Three-plate type air conditioner heat exchange system and refrigerating and heating control method thereof

Abstract

The invention discloses a three-plate type air conditioner heat exchange system and a refrigerating and heating control method thereof, and belongs to the technical field of air conditioners. The three-plate type air conditioner heat exchange system comprises a compressor, a main reversing valve, a first plate heat exchanger, a second plate heat exchanger, a third plate heat exchanger and an air heat exchange mechanism, the third plate heat exchanger is connected with the main reversing valve and the air heat exchange mechanism, and the air heat exchange mechanism is connected with the first plate heat exchanger. The first plate heat exchanger is connected with a thermostatic expansion valve which is connected with a second plate heat exchanger; an air-conditioning medium needing to be cooled or heated is subjected to temperature regulation through an air heat exchange mechanism with less energy consumption, and then is further subjected to temperature regulation through a plate heat exchanger for transduction by using geothermal energy or a cooling tower, so that the air heat exchange mechanism and the plate heat exchanger are combined for application; the relative temperature difference between the air-conditioning medium and the set air-conditioning temperature can be reduced, the output power of an air-conditioning compressor is reduced, and energy conservation is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a three-plate air conditioning heat exchange system and a cooling and heating control method thereof. Background Art

[0002] Shallow geothermal resources on the surface can be called geothermal energy, which refers to the low-temperature heat energy stored in the surface soil, groundwater or rivers and lakes by absorbing solar energy and geothermal energy. The shallow surface is a huge solar collector. It is not limited by regions and resources, and is truly large in quantity and ubiquitous. This almost unlimited renewable energy stored in the shallow surface makes geothermal energy a form of clean renewable energy.

[0003] Ground source heat pump air conditioner or water-cooled air conditioner unit technology is an efficient and energy-saving device that uses shallow underground geothermal resources (including groundwater, underground rock and soil or surface water, etc.) to provide both heating and cooling. Among them, the buried pipe ground source heat pump system is less restricted by environmental conditions, and is therefore increasingly valued. It uses the relatively stable temperature of underground soil. On the basis of a small amount of high-potential energy, it exchanges heat and cold with the earth through the buried pipe heat exchanger buried underground, achieving summer cooling, winter heating, and domestic hot water. Compared with conventional central air conditioners, the effect is more stable. Only a small amount of electrical energy output can realize the conversion from low-potential energy to high-potential energy, which is cleaner and more environmentally friendly, and can realize cooling, floor heating and domestic hot water supply. One machine has multiple uses, stable performance, and long service life.

[0004] The existing ground source heat pump air conditioning system completes energy transfer in the heat exchanger through the air conditioning medium and the heat exchange medium. For example, under the premise of using groundwater as the heat exchange medium, when the temperature of the air conditioning medium is high or low, the heat exchange process of the air conditioning medium requires the input of a higher flow of heat exchange water and a longer well. Other cooling media as heat exchange media also have similar problems. These problems will lead to a high overall energy consumption of the ground source heat pump air conditioning system and insufficient energy saving. The water-cooled unit also has the above problems.

[0005] Therefore, how to provide an air-conditioning heat exchange system that can reduce energy consumption is a technical problem that urgently needs to be solved in the current air-conditioning industry. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a three-plate air conditioning heat exchange system capable of reducing energy consumption.

[0007] In order to achieve the above object, the solution of the present invention is:

[0008] A three-plate air conditioning heat exchange system, comprising a compressor, a main reversing valve, a first plate heat exchanger, a second plate heat exchanger, a third plate heat exchanger and an air heat exchange mechanism, wherein the main reversing valve is arranged at the rear end of the compressor in the direction of travel of the air conditioning medium, one end of the main reversing valve is provided with an A1 port connected to the compressor, and the other end is provided with an A2 port, an A3 port and an A4 port from left to right, the A2 port of the main reversing valve is connected to the third plate heat exchanger, the A3 port is connected to the input end of the compressor, and the A4 port is connected to the second plate heat exchanger, when the A1 port of the main reversing valve is connected to the A2 port, the A3 port is connected to the A4 port, and when the A1 port is connected to the A4 port, the A2 port is connected to the A3 port is connected; the third plate heat exchanger is connected to the A2 port of the main reversing valve and the air heat exchange mechanism, the air heat exchange mechanism is connected to the first plate heat exchanger and the third plate heat exchanger, the first plate heat exchanger is connected to the air heat exchange mechanism and the thermal expansion valve, and the thermal expansion valve is connected to the second plate heat exchanger; the first plate heat exchanger and the third plate heat exchanger are respectively connected to the pipeline flowing through the underground well or the cooling tower, and a variable frequency pump is provided between the first plate heat exchanger and the pipeline flowing through the underground well or the cooling tower or between the third plate heat exchanger and the pipeline flowing through the underground well or the cooling tower, and the second plate heat exchanger is connected to the indoor duct machine through the second variable frequency pump.

