A two-pipe condensation reheat heating and fresh air recovery system and control method thereof

Abstract

The present invention relates to a two-pipe condensing reheat heating and fresh air recovery system, comprising an indoor unit and an outdoor unit; the indoor unit comprises a fresh air unit and a return air unit separated from each other; the fresh air unit is provided with an outdoor air inlet and a fresh air supply outlet; the return air unit is provided with a return air inlet and a return air exhaust outlet; the outdoor air inlet and the return air exhaust outlet are located on the outdoor side; the fresh air supply outlet and the return air inlet are located on the indoor side; the fresh air unit is provided with a fresh air fan, electric auxiliary heat, a first indoor heat exchanger and a second indoor heat exchanger in sequence from the outdoor air inlet; the return air unit is provided with a return air fan and a third indoor heat exchanger in sequence from the return air exhaust outlet. The present invention can realize heat recovery in the fresh air, cooling fresh air, heating fresh air and dehumidification and reheating modes by controlling the on and off of components such as an indoor solenoid valve, a first indoor electronic expansion valve, a second indoor electronic expansion valve and an outdoor solenoid valve, thereby improving the versatility of the system.

Description

Technical Field

[0001] The present invention relates to an air conditioning system and a control method thereof, in particular to a two-pipe air conditioning system and a control method thereof, specifically to a two-pipe condensation reheat heating and fresh air recovery system and a control method thereof. Background Art

[0002] With the development of artificial environment technology, higher requirements are put forward for the comfort and energy-saving effect of fresh air systems. Traditional two-way flow fresh air fans only meet the basic function of supplying fresh air, and the return air is directly discharged to the outside, resulting in energy waste. If the energy of the cold and hot return air in the room is recovered and then discharged to the outside, the recovered energy is used for the fresh air unit to process the temperature and humidity of the fresh air, thus obtaining considerable energy-saving effect and comfort. At present, the existing technologies that can realize air supply dehumidification and reheating and return air energy recovery mostly adopt three-pipe control, and most of them are integrated. With the prevalence of home decoration fresh air systems, the disadvantage of the integrated fresh air fan with heat recovery is that it will generate a large compressor noise, and the disadvantage of the split three-pipe control is that the pipeline is long and the structure is complex. When long pipes are installed, more refrigerant needs to be filled, resulting in poor reliability, high installation cost, and easy leakage of pipelines.

[0003] Therefore, it needs to be improved in order to better adapt to the needs of the market. Summary of the invention

[0004] The purpose of the present invention is to provide a two-pipe condensing reheat heating and fresh air recovery system and a control method thereof in view of the deficiencies in the prior art, which has the characteristics of simple structure and high versatility, can effectively improve the reliability of the system and reduce the cost of use.

[0005] The technical solution of the present invention is:

[0006] A two-pipe condensing reheat heating and fresh air recovery system, comprising an indoor unit and an outdoor unit;

[0007] The indoor unit comprises a fresh air unit and a return air unit separated from each other; the fresh air unit is provided with an outdoor air inlet and a fresh air supply outlet; the return air unit is provided with a return air inlet and a return air exhaust outlet; the outdoor air inlet and the return air exhaust outlet are located on the outdoor side; the fresh air supply outlet and the return air inlet are located on the indoor side; the fresh air unit is provided with a fresh air fan, an electric auxiliary heat, a first indoor heat exchanger and a second indoor heat exchanger in sequence starting from the outdoor air inlet; the return air unit is provided with a return air fan and a third indoor heat exchanger in sequence starting from the return air exhaust outlet;

[0008] The outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger and a gas-liquid separator;

[0009] The exhaust port of the compressor is connected to the D port of the four-way valve, and its air intake port is connected to the outlet of the gas-liquid separator; the first end of the outdoor heat exchanger is connected to the C port of the four-way valve, and the second end thereof is respectively connected to the first end of the second indoor heat exchanger and the first end of the third indoor heat exchanger through a liquid pipe; the two ends of the outdoor heat exchanger are also connected through an outdoor solenoid valve; the E port of the four-way valve is connected to the first end of the first indoor heat exchanger through an air pipe; the second end of the first indoor heat exchanger, the second end of the second indoor heat exchanger and the second end of the third indoor heat exchanger are connected in parallel; the S port of the four-way valve is connected to the inlet of the gas-liquid separator;

[0010] An indoor electromagnetic valve is disposed at the first end of the indoor second heat exchanger, and an indoor first electronic expansion valve is disposed at the second end of the indoor third heat exchanger; an indoor second electronic expansion valve is disposed at the second end of the indoor third heat exchanger.

