Energy-saving primary air return air conditioning system based on heat recovery of heat pump

Abstract

A cold circulation system comprises a compressor, a first four-way valve, a second four-way valve, an air exhaust heat exchanger, a first throttling valve, a second throttling valve, a fresh air heat exchanger, a reheating heat exchanger, a third throttling valve and an air supply heat exchanger. The air circulation part 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 optimized 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 remove heat and dehumidify fresh air and recover heat in the fresh air and supplied air to perform secondary heating on the supplied air, and can recover heat in the exhaust air in winter to preheat the fresh air and the supplied air to perform secondary heating on the supplied air; 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 present invention relates to the technical field of exhaust air full heat recovery air conditioning, in particular to an energy-saving primary return air air conditioning system based on heat recovery of a heat pump. Background Art

[0002] Air conditioning consumes enormous amounts of energy in buildings, accounting for 50% to 70% of total energy consumption. Therefore, energy-saving measures for building air conditioning systems are essential. This proportion of energy consumption remains high. Traditional central air conditioning systems combine outdoor fresh air with indoor return air, centrally treating its heat and moisture before distributing it to the building to alleviate internal loads. Fresh air, as a component of the air conditioning load, typically accounts for 30% to 50% of the total, exceeding 60% in winter and even exceeding 70% in densely populated public buildings. Exhaust heat recovery devices in air conditioning systems can recycle and utilize the heat and cold contained in exhaust air, pre-treating the fresh air and thus reducing the energy consumption associated with processing it. Research has shown that when a heat recovery device achieves a 70% heat recovery efficiency, it can effectively reduce heating energy consumption by 40% to 50%.

[0003] The most widely used air-conditioning system at present is the single-return air 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 into the air-conditioned room or sent into the air-conditioned room after heating.

[0004] To remove water vapor from the air under cooling conditions, the evaporation temperature of the refrigerant in traditional central air conditioning systems needs to be significantly lower than the dew point of the air. This increases the temperature difference between the evaporation and condensation temperatures of the refrigeration unit, and the lower evaporation temperature reduces the refrigerant unit's coefficient of performance to a certain extent. Furthermore, under dew-point air supply conditions, indoor temperature and humidity parameters may deviate from the design operating point, and reheated air supply consumes additional energy. Furthermore, the simultaneous coupled treatment of air temperature and humidity during surface cooling does not truly maximize the energy efficiency of the cooling source, hindering subsequent operational control. In a single-return air handling unit, the mixed air is cooled and dehumidified in the surface cooler before being reheated in the reheater. This cooling followed by reheating process is known as "cold and heat offset," resulting in significant energy waste.

[0005] The secondary return air system, developed to address this drawback of the primary return air system, reduces the extra energy required by the reheater, but does so at the expense of a lower dew point. This reduces refrigeration system efficiency and further limits the use of natural cooling sources. Furthermore, the secondary return air system's poor resistance to moisture disturbances and inconvenient adjustment and control also restrict its use.

[0006] In addition, 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 an energy-saving primary return air air conditioning system based on heat pump heat recovery. Summary of the Invention

[0008] The purpose of the present invention is to provide an energy-saving single return air air-conditioning system based on heat pump heat recovery, which adds a heat pump refrigerant circulation device to the conventional single return air air-conditioning system to optimize the air treatment process of the single return air air-conditioning system, and innovatively integrates the heat pump hot and cold supply with the different treatment processes of fresh air, exhaust air and supply air of the single return air air-conditioning system to solve the problem proposed in the above background technology that in the single return air 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 heat offset", which causes a lot of energy waste.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] An energy-saving single-return air conditioning system based on heat pump heat recovery, comprising a cold circulation system and an air circulation system, wherein the cold circulation system comprises a compressor, a first four-way valve, a second 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, a third throttle valve, and a supply air heat exchanger;

[0011] A compressor, the compressor comprising an exhaust port disposed at one end of the compressor and an intake port disposed at the other end of the compressor;

[0012] A first four-way valve, the first four-way valve is arranged outside the compressor, and the first four-way valve consists of four groups of ports "a", "b", "c" and "d";

[0013] A second four-way valve, the second four-way valve is arranged outside the compressor, and the second four-way valve is composed of four groups of ports "e", "f", "g" and "h";

[0014] Exhaust heat exchanger, which is arranged outside the compressor and is used for subsequent heat exchange of exhaust air entering from the exhaust port of the air conditioner;

[0015] a first throttle valve, the first throttle valve being arranged outside the exhaust heat exchanger;

[0016] a second throttle valve, the second throttle valve being arranged outside the first throttle valve;

[0017] The fresh air heat exchanger is set on the outside of the second throttle valve, and is used for the fresh air entering the fresh air outlet of the air conditioner.