[0009] Furthermore, the air heat exchange mechanism includes a radiator and a blowing structure arranged on one side of the radiator, and the third plate heat exchanger and the first plate heat exchanger are respectively connected to the radiator.

[0010] Furthermore, a speed regulating component is provided in the air heat exchange mechanism, and the speed regulating component is connected to the control circuit of the blowing structure to control the operating speed of the blowing structure.

[0011] Furthermore, the first plate heat exchanger is provided with a first temperature sensor for detecting the temperature of the first plate heat exchanger, the second plate heat exchanger is provided with a second temperature sensor for detecting the temperature of the second plate heat exchanger, and the third plate heat exchanger is provided with a third temperature sensor for detecting the temperature of the third plate heat exchanger.

[0012] Furthermore, the air heat exchange mechanism is provided with a fourth temperature sensor for detecting the external environment temperature, and the radiator of the air heat exchange mechanism is provided with a fifth temperature sensor for detecting the internal temperature of the radiator.

[0013] Furthermore, a frost sensor is provided in the radiator of the air heat exchange mechanism, and a heating component or heat exchange mechanism for defrosting is provided in the radiator.

[0014] Furthermore, filters are provided at both ends of the thermal expansion valve, a liquid reservoir is provided between the thermal expansion valve and the second plate heat exchanger, and a gas-liquid separator is provided between the A3 port of the main reversing valve and the compressor.

[0015] Furthermore, a first variable frequency pump is provided between the first plate heat exchanger and the pipeline flowing through the underground well or the cooling tower, and a third variable frequency pump is provided between the third plate heat exchanger and the pipeline flowing through the underground well or the cooling tower. In the heating mode, the third variable frequency pump works and modulates the frequency according to the values ​​of each temperature sensor and the set temperature value to achieve energy saving effect. In the cooling mode, the first variable frequency pump works and modulates the frequency according to the values ​​of each temperature sensor and the set temperature value to achieve energy saving effect.

[0016] Another object of the present invention is to overcome the deficiencies of the prior art and provide a refrigeration control method for a three-plate air conditioning heat exchange system that can reduce energy consumption.

[0017] In order to achieve the above object, the solution of the present invention is:

[0018] A refrigeration control method for a three-plate air conditioning heat exchange system, characterized in that: during refrigeration, the A1 port of the main reversing valve is connected to the A2 port, the A3 port is connected to the A4 port, and the compressor compresses the air conditioning medium so that the air conditioning medium changes from gas to liquid, and the temperature of the liquid increases;

[0019] After the high-temperature air-conditioning medium enters the A2 port through the A1 port of the main reversing valve, it flows through the third plate heat exchanger and reaches the radiator of the air exchange mechanism. At this time, there is a large temperature difference between the high-temperature air-conditioning medium and the ambient temperature. The air flowing through the air heat exchange mechanism takes away the heat, so that the temperature of the air-conditioning medium drops to close to the ambient temperature.

[0020] The cooled air-conditioning medium flows out of the air heat exchange mechanism and enters the first plate heat exchanger, and the low-temperature heat exchange loop medium circulating through the pipeline of the underground well or cooling tower takes away the heat of the first plate heat exchanger, and further cools the air-conditioning medium to a temperature close to the low-temperature heat exchange medium temperature of the pipeline of the underground well or cooling tower;

[0021] The secondary cooled air conditioning medium enters the thermal expansion valve from the first plate heat exchanger and becomes gas, and the temperature drops to a lower temperature;

[0022] The low-temperature air-conditioning medium enters the second plate heat exchanger, causing the second plate heat exchanger to cool down, thereby cooling the heat exchange medium flowing through the second plate heat exchanger. The low-temperature heat exchange medium is driven to the indoor duct unit through the second variable frequency pump, causing the indoor duct unit to cool down, thereby causing the air or other substances in contact with the indoor duct unit to cool down to the set temperature.

