Fresh air air-conditioning system and control method

Abstract

The present invention discloses a fresh air air-conditioning system and a control method. The fresh air air-conditioning system includes a compressor, a four-way reversing valve, a fresh air treatment heat exchanger, and an air source heat exchanger. The fresh air treatment heat exchanger includes a first heat exchanger, a second heat exchanger, and a third heat exchanger. The fresh air air-conditioning system has a refrigeration mode and a heating mode. When the fresh air air-conditioning system is in the refrigeration mode, the first heat exchanger is configured as an evaporator, the second heat exchanger is configured as a cold quantity recovery device, the third heat exchanger is configured as a condenser, and the air source heat exchanger is configured as a condenser. When the fresh air air-conditioning system is in the heating mode, the first heat exchanger is configured as a condenser, the third heat exchanger is configured as a condenser, and the air source heat exchanger is configured as an evaporator. The present invention can increase the air temperature, ensure comfort, and recover the cold quantity by using the second heat exchanger, which is beneficial to increasing the dehumidification capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly relates to a fresh air air conditioner system and a control method thereof. Background Art

[0002] Existing fresh air handling units include a fresh air handling heat exchanger, an air source side heat exchanger, a compressor, and a four-way reversing valve. The four-way reversing valve is used for mode switching. In spring and summer, the unit is in the cooling mode. The fresh air handling heat exchanger serves as an evaporator, reducing the temperature of fresh air to below the dew point. Moisture condenses on the heat exchanger fins to form dehumidification. However, the supply air temperature is relatively low, which is not conducive to human comfort and may cause local condensation. Especially in spring, the temperature of the dehumidified air is even lower, resulting in a decrease in room temperature and the need to additionally increase a heat source.

[0003] Currently, in order to improve comfort, a reheater is provided downstream of the fresh air handling heat exchanger in a single-cooling fresh air handling unit, but this is not the case in a heat pump system because the installation of a reheater will lead to complex pipelines and difficult control. Summary of the Invention

[0004] The purpose of the present invention is to provide a fresh air air conditioner system with a reheating function and a control method thereof.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A fresh air air conditioner system, the fresh air air conditioner system includes a compressor, a four-way reversing valve, a fresh air handling heat exchanger, and an air source heat exchanger. The fresh air handling heat exchanger includes a first heat exchanger, a second heat exchanger, and a third heat exchanger. The fresh air air conditioner system has a cooling mode and a heating mode:

[0007] When the fresh air air conditioner system is in the cooling mode, the first heat exchanger is configured to serve as an evaporator, the second heat exchanger is configured to serve as a cold recovery device, the third heat exchanger is configured to serve as a condenser, and the air source heat exchanger is configured to serve as a condenser;

[0008] When the fresh air air conditioner system is in the heating mode, the first heat exchanger is configured to serve as a condenser, the third heat exchanger is configured to serve as a condenser, and the air source heat exchanger is configured to serve as an evaporator.

[0009] Further, the four-way reversing valve has ports A, B, C, and D; the suction port of the compressor is connected to port A of the four-way reversing valve, the discharge port of the compressor is connected to port B of the four-way reversing valve, ports C of the four-way reversing valve, the first heat exchanger, the second heat exchanger, the air source heat exchanger, and port D of the four-way reversing valve are connected in sequence, the discharge port of the compressor, the third heat exchanger, and the first heat exchanger are connected in sequence, and the third heat exchanger is also connected to the air source heat exchanger.

[0010] Further, the fresh air air-conditioning system further includes a first expansion valve and a first check valve. Among them, the first expansion valve is connected between the first heat exchanger and the second heat exchanger, and one end of the first expansion valve connected to the second heat exchanger is also connected to one end of the first check valve. The other end of the first check valve is connected to the air source heat exchanger, and the direction of the first check valve points to the air source heat exchanger.