[0011] Furthermore, the liquid pipe is provided with a liquid pipe stop valve; the gas pipe is provided with a gas pipe stop valve.

[0012] Furthermore, an outdoor fan is provided next to the device.

[0013] A control method for a two-pipe condensing reheat heating and fresh air recovery system comprises the following steps:

[0014] 1) In fresh air mode, the compressor is turned off, and the fresh air fan and return air fan are turned on at the same time;

[0015] 2) In the cooling fresh air energy recovery mode, the compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time;

[0016] 3) Heating fresh air energy recovery mode,

[0017] 3.1) The compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time;

[0018] 3.2) Detect the fresh air outlet temperature T on the indoor side;

[0019] 3.3) If T < preset value, turn on the electric auxiliary heating; otherwise, return to step 3.2);

[0020] 4) Dehumidification and reheating fresh air mode,

[0021] 4.1) The outdoor solenoid valve is closed; the first indoor electronic expansion valve and the second indoor electronic expansion valve are opened at the same time, both of which play a throttling role; the indoor solenoid valve is opened; the fresh air fan and the return air fan are turned on at the same time;

[0022] 4.2) Detect the fresh air outlet temperature T on the indoor side;

[0023] 4.3) If T < preset value, open the outdoor solenoid valve; otherwise, return to step 4.2).

[0024] Furthermore, the fresh air fan and the return air fan both operate at a constant speed.

[0025] Beneficial effects of the present invention:

[0026] The invention has reasonable design, simple structure, convenient control, and can realize heat recovery in fresh air, cooling fresh air, heating fresh air, dehumidification and reheating modes, thereby improving the versatility of the system and facilitating promotion. At the same time, it can also effectively improve the reliability of the system and reduce the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a schematic diagram of the indoor unit operation in the fresh air mode of the present invention.

[0029] Figure 3 It is a schematic diagram of the refrigerant flow direction in the refrigeration fresh air energy recovery mode of the present invention.

[0030] Figure 4 It is a schematic diagram of the refrigerant flow direction in the heating fresh air energy recovery mode of the present invention.

[0031] Figure 5 It is a schematic diagram of the refrigerant flow direction when the present invention is in the dehumidification and reheating fresh air mode and the outdoor solenoid valve is opened.

[0032] Figure 6 It is a schematic diagram of the refrigerant flow direction when the present invention is in the dehumidification and reheating fresh air mode and the outdoor solenoid valve is closed.

[0033] Among them: 100-indoor unit; 100A-fresh air unit; 100B-return air unit; 101A-fresh air fan; 102A-electric auxiliary heating; 103A-indoor first heat exchanger; 104A-indoor first electronic expansion valve; 105A-indoor second heat exchanger; 106A-indoor second electronic expansion valve; 107A-outdoor air inlet; 108A-fresh air supply outlet; 109A-indoor solenoid valve; 101B-return air exhaust outlet; 102B-return air fan; 103B-indoor third heat exchanger; 104B-return air inlet; 200-outdoor unit; 201 outdoor heat exchanger; 202-four-way valve; 203-outdoor fan; 204-compressor; 205-gas pipe stop valve; 206-liquid pipe stop valve; 207-outdoor solenoid valve; 208-gas-liquid separator. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0035] like Figure 1 shown.

[0036] A two-pipe condensing reheat heating and fresh air recovery system comprises an indoor unit 100 and an outdoor unit 200.

[0037] The indoor unit 100 includes a fresh air unit 100A and a return air unit 100B which are separated from each other. The fresh air unit 100A is provided with an outdoor air inlet 107A and a fresh air supply outlet 108A. The return air unit 100B is provided with a return air inlet 104B and a return air exhaust outlet 101B; the outdoor air inlet 107A and the return air exhaust outlet 101B are located on the outdoor side; the fresh air supply outlet 108A and the return air inlet 104B are located on the indoor side; the fresh air unit 100A is provided with a fresh air fan 101A, an electric auxiliary heat 102A, an indoor first heat exchanger 103A and an indoor second heat exchanger 105A in sequence from the outdoor air inlet 107A; the return air unit 100B is provided with a return air fan 102B and an indoor third heat exchanger 103B in sequence from the return air exhaust outlet 101B.