[0023] The air-conditioning medium heated by the second plate heat exchanger flows through the A4 port of the main reversing valve, returns to the A3 port, and then returns to the compressor input end, so that the air-conditioning medium circulates.

[0024] Another object of the present invention is to overcome the deficiencies of the prior art and provide a heating control method for a three-plate air conditioning heat exchange system that can reduce energy consumption.

[0025] In order to achieve the above object, the solution of the present invention is:

[0026] A heating control method for a three-plate air conditioning heat exchange system, characterized in that: during heating, the A1 port of the main reversing valve is connected to the A4 port, the A2 port is connected to the A3 port, and the compressor compresses the air conditioning medium so that the air conditioning medium changes from gas to liquid, and the liquid temperature increases;

[0027] The high-temperature air-conditioning medium enters the A4 port through the A1 port of the main reversing valve and reaches the second plate heat exchanger, which increases the temperature of the second plate heat exchanger, thereby heating the heat exchange medium flowing through the second plate heat exchanger. The high-temperature heat exchange medium is driven by the second variable frequency pump to reach the indoor duct unit, which increases the temperature of the indoor duct unit, thereby causing the air or other substances in contact with the indoor duct unit to heat up to the set temperature.

[0028] After the air-conditioning medium passes through the second plate heat exchanger and enters the thermal expansion valve to become gas, the temperature is reduced. The low-temperature gas flows out of the thermal expansion valve and enters the first plate heat exchanger, and then flows out of the first plate heat exchanger and enters the air heat exchange mechanism. At this time, there is a large temperature difference between the lower temperature air-conditioning medium and the ambient temperature. The air flows through the air heat exchange mechanism so that the temperature of the air-conditioning medium is close to the ambient temperature.

[0029] The air conditioning medium heated by the air heat exchange mechanism enters the third plate heat exchanger, and the heat exchange medium of the third plate heat exchanger heats the pipeline through the pipeline flowing through the underground well or cooling tower to a temperature close to the high-temperature heat exchange medium temperature of the pipeline flowing through the underground well or cooling tower;

[0030] The air-conditioning medium that has been heated twice returns to the input end of the compressor through port A2 to port A3 to continue to be compressed and heated, so that the air-conditioning medium circulates.

[0031] After adopting the above scheme, the three-plate air-conditioning heat exchange system of the present invention first adjusts the temperature of the huge temperature difference between the air-conditioning medium to be cooled or heated and the ambient temperature through an air heat exchange mechanism with less energy consumption, and then further adjusts the temperature through a plate heat exchanger that uses geothermal energy or cooling tower energy conversion. The air heat exchange mechanism is combined with the plate heat exchanger to reduce the relative temperature difference between the air-conditioning medium and the set air-conditioning temperature, reduce the output power of the air-conditioning compressor, and is beneficial to energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the present invention.

[0033] Figure 2 This is a heating flow chart of the present invention.

[0034] Figure 3 This is a refrigeration flow chart of the present invention.

[0035] Description of labels:

[0036] Liquid receiver 110 Compressor 130 Gas-liquid separator 150 Main reversing valve 160

[0037] Thermal expansion valve 180 Filter 190 A1 port 10 A2 port 20

[0038] A3 port 30 A4 port 40 First plate heat exchanger 210

[0039] First temperature sensor 211 Second plate heat exchanger 220 Second temperature sensor 221

[0040] First variable frequency pump 230 pipeline 240 radiator 310 blowing structure 320

[0041] Fourth temperature sensor 330 Fifth temperature sensor 340 Frost sensor 350

[0042] Electric heating rod 370 Duct machine 500 Coil 510 Third plate heat exchanger 710

[0043] The third temperature sensor 711 DETAILED DESCRIPTION

[0044] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0045] like Figure 1 As shown, a preferred embodiment of a three-plate air conditioning heat exchange system of the present invention includes a main reversing valve 160, a first plate heat exchanger 210, a second plate heat exchanger 220, a third plate heat exchanger 710 and an air heat exchange mechanism, the air heat exchange mechanism includes a radiator 310 and a blowing structure 320 arranged on one side of the radiator 310, an air flow is generated by the blowing structure so that the air conditioning medium circulates in the radiator 310, and the radiator 310 performs heat exchange by contacting with the air driven by the blowing structure 320 to realize cooling or heating operation of the air conditioning medium driven by the air conditioning compressor.