[0018] wind

[0019] Perform subsequent heat exchange;

[0020] The reheat heat exchanger is installed outside the compressor and is used to heat the air entering the reheat section of the air cabinet.

[0021] back

[0022] Continue reheat exchange;

[0023] a third throttle valve, arranged on the outside of the air supply heat exchanger;

[0024] Air supply heat exchanger, used for indirect heat exchange between the external cold and heat source circulation coil and the air;

[0025] The air circulation system includes an exhaust air regulating valve, a return air regulating valve, a fresh air regulating valve, an exhaust fan,

[0027] A heat exchange coil, a humidifier and an air supply fan; an exhaust fan, the exhaust fan being arranged outside the exhaust heat exchanger and being used to discharge part of the return air into the outdoor environment;

[0028] A heat exchange coil, the heat exchange coil being arranged outside the return air regulating valve and the fresh air regulating valve;

[0029] a humidifier, the humidifier being arranged outside the reheat heat exchanger;

[0030] An air supply fan is arranged on the outside of the humidifier.

[0031] Preferably, the cold circulation system further comprises

[0032] a first pipeline, wherein both ends of the first pipeline are respectively connected to the compressor and end a of the first four-way valve;

[0033] A second pipeline, wherein both ends of the second pipeline are respectively connected to the b end of the first four-way valve and the exhaust heat exchanger;

[0034] a third pipeline, wherein both ends of the third pipeline are respectively connected to the exhaust heat exchanger and the first throttle valve;

[0035] a fourth pipeline, wherein both ends of the fourth pipeline are respectively connected to the first throttle valve and the second throttle valve;

[0036] a fifth pipeline, wherein both ends of the fifth pipeline are respectively connected to the second throttle valve and the fresh air heat exchanger;

[0037] a sixth pipeline, wherein both ends of the sixth pipeline are respectively connected to the fresh air heat exchanger and the d end of the first four-way valve;

[0038] a seventh pipeline, wherein both ends of the seventh pipeline are respectively connected to the C end of the first four-way valve and one end of the compressor;

[0039] an eighth pipeline, wherein two ends of the eighth pipeline are respectively connected to the compressor and one end of the first one-way valve;

[0040] a ninth pipeline, wherein both ends of the ninth pipeline are respectively connected to the h end of the second four-way valve and the reheat heat exchanger;

[0041] a tenth pipeline, wherein two ends of the tenth pipeline are respectively connected to the e end of the second four-way valve and the other end of the first one-way valve;

[0042] an eleventh pipeline, wherein both ends of the eleventh pipeline are respectively connected to the third throttle valve and the reheat heat exchanger;

[0043] a twelfth pipeline, wherein both ends of the twelfth pipeline are respectively connected to the third throttle valve and the air supply heat exchanger;

[0044] A thirteenth pipeline, both ends of which are connected to the g end of the second four-way valve and the air supply heat exchanger respectively;

[0045] A fourteenth pipeline, both ends of which are connected to one end of the compressor and the f end of the second four-way valve respectively;

[0046] A fifteenth pipeline, wherein both ends of the fifteenth pipeline L are respectively connected to one end of the second one-way valve and one end of the first throttle valve;

[0047] a first one-way valve, wherein a cut-off end of the first one-way valve is connected to the compressor exhaust port, and a pass end is connected to the e-end of the second four-way valve;

[0048] A second one-way valve, wherein the cut-off end of the second one-way valve is connected to the first throttle valve and one end of the second throttle valve, and the through end is connected to the e end of the third throttle valve.