[0011] Further, the fresh air air-conditioning system further includes a second expansion valve, a second check valve, and a third check valve. Among them, the third heat exchanger, the second expansion valve, and the first heat exchanger are connected in sequence, and the direction of the second check valve points to the third heat exchanger; the third heat exchanger, the second expansion valve, the third check valve, and the air source heat exchanger are connected in sequence, and the direction of the third check valve points to the air source heat exchanger.

[0012] Further, when the fresh air air-conditioning system is in the cooling mode, ports B and D of the four-way reversing valve are connected, and ports A and C of the four-way reversing valve are connected;

[0013] The fresh air air-conditioning system has a first flow circuit: the refrigerant flows along the discharge port of the compressor, port B of the four-way reversing valve, port D of the four-way reversing valve, the air source heat exchanger, the second heat exchanger, the first expansion valve, the first heat exchanger, port C of the four-way reversing valve, port A of the four-way reversing valve, and the suction port of the compressor.

[0014] Further, when the fresh air air-conditioning system is in the cooling mode, the fresh air air-conditioning system also has a second flow circuit: the refrigerant flows along the discharge port of the compressor, the third heat exchanger, the second expansion valve, the first heat exchanger, port C of the four-way reversing valve, port A of the four-way reversing valve, and the suction port of the compressor.

[0015] Further, when the fresh air air-conditioning system is in the heating mode, ports B and C of the four-way reversing valve are connected, and ports A and D of the four-way reversing valve are connected;

[0016] The fresh air air - conditioning system has a third flow circuit: the refrigerant flows along the exhaust port of the compressor, port B of the four - way reversing valve, port C of the four - way reversing valve, the first heat exchanger, the second expansion valve, the air - source heat exchanger, port D of the four - way reversing valve, port A of the four - way reversing valve, and the suction port of the compressor.

[0017] Further, when the fresh air air - conditioning system is in the heating mode, the fresh air air - conditioning system also has a fourth flow circuit: the refrigerant flows along the exhaust port of the compressor, the third heat exchanger, the second expansion valve, the air - source heat exchanger, port D of the four - way reversing valve, port A of the four - way reversing valve, and the suction port of the compressor.

[0018] Further, the fresh air air - conditioning system further includes a fan, a filter screen, a humidifier, and a supply fan;

[0019] The unit of the fresh air air - conditioning system has an up - and - down structure. The compressor, the four - way reversing valve, the air - source heat exchanger, and the fan are arranged at the lower part of the unit, and the first heat exchanger, the second heat exchanger, the third heat exchanger, the filter screen, the humidifier, and the supply fan are arranged at the upper part of the unit.

[0020] A control method for a fresh air air - conditioning system, the control method includes: adjusting the first expansion valve according to the suction superheat of the compressor, and adjusting the second expansion valve according to the outlet air temperature of the compressor.

[0021] Further, the control method further includes: adjusting the rotational speed of the fresh air fan according to the indoor fresh air demand, and adjusting the rotational speed of the compressor according to the outlet air temperature of the compressor.

[0022] The advantages of the present invention are: it can increase the air temperature, ensure comfort, and recover the cooling capacity by using the second heat exchanger, which is beneficial to increasing the dehumidification amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is the first schematic diagram of the fresh air air - conditioning system provided by an exemplary embodiment of the embodiment of the present invention;

[0025] Figure 2It is a schematic diagram of the fresh air air-conditioning system provided by an exemplary embodiment of the present invention in the cooling mode;

[0026] Figure 3 It is a schematic diagram of the fresh air air-conditioning system provided by an exemplary embodiment of the present invention in the heating mode;

[0027] Figure 4 It is a second schematic diagram of the fresh air air-conditioning system provided by an exemplary embodiment of the present invention.

