and the whole realizes block-like falling, greatly improving the defrosting efficiency and reducing the heat consumption and duration of defrosting; at the same time, through the parallel connection of two evaporators, single evaporator defrosting and single evaporator refrigeration are realized to ensure continuous operation under low dew point conditions.

[0005] Technical Solution: The present invention includes a compressor, the outlet of the compressor is connected to a four-way reversing valve, the C port of the four-way reversing valve is connected to a first evaporator module, the E port of the four-way reversing valve is connected to a second evaporator module, and the first evaporator module and the second evaporator module realize the two-way flow of refrigerant through a plurality of control valves; the S port of the four-way reversing valve is connected to the compressor inlet through a gas-liquid separator; an air-cooled condenser is connected between the first evaporator module and the second evaporator module.

[0006] The C port of the four-way reversing valve is divided into three parallel branches, which are respectively connected with a first solenoid valve, a second solenoid valve and a third solenoid valve; the first solenoid valve is respectively connected to a fifth solenoid valve and a first evaporator. Among them, the fifth solenoid valve is connected to the outlet of the accumulator through a first expansion valve and a seventh solenoid valve, and the inlet of the accumulator is connected to the outlet of the air-cooled condenser; the fifth solenoid valve is also connected to a fourth solenoid valve; the second solenoid valve is respectively connected to the fourth solenoid valve and the first evaporator.

[0007] The first evaporator is configured with a first variable frequency centrifugal fan.

[0008] The E port of the four-way reversing valve is divided into three branches connected in parallel, and is respectively connected with a twelfth solenoid valve, a thirteenth solenoid valve and a fourteenth solenoid valve; the twelfth solenoid valve is respectively connected with a tenth solenoid valve and a second evaporator, wherein the tenth solenoid valve is connected with the outlet of the liquid receiver through a second expansion valve and an eighth solenoid valve; the tenth solenoid valve is also connected with an eleventh solenoid valve; the thirteenth solenoid valve is respectively connected with the eleventh solenoid valve and the second evaporator.

[0009] The second evaporator is equipped with a second variable-frequency centrifugal fan.

[0010] A high-pressure gauge, a needle valve and a high-pressure controller are sequentially connected between the outlet of the compressor and the four-way reversing valve.

[0011] The outlet of the air-cooled condenser is connected to the inlet of the liquid receiver, and the outlet of the liquid receiver is sequentially connected with a ball valve, a drying filter and a sight glass.

[0012] The air-conditioning unit adopts heat-insulating wall panels to form an overall framework.

[0013] The compressor adopts a variable-frequency or variable-capacity compressor.

[0014] Beneficial effects: Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By adopting a design of parallel arrangement of double evaporators, cooperating with the opening and closing of the air valves of the unit, and using a new defrosting method different from the conventional heat pump defrosting, that is, after the reverse defrosting liquid collection process, the forward defrosting is carried out, which can more reasonably match the heat quality of the refrigerant vapor and the heat requirement for frost layer melting; (2) It can realize the rapid melting of the frost layer on the surface of the evaporator as a whole and the detachment from the evaporator wall surface, greatly improving the defrosting efficiency and reducing the heat consumption and duration of defrosting. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the schematic diagram of the present invention;

[0016] Figure 2 is the schematic diagram of the simple functional section layout and air duct switching of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be further described in detail below in conjunction with the specific embodiments and the drawings of the specification.

[0018] As Figure 1 shown, the present invention includes a compressor 1, the inlet of the compressor 1 is connected with a low-pressure gauge 3, and after the outlet of the compressor 1 is sequentially connected with a high-pressure gauge 4, a needle valve 5 and a high-pressure controller 6, it is then connected with a four-way reversing valve 7; in addition, a high-low pressure controller 2 is also arranged at the outlet of the compressor 1. In this embodiment, the compressor 1 is a variable-frequency or variable-capacity compressor, and the total load can be adjusted during the operation of the unit.