[0046] The main reversing valve 160 is arranged at the rear end of the compressor 130 in the direction of travel of the air-conditioning medium. An A1 port 10 is provided at one end of the main reversing valve 160 to connect with the compressor 130, and an A2 port 20, an A3 port 30 and an A4 port 40 are provided at the other end from left to right. The A2 port 20 of the main reversing valve 160 is connected to the C4 port of the third plate heat exchanger 710, the A3 port 30 is connected to the gas-liquid separator 150, the gas-liquid separator 150 is connected to the input end of the compressor 130, and the A4 port 40 is connected to the D2 port of the second plate heat exchanger 220, wherein when the A1 port 10 of the main reversing valve 160 is connected to the A2 port 20, the A3 port 30 is connected to the A4 port 40, and when the A1 port 10 is connected to the A4 port 40, the A2 port 20 is connected to the A3 port 30.

[0047] The C4 port of the third plate heat exchanger 710 is connected to the A2 port 20 of the main reversing valve 160, the C3 port of the third plate heat exchanger 710 is connected to the B1 port of the radiator 310, the B2 end of the radiator 310 is connected to the C1 port of the first plate heat exchanger 210, the C2 port of the first plate heat exchanger 210 is connected to the E1 port of the thermal expansion valve 180, and the E2 port of the thermal expansion valve 180 is connected to the D1 port of the second plate heat exchanger 220; the first plate heat exchanger 210 is connected to the pipeline 240 flowing through the underground well or the cooling tower through the first variable frequency pump 230, the second plate heat exchanger 220 is connected to the coil 510 of the indoor air duct unit 500 through the second variable frequency pump 520, and the third plate heat exchanger 710 is connected to the pipeline 240 flowing through the underground well or the cooling tower through the third variable frequency pump 730.

[0048] Among them, the first plate heat exchanger 210 is provided with a first temperature sensor 211 for detecting the temperature of the first plate heat exchanger 210, the second plate heat exchanger 220 is provided with a second temperature sensor 221 for detecting the temperature of the second plate heat exchanger 220, the third plate heat exchanger 710 is provided with a third temperature sensor 711 for detecting the temperature of the third plate heat exchanger 710, the air heat exchange mechanism is provided with a fourth temperature sensor 330 for detecting the external ambient temperature, and the radiator 310 of the air heat exchange mechanism is provided with a fifth temperature sensor 340 for detecting the internal temperature of the radiator.

[0049] A speed regulating component is disposed in the air heat exchange mechanism, and the speed regulating component is connected to the control circuit of the blowing structure 320 to control the operating speed of the blowing structure 320 .

[0050] A frost sensor 350 is provided in the radiator 310 of the air heat exchange mechanism, and a heating component or heat exchange mechanism for defrosting is provided in the radiator 310 .

[0051] Filters 190 are provided at both ends of the thermal expansion valve 180 , and a liquid storage tank 110 is further provided between the thermal expansion valve 180 and the D1 port of the second plate heat exchanger 220 .

[0052] like Figure 2 As shown, when the air conditioning heat exchange system of the present invention performs heating (i.e., temperature increase), the A1 port 10 of the main reversing valve 160 is connected to the A4 port 40, and the A2 port 20 is connected to the A3 port 30. After the compressor 130 compresses the air conditioning medium, the air conditioning medium is changed from gas to liquid, and the temperature of the liquid increases;

[0053] The high-temperature air-conditioning medium enters the A4 port 40 through the A1 port 10 of the main reversing valve 160 and reaches the D2 port of the second plate heat exchanger 220, and comes out from the D1 port of the second plate heat exchanger 220, so that the temperature of the second plate heat exchanger 220 is increased, thereby heating the heat exchange medium flowing through the second plate heat exchanger 220. The high-temperature heat exchange medium is driven by the second variable frequency pump 520 to reach the coil 510 of the air duct unit 500, so that the temperature of the coil 510 is increased, and then the air or other substances in contact with the coil 510 of the air duct unit are heated to the set temperature;

[0054] After the air conditioning medium of the second plate heat exchanger 220 enters the thermal expansion valve 180 from the E2 port of the thermal expansion valve 180 and becomes gas, the temperature drops to a relatively low temperature. The low-temperature gas flows out from the E1 port of the thermal expansion valve 180 and enters the C2 port of the first plate heat exchanger 210 and flows through the first plate heat exchanger 210. Then, it flows out from the C1 port of the first plate heat exchanger 210 and enters the B2 port of the radiator 310 of the air heat exchange mechanism. At this time, there is a large temperature difference between the air conditioning medium at a relatively low temperature and the ambient temperature. The air flows through the air heat exchange mechanism so that the temperature of the air conditioning medium is close to the ambient temperature. In this process, the first variable frequency pump 230 of the first plate heat exchanger 210 does not operate, or in order to prevent the heat exchange medium of the first plate heat exchanger 210 from freezing, the first variable frequency pump 230 operates slowly according to the value of the first temperature sensor 211.