[0028] Among them, the reference numerals include: 1 - compressor, 2 - four-way reversing valve, 3 - first heat exchanger, 4 - second heat exchanger, 5 - third heat exchanger, 6 - air source heat exchanger, 7 - second expansion valve, 8 - first expansion valve, 9 - first check valve, 10 - second check valve, 11 - third check valve, 12 - fan, 13 - filter screen, 14 - evaporator, 15 - subcooler, 16 - reheater, 17 - third expansion valve, 18 - fourth check valve, 19 - fifth check valve, 20 - humidifier, 21 - fourth expansion valve. Detailed implementation manners

[0029] In order to enable those skilled in the art to better understand the solution of the present invention, and to more clearly understand the purpose, technical solution and its advantages of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that the implementation manners not depicted or described in the drawings are forms known to those of ordinary skill in the art. Additionally, although this document may provide examples containing parameters with specific values, it should be understood that the parameters need not exactly equal the corresponding values, but may approximate the corresponding values within an acceptable tolerance or design constraint. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. In addition, the terms "including" and "having" and any variations thereof in the description and claims of the present invention are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0030] In an embodiment of the present invention, a fresh air air-conditioning system is provided, such as Figure 1 , 4As shown, this fresh air air-conditioning system includes a compressor 1, a four-way reversing valve 2, a fresh air treatment heat exchanger, an air source heat exchanger 6, a first expansion valve 8, a first check valve 9, a second expansion valve 7, a second check valve 10, a third check valve 11, a fan 12, a filter screen 13, a humidifier 20 and a supply fan. Among them, the fresh air treatment heat exchanger includes a first heat exchanger 3, a second heat exchanger 4 and a third heat exchanger 5. The first expansion valve 8 is adjusted according to the suction superheat of the compressor 1, the second expansion valve 7 is adjusted according to the outlet air temperature, the rotation speed of the fresh air fan 12 is adjusted according to the indoor fresh air demand, and the rotation speed of the compressor 1 is adjusted according to the outlet air temperature.

[0031] The four-way reversing valve 2 has ports A, B, C and D. As Figure 1 shown, the suction port of the compressor 1 is connected to port A of the four-way reversing valve 2, the discharge port of the compressor 1 is connected to port B of the four-way reversing valve 2, ports C, D of the four-way reversing valve 2, the first heat exchanger 3, the second heat exchanger 4, the air source heat exchanger 6, and port D of the four-way reversing valve 2 are connected in sequence. The discharge port of the compressor 1, the third heat exchanger 5, and the first heat exchanger 3 are connected in sequence. The third heat exchanger 5 is also connected to the air source heat exchanger 6; the first expansion valve 8 is connected between the first heat exchanger 3 and the second heat exchanger 4, and one end of the first expansion valve 8 connected to the second heat exchanger 4 is also connected to one end of the first check valve 9. The other end of the first check valve 9 is connected to the air source heat exchanger 6, and the direction of the first check valve 9 points to the air source heat exchanger 6; the third heat exchanger 5, the second expansion valve 7, and the first heat exchanger 3 are connected in sequence, and the direction of the second check valve 10 points to the third heat exchanger 5; the third heat exchanger 5, the second expansion valve 7, the third check valve 11, and the air source heat exchanger 6 are connected in sequence, and the direction of the third check valve 11 points to the air source heat exchanger 6.

[0032] This fresh air air-conditioning system has a cooling mode. When the fresh air air-conditioning system is in the cooling mode, the first heat exchanger 3 is configured as an evaporator, the second heat exchanger 4 is configured as a cold recovery device, the third heat exchanger 5 is configured as a condenser, and the air source heat exchanger 6 is configured as a condenser.

[0033] Specifically, when the fresh air air-conditioning system is in the cooling mode, as Figure 2As shown, port B and port D of the four-way reversing valve 2 are connected, and port A and port C of the four-way reversing valve 2 are connected. At this time, the fresh air air-conditioning system has a first flow circuit: the refrigerant (air) flows along the exhaust port of the compressor 1, port B of the four-way reversing valve 2, port D of the four-way reversing valve 2, the air source heat exchanger 6, the second heat exchanger 4, the first expansion valve 8, the first heat exchanger 3, port C of the four-way reversing valve 2, port A of the four-way reversing valve 2, and the suction port of the compressor 1. At the same time, the fresh air air-conditioning system also has a second flow circuit: the refrigerant (air) flows along the exhaust port of the compressor 1, the third heat exchanger 5, the second expansion valve 7, the first heat exchanger 3, port C of the four-way reversing valve 2, port A of the four-way reversing valve 2, and the suction port of the compressor 1.