[0019] The C port of the four-way reversing valve 7 is divided into three branches connected in parallel, which are respectively connected to the port 1 of the first solenoid valve 8, the port 1 of the second solenoid valve 9, and the port 1 of the third solenoid valve 10. The port 2 of the first solenoid valve 8 is divided into two parallel paths, which are respectively connected to the port 1 of the first evaporator 13 and the port 1 of the fifth solenoid valve 14. The port 2 of the second solenoid valve 9 is divided into two parallel paths, which are respectively connected to the port 1 of the fourth solenoid valve 11 and the port 2 of the first evaporator 13. The port 2 of the fifth solenoid valve 14 is divided into two parallel paths, one path is connected to the port 1 of the sixth solenoid valve 15, and the other path is connected to the port 2 of the fourth solenoid valve 11. The port 2 of the fourth solenoid valve 11 is connected to the port 1 of the first check valve 17. The port 2 of the first check valve 17 is connected to the port 2 of the third solenoid valve 10, the port 2 of the sixth solenoid valve 15 is connected to the port 1 of the first expansion valve 16, and the port 2 of the first expansion valve 16 is connected to the port 1 of the seventh solenoid valve 23.

[0020] The E port of the four-way reversing valve 7 is divided into three branches connected in parallel, which are respectively connected to the port 1 of the twelfth solenoid valve 30, the port 1 of the thirteenth solenoid valve 31, and the port 1 of the fourteenth solenoid valve 32. The port 2 of the twelfth solenoid valve 30 is divided into two parallel paths, which are respectively connected to the port 1 of the second evaporator 28 and the port 1 of the tenth solenoid valve 27. The port 2 of the thirteenth solenoid valve 31 is divided into two parallel paths, which are respectively connected to the port 1 of the eleventh solenoid valve 29 and the port 2 of the second evaporator 28. The port 2 of the tenth solenoid valve 27 is divided into two parallel paths, one path is connected to the port 1 of the ninth solenoid valve 26, and the other path is connected to the port 2 of the eleventh solenoid valve 29. The port 2 of the eleventh solenoid valve 29 is connected to the port 1 of the second check valve 33. The port 2 of the second check valve 33 is connected to the port 2 of the fourteenth solenoid valve 32, the port 2 of the ninth solenoid valve 26 is connected to the port 1 of the second expansion valve 25, and the port 2 of the second expansion valve 25 is connected to the port 1 of the eighth solenoid valve 24. The S port of the four-way reversing valve 7 is connected to the inlet of the compressor 1 through the gas-liquid separator 34.

[0021] The port 2 of the seventh solenoid valve 23 is connected to the port 2 of the eighth solenoid valve 24, and is also connected to the port 2 of the sight glass 22. The port 1 of the sight glass 22 is connected to the port 2 of the dryer filter 21. The port 1 of the dryer filter 21 is connected to the port 2 of the ball valve 20. The port 1 of the ball valve 20 is connected to the outlet of the liquid receiver 19. The inlet of the liquid receiver 19 is connected to the outlet of the air-cooled condenser 18. The inlets of the air-cooled condenser 18 are respectively connected to the first check valve 17, the third solenoid valve 10, the fourteenth solenoid valve 32, and the second check valve 33. The fan configured on the air-cooled condenser 18 is adjustable to realize the adjustment of the condensation load.

[0022] The first evaporator 13 is equipped with a first variable-frequency centrifugal fan 12, and the second evaporator 28 is equipped with a second variable-frequency centrifugal fan 35. In the specific product design, the first variable-frequency centrifugal fan 12 and the second variable-frequency centrifugal fan 35 can share one.

[0023] In the refrigeration mode, one of the evaporators is in the deactivated state. The refrigerant enters the air-cooled condenser 18 from the compressor 1, then enters the other evaporator, and finally returns to the compressor 1 to complete the refrigeration cycle. As the frost layer on the evaporator increases during refrigeration operation, the system automatically enters the defrost mode according to the monitoring of relevant parameters. The specific refrigeration process is as follows:

[0024] In refrigeration mode one, port D of the four-way reversing valve 7 is connected to port C, the first solenoid valve 8 and the second solenoid valve 9 are in the closed state, the third solenoid valve 10 is open, and the refrigerant vapor enters the air-cooled condenser 18 through the third solenoid valve 10. After condensing into liquid refrigerant, it successively passes through the liquid receiver 19, the ball valve 20, the dryer filter 21, and the sight glass 22. The seventh solenoid valve 23 is in the closed state. The refrigerant liquid enters the second evaporator 28 through the eighth solenoid valve 24, the second expansion valve 25, the ninth solenoid valve 26, and the eleventh solenoid valve 29. In this mode, the fourteenth solenoid valve 32, the tenth solenoid valve 27, and the thirteenth solenoid valve 31 are all in the closed state.

