Primary air return air conditioning system for reheating by using fresh air heat

Abstract

The invention discloses a primary return air conditioning system capable of reheating by using fresh air heat, which is characterized in that a cold circulation system comprises a compressor, a four-way valve, an exhaust heat exchanger, a first throttle valve, a second throttle valve, a fresh air heat exchanger and a reheating heat exchanger, the air circulation system comprises an air exhaust adjusting valve, an air return adjusting valve, a fresh air adjusting valve, an air exhaust fan, a heat exchange coil, a humidifier and an air supply fan. The primary air return air conditioning system has the beneficial effects that the optimized primary air return air conditioning system can recover cold energy in exhaust air in summer to conduct heat removal and dehumidification on fresh air and recover heat in the fresh air to conduct secondary heating on supplied air, and the optimized primary air return air conditioning system can recover heat in the exhaust air to conduct preheating on the fresh air and conduct secondary heating on the supplied air in winter; the air supply cooling capacity requirement is reduced, meanwhile, the energy consumption loss caused by cold and heat offset of a conventional primary air return air conditioning system is reduced, the air treatment process of the conventional primary air return air conditioning system is well optimized, and the energy consumption of the conventional primary air return air conditioning system is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of building air conditioning and heating energy, and in particular to a single-return air conditioning system that utilizes fresh air heat for reheating. Background Art

[0002] Air conditioning consumes a lot of energy in buildings, accounting for 50% to 70% of the total energy consumption. Therefore, it is very necessary to take energy-saving measures for the air conditioning system of the building. The proportion of air conditioning energy consumption in building energy consumption has always been high. The traditional central air conditioning system mixes outdoor fresh air and indoor return air for heat and humidity treatment, and then supplies air to the building to eliminate the load in the building. Among them, the fresh air load, as one of the components of the air conditioning load, generally accounts for 30% to 50% of the air conditioning load, and even exceeds 60% in winter, and even exceeds 70% in public buildings with a large population density. The use of exhaust heat recovery devices in the air conditioning system can recover and utilize the cold / heat contained in the exhaust air, pre-treat the fresh air, and thus reduce the energy consumption generated by processing the fresh air. Studies have shown that when the heat recovery efficiency of the heat recovery device reaches 70%, it can effectively reduce the heating energy consumption by 40% to 50%.

[0003] The most widely used air-conditioning system at present is the single-return air-conditioning system. The single-return air-conditioning system is an air-conditioning system that fully mixes the indoor return air and the outdoor fresh air during the centralized air processing process. The mixed air is then cooled by the surface cooler and then directly sent to the air-conditioned room or sent to the return air of the air-conditioned room after heating.

[0004] Under refrigeration conditions, in order to remove water vapor from the air, the evaporation temperature of the refrigerant in the traditional central air-conditioning system needs to be much lower than the dew point temperature of the air, which increases the temperature difference between the evaporation temperature and the condensation temperature of the refrigeration unit. The lower evaporation temperature reduces the performance coefficient of the refrigerant group to a certain extent. At the same time, under the dew point air supply state, the indoor temperature and humidity parameters may deviate from the design operating point, and the reheat air supply will consume more energy; and the temperature and humidity of the air are coupled in the surface cooling treatment, which does not really bring into play the energy efficiency of the cold source, which is not conducive to the subsequent operation and regulation. In the single return air handling unit, the mixed air is cooled and dehumidified by the surface cooler and then reheated by the reheater. This process of cooling and reheating is called "cold and hot offset", which causes a lot of energy waste.

[0005] The secondary return air system, which was created to address the drawback of the primary return air system, saves the extra energy applied by the reheater, but at the cost of lowering the dew point of the machine. As a result, on the one hand, the operating efficiency of the refrigeration system is reduced, and on the other hand, the use of natural cooling sources is further restricted. At the same time, the secondary return air system is also restricted in its use due to its poor ability to resist moisture disturbance and the inconvenience of adjustment and control.

[0006] Traditional central air-conditioning systems have numerous loops and complex systems. The energy consumption during the energy transmission process of each loop is huge, almost equivalent to the energy consumption of the cold and heat sources, resulting in a significant reduction in the performance coefficient of the entire air-conditioning system.