[0034] The fresh air air-conditioning system also has a heating mode. When the fresh air air-conditioning system is in the heating mode, the first heat exchanger 3 is configured to act as a condenser, the second heat exchanger 4 is idle, the third heat exchanger 5 is configured to act as a condenser, and the air source heat exchanger 6 is configured to act as an evaporator.

[0035] Specifically, when the fresh air air-conditioning system is in the heating mode, as Figure 3 shown, port B and port C of the four-way reversing valve 2 are connected, and port A and port D of the four-way reversing valve 2 are connected. At this time, the fresh air air-conditioning system has a third flow circuit: the refrigerant (air) flows along the exhaust port of the compressor 1, port B of the four-way reversing valve 2, port C of the four-way reversing valve 2, the first heat exchanger 3, the second expansion valve 7, the air source heat exchanger 6, port D of the four-way reversing valve 2, port A of the four-way reversing valve 2, and the suction port of the compressor 1. At the same time, the fresh air air-conditioning system also has a fourth flow circuit: the refrigerant (air) flows along the exhaust port of the compressor 1, the third heat exchanger 5, the second expansion valve 7, the air source heat exchanger 6, port D of the four-way reversing valve 2, port A of the four-way reversing valve 2, and the suction port of the compressor 1.

[0036] The unit of the fresh air air-conditioning system has an up-and-down structure. The compressor 1, the four-way reversing valve 2, the air source heat exchanger 6 and the air source fan 12 are arranged at the lower part of the unit. The air source fan 12 blows forward. The first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 5, the filter net 13, the humidifier 20 and the air supply fan are arranged at the upper part of the unit. Along the direction of the fresh air, the air filter, that is, the filter net 13, the first heat exchanger 3, the second heat exchanger 4, the third heat exchanger 5, the humidifier 20 and the air supply fan are arranged in sequence. The unit is a cuboid structure, including width, thickness and height. The air supply fan used is a centrifugal fan, and the air supply outlet of the air supply fan is on the side. The filter net 13, the first heat exchanger 3, the second heat exchanger 4 and the third heat exchanger 5 are parallel to the side. An opening is arranged at the top of the filter net 13 for disassembly and replacement.

[0037] As Figure 4As shown, the compressor 1 utilizes two refrigerant flows. Refrigerant one passes through the four-way reversing valve 2, the outdoor condenser, the subcooler 15, the fourth expansion valve 21, the evaporator 14, the four-way reversing valve 2, and the compressor 1; refrigerant two passes through the reheater 16, the third expansion valve 17, the fourth check valve 18 and the fifth check valve 19, the evaporator 14, the four-way reversing valve 2, and the compressor 1.

[0038] The third heat exchanger 5 of this fresh air air-conditioning system is connected to the exhaust port of the compressor 1 and has always been used as a condenser. When the fresh air needs to be dehumidified, the first heat exchanger 3 is used for cooling and dehumidifying, and the second heat exchanger 4 recovers the cooling capacity of the air after cooling and dehumidifying, which is beneficial to increasing the dehumidification amount. The third heat exchanger 5 further heats the air. By adopting this structure, it can be ensured that the fresh air after dehumidification is dry air, guaranteeing the health of users. In addition, in winter, the third heat exchanger 5 can also be used as a condenser, improving the utilization efficiency of the heat exchanger.