[0049] Preferably, the air circulation system further includes

[0050] An exhaust regulating valve is provided on the outside of the exhaust heat exchanger and is used to control the return air from the return air section of a portion of the air conditioner cabinet to pass through the exhaust heat exchanger for heat exchange;

[0051] The return air regulating valve is arranged outside the exhaust regulating valve and is used to control the return air from the return air section of the other air conditioner to pass to the mixing section of the air conditioner;

[0052] A fresh air regulating valve is provided on the outside of the fresh air heat exchanger and 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;

[0053] An exhaust fan, the exhaust fan being arranged outside the exhaust heat exchanger and being used to discharge part of the return air into the outdoor environment;

[0054] A heat exchange coil, the heat exchange coil being arranged outside the return air regulating valve and the fresh air regulating valve;

[0055] a humidifier, the humidifier being arranged outside the reheat heat exchanger;

[0056] An air supply fan is arranged on the outside of the humidifier.

[0057] Preferably, when the exhaust air heat exchanger and the reheat heat exchanger are condensers, the fresh air heat exchanger and the supply air heat exchanger are evaporators.

[0058] Preferably, when the fresh air heat exchanger, the reheat heat exchanger and the supply air heat exchanger are condensers, the exhaust air heat exchanger is an evaporator.

[0059] Preferably, the first throttle valve, the second throttle valve and the third throttle valve are preferably solenoid valves when they have a throttling effect.

[0060] Preferably, the exhaust heat exchanger, fresh air heat exchanger, reheat heat exchanger and supply air heat exchanger equipment can be external cold and heat source circulation coils for indirect heat exchange with the air or refrigerant circulation equipment for direct heat exchange with the air, preferably refrigerant circulation equipment for direct heat exchange with the air.

[0061] Preferably, the exhaust fan is a device inside an air conditioning cabinet or a fan in an external exhaust duct; the supply fan is a device inside an air conditioning cabinet or a fan in an external supply duct.

[0062] In summary, the present invention has the following beneficial effects:

[0063] 1. In view of the air conditioning processing flow of the conventional single return air air conditioning system, the present invention proposes a new single return air air conditioning system that combines a heat pump combined cooling and heating circulation system with single return air conditioning air treatment.

[0064] 2. Under summer working conditions, the cold energy in the exhaust air can be recovered to remove heat and dehumidify the fresh air and supply air. The cold energy in the exhaust air can be recovered to remove heat and dehumidify the fresh air and supply air while recovering the heat in the fresh air, supply air and outdoor air for secondary heating of the supply air. Under winter working conditions, the heat in the exhaust air can be recovered to heat the fresh air. The heat in the exhaust air can also be recovered to heat the fresh air and supply air while heating the supply air, thus realizing sensible heat and latent heat recovery.

[0065] 3. By utilizing the heat in the fresh air and exhaust air, the conventional single-return air conditioning system greatly reduces the waste of a lot of energy caused by the mixed air being cooled and dehumidified by the surface cooler and then reheated by the electric heater.

[0066] 4. By utilizing the fresh air heat exchanger and the supply air heat exchanger to remove heat and humidify the fresh air and supply air in summer and preheat the fresh air in winter, 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 are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic diagram of the energy-saving primary return air air conditioning system of the present invention.

[0068] Reference numerals in the figure are: 1, compressor; 101, exhaust port of the first compressor; 102, intake port of the second compressor; 2, first four-way valve; 3, second four-way valve; 4, exhaust air heat exchanger; 5, first throttle valve; 6, second throttle valve; 7, fresh air heat exchanger; 8, reheat heat exchanger; 9, third throttle valve; 10, supply air heat exchanger; 11, first one-way valve; 12, second one-way valve.

[0069] 13. Exhaust air regulating valve; 14. Return air regulating valve; 15. Fresh air regulating valve; 16. Exhaust fan; 17. Heat exchange coil; 18. Humidifier; 19. Supply air fan.

[0070] L1, first pipeline; L2, second pipeline; L3, third pipeline; L4, fourth pipeline; L5, fifth pipeline; L6, sixth pipeline; L7, seventh pipeline; L8, eighth pipeline; L9, ninth pipeline; L10, tenth pipeline; L11, eleventh pipeline; L12, twelfth pipeline; L13, thirteenth pipeline; L14, fourteenth pipeline; L15, fifteenth pipeline. DETAILED DESCRIPTION

[0071] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0072] The following is combined with Figure 1 The embodiments of the present invention are described in further detail.