[0007] Therefore, in order to solve the above problems, it is necessary to propose a single return air conditioning system that utilizes the heat of fresh air for reheating. Summary of the invention

[0008] The object of the present invention is to provide a single return air conditioning system which utilizes the heat of fresh air for reheating, so as to solve the problem proposed in the above background technology that in a single return air handling unit, the mixed air is cooled and dehumidified by a surface cooler and then reheated by a reheater. This process of reheating after cooling is called "cold and heat offset", which causes a large amount of energy waste.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a single return air air conditioning system using fresh air heat for reheating, comprising a cold circulation system and an air circulation system, the cold circulation system comprising: a compressor, a four-way valve, an exhaust air heat exchanger, a first throttle valve, a second throttle valve, a fresh air heat exchanger and a reheat heat exchanger, the compressor comprising an exhaust port arranged at one end of the compressor and an air intake port arranged at the other end of the compressor, the four-way valve is arranged on the outside of the compressor, the four-way valve is composed of four groups of ports "a", "b", "c" and "d", the exhaust air heat exchanger is arranged on the outside of the compressor, the first throttle valve is arranged on the outside of the exhaust air heat exchanger, the second throttle valve is arranged on the outside of the first throttle valve, the fresh air heat exchanger is arranged on the outside of the second throttle valve, the fresh air heat exchanger is used for subsequent heat exchange of the fresh air entering at the fresh air inlet of the air conditioning cabinet, the reheat heat exchanger is arranged on the outside of the compressor, and the air circulation system comprises: an exhaust air regulating valve, a return air regulating valve, a fresh air regulating valve, an exhaust fan, a heat exchange coil, a humidifier and a supply air fan.

[0010] By adopting the above technical scheme, it is achieved that the fresh air heat exchanger is used to remove heat and humidify the fresh air in summer conditions and preheat the fresh air in winter conditions, thereby reducing the energy consumption caused by "cold and heat offset" and the energy waste caused by the need for electric heating and preheating of fresh air in cold areas in winter.

[0011] Preferably, the single return air air conditioning system using fresh air heat for reheating further comprises: a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline, a seventh pipeline, an eighth pipeline and a ninth pipeline, wherein the two ends of the first pipeline are respectively connected to the exhaust port and the "a" port of the four-way valve, the two ends of the second pipeline are respectively connected to one end of the exhaust heat exchanger and the "b" port of the four-way valve, the two ends of the third pipeline are respectively connected to the other end of the exhaust heat exchanger and one end of the first throttle valve, the two ends of the fourth pipeline are respectively connected to the other end of the first throttle valve and the second One end of the throttle valve is connected, two ends of the fifth pipeline are respectively connected to the other end of the second throttle valve and one end of the fresh air heat exchanger, two ends of the sixth pipeline are respectively connected to the other end of the fresh air heat exchanger and the "d" port of the four-way valve, two ends of the seventh pipeline are respectively connected to the "c" port of the four-way valve and the air intake, one end of the eighth pipeline is connected to the pipe body of the first pipeline, and the other end of the eighth pipeline is connected to the reheat heat exchanger, one end of the ninth pipeline is connected to the other end of the reheat heat exchanger, and the other end of the ninth pipeline is connected to the pipe body of the fourth pipeline.

[0012] By adopting the above technical solution and connecting the pipelines, continuous transportation can be achieved.

[0013] Preferably, the single return air air-conditioning system that utilizes fresh air heat for reheating also includes: an exhaust air regulating valve, a return air regulating valve and a fresh air regulating valve. The exhaust air regulating valve is arranged on the outside of the exhaust air heat exchanger, and the exhaust air regulating valve is used to transport a part of the return air at the return air outlet of the air conditioning air cabinet to the exhaust air heat exchanger for heat exchange. The return air regulating valve is arranged on the outside of the exhaust air regulating valve, and the return air regulating valve transports the return air at the return air outlet of another part of the air conditioning air cabinet to the mixing section of the air conditioning air cabinet. The fresh air regulating valve is arranged on the outside of the fresh air heat exchanger, and the fresh air regulating valve is used to transport the fresh air in the fresh air heat exchanger to the mixing section of the air conditioning air cabinet.

[0014] By adopting the above technical solution, subsequent air circulation work can be carried out.

[0015] Preferably, the single return air air conditioning system utilizing the heat of fresh air for reheating further comprises: an exhaust fan, wherein the exhaust fan is arranged outside the exhaust heat exchanger, and the exhaust fan is used to discharge part of the return air into the outdoor environment.