[0025] As the frost layer on the second evaporator 28 increases, the system switches to defrost mode one. The D port of the four-way reversing valve 7 is switched to connect with the E port. The thirteenth solenoid valve 31, the fourteenth solenoid valve 32, the ninth solenoid valve 26, and the tenth solenoid valve 27 are closed. The refrigerant vapor enters the second evaporator 28 reversely through the twelfth solenoid valve 30, pushing the accumulated low-temperature refrigerant liquid therein to enter the air-cooled condenser 18 through the eleventh solenoid valve 29 and the second check valve 33. This process can be called reverse defrost liquid collection. Through this operation, almost all the low-temperature refrigerant liquid in the evaporator to be defrosted can be discharged, ensuring that the heat of the refrigerant vapor during the formal defrosting process will not be absorbed by the low-temperature refrigerant liquid and affecting the defrosting speed. After running for about 10 seconds, the eleventh solenoid valve 29 and the twelfth solenoid valve 30 are closed, the thirteenth solenoid valve 31 and the tenth solenoid valve 27 are opened. The refrigerant vapor enters from the lower part of the second evaporator 28 with a thicker frost layer. The high-temperature refrigerant is used to melt the thicker part of the frost layer. As the refrigerant vapor flows from the thicker end of the frost layer to the thinner end, its temperature continuously decreases, but it can still meet the defrosting requirements. The cooled refrigerant vapor is used for the thinner part of the frost layer, realizing synchronous and rapid defrosting of the entire evaporator. The refrigerant enters the liquid receiver 19 through the air-cooled condenser 18, and then comes to the first expansion valve 16 through the ball valve 20, the dryer filter 21, the sight glass 22, and the seventh solenoid valve 23. The refrigerant liquid passes through the first expansion valve 16 for throttling and pressure reduction, and then enters the first evaporator 13 through the sixth solenoid valve 15 and the fourth solenoid valve 11 in sequence. After absorbing heat, the first evaporator 13 enters the C port of the four-way reversing valve 7 through the first solenoid valve 8, and then enters the compressor 1 through the S port and the gas-liquid separator 34 in sequence. In this mode, the second solenoid valve 9, the third solenoid valve 10, and the fifth solenoid valve 14 are all in the closed state. In defrost mode one, the refrigerant first enters the frosted second evaporator 28, then enters the air-cooled condenser 18, and finally enters the evaporator 13 that is deactivated in refrigeration mode one. At the same time, the air valve adjustment of the unit is carried out synchronously, realizing the air flow from the flow channel of the frosted second evaporator 28 to the flow channel of the deactivated evaporator 13, so as to realize the continuous operation of the unit.

[0026] After defrosting is completed, the refrigerant vapor directly enters the air-cooled condenser 18 by adjusting the parallel solenoid valves of the frosted second evaporator 28. The second evaporator 28 after defrosting enters the deactivated state, and the unit enters refrigeration mode two. The simultaneous operation of defrosting and refrigeration is realized through the alternating switching of the evaporators.

[0027] In the second refrigeration mode, the D port of the four-way reversing valve 7 is still connected to the E port. The twelfth solenoid valve 30 and the thirteenth solenoid valve 31 are in the closed state, and the fourteenth solenoid valve 32 is open. The refrigerant vapor enters the air-cooled condenser 18 through the fourteenth solenoid valve 32, condenses into liquid refrigerant and sequentially passes through the liquid receiver 19, the ball valve 20, the drier filter 21 and the sight glass 22. The eighth solenoid valve 24 is in the closed state. The refrigerant liquid enters the first evaporator 13 through the seventh solenoid valve 23, the first expansion valve 16, the sixth solenoid valve 15 and the fourth solenoid valve 11. In this mode, the second solenoid valve 9, the third solenoid valve 10 and the fifth solenoid valve 14 are all in the closed state.