[0073] An energy-saving single-return air conditioning system based on heat pump heat recovery, comprising a cold circulation system and an air circulation system, wherein the cold circulation system comprises a compressor 1, a first four-way valve 2, a second four-way valve 3, an exhaust air heat exchanger 4, a first throttle valve 5, a second throttle valve 6, a fresh air heat exchanger 7, a reheat heat exchanger 8, a third throttle valve 9, and a supply air heat exchanger 10;

[0074] A compressor 1, comprising an exhaust port 101 provided at one end of the compressor 1 and an intake port 102 provided at the other end of the compressor 1;

[0075] A first four-way valve 2, which is arranged outside the compressor 1 and consists of four groups of ports "a", "b", "c" and "d";

[0076] A second four-way valve 3 is provided outside the compressor 1 and is composed of four groups of ports, namely, "e", "f", "g" and "h";

[0077] Exhaust heat exchanger 4, the exhaust heat exchanger 4 is arranged outside the compressor 1, and the exhaust heat exchanger 4 is used for subsequent heat exchange of the exhaust air entering the exhaust port of the air cabinet;

[0078] a first throttle valve 5 , the first throttle valve 4 being arranged outside the exhaust heat exchanger 4 ;

[0079] a second throttle valve 6 , which is arranged outside the first throttle valve 5 ;

[0080] The fresh air heat exchanger 7 is arranged on the outside of the second throttle valve 6 and is used for subsequent heat exchange of the fresh air entering from the fresh air inlet of the air conditioner;

[0081] The reheat heat exchanger 8 is arranged outside the compressor 1 and is used for subsequent reheat exchange of the supply air entering the reheat section of the air conditioner;

[0082] The third throttle valve 9 is arranged outside the air supply heat exchanger 10;

[0083] The air supply heat exchanger 10 is used to indirectly exchange heat with the air for the external cold and heat source circulation coil;

[0084] The air circulation system includes an exhaust air regulating valve 13, a return air regulating valve 14, a fresh air regulating valve 15,

[0085] Row

[0086] air blower 16, heat exchange coil 17, humidifier 18 and air supply blower 19;

[0087] The exhaust regulating valve 13 is arranged outside the exhaust heat exchanger 4 and is used to control the return air from the return air section of the air conditioner to pass through the exhaust heat exchanger 4 for heat exchange;

[0088] The return air regulating valve 14 is arranged outside the exhaust regulating valve 13 and is used to control the return air from the return air section of the air conditioner to pass to the mixing section of the air conditioner;

[0089] The fresh air regulating valve 15 is arranged on the outside of the fresh air heat exchanger 7. The fresh air regulating valve 15 is used to control the fresh air at the fresh air section of the air conditioning cabinet to pass to the mixing section of the air conditioning cabinet.

[0090] Preferably, the cold circulation system further comprises

[0091] A first pipeline L1, wherein both ends of the first pipeline L1 are connected to the compressor 1 and the end a of the first four-way valve 2 respectively;

[0092] The second pipeline L2, the two ends of the second pipeline L2 are respectively connected to the b end of the first four-way valve 2 and the exhaust heat exchanger 4;

[0093] The third pipeline L3, both ends of which are connected to the exhaust heat exchanger 4 and the first throttle valve 5 respectively;

[0094] a fourth pipeline L4, both ends of which are connected to the first throttle valve 5 and the second throttle valve 6 respectively;

[0095] a fifth pipeline L5, the two ends of which are connected to the second throttle valve 6 and the fresh air heat exchanger 7 respectively;

[0096] The sixth pipeline L6, both ends of which are connected to the fresh air heat exchanger 7 and the end d of the first four-way valve 2 respectively;

[0097] a seventh pipeline L7, the two ends of which are respectively connected to the c-end of the first four-way valve 2 and one end of the compressor 1;

[0098] an eighth pipeline L8, the two ends of which are respectively connected to the compressor 1 and one end of the first one-way valve 11;

[0099] a ninth pipeline L9, the two ends of which are respectively connected to the h end of the second four-way valve 3 and the reheat heat exchanger 8;

[0100] a tenth pipeline L10, the two ends of which are respectively connected to the e end of the second four-way valve 3 and the other end of the first one-way valve 11;