[0016] By adopting the above technical solution, the wind can be driven to be discharged to the outside of the air conditioning cabinet.

[0017] Preferably, the single return air air conditioning system utilizing the heat of fresh air for reheating further comprises: a heat exchange coil, wherein the heat exchange coil is arranged outside the return air regulating valve and the fresh air regulating valve.

[0018] By adopting the above technical solution, the heat exchange coil can be used as a heat source to heat the wind.

[0019] Preferably, the single return air air conditioning system utilizing fresh air heat for reheating further comprises: a humidifier, wherein the humidifier is disposed outside the reheat heat exchanger.

[0020] By adopting the above technical solution, the supply air can be humidified to ensure the humidity requirement of the air in the air-conditioned room.

[0021] Preferably, the single return air air conditioning system utilizing the heat of fresh air for reheating further comprises: an air supply fan, wherein the air supply fan is arranged outside the humidifier.

[0022] By adopting the above technical solution, the air can be driven by the air supply fan to carry out the transportation work.

[0023] Preferably, the exhaust fan is an internal device of the air conditioning cabinet or a fan of an external exhaust duct; the supply fan is an internal device of the air conditioning cabinet or a fan of an external supply duct. Under winter conditions, the heat exchange coil may or may not exist as a heat source; the humidifier may be located after the reheat heat exchanger, or at other locations in the air conditioning cabinet depending on the humidification method.

[0024] In summary, the present invention includes the following beneficial effects: by providing a compressor, a four-way valve, an exhaust air heat exchanger, a first throttle valve, a second throttle valve, a fresh air heat exchanger, a reheat heat exchanger, an exhaust air regulating valve, a return air regulating valve, a fresh air regulating valve, an exhaust fan, a heat exchange coil, a humidifier and a supply air fan, the single return air air conditioning system that utilizes the fresh air heat for reheating can meet the needs of exhaust air heat recovery, fresh air heat treatment and supply air secondary heating under various working conditions; in summer, the cold energy in the exhaust air can be recovered to deheat and dehumidify the fresh air, and the heat in the fresh air can be recovered to perform secondary heating of the supply air; while reducing the demand for supply air cold energy, the energy consumption loss caused by the cold and heat offset of the conventional single return air air conditioning system is reduced; in winter, the heat in the exhaust air can be recovered to heat the fresh air and perform secondary heating of the supply air. The system can recover the cold and heat of the exhaust air, perform cold and heat treatment on the fresh air, and perform secondary heating on the supply air under winter and summer working conditions, thus avoiding the energy consumption of the conventional single-return air conditioning system using electric heating. The heat recovery amount is well adjustable, which well optimizes the air treatment process of the conventional single-return air conditioning system and greatly reduces the energy consumption of the conventional single-return air conditioning system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structural principle of the present invention.

[0026] The accompanying drawings are denoted as follows: 1. compressor; 101. exhaust port; 102. intake port; 2. four-way valve; 3. exhaust heat exchanger; 4. first throttle valve; 5. second throttle valve; 6. fresh air heat exchanger; 7. reheat heat exchanger; 8. exhaust air regulating valve; 9. return air regulating valve; 10. fresh air regulating valve; 11. exhaust fan; 12. heat exchange coil; 13. humidifier; 14. supply air fan; 15. first pipeline; 16. second pipeline; 17. third pipeline; 18. fourth pipeline; 19. fifth pipeline; 20. sixth pipeline; 21. seventh pipeline; 22. eighth pipeline; 23. ninth pipeline. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The following is combined with Figure 1 The embodiments of the present invention are described in further detail.

[0029] like Figure 1 As shown, this embodiment provides a technical solution: a single return air conditioning system using fresh air heat for reheating, including a cold circulation system and an air circulation system, the cold circulation system including: a compressor 1, a four-way valve 2, an exhaust air heat exchanger 3, a first throttle valve 4, a second throttle valve 5, a fresh air heat exchanger 6, a reheat heat exchanger 7, an exhaust air regulating valve 8, a return air regulating valve 9, a fresh air regulating valve 10, an exhaust fan 11, a heat exchange coil 12, a humidifier 13 and a supply air fan 14;