[0038] The outdoor unit 200 includes a compressor 204, a four-way valve 202, an outdoor heat exchanger 201, and a gas-liquid separator 208. The exhaust port of the compressor 204 is connected to the D port of the four-way valve 202, and the air intake port thereof is connected to the outlet of the gas-liquid separator 208; the first end of the outdoor heat exchanger 201 is connected to the C port of the four-way valve 202, and the second end thereof is respectively connected to the first end of the indoor second heat exchanger 105A and the first end of the indoor third heat exchanger 103B through a liquid pipe; the two ends of the outdoor heat exchanger 201 are also connected through an outdoor solenoid valve 207; the E port of the four-way valve 202 is connected to the first end of the indoor first heat exchanger 103A through a gas pipe; the second end of the indoor first heat exchanger 103A, the second end of the indoor second heat exchanger 105A, and the second end of the indoor third heat exchanger 103B are connected in parallel; the S port of the four-way valve 202 is connected to the inlet of the gas-liquid separator 208;

[0039] The first end of the indoor second heat exchanger 105A is provided with an indoor solenoid valve 109A, and the second end thereof is provided with an indoor first electronic expansion valve 104A. The second end of the indoor third heat exchanger 103B is provided with an indoor second electronic expansion valve 106A. The indoor first electronic expansion valve 104A and the indoor second electronic expansion valve 106A can be opened and closed as needed, and have a throttling effect.

[0040] The liquid pipe is provided with a liquid pipe stop valve 206; the gas pipe is provided with a gas pipe stop valve 205, which can shut off the flow of refrigerant between the indoor unit and the outdoor unit, making installation and maintenance convenient.

[0041] An outdoor fan 203 is provided next to the outdoor heat exchanger to enhance the heat exchange effect.

[0042] A control method for a two-pipe condensing reheat heating and fresh air recovery system comprises the following steps:

[0043] 1) In fresh air mode, the compressor is turned off, and the fresh air fan and return air fan are turned on at the same time;

[0044] 2) In the cooling fresh air energy recovery mode, the compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time;

[0045] 3) Heating fresh air energy recovery mode,

[0046] 3.1) The compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time;

[0047] 3.2) Detect the fresh air outlet temperature T on the indoor side;

[0048] 3.3) If T < preset value, turn on the electric auxiliary heating; otherwise, return to step 3.2);

[0049] 4) Dehumidification and reheating fresh air mode,

[0050] 4.1) The outdoor solenoid valve is closed; the first indoor electronic expansion valve and the second indoor electronic expansion valve are opened at the same time, both of which play a throttling role; the indoor solenoid valve is opened; the fresh air fan and the return air fan are turned on at the same time;

[0051] 4.2) Detect the fresh air outlet temperature T on the indoor side;

[0052] 4.3) If T < preset value, open the outdoor solenoid valve; otherwise, return to step 4.2).

[0053] Furthermore, the fresh air fan and the return air fan both operate at a constant speed.

[0054] The specific implementation process of the present invention is:

[0055] 1. Fresh air mode, such as Figure 2 shown.

[0056] This mode is turned on when the outdoor temperature and humidity are not much different from the indoor set temperature and humidity and there is a demand for fresh air indoors. At this time, only the indoor fresh air fan 100 is turned on, the outdoor unit 200 is on standby and not started, and the indoor first fan 101A runs at the set speed, sucking the outdoor fresh air from the outdoor air inlet 107A into the cavity of the fresh air unit 100A, and then sending the fresh air into the room through the fresh air supply port 108A, thereby achieving the effect of sending fresh air indoors. At the same time, the indoor second fan 103B runs synchronously at the set speed, sucking the indoor air from the return air inlet 104B into the return air unit cavity, and then exhausting it to the outside through the return air exhaust port 101B, thereby updating the indoor air.

[0057] 2. Cooling fresh air energy recovery mode, such as Figure 3 shown.