[0101] an eleventh pipeline L11, wherein both ends of the eleventh pipeline L11 are respectively connected to the third throttle valve 9 and the reheat heat exchanger 8;

[0102] A twelfth pipeline L12, both ends of which are connected to the third throttle valve 9 and the air supply heat exchanger 10 respectively;

[0103] The thirteenth pipeline L13, both ends of which are connected to the g end of the second four-way valve 3 and the air supply heat exchanger 10 respectively;

[0104] A fourteenth pipeline L14, both ends of which are connected to one end of the compressor 1 and the f end of the second four-way valve 3 respectively;

[0105] A fifteenth pipeline L15, both ends of which are connected to the second one-way valve 12 and one end of the first throttle valve 5 respectively;

[0106] A first one-way valve 11, wherein a cut-off end of the first one-way valve 11 is connected to the exhaust port 101 of the compressor 1, and a pass end is connected to the e-end of the second four-way valve 3;

[0107] The second one-way valve 12 has a cut-off end connected to one end of the first throttle valve 5 and the second throttle valve 6 , and a passing end connected to the e end of the third throttle valve 9 .

[0108] Preferably, the air circulation system further includes

[0109] An exhaust fan 16 is provided outside the exhaust heat exchanger 4 and is used to discharge part of the return air into the outdoor environment;

[0110] The heat exchange coil 17 is arranged outside the return air regulating valve 14 and the fresh air regulating valve 15;

[0111] A humidifier 18, which is arranged outside the reheat heat exchanger 8;

[0112] The air supply fan 19 is provided outside the humidifier 18 .

[0113] Furthermore, when the exhaust air heat exchanger 4 and the reheat heat exchanger 8 are condensers, the fresh air heat exchanger 7 and the supply air heat exchanger 10 are evaporators.

[0114] Furthermore, when the fresh air heat exchanger 7, the reheat heat exchanger 8, and the supply air heat exchanger 10 are condensers, the exhaust air heat exchanger 4 is an evaporator.

[0115] Furthermore, the first throttle valve 5 , the second throttle valve 6 , and the third throttle valve 9 are preferably solenoid valves when they have a throttling effect.

[0116] Furthermore, the exhaust air heat exchanger 4, the fresh air heat exchanger 7, the reheat heat exchanger 8 and the supply air heat exchanger 10 can be external cold and heat source circulation coils for indirect heat exchange with the air or refrigerant circulation equipment for direct heat exchange with the air, preferably refrigerant circulation equipment for direct heat exchange with the air.

[0117] Furthermore, the exhaust fan 16 is a device inside the air conditioning cabinet or a fan in an external exhaust pipe; the supply fan 19 is a device inside the air conditioning cabinet or a fan in an external supply pipe.

[0118] After the return air in the air-conditioned room enters through the return air outlet of the air-conditioning cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 4, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 7; the mixed air passes through the supply air heat exchanger 10, the heat exchange coil 17, the reheat heat exchanger 8, and the humidifier 18 to complete the heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0119] In the present invention, under summer working conditions, when the exhaust air heat exchanger 4 and the reheat heat exchanger 8 are condensers, the fresh air heat exchanger 7 and the supply air heat exchanger 10 are evaporators.

[0120] In the present invention, under winter working conditions, when the fresh air heat exchanger 7, the reheat heat exchanger 8, and the supply air heat exchanger 10 are condensers, the exhaust air heat exchanger 4 is an evaporator.

[0121] Equipment such as the exhaust heat exchanger 4, the fresh air heat exchanger 7, the reheat heat exchanger 8, and the supply air heat exchanger 10 can be external cold or heat sources (water, heat pipe working fluid, thermal oil, etc.) circulating coils that indirectly exchange heat with the air, or they can be refrigerant circulation equipment that directly exchanges heat with the air. Preferably, the refrigerant circulation equipment directly exchanges heat with the air.

[0122] The exhaust fan 16 can be an internal device of the air conditioning cabinet, or it can be a fan of the exhaust external duct; the supply fan 19 can be an internal device of the air conditioning cabinet, or it can be a fan of the supply external duct; under winter working conditions, the heat exchange coil can exist as a heat source or not; the humidifier 18 can be located after the reheat heat exchanger 8, or it can be located at other positions of the air conditioning cabinet depending on the humidification method (such as isothermal, isenthalpic).