[0030] The compressor 1 includes an exhaust port 101 arranged at one end of the compressor 1 and an intake port 102 arranged at the other end of the compressor 1. The compressor 1 is an important mechanical equipment. Its main function is to compress low-pressure gas to increase its pressure and convert it into high-pressure gas. The compressor 1 is widely used. In the refrigeration system, the compressor 1 is the heart. It compresses the refrigerant vapor to increase its temperature and pressure, and then releases heat through the condenser to liquefy the refrigerant. This process is a key part of the refrigeration cycle. The four-way valve 2 is arranged on the outside of the compressor 1. The four-way valve 2 is composed of four groups of ports "a", "b", "c" and "d". The four-way valve 2 can provide four directions for connection, thereby achieving internal fluidity. The exhaust heat exchanger 3 is arranged on the outside of the compressor 1. The exhaust heat exchanger 3 can be used as a condenser and can be an external cold and heat source. Circulating coils such as water, heat pipe working fluid, and heat transfer oil can indirectly exchange heat with the air, or the refrigerant circulation equipment can directly exchange heat with the air. Preferably, the refrigerant circulation equipment directly exchanges heat with the air. The first throttle valve 4 is arranged on the outside of the exhaust heat exchanger 3. The main function of the first throttle valve 4 is to control the fluid flow rate by changing the throttling section or throttling length. It can control the fluid flow rate and is preferably a solenoid valve. The second throttle valve 5 is arranged on the outside of the first throttle valve 4. Generally speaking, when the pressure difference of the second throttle valve 5 is constant, the size of the opening of the second throttle valve 5 affects the change of the liquid flow rate, and is preferably a solenoid valve.

[0031] The fresh air heat exchanger 6 is arranged on the outside of the second throttle valve 5. When the exhaust air heat exchanger 3 is used as a condenser, the fresh air heat exchanger 6 can be used as an evaporator. The fresh air heat exchanger 6 is used for subsequent heat exchange of the fresh air entering at the fresh air inlet of the air conditioning cabinet. It can be a circulating coil connected to an external cold or hot source water, heat pipe working fluid, heat transfer oil, etc. to indirectly exchange heat with the air, or it can be a refrigerant circulation equipment to directly exchange heat with the air, preferably, the refrigerant circulation equipment directly exchanges heat with the air. The reheat heat exchanger 7 is arranged on the outside of the compressor 1. The reheat heat exchanger 7 can be used as a condenser. It can be a circulating coil connected to an external cold or hot source water, heat pipe working fluid, heat transfer oil, etc. to indirectly exchange heat with the air, or it can be a refrigerant circulation equipment to directly exchange heat with the air, preferably, the refrigerant circulation equipment directly exchanges heat with the air.

[0032] The exhaust regulating valve 8 is arranged on the outside of the exhaust heat exchanger 3, and the exhaust regulating valve 8 can adjust the air volume during transportation. The exhaust regulating valve 8 is used to transport a part of the return air at the return air outlet of the air conditioner to the exhaust heat exchanger 3 for heat exchange. The return air regulating valve 9 is arranged on the outside of the exhaust regulating valve 8, and the return air regulating valve 9 can adjust the air volume during transportation. The return air regulating valve 9 transports the return air at the return air outlet of another part of the air conditioner to the mixing section of the air conditioner. The fresh air regulating valve 10 is arranged on the outside of the fresh air heat exchanger 6, and the fresh air regulating valve 10 can adjust the air volume during transportation. The fresh air regulating valve 10 is used to transport the fresh air in the fresh air heat exchanger 6 to the mixing section of the air conditioner.

[0033] The exhaust fan 11 is arranged on the outside of the exhaust heat exchanger 3. The exhaust fan 11 can be a device in the air conditioning cabinet, or it can be a fan of a part of the exhaust external pipeline. The exhaust fan 11 is used to discharge part of the return air to the outdoor environment. The heat exchange coil 12 is arranged on the outside of the return air regulating valve 9 and the fresh air regulating valve 10. Under winter conditions, the heat exchange coil 12 can exist as a heat source or not exist as a heat source; the humidifier 13 is arranged on the outside of the reheat heat exchanger 7. The humidifier 13 can be located after the reheat heat exchanger 7, or it can be located at other positions of the air conditioning cabinet according to different humidification methods such as isothermal and isenthalpic. The supply air fan 14 is arranged on the outside of the humidifier 13. The supply air fan 14 can be a device in the air conditioning cabinet, or it can be a fan of a part of the supply air external pipeline.