[0058] In summer, the outdoor air is hot and humid, and the outdoor air needs to be cooled and dehumidified before being sent indoors. At this time, the indoor fresh air fan 100 and the outdoor unit 200 are turned on at the same time, the compressor 204 is turned on, the indoor first fan 101A and the indoor second fan 102B are operated at the set speed, the outdoor solenoid valve 207 is closed, and the high-temperature and high-pressure refrigerant is condensed and dissipated by the outdoor heat exchanger 201, and then enters the indoor third heat exchanger 103B of the return air unit 100B for condensation and heat dissipation, and the cold air sucked in by the return air inlet 104B is recovered, and the cold air is heated and discharged outdoors from the return air outlet 101B. At this time, the indoor first electronic expansion valve 104A and the solenoid valve 109A are closed and the refrigerant is blocked. The refrigerant comes out from the indoor third heat exchanger 103B, and then enters the indoor second electronic expansion valve 106A for throttling and pressure reduction, and then enters the indoor first heat exchanger 103A for evaporation and heat absorption. At the same time, outdoor fresh air is sucked into the indoor unit 100A through the outdoor air inlet 107A, cooled and dehumidified when passing through the indoor heat exchanger 103A, and finally delivered into the room through the indoor air supply port 108A. In this way, the outdoor high-temperature and high-humidity fresh air can be cooled and dehumidified, and the return air cooling capacity can be recovered.

[0059] 3. Heating fresh air energy recovery mode, such as Figure 4 shown.

[0060] In winter, the outdoor air is cold, and the outdoor air needs to be heated before being sent indoors. At this time, the indoor unit 100 and the outdoor unit 200 are turned on at the same time, the compressor 204 is turned on, the indoor first fan 101A and the indoor second fan 102B operate at the set speed, and the outdoor unit 200 sends the high-temperature and high-pressure refrigerant to the indoor unit 100 through the gas pipe stop valve 205. At this time, the indoor first electronic expansion valve 104A and the solenoid valve 109A are closed and the refrigerant is not passed. The refrigerant is condensed and dissipated through the indoor first heat exchanger 103A, and the outdoor fresh air sucked in by the fresh air inlet 107A is heated, and the fresh air temperature value is detected at the same time. When the fresh air temperature value is greater than the preset value, the electric auxiliary heating 102A is not turned on, and the heated fresh air is directly sent indoors. When the difference is less than the preset value, the electric auxiliary heating 102A is turned on to supplement the heat, and then the fresh air after secondary heating is sent indoors. Then, the refrigerant enters the third indoor heat exchanger 103B after throttling and reducing pressure through the second indoor electronic expansion valve 106A, evaporates and absorbs heat, and recovers the heat of the indoor return air sucked in by the return air inlet 104B. After that, the refrigerant enters the outdoor unit 200 through the liquid pipe stop valve 206, and then enters the outdoor heat exchanger 203 to evaporate and absorb heat. At this time, the outdoor solenoid valve 207 is closed, and the refrigerant returns to the compressor through the four-way valve 202, completing the cycle and achieving the effect of heating the cold outdoor fresh air and recovering the heat of the indoor return air.

[0061] 4. Dehumidification and reheating fresh air mode, such as Figure 5 and 6 shown.

[0062] During the transitional season of plum rains, the outdoor air is damp and cold. At this time, the indoor air needs dry but not cold fresh air, so the air needs to be dehumidified and then heated before being sent indoors. At this time, the indoor unit 100 and the outdoor unit 200 are turned on at the same time, the compressor 204 is turned on, and the indoor first fan 101A and the indoor second fan 102B operate at the set speed. When the indoor reheating demand is determined and the outlet air temperature is lower than the reheating target outlet air temperature, if Figure 5 As shown, the outdoor solenoid valve 207 is opened, and the refrigerant is divided into two paths, passing through the outdoor heat exchanger 201 and the outdoor solenoid valve 207 respectively, and then sent to the indoor unit 100 through the liquid pipe stop valve 206. When the outlet air temperature is greater than or equal to the reheat target outlet air temperature, as shown in FIG. Figure 6As shown, the outdoor electromagnetic valve 207 is closed and the refrigerant is blocked, so that the refrigerant passes through the outdoor heat exchanger 201 and condenses, and then passes through the liquid pipe stop valve 206 to enter the indoor unit 100. Then, the refrigerant is divided into two paths, one of which is condensed and dissipated in the third indoor heat exchanger 103B, and the cold air sucked in by the return air inlet 104B is recovered, so that the cold air is heated and discharged to the outside through the return air outlet 101B. The other path enters the second indoor heat exchanger 105A for condensation and heat dissipation. At this time, the electromagnetic valve 109A is opened, and the first indoor electronic expansion valve 104A and the second indoor electronic expansion valve 106A simultaneously throttle and reduce the pressure of the two refrigerants and then collect them, and then enter the first indoor heat exchanger 103A for evaporation and heat absorption. After the outdoor fresh air is cooled and dehumidified by the indoor heat exchanger 103A, it is heated by the indoor second heat exchanger 105A and finally the dehumidified and reheated fresh air is delivered to the room through the indoor air supply port 108A. Thus, the outdoor wet and cold fresh air can be dehumidified and reheated during the rainy season, and the indoor return air cooling can be recovered.