[0028] As the frost layer on the first evaporator 13 increases, the system switches to the second defrost mode. The D port of the four-way reversing valve 7 switches to be connected to the C port. The second solenoid valve 9, the third solenoid valve 10, the fifth solenoid valve 14 and the sixth solenoid valve 15 are closed. The refrigerant vapor enters the first evaporator 13 reversely through the first solenoid valve 8, pushing the accumulated low-temperature refrigerant liquid therein to enter the air-cooled condenser 18 through the fourth solenoid valve 11 and the first check valve 17. This process can be called reverse defrost liquid collection. After running for about 10 seconds, the first solenoid valve 8 and the fourth solenoid valve 11 are closed, and the second solenoid valve 9 and the fifth solenoid valve 14 are opened. The refrigerant vapor enters from the lower part of the first evaporator 13 with a thicker frost layer. The high-temperature refrigerant is used to melt the thicker part of the frost layer, and the cooled refrigerant vapor is used for the thinner part of the frost layer, realizing synchronous and rapid defrosting of the whole evaporator. The refrigerant enters the liquid receiver 19 through the air-cooled condenser 18, and then comes to the second expansion valve 25 through the ball valve 20, the drier filter 21, the sight glass 22 and the eighth solenoid valve 24. The refrigerant liquid passes through the second expansion valve 25 for throttling and pressure reduction and then sequentially passes through the ninth solenoid valve 26 and the eleventh solenoid valve 29 to enter the second evaporator 28. After absorbing heat, the second evaporator 28 enters the E port of the four-way reversing valve 7 through the twelfth solenoid valve 30, and then sequentially passes through the S port and the gas-liquid separator 34 to enter the compressor 1. In this mode, the thirteenth solenoid valve 31, the fourteenth solenoid valve 32 and the tenth solenoid valve 27 are all in the closed state.

[0029] After defrosting is completed, the unit enters the first refrigeration mode again, thus realizing the switching of the parallel circulation of the double evaporators and ensuring that the unit can operate continuously under low dew point conditions.

[0030] As Figure 2 shown, the first evaporation section 40 corresponds to Figure 1 the first evaporator 13, the second evaporation section 43 corresponds to the second evaporator 28, and the centrifugal blower 45 corresponds to Figure 1The first variable-frequency centrifugal fan 12 and the second variable-frequency centrifugal fan 35. The air-conditioning unit uses the heat-insulating wall panels 36 to form the overall framework. In the first refrigeration mode, air enters from the air inlet 37 and passes through the air filtration section 38, the second evaporation section 43, the air supply fan section 45 and the air outlet 46 in sequence. In this mode, the first air valve 39 and the second air valve 41 are in the closed state, and the third air valve 42 and the fourth air valve 44 are open; when the unit working mode is switched to the first defrosting mode, the first air valve 39 and the second air valve 41 are open, the third air valve 42 and the fourth air valve 44 are closed, and the air passes through the first evaporation section 40; when the unit working mode is switched to the second refrigeration mode, the opening and closing states of the air valves remain unchanged; when the unit working mode is switched to the second defrosting mode, the first air valve 39 and the second air valve 41 are closed, and the third air valve 42 and the fourth air valve 44 are open; during the entire working cycle of the unit, the conversion of the air flow path is realized through the first air valve 39, the second air valve 41, the third air valve 42 and the fourth air valve 44.