[0055] The air conditioning medium heated by the radiator 310 of the air heat exchange mechanism comes out from the B1 port, enters the third plate heat exchanger 710 through the C3 port, and then comes out from the C4 port. The heat exchange medium flowing through the third plate heat exchanger 710 is driven by the third variable frequency pump 730 to heat the pipe 240 flowing through the underground well or cooling tower to a temperature close to the underground well.

[0056] The air-conditioning medium that has been heated twice returns to the input end of the compressor 130 through the A2 port 20 to the A3 port 30 to continue to be compressed and heated. The air-conditioning medium with a higher temperature is easier to be compressed during the compression process, and the temperature of the compressed air-conditioning medium is also higher, with a higher energy efficiency ratio, and a smaller power compressor can be used to reach the temperature required by the indoor duct unit 500, with lower engineering costs and less power consumption.

[0057] When the frost sensor 350 triggers a frost event, the compressor 130 stops working, and the air heat exchanger is defrosted by the heat exchange medium flowing through the pipeline structure of the air heat exchanger. The electric heating rod 370 can also be used for heating and defrosting. Or the main reversing valve 160 reverses to enter the cooling mode, and the first variable frequency pump 230, the third variable frequency pump 730 and the second variable frequency pump 520 do not work, so that the air heat exchanger is heated to achieve the defrosting effect.

[0058] like Figure 3 As shown, when the three-plate air conditioning heat exchange system of the present invention performs cooling (i.e., cooling), the A1 port of the main reversing valve 160 is connected to the A2 port, and the A3 port is connected to the A4 port. After the compressor 130 compresses the air conditioning medium, the air conditioning medium changes from gas to liquid, and the liquid temperature increases;

[0059] After the high-temperature air-conditioning medium enters the A2 port 20 through the A1 port 10 of the main reversing valve 160, it flows through the third plate heat exchanger 710 from the C4 port of the third plate heat exchanger 710 and flows out from the C3 port. At this time, the third variable frequency pump 711 does not work, and reaches the B1 port of the air exchange mechanism radiator 310 to enter the air heat exchange mechanism. At this time, there is a large temperature difference between the high-temperature air-conditioning medium and the ambient temperature. The air flowing through the air heat exchange mechanism can easily take away heat at a lower energy consumption, so that the temperature of the air-conditioning medium drops to close to the ambient temperature.

[0060] The cooled air-conditioning medium flows out from the B2 port of the air heat exchange mechanism, enters the first plate heat exchanger 210 from the C1 port of the first plate heat exchanger 210, and takes away the heat of the first plate heat exchanger 210 through the low-temperature heat exchange ring medium circulating through the underground well, further cooling the air-conditioning medium to a temperature close to that of the underground well. The air-conditioning medium cooled by the air heat exchanger reduces the total amount of heat exchanged by the first plate heat exchanger 210, which can reduce the length of the pipeline flowing through the underground well and the number of underground wells, and can also make the air-conditioning medium closer to the temperature of the underground well.

[0061] The secondary cooled air-conditioning medium flows out from the C2 port of the first plate heat exchanger 210, enters the thermal expansion valve 180 from the E1 port and becomes gas, and the temperature drops to a lower temperature. The air-conditioning medium at a lower temperature can take away more heat after becoming gas, thereby improving the energy efficiency ratio of the compressor and reducing the energy consumption of the compressor. A compressor with a smaller power can be used to achieve the temperature required by the indoor duct unit 500, with lower engineering cost and less power consumption.