[0063] The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

Claims

1. A two-pipe condensation reheat heating and fresh air recovery system, comprising an indoor unit and an outdoor unit; its characteristics are: The indoor unit comprises a fresh air unit and a return air unit separated from each other; the fresh air unit is provided with an outdoor air inlet and a fresh air supply outlet; the return air unit is provided with a return air inlet and a return air exhaust outlet; the outdoor air inlet and the return air exhaust outlet are located on the outdoor side; the fresh air supply outlet and the return air inlet are located on the indoor side; the fresh air unit is provided with a fresh air fan, an electric auxiliary heat, a first indoor heat exchanger and a second indoor heat exchanger in sequence starting from the outdoor air inlet; the return air unit is provided with a return air fan and a third indoor heat exchanger in sequence starting from the return air exhaust outlet; The outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger and a gas-liquid separator; The exhaust port of the compressor is connected to the D port of the four-way valve, and its air intake port is connected to the outlet of the gas-liquid separator; the first end of the outdoor heat exchanger is connected to the C port of the four-way valve, and the second end thereof is respectively connected to the first end of the second indoor heat exchanger and the first end of the third indoor heat exchanger through a liquid pipe; the two ends of the outdoor heat exchanger are also connected through an outdoor solenoid valve; the E port of the four-way valve is connected to the first end of the first indoor heat exchanger through an air pipe; the second end of the first indoor heat exchanger, the second end of the second indoor heat exchanger and the second end of the third indoor heat exchanger are connected in parallel; the S port of the four-way valve is connected to the inlet of the gas-liquid separator; The first end of the indoor second heat exchanger is provided with an indoor solenoid valve, and the second end thereof is provided with an indoor first electronic expansion valve; the second end of the indoor third heat exchanger is provided with an indoor second electronic expansion valve; The control method of the two-pipe condensation reheat heating and fresh air recovery system comprises the following steps: 1) In fresh air mode, the compressor is turned off, and the fresh air fan and return air fan are turned on at the same time; 2) In the cooling fresh air energy recovery mode, the compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time; 3) Heating fresh air energy recovery mode, 3.1) The compressor is running, the outdoor solenoid valve is closed; the first indoor electronic expansion valve and the indoor solenoid valve are closed at the same time; the second indoor electronic expansion valve is opened to play a throttling role; the fresh air fan and the return air fan are turned on at the same time; 3.2) Detect the fresh air outlet temperature T on the indoor side; 3.3) If T < preset value, turn on the electric auxiliary heating; otherwise, return to step 3.2); 4) Dehumidification and reheating fresh air mode, 4.1) The outdoor solenoid valve is closed; the first indoor electronic expansion valve and the second indoor electronic expansion valve are opened at the same time, both of which play a throttling role; the indoor solenoid valve is opened; the fresh air fan and the return air fan are turned on at the same time; 4.2) Detect the fresh air outlet temperature T on the indoor side; 4.3) If T < preset value, open the outdoor solenoid valve; otherwise, return to step 4.2).

2. The two-pipe condensation reheat heating and fresh air recovery system according to claim 1 is characterized by: The liquid pipe is provided with a liquid pipe stop valve; the gas pipe is provided with a gas pipe stop valve.

3. The two-pipe condensation reheat heating and fresh air recovery system according to claim 1 is characterized by: An outdoor fan is arranged beside the outdoor heat exchanger.

4. The two-pipe condensation reheat heating and fresh air recovery system according to claim 1 is characterized by: The fresh air fan and the return air fan both operate at a constant speed.

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