[0123] Use Example 1:

[0124] In summer, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a summer refrigeration cycle to realize only fresh air heat recovery and secondary heating of the supply air:

[0125] The refrigerant cycle of this system is as follows: the first throttle valve 5 is closed, the third throttle valve 9 is closed, the exhaust gas of the compressor 1 is condensed and releases heat in the reheat heat exchanger 8, the liquid working medium is throttled by the second throttle valve 6, evaporates and absorbs heat in the fresh air heat exchanger 7, and the gaseous working medium flows through the d end of the first four-way valve 2, the c end of the first four-way valve 2 and then returns to the compressor 1.

[0126] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0127] Use Example 2:

[0128] In summer, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a summer refrigeration cycle to realize heat extraction from the supply air and perform secondary heating on the supply air:

[0129] The refrigerant cycle of this system is as follows: the first throttle valve 5 is closed, the second throttle valve 6 is closed, the exhaust gas of the compressor 1 is condensed and releases heat in the reheat heat exchanger 8, the liquid working medium is throttled by the third throttle valve 9 and evaporates and absorbs heat in the air supply heat exchanger 10, and the gaseous working medium flows through the g end of the second four-way valve 3, the f end of the second four-way valve 3 and then returns to the compressor 1.

[0130] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0131] Use Example 3

[0132] Under summer conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a summer refrigeration cycle to realize simultaneous exhaust air cooling recovery, fresh air heat recovery, and supply air without taking heat, and performs secondary heating on the supply air:

[0133] The refrigerant cycle of this system is as follows: the first throttle valve 5 is opened, the third throttle valve 9 is closed, the exhaust gas of the compressor 1 flows through the a end of the first four-way valve 2 and the b end of the first four-way valve 2 to the exhaust heat exchanger 4 for condensation and heat release, and the other way flows to the reheat heat exchanger 8 for condensation and heat release. The liquid working medium flowing out of the exhaust heat exchanger 4 is mixed with the liquid working medium flowing out of the reheat heat exchanger 8 after passing through the first throttle valve 5, and then throttled by the second throttle valve 6 to evaporate and absorb heat in the fresh air heat exchanger 7. The gaseous working medium flows through the d end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1.

[0134] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0135] Use Example 4

[0136] Under summer conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a summer refrigeration cycle to achieve the following working conditions: no exhaust cooling is recovered, fresh air heat is recovered, and supply air heat is taken, and the supply air is heated twice:

[0137] The refrigerant cycle of this system is as follows: the first throttle valve 5 is closed, the exhaust gas of the compressor 1 is condensed and releases heat in the reheat heat exchanger 8, and a part of the liquid working medium flowing out of the reheat heat exchanger 8 is throttled by the second throttle valve 6 and evaporates and absorbs heat in the fresh air heat exchanger 7, and the gaseous working medium flows through the d end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1; the other part of the liquid working medium is throttled by the third throttle valve 9 and evaporates and absorbs heat in the supply air heat exchanger 10, and the gaseous working medium flows through the g end of the second four-way valve 3 and the f end of the second four-way valve 3 and then returns to the compressor 1.

[0138] The air circulation of this system is as follows: after the return air in the air-conditioned room enters through the return air outlet of the air-conditioning cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13, exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0139] Use Example 5

[0140] Under summer conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a summer refrigeration cycle to simultaneously recover exhaust air cooling, recover fresh air heat, and extract heat from supply air, thereby performing secondary heating of the supply air:

[0141] The refrigerant cycle of the system is as follows: the first throttle valve 5 is opened, and the exhaust gas of the compressor 1 flows through the a end of the first four-way valve 2 and the b end of the first four-way valve 2 to the exhaust heat exchanger 4 for condensation and heat release, and the other way flows to the reheat heat exchanger 8 for condensation and heat release. The liquid working medium flowing out of the exhaust heat exchanger 8 is mixed with the liquid working medium flowing out of the reheat heat exchanger 8 after passing through the first throttle valve 5. A part of the liquid working medium is throttled by the second throttle valve 6 and evaporates and absorbs heat in the fresh air heat exchanger 7. The gaseous working medium flows through the d end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1. The other part of the liquid working medium is throttled by the third throttle valve 9 and evaporates and absorbs heat in the supply air heat exchanger 10. The gaseous working medium flows through the g end of the second four-way valve 3 and the f end of the second four-way valve 3 and then returns to the compressor 1.