Claims

1. An air conditioner unit capable of continuous operation with a low dew point, characterized in that: it includes a compressor (1), the outlet of the compressor (1) is connected to a four-way reversing valve (7), the C port of the four-way reversing valve (7) is connected to a first evaporator module, the E port of the four-way reversing valve (7) is connected to a second evaporator module, and the first evaporator module and the second evaporator module realize two-way refrigerant flow through a plurality of control valves; the S port of the four-way reversing valve (7) is connected to the inlet of the compressor (1) through a gas-liquid separator (34); an air-cooled condenser (18) is connected between the first evaporator module and the second evaporator module; the C port of the four-way reversing valve (7) is divided into three parallel branches, which are respectively connected to port 1 of a first solenoid valve (8), port 1 of a second solenoid valve (9), and port 1 of a third solenoid valve (10); port 2 of the first solenoid valve (8) is divided into two parallel paths, which are respectively connected to port 1 of a first evaporator (13) and port 1 of a fifth solenoid valve (14); port 2 of the second solenoid valve (9) is divided into two parallel paths, which are respectively connected to port 1 of a fourth solenoid valve (11) and port 2 of the first evaporator (13); port 2 of the fifth solenoid valve (14) is divided into two parallel paths, one path is connected to port 1 of a sixth solenoid valve (15), and the other path is connected to port 2 of the fourth solenoid valve (11); port 2 of the fourth solenoid valve (11) is connected to port 1 of a first check valve (17); port 2 of the first check valve (17) is connected to port 2 of the third solenoid valve (10), port 2 of the sixth solenoid valve (15) is connected to port 1 of a first expansion valve (16), and port 2 of the first expansion valve (16) is connected to port 1 of a seventh solenoid valve (23); port 2 of the seventh solenoid valve (23) is connected to port 2 of a sight glass (22), port 1 of the sight glass (22) is connected to port 2 of a dryer filter (21), port 1 of the dryer filter (21) is connected to port 2 of a ball valve (20), port 1 of the ball valve (20) is connected to the outlet of a liquid receiver (19), the inlet of the liquid receiver (19) is connected to the outlet of the air-cooled condenser (18), and the inlet of the air-cooled condenser (18) is respectively connected to the first check valve (17) and the third solenoid valve (10).

2. The air conditioner unit capable of continuous operation with a low dew point according to claim 1, characterized in that: the first evaporator (13) is configured with a first variable-frequency centrifugal fan (12).

3. The air conditioner unit capable of continuous operation with a low dew point according to claim 1, characterized in that: The E port of the four-way reversing valve (7) is divided into three branches connected in parallel, which are respectively connected to port 1 of the twelfth solenoid valve (30), port 1 of the thirteenth solenoid valve (31), and port 1 of the fourteenth solenoid valve (32); port 2 of the twelfth solenoid valve (30) is divided into two parallel paths, which are respectively connected to port 1 of the second evaporator (28) and port 1 of the tenth solenoid valve (27); port 2 of the thirteenth solenoid valve (31) is divided into two parallel paths, which are respectively connected to port 1 of the eleventh solenoid valve (29) and port 2 of the second evaporator (28); port 2 of the tenth solenoid valve (27) is divided into two parallel paths, one path is connected to port 1 of the ninth solenoid valve (26), and the other path is connected to port 2 of the eleventh solenoid valve (29); port 2 of the eleventh solenoid valve (29) is connected to port 1 of the second check valve (33); port 2 of the second check valve (33) is connected to port 2 of the fourteenth solenoid valve (32), port 2 of the ninth solenoid valve (26) is connected to port 1 of the second expansion valve (25), and port 2 of the second expansion valve (25) is connected to port 1 of the eighth solenoid valve (24); the S port of the four-way reversing valve (7) is connected to the inlet of the compressor (1) through a gas-liquid separator (34).

4. The low dew point continuously operable air conditioning unit according to claim 3, characterized in that: The second evaporator (28) is equipped with a second variable frequency centrifugal fan (35).

5. The low dew point continuously operable air conditioning unit according to claim 1, characterized in that: A high pressure gauge (4), a needle valve (5), and a high pressure controller (6) are sequentially connected between the outlet of the compressor (1) and the four-way reversing valve (7).

6. The low dew point continuously operable air conditioning unit according to claim 1, characterized in that: The outlet of the air-cooled condenser (18) is connected to the inlet of the liquid receiver (19), and the outlet of the liquid receiver (19) is sequentially connected to a ball valve (20), a dryer filter (21), and a sight glass (22).

7. The low dew point continuously operable air conditioning unit according to any one of claims 1 to 6, characterized in that: The compressor (1) is a variable frequency or variable capacity compressor.

8. The low dew point continuously operable air conditioning unit according to any one of claims 1 to 6, characterized in that: The air conditioning unit is composed of heat-insulating wall panels (36) to form an overall framework.

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