[0039] This fresh air air-conditioning system adopts the above structure. In spring, it adopts the dehumidification mode, opens the second expansion valve 7 to increase the air temperature and ensure comfort; in summer, it adopts the refrigeration and dehumidification mode, closes the second expansion valve 7 to ensure the total refrigeration capacity; in winter, it adopts the heating and temperature-raising mode, and the opening degree of the second expansion valve 7 is 25% of that of the first expansion valve 8. The first expansion valve 8 is controlled by the suction superheat. The second expansion valve 7 has refrigerant flowing through, effectively utilizing the heat exchange area, and at the same time fixing a general opening degree, which is beneficial to the stability of the control system.

[0040] In an embodiment of the present invention, a control method for the fresh air air-conditioning system described above is provided. This control method includes: adjusting the first expansion valve 8 according to the suction superheat of the compressor 1, adjusting the second expansion valve 7 according to the outlet air temperature of the compressor 1, and adjusting the rotational speed of the fresh air fan according to the indoor fresh air demand, and adjusting the rotational speed of the compressor 1 according to the outlet air temperature of the compressor 1.

[0041] The idea of the embodiment of this control method is the same as the working process of the fresh air air-conditioning system in the above embodiment. The entire content of the above embodiment of the fresh air air-conditioning system is incorporated into the embodiment of this control method by way of full reference and will not be elaborated here.

[0042] The above are only the preferred embodiments of the present invention, and do not limit its patent scope accordingly. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present invention, directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A fresh air air-conditioning system, characterized in that, the fresh air air-conditioning system includes a compressor (1), a four-way reversing valve (2), a fresh air treatment heat exchanger and an air source heat exchanger (6), and the fresh air treatment heat exchanger includes a first heat exchanger (3), a second heat exchanger (4) and a third heat exchanger (5); the fresh air air-conditioning system has a refrigeration mode, a heating mode and a dehumidification mode: when the fresh air air-conditioning system is in the refrigeration mode, the first heat exchanger (3) is configured as an evaporator, the second heat exchanger (4) is configured as a cold recovery device, the third heat exchanger (5) is configured as a condenser, and the air source heat exchanger (6) is configured as a condenser; the fresh air air-conditioning system has a first flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the four-way reversing valve (2), the air source heat exchanger (6), the second heat exchanger (4), the first heat exchanger (3), the four-way reversing valve (2), and the suction port of the compressor (1); the fresh air air-conditioning system has a second flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the third heat exchanger (5), the first heat exchanger (3), the four-way reversing valve (2), and the suction port of the compressor (1); when the fresh air air-conditioning system is in the heating mode, the first heat exchanger (3) is configured as a condenser, the third heat exchanger (5) is configured as a condenser, and the air source heat exchanger (6) is configured as an evaporator; the fresh air air-conditioning system has a third flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the four-way reversing valve (2), the first heat exchanger (3), the air source heat exchanger (6), the four-way reversing valve (2), and the suction port of the compressor (1); the fresh air air-conditioning system has a fourth flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the third heat exchanger (5), the air source heat exchanger (6), the four-way reversing valve (2), and the suction port of the compressor (1); when the fresh air air-conditioning system is in the dehumidification mode, the first heat exchanger (3) is used for cooling and dehumidifying, the second heat exchanger (4) recovers the cold of the air after cooling and dehumidifying, and the third heat exchanger (5) further heats the air.

2. The fresh air air-conditioning system according to claim 1, characterized in that, The four-way reversing valve (2) has ports A, B, C, and D; the suction port of the compressor (1) is connected to port A of the four-way reversing valve (2), the discharge port of the compressor (1) is connected to port B of the four-way reversing valve (2), ports C of the four-way reversing valve (2), the first heat exchanger (3), the second heat exchanger (4), the air source heat exchanger (6), and port D of the four-way reversing valve (2) are connected in sequence, the discharge port of the compressor (1), the third heat exchanger (5), and the first heat exchanger (3) are connected in sequence, and the third heat exchanger (5) is also connected to the air source heat exchanger (6).