[0034] like Figure 1 As shown, this embodiment provides a technical solution: a single return air conditioning system using fresh air heat for reheating, comprising: a first pipeline 15, a second pipeline 16, a third pipeline 17, a fourth pipeline 18, a fifth pipeline 19, a sixth pipeline 20, a seventh pipeline 21, an eighth pipeline 22 and a ninth pipeline 23;

[0035] The two ends of the first pipeline 15 are respectively connected to the exhaust port 101 and the "a" port of the four-way valve 2. Through the connection of the two ends of the first pipeline 15, the first pipeline 15 can be used for internal transportation. The two ends of the second pipeline 16 are respectively connected to one end of the exhaust heat exchanger 3 and the "b" port of the four-way valve 2. Through the connection of the two ends of the second pipeline 16, the second pipeline 16 can be used for internal transportation. The two ends of the third pipeline 17 are respectively connected to the other end of the exhaust heat exchanger 3 and one end of the first throttle valve 4. Through the connection of the two ends of the third pipeline 17, the third pipeline 17 can be used for internal transportation. The two ends of the fourth pipeline 18 are respectively connected to the other end of the first throttle valve 4 and one end of the second throttle valve 5. Through the connection of the two ends of the fourth pipeline 18, the fourth pipeline 18 can be used for internal transportation. The two ends of the fifth pipeline 19 are respectively connected to the other end of the second throttle valve 5 and one end of the fresh air heat exchanger 6. Through the connection of the two ends of the fifth pipeline 19, the internal transportation is carried out through the fourth pipeline 18. The fifth pipeline 19 is connected to the other end of the fresh air heat exchanger 6 and the "d" port of the four-way valve 2, respectively. The sixth pipeline 20 has two ends connected to the other end of the fresh air heat exchanger 6 and the "d" port of the four-way valve 2. The sixth pipeline 20 is ...c" port of the four-way valve 2 and the air inlet 102. The seventh pipeline 21 is connected to the other end of the fresh air heat exchanger 6 and the "c" port of the four-way valve 2 and the air inlet 102. The seventh pipeline 21 is connected to the other end of the fresh air heat exchanger 6 and the "c" port of the four-way valve 2 and the air inlet 102. The seventh pipeline 21 is connected to the other end of the fresh air heat exchanger 6 and the "d" port of the four-way valve 2. One end of the eighth pipeline 22 is connected to the tube body of the first pipeline 15, and the other end of the eighth pipeline 22 is connected to the reheat heat exchanger 7. Through the connection of the two ends of the eighth pipeline 22, the eighth pipeline 22 can be used for internal transportation. One end of the ninth pipeline 23 is connected to the other end of the reheat heat exchanger 7, and the other end of the ninth pipeline 23 is connected to the tube body of the fourth pipeline 18. Through the connection of the two ends of the ninth pipeline 23, the ninth pipeline 23 can be used for internal transportation.

[0036] The implementation principle of the one-way return air conditioning system of the present invention that utilizes the heat of fresh air for reheating is as follows:

[0037] In the summer refrigeration cycle: (1) Only the exhaust air cooling capacity is recovered: the first throttle valve 4 is opened, and the exhaust gas of the compressor 1 flows through the "a" end and the "b" end of the four-way valve 2 to the exhaust air heat exchanger 3 to condense and release heat. After the liquid working medium passes through the first throttle valve 4, it is throttled by the second throttle valve 5 to evaporate and absorb heat in the fresh air heat exchanger 6. The gaseous working medium flows through the "d" end and the "c" end of the four-way valve 2 and then returns to the compressor 1. (2) At the same time, the exhaust air cooling capacity and the fresh air heat are recovered, and the supply air is subjected to secondary heating: the exhaust gas of the compressor 1 flows through the "a" end and the "b" end of the four-way valve 2 to the exhaust air heat exchanger 3 to condense and release heat, and the other way to the reheat heat exchanger 7 to condense and release heat. The liquid working medium flowing out of the exhaust air heat exchanger 3 is mixed with the liquid working medium flowing out of the reheat heat exchanger 7 after passing through the first throttle valve 4, and then throttled by the second throttle valve 5 to evaporate and absorb heat in the fresh air heat exchanger 6. The gaseous working medium flows through the "d" end and the "c" end of the four-way valve 2 and then returns to the compressor 1.