[0142] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0143] Use Example 6

[0144] Under winter conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a winter heating cycle to realize simultaneous exhaust heat recovery, fresh air heating, and non-heating of supply air, thereby performing secondary heating of the supply air:

[0145] The refrigerant cycle of this system is as follows: the second throttle valve 6 is opened and the third throttle valve 9 is closed. The exhaust gas of the compressor 1 flows through the a end of the first four-way valve 2 and the d end of the first four-way valve 2 to the fresh air heat exchanger 7 for condensation and heat release, and the other way flows to the reheat heat exchanger 8 for condensation and heat release. The liquid working medium passes through the second throttle valve 6 and is mixed with the liquid working medium flowing out of the reheat heat exchanger 8. Then, it passes through the first throttle valve 5 and evaporates in the exhaust heat exchanger 4 to absorb heat. The gaseous working medium flows through the b end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1.

[0146] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0147] Use Example 7

[0148] Under winter conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a winter heating cycle to realize simultaneous exhaust heat recovery, no heating of fresh air, no heating of supply air, and secondary heating of supply air:

[0149] The refrigerant cycle of this system is as follows: the second throttle valve 6 is closed and the third throttle valve 9 is closed, the exhaust gas from the compressor 1 is condensed and releases heat in the reheat heat exchanger 8, the liquid working medium flowing out of the reheat heat exchanger 8 passes through the first throttle valve 5 and evaporates and absorbs heat in the exhaust heat exchanger 4, and the gaseous working medium flows through the b end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1.

[0150] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0151] Use Example 8

[0152] Under winter conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a winter heating cycle to realize simultaneous exhaust heat recovery, non-heating of fresh air, heating of supply air, and secondary heating of the supply air:

[0153] The refrigerant cycle of this system is as follows: the second throttle valve 6 is closed and the third throttle valve 9 is opened. The exhaust gas of the compressor 1 goes to the reheat heat exchanger 8 for condensation and heat release in one way, and flows through the h end of the second four-way valve 3 and the g end of the second four-way valve 3 to the supply air heat exchanger 10 for condensation and heat release in the other way. The liquid working medium passes through the third throttle valve 9 and is mixed with the liquid working medium flowing out of the reheat heat exchanger 8. Then, it passes through the first throttle valve 5 and evaporates in the exhaust air heat exchanger 4 to absorb heat. The gaseous working medium flows through the b end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1.

[0154] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0155] Use Example 9

[0156] Under winter conditions, the energy-saving single-return air conditioning system based on heat pump heat recovery of the present invention is used as a winter heating cycle to realize simultaneous exhaust heat recovery, fresh air heating, and supply air heating, and performs secondary heating of the supply air:

[0157] The refrigerant cycle of this system is as follows: the second throttle valve 5 is opened, the exhaust gas of the compressor 1 first flows through the a end of the first four-way valve 2 and the d end of the first four-way valve 2 to the fresh air heat exchanger 7 for condensation and heat release, the second flow flows through the reheat heat exchanger 8 for condensation and heat release, the third flow flows through the h end of the second four-way valve 3 and the g end of the second four-way valve 3 to the supply air heat exchanger 10 for condensation and heat release, the liquid working medium passes through the third throttle valve 9 and is mixed with the liquid working medium flowing out of the reheat heat exchanger 8 and the liquid working medium after passing through the second throttle valve 6, and then evaporates and absorbs heat in the exhaust air heat exchanger 4 after passing through the first throttle valve 5, and the gaseous working medium flows through the b end of the first four-way valve 2 and the c end of the first four-way valve 2 and then returns to the compressor 1.