3. The fresh air air-conditioning system according to claim 2, characterized in that, the fresh air air-conditioning system further includes a first expansion valve (8) and a first check valve (9), wherein the first expansion valve (8) is connected between the first heat exchanger (3) and the second heat exchanger (4), and one end of the first expansion valve (8) connected to the second heat exchanger (4) is also connected to one end of the first check valve (9), the other end of the first check valve (9) is connected to the air source heat exchanger (6), and the direction of the first check valve (9) points to the air source heat exchanger (6); the fresh air air-conditioning system further includes a second expansion valve (7), a second check valve (10), and a third check valve (11), wherein the third heat exchanger (5), the second expansion valve (7), and the first heat exchanger (3) are connected in sequence, and the direction of the second check valve (10) points to the third heat exchanger (5); the third heat exchanger (5), the second expansion valve (7), the third check valve (11), and the air source heat exchanger (6) are connected in sequence, and the direction of the third check valve (11) points to the air source heat exchanger (6).

4. The fresh air air-conditioning system according to claim 3, characterized in that, when the fresh air air-conditioning system is in the cooling mode, ports B and D of the four-way reversing valve (2) are communicated, and ports A and C of the four-way reversing valve (2) are communicated; the fresh air air-conditioning system has a first flow circuit: the refrigerant flows along the discharge port of the compressor (1), port B of the four-way reversing valve (2), port D of the four-way reversing valve (2), the air source heat exchanger (6), the second heat exchanger (4), the first expansion valve (8), the first heat exchanger (3), port C of the four-way reversing valve (2), port A of the four-way reversing valve (2), and the suction port of the compressor (1).

5. The fresh air air-conditioning system according to claim 3 or 4, characterized in that, When the fresh air air - conditioner system is in the refrigeration mode, the fresh air air - conditioner system has a second flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the third heat exchanger (5), the second expansion valve (7), the first heat exchanger (3), port C of the four - way reversing valve (2), port A of the four - way reversing valve (2), and the suction port of the compressor (1).

6. The fresh air air - conditioner system according to claim 3, characterized in that, when the fresh air air - conditioner system is in the heating mode, port B and port C of the four - way reversing valve (2) are connected, and port A and port D of the four - way reversing valve (2) are connected; the fresh air air - conditioner system has a third flow circuit: the refrigerant flows along the exhaust port of the compressor (1), port B of the four - way reversing valve (2), port C of the four - way reversing valve (2), the first heat exchanger (3), the second expansion valve (7), the air - source heat exchanger (6), port D of the four - way reversing valve (2), port A of the four - way reversing valve (2), and the suction port of the compressor (1).

7. The fresh air air - conditioner system according to claim 3 or 6, characterized in that, when the fresh air air - conditioner system is in the heating mode, the fresh air air - conditioner system has a fourth flow circuit: the refrigerant flows along the exhaust port of the compressor (1), the third heat exchanger (5), the second expansion valve (7), the air - source heat exchanger (6), port D of the four - way reversing valve (2), port A of the four - way reversing valve (2), and the suction port of the compressor (1).

8. The fresh air air - conditioner system according to claim 1, characterized in that, the fresh air air - conditioner system further includes a fan (12), a filter screen (13), a humidifier (20) and a supply fan; the unit of the fresh air air - conditioner system has an up - and - down structure, the compressor (1), the four - way reversing valve (2), the air - source heat exchanger (6) and the fan (12) are arranged at the lower part of the unit, and the first heat exchanger (3), the second heat exchanger (4), the third heat exchanger (5), the filter screen (13), the humidifier (20) and the supply fan are arranged at the upper part of the unit.

9. A control method for the fresh air air - conditioner system as claimed in claim 1, characterized in that, the control method includes: adjusting the first expansion valve (8) according to the suction superheat degree of the compressor (1), and adjusting the second expansion valve (7) according to the outlet air temperature of the compressor (1).

10. The control method for the fresh air air - conditioner system according to claim 9, characterized in that, the control method further includes: adjusting the rotation speed of the fresh air fan according to the indoor fresh air demand, and adjusting the rotation speed of the compressor (1) according to the outlet air temperature of the compressor (1).

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