[0038] In the winter heating cycle: (1) Only the exhaust heat recovery condition: the second throttle valve 5 is opened, the exhaust gas of the compressor 1 flows through the "a" end and the "d" end of the four-way valve 2 to the fresh air heat exchanger 6 to condense and release heat. After the liquid working medium passes through the second throttle valve 5, it is throttled by the first throttle valve 4 and evaporates and absorbs heat in the exhaust heat exchanger 3. The gaseous working medium flows through the "b" end and the "c" end of the four-way valve 2 and then returns to the compressor 1. (2) At the same time, the exhaust air heat is recovered and the fresh air is heated, and the supply air is heated twice: the exhaust gas of the compressor 1 flows through the "a" end and the "d" end of the four-way valve 2 to the fresh air heat exchanger 6 for condensation and heat release, and the other way is to the reheat heat exchanger 7 for condensation and heat release. The liquid working medium flowing out of the fresh air heat exchanger 6 is mixed with the liquid working medium flowing out of the reheat heat exchanger 7 after passing through the second throttle valve 5, and then throttled by the first throttle valve 4 to evaporate and absorb heat in the exhaust air heat exchanger 3. The gaseous working medium flows through the "b" end and the "c" end of the four-way valve 2 and then returns to the compressor 1.

[0039] Use Example 1

[0040] In summer conditions, the present invention uses a single return air air conditioning system that uses fresh air heat for reheating as a summer refrigeration cycle to achieve only exhaust air cooling recovery conditions:

[0041] The refrigerant cycle of the system is as follows: the first throttle valve 4 is opened, the exhaust gas of the compressor 1 flows through the a end of the four-way valve 2 and the b end of the four-way valve 2 to the exhaust air heat exchanger 3 to condense and release heat, the liquid working medium passes through the first throttle valve 4, is throttled by the second throttle valve 5, evaporates and absorbs heat in the fresh air heat exchanger 6, and the gaseous working medium flows through the d end of the four-way valve 2 and the c end of the four-way valve 2 and then returns to the compressor 1.

[0042] The air circulation of the system is as follows: after the return air in the air-conditioned room enters through the return air outlet of the air-conditioning air cabinet, a part of it enters the exhaust passage through the exhaust air regulating valve 8 and exchanges heat with the exhaust air heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 11; the other part enters the mixing section of the air-conditioning air cabinet through the return air regulating valve 9 and is mixed with the fresh air entering through the fresh air regulating valve 10. Before the fresh air enters the mixing section of the air-conditioning air cabinet, it first enters through the fresh air outlet of the air-conditioning air cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 12, the reheat heat exchanger 7, and the humidifier 13 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 14.

[0043] Use Example 2

[0044] In summer conditions, the present invention uses a single return air air conditioning system that uses fresh air heat for reheating as a summer refrigeration cycle to simultaneously recover exhaust air cooling and fresh air heat, and perform secondary heating on the supply air:

[0045] The refrigerant cycle of the system is as follows: the exhaust gas of the compressor 1 flows through the a end of the four-way valve 2 and the b end of the four-way valve 2 to the exhaust heat exchanger 3 to condense and release heat, and flows through the other end to the reheat heat exchanger 7 to condense and release heat. The liquid working medium flowing out of the exhaust heat exchanger 3 is mixed with the liquid working medium flowing out of the reheat heat exchanger 7 after passing through the first throttle valve 4, and then is throttled by the second throttle valve 5 to evaporate and absorb heat in the fresh air heat exchanger 6. The gaseous working medium flows through the d end of the four-way valve 2 and the c end of the four-way valve 2 and then returns to the compressor 1.

[0046] The air circulation of the system is as follows: after the return air in the air-conditioned room enters through the return air outlet of the air-conditioning air cabinet, a part of it enters the exhaust passage through the exhaust air regulating valve 8 and exchanges heat with the exhaust air heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 11; the other part enters the mixing section of the air-conditioning air cabinet through the return air regulating valve 9 and is mixed with the fresh air entering through the fresh air regulating valve 10. Before the fresh air enters the mixing section of the air-conditioning air cabinet, it first enters through the fresh air outlet of the air-conditioning air cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 12, the reheat heat exchanger 7, and the humidifier 13 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 14.