[0062] The low-temperature air-conditioning medium enters the second plate heat exchanger 220 from the D1 port of the second plate heat exchanger 220 and then exits from the D2 port, so that the second plate heat exchanger 220 is cooled down, thereby cooling the heat exchange medium flowing through the second plate heat exchanger 220. The low-temperature heat exchange medium is driven to the coil 510 of the air duct unit 500 through the second variable frequency pump 520, so that the coil 510 of the air duct unit 500 is cooled down, and the air or other substances in contact with the coil 510 are cooled down to the set temperature.

[0063] The air conditioning medium heated by the second plate heat exchanger 220 flows through the main reversing valve A4 port 40 back to the A3 port 30 and then back to the input end of the compressor 130. The second plate heat exchanger 230 adjusts the flow rate according to the temperature of the second temperature sensor 211, so that the present invention maintains low energy consumption.

[0064] When the temperature rises, the third variable frequency pump 730 works, and the second variable frequency pump 230 does not work or works slowly; when the temperature drops, the second variable frequency pump 230 works and the third variable frequency pump 730 does not work.

[0065] The opposite action can also be adopted, that is: when the temperature rises, the second frequency conversion 230 works and the third frequency conversion 730 does not work, and when the temperature drops, the third frequency conversion 730 works and the second frequency conversion 230 does not work; or regardless of whether the temperature is rising or falling, the second frequency conversion 230 and the third frequency conversion 730 work by frequency modulation as needed.

[0066] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A three-plate air conditioning heat exchange system, characterized in that: include: A compressor, a main reversing valve, a first plate heat exchanger, a second plate heat exchanger, a third plate heat exchanger and an air heat exchange mechanism, wherein the main reversing valve is arranged at the rear end of the compressor in the direction of travel of the air-conditioning medium, an A1 port is arranged at one end of the main reversing valve to connect to the compressor, and an A2 port, an A3 port and an A4 port are arranged at the other end from left to right, the A2 port of the main reversing valve is connected to the third plate heat exchanger, the A3 port is connected to the input end of the compressor, and the A4 port is connected to the second plate heat exchanger, when the A1 port of the main reversing valve is connected to the A2 port, the A3 port is connected to the A4 port, and when the A1 port is connected to the A4 port, the A2 port is connected to the A3 port; The third plate heat exchanger is connected to the A2 port of the main reversing valve and the air heat exchange mechanism, the air heat exchange mechanism is connected to the first plate heat exchanger and the third plate heat exchanger, the first plate heat exchanger is connected to the air heat exchange mechanism and the thermal expansion valve, and the thermal expansion valve is connected to the second plate heat exchanger; the first plate heat exchanger and the third plate heat exchanger are respectively connected to the pipeline flowing through the underground well or the cooling tower, and at least one of the first plate heat exchanger and the pipeline flowing through the underground well or the cooling tower or the third plate heat exchanger and the pipeline flowing through the underground well or the cooling tower is provided with a variable frequency pump, and the second plate heat exchanger is connected to the indoor duct machine through the second variable frequency pump.

2. A three-plate air conditioning heat exchange system as claimed in claim 1, characterized in that: The air heat exchange mechanism comprises a radiator and a blowing structure arranged on one side of the radiator, and the third plate heat exchanger and the first plate heat exchanger are respectively connected to the radiator.

3. A three-plate air conditioning heat exchange system as claimed in claim 2, characterized in that: A speed regulating component is arranged in the air heat exchange mechanism, and the speed regulating component is connected to the control circuit of the blowing structure to control the running speed of the blowing structure.

4. A three-plate air conditioning heat exchange system as claimed in claim 1, characterized in that: The first plate heat exchanger is provided with a first temperature sensor for detecting the temperature of the first plate heat exchanger, the second plate heat exchanger is provided with a second temperature sensor for detecting the temperature of the second plate heat exchanger, and the third plate heat exchanger is provided with a third temperature sensor for detecting the temperature of the third plate heat exchanger.

5. A three-plate air conditioning heat exchange system as claimed in claim 2 or 3, characterized in that: The air heat exchange mechanism is provided with a fourth temperature sensor for detecting the external environment temperature, and the radiator of the air heat exchange mechanism is provided with a fifth temperature sensor for detecting the internal temperature of the radiator.

6. A three-plate air conditioning heat exchange system as claimed in claim 2 or 3, characterized in that: A frost sensor is arranged in the radiator of the air heat exchange mechanism, and a heating component or a heat exchange mechanism for defrosting is arranged in the radiator.