[0047] Use Example 3

[0048] Under winter conditions, the present invention uses a single return air air conditioning system that uses fresh air heat for reheating as a winter heating cycle to achieve exhaust air heat recovery only:

[0049] The refrigerant cycle of this system is as follows: the second throttle valve 5 is opened, the exhaust gas of the compressor 1 flows through the a end of the four-way valve 2 and the d end of the four-way valve 2 to the fresh air heat exchanger 6 to condense and release heat, the liquid working medium passes through the second throttle valve 5, is throttled by the first throttle valve 4, evaporates and absorbs heat in the exhaust air heat exchanger 3, and the gaseous working medium flows through the b end of the four-way valve 2 and the c end of the four-way valve 2 and then returns to the compressor 1.

[0050] The air circulation of the system is as follows: after the return air in the air-conditioned room enters through the return air outlet of the air-conditioning air cabinet, a part of it enters the exhaust passage through the exhaust air regulating valve 8 and exchanges heat with the exhaust air heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 11; the other part enters the mixing section of the air-conditioning air cabinet through the return air regulating valve 9 and is mixed with the fresh air entering through the fresh air regulating valve 10. Before the fresh air enters the mixing section of the air-conditioning air cabinet, it first enters through the fresh air outlet of the air-conditioning air cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 12, the reheat heat exchanger 7, and the humidifier 13 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 14.

[0051] Use Example 4

[0052] Under winter conditions, the present invention uses a single return air air conditioning system that uses fresh air heat for reheating as a winter heating cycle to simultaneously recover exhaust air heat and heat fresh air, and perform secondary heating on the supply air:

[0053] The refrigerant cycle of this system is as follows: the exhaust gas of the compressor 1 flows through the a end of the four-way valve 2 and the d end of the four-way valve 2 to the fresh air heat exchanger 6 for condensation and heat release, and flows through the other end to the reheat heat exchanger 7 for condensation and heat release. The liquid working medium flowing out of the fresh air heat exchanger 6 is mixed with the liquid working medium flowing out of the reheat heat exchanger 7 after passing through the second throttle valve 5, and then is throttled by the first throttle valve 4 to evaporate and absorb heat in the exhaust air heat exchanger 3. The gaseous working medium flows through the b end of the four-way valve 2 and the c end of the four-way valve 2 and then returns to the compressor 1.

[0054] The air circulation of the system is as follows: after the return air in the air-conditioned room enters through the return air outlet of the air-conditioning air cabinet, a part of it enters the exhaust passage through the exhaust air regulating valve 8 and exchanges heat with the exhaust air heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 11; the other part enters the mixing section of the air-conditioning air cabinet through the return air regulating valve 9 and is mixed with the fresh air entering through the fresh air regulating valve 10. Before the fresh air enters the mixing section of the air-conditioning air cabinet, it first enters through the fresh air outlet of the air-conditioning air cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 12, the reheat heat exchanger 7, and the humidifier 13 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 14.

[0055] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A single return air conditioning system that utilizes fresh air heat for reheating, comprising a cold circulation system and an air circulation system, Features: The cold circulation system comprises: a compressor (1), the compressor (1) comprising an exhaust port (101) arranged at one end of the compressor (1) and an intake port (102) arranged at the other end of the compressor (1); a four-way valve (2), the four-way valve (2) being arranged outside the compressor (1), the four-way valve (2) being composed of four groups of ports, namely, "a", "b", "c" and "d"; An exhaust heat exchanger (3), the exhaust heat exchanger (3) being arranged outside the compressor (1), and the exhaust heat exchanger (3) being used for subsequent heat exchange of exhaust air entering from the exhaust port of the air cabinet of the air conditioner; A first throttle valve (4), the first throttle valve (4) being arranged outside the exhaust air heat exchanger (3); A second throttle valve (5), the second throttle valve (5) being arranged outside the first throttle valve (4); A fresh air heat exchanger (6), the fresh air heat exchanger (6) being arranged outside the second throttle valve (5), the fresh air heat exchanger (6) being used for subsequent heat exchange of the fresh air entering from the fresh air outlet of the air conditioner; A reheat heat exchanger (7), the reheat heat exchanger (7) being arranged outside the compressor (1), the reheat heat exchanger (7) being used for subsequent reheat exchange of the supply air entering the reheat section of the air cabinet of the air conditioner; The air circulation system comprises an exhaust air regulating valve (8), the exhaust air regulating valve (8) being arranged outside the exhaust air heat exchanger (3), and the exhaust air regulating valve (8) being used to control the return air at a part of the return air section of the air conditioner to pass through the exhaust air heat exchanger (3) for heat exchange; A return air regulating valve (9), the return air regulating valve (9) being arranged outside the exhaust air regulating valve (8), the return air regulating valve (9) being used to control the return air at the return air section of another part of the air conditioner cabinet to pass to the mixing section of the air conditioner cabinet; A fresh air regulating valve (10), wherein the fresh air regulating valve (10) is arranged on the outside of the fresh air heat exchanger (6), and the fresh air regulating valve (10) is used to control the fresh air at the fresh air section of the air conditioner to pass to the mixing section of the air conditioner.

2. A single return air conditioning system utilizing fresh air heat for reheating as claimed in claim 1, Features: The cold circulation system also includes: A first pipeline (15), wherein two ends of the first pipeline (15) are respectively connected to the exhaust port (101) and the "a" port of the four-way valve (2); A second pipeline (16), the two ends of which are respectively connected to one end of the exhaust heat exchanger (3) and the "b" port of the four-way valve (2); A third pipeline (17), wherein two ends of the third pipeline (17) are respectively connected to the other end of the exhaust heat exchanger (3) and one end of the first throttle valve (4); a fourth pipeline (18), wherein two ends of the fourth pipeline (18) are respectively connected to the other end of the first throttle valve (4) and one end of the second throttle valve (5); A fifth pipeline (19), the two ends of which are respectively connected to the other end of the second throttle valve (5) and one end of the fresh air heat exchanger (6); A sixth pipeline (20), wherein two ends of the sixth pipeline (20) are respectively connected to the other end of the fresh air heat exchanger (6) and the "d" port of the four-way valve (2); A seventh pipeline (21), wherein two ends of the seventh pipeline (21) are respectively connected to the "c" port of the four-way valve (2) and the air intake port (102); an eighth pipeline (22), one end of the eighth pipeline (22) being connected to the pipe body of the first pipeline (15), and the other end of the eighth pipeline (22) being connected to the reheat heat exchanger (7); A ninth pipeline (23), one end of the ninth pipeline (23) is connected to the other end of the reheat heat exchanger (7), and the other end of the ninth pipeline (23) is connected to the pipe body of the fourth pipeline (18).

3. A primary return air conditioning system utilizing fresh air heat for reheating as claimed in any one of claims 1 to 2, Features: The wind circulation system also includes An exhaust fan (11), the exhaust fan (11) being arranged outside the exhaust heat exchanger (3), and the exhaust fan (11) being used to exhaust part of the return air into the outdoor environment; A heat exchange coil (12), wherein the heat exchange coil (12) is arranged outside the return air regulating valve (9) and the fresh air regulating valve (10); a humidifier (13), wherein the humidifier (13) is arranged outside the reheat heat exchanger (7); An air supply fan (14), wherein the air supply fan (14) is arranged outside the humidifier (13).

4. A primary return air conditioning system utilizing fresh air heat for reheating according to any one of claims 1 to 3, Features: When the exhaust air heat exchanger (3) and the reheat heat exchanger (7) are condensers, the fresh air heat exchanger (6) is an evaporator.

5. A primary return air conditioning system for reheating using fresh air heat according to any one of claims 1 to 3, Features: When the fresh air heat exchanger (6) and the reheat heat exchanger (7) are condensers, the exhaust air heat exchanger (3) is an evaporator.

6. A primary return air conditioning system utilizing fresh air heat for reheating according to any one of claims 1 to 3, Features: The first throttle valve (4) and the second throttle valve (7) are preferably solenoid valves.

7. A primary return air conditioning system utilizing fresh air heat for reheating according to any one of claims 1 to 3, Features: The exhaust air heat exchanger (3), the fresh air heat exchanger (6), and the reheat heat exchanger (7) can be external cold and heat source circulation coils for indirect heat exchange with the air, or can be refrigerant circulation equipment for direct heat exchange with the air, preferably, refrigerant circulation equipment for direct heat exchange with the air.

8. A primary return air conditioning system utilizing fresh air heat for reheating according to any one of claims 1 to 3, Features: The exhaust fan (11) is a device inside the air conditioning cabinet or a fan of an external exhaust pipe; the supply fan (14) is a device inside the air conditioning cabinet or a fan of an external supply pipe.

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