7. A three-plate air conditioning heat exchange system as claimed in claim 1, characterized in that: Filters are provided at both ends of the thermal expansion valve, a liquid reservoir is provided between the thermal expansion valve and the second plate heat exchanger, and a gas-liquid separator is provided between the A3 port of the main reversing valve and the compressor.

8. A three-plate air conditioning heat exchange system as claimed in claim 1, characterized in that: A first variable frequency pump is provided between the first plate heat exchanger and the pipeline flowing through the underground well or the cooling tower, and a third variable frequency pump is provided between the third plate heat exchanger and the pipeline flowing through the underground well or the cooling tower. In the heating mode, the third variable frequency pump works and modulates the frequency according to the values ​​of each temperature sensor and the set temperature value. In the cooling mode, the first variable frequency pump works and modulates the frequency according to the values ​​of each temperature sensor and the set temperature value.

9. A refrigeration control method for a three-plate air conditioning heat exchange system according to claim 1, characterized in that: During cooling, the A1 port of the main reversing valve is connected to the A2 port, and the A3 port is connected to the A4 port. After the compressor compresses the air-conditioning medium, the air-conditioning medium changes from gas to liquid, and the liquid temperature rises; After the high-temperature air-conditioning medium enters the A2 port through the A1 port of the main reversing valve, it flows through the third plate heat exchanger and reaches the radiator of the air exchange mechanism. At this time, there is a large temperature difference between the high-temperature air-conditioning medium and the ambient temperature. The air flowing through the air heat exchange mechanism takes away the heat, so that the temperature of the air-conditioning medium drops to close to the ambient temperature. The cooled air-conditioning medium flows out of the air heat exchange mechanism and enters the first plate heat exchanger, and the low-temperature heat exchange loop medium circulating through the pipeline of the underground well or cooling tower takes away the heat of the first plate heat exchanger, and further cools the air-conditioning medium to a temperature close to the low-temperature heat exchange medium temperature of the pipeline of the underground well or cooling tower; The secondary cooled air conditioning medium enters the thermal expansion valve from the first plate heat exchanger and becomes gas, and the temperature drops to a lower temperature; The low-temperature air-conditioning medium enters the second plate heat exchanger, causing the second plate heat exchanger to cool down, thereby cooling the heat exchange medium flowing through the second plate heat exchanger. The low-temperature heat exchange medium is driven to the indoor duct unit through the second variable frequency pump, causing the indoor duct unit to cool down, thereby causing the air or other substances in contact with the indoor duct unit to cool down to the set temperature. The air-conditioning medium heated by the second plate heat exchanger flows through the A4 port of the main reversing valve, returns to the A3 port, and then returns to the compressor input end, so that the air-conditioning medium circulates.

10. A heating control method for a three-plate air conditioning heat exchange system according to claim 1, characterized in that: When heating, the A1 port of the main reversing valve is connected to the A4 port, and the A2 port is connected to the A3 port. After the compressor compresses the air-conditioning medium, the air-conditioning medium changes from gas to liquid, and the liquid temperature rises; The high-temperature air-conditioning medium enters the A4 port through the A1 port of the main reversing valve and reaches the second plate heat exchanger, which increases the temperature of the second plate heat exchanger, thereby heating the heat exchange medium flowing through the second plate heat exchanger. The high-temperature heat exchange medium is driven by the second variable frequency pump to reach the indoor duct unit, which increases the temperature of the indoor duct unit, thereby causing the air or other substances in contact with the indoor duct unit to heat up to the set temperature. After the air-conditioning medium passes through the second plate heat exchanger and enters the thermal expansion valve to become gas, the temperature is reduced. The low-temperature gas flows out of the thermal expansion valve and enters the first plate heat exchanger, and then flows out of the first plate heat exchanger and enters the air heat exchange mechanism. At this time, there is a large temperature difference between the lower temperature air-conditioning medium and the ambient temperature. The air flows through the air heat exchange mechanism so that the temperature of the air-conditioning medium is close to the ambient temperature. The air conditioning medium heated by the air heat exchange mechanism enters the third plate heat exchanger, and the heat exchange medium of the third plate heat exchanger heats the pipeline through the pipeline flowing through the underground well or cooling tower to a temperature close to the high-temperature heat exchange medium temperature of the pipeline flowing through the underground well or cooling tower; The air-conditioning medium that has been heated twice returns to the input end of the compressor through port A2 to port A3 to continue to be compressed and heated, so that the air-conditioning medium circulates.

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