[0158] 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 cabinet, a part of it enters the exhaust duct through the exhaust regulating valve 13 and exchanges heat with the exhaust heat exchanger 3, and is then discharged to the outdoor environment by the exhaust fan 16; the other part enters the mixing section of the air-conditioning cabinet through the return air regulating valve 14 and is mixed with the fresh air entering through the fresh air regulating valve 15. Before the fresh air enters the mixing section of the air-conditioning cabinet, it first enters through the fresh air outlet of the air-conditioning cabinet and completes heat exchange with the fresh air heat exchanger 6; the mixed air passes through the heat exchange coil 17, the reheat heat exchanger 7, and the humidifier 18 to complete heat and humidity treatment in sequence, and is then sent into the air-conditioned room through the supply air fan 19.

[0159] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. An energy-saving single-return air conditioning system based on heat pump heat recovery, comprising a cold circulation system and an air circulation system, characterized in that: The cold circulation system comprises a compressor (1), a first four-way valve (2), a second four-way valve (3), an exhaust air heat exchanger (4), a first throttle valve (5), a second throttle valve (6), a fresh air heat exchanger (7), a reheat heat exchanger (8), a third throttle valve (9), and a supply air heat exchanger (10); 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 first four-way valve (2), the first four-way valve (2) being arranged outside the compressor (1), the first four-way valve (2) being composed of four groups of ports, namely, "a", "b", "c" and "d"; A second four-way valve (3), the second four-way valve (3) being arranged outside the compressor (1), the second four-way valve (2) being composed of four groups of ports, namely, "e", "f", "g" and "h"; An exhaust heat exchanger (4), the exhaust heat exchanger (4) being arranged outside the first four-way valve (2) and the second four-way valve (3), and the exhaust heat exchanger (4) 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 (5), the first throttle valve (4) being arranged outside the exhaust air heat exchanger (4); a second throttle valve (6), the second throttle valve (6) being arranged outside the first throttle valve (5); The fresh air heat exchanger (7) is arranged on the outside of the second throttle valve (6) and is used for subsequent heat exchange of the fresh air entering from the fresh air outlet of the air conditioner; The reheat heat exchanger (8) is arranged outside the compressor (1) and is used for subsequent reheat exchange of the supply air entering the reheat section of the air conditioner; a third throttle valve (9) arranged on the outside of the air supply heat exchanger (10); The air supply heat exchanger (10) is used to indirectly exchange heat between the external cold and hot source circulation coil and the air; The air circulation system comprises an exhaust air regulating valve (13), a return air regulating valve (14), a fresh air regulating valve (15), an exhaust air fan (16), a heat exchange coil (17), a humidifier (18) and an air supply fan (19); An exhaust fan (16), the exhaust fan (16) being arranged outside the exhaust heat exchanger (4), and the exhaust fan (16) being used to exhaust part of the return air into the outdoor environment; A heat exchange coil (17), wherein the heat exchange coil (17) is arranged outside the return air regulating valve (14) and the fresh air regulating valve (15); a humidifier (18), wherein the humidifier (18) is arranged outside the reheat heat exchanger (8); An air supply fan (19), wherein the air supply fan (19) is arranged outside the humidifier (18).

2. An energy-saving primary return air conditioning system based on heat pump heat recovery as claimed in claim 1, characterized in that: The cold cycle system also includes A first pipeline (L1), wherein two ends of the first pipeline (L1) are respectively connected to the compressor (1) and the end a of the first four-way valve (2); A second pipeline (L2), the two ends of which are respectively connected to the b end of the first four-way valve (2) and the exhaust heat exchanger (4); A third pipeline (L3), wherein both ends of the third pipeline (L3) are respectively connected to the exhaust air heat exchanger (4) and the first throttle valve (5); a fourth pipeline (L4), wherein two ends of the fourth pipeline (L4) are respectively connected to the first throttle valve (5) and the second throttle valve (6); a fifth pipeline (L5), wherein both ends of the fifth pipeline (L5) are respectively connected to the second throttle valve (6) and the fresh air heat exchanger (7); A sixth pipeline (L6), the two ends of the sixth pipeline (L6) being respectively connected to the fresh air heat exchanger (7) and the d end of the first four-way valve (2); a seventh pipeline (L7), wherein two ends of the seventh pipeline (L7) are respectively connected to the C end of the first four-way valve (2) and one end of the compressor (1); an eighth pipeline (L8), two ends of the eighth pipeline (L8) being respectively connected to the compressor (1) and one end of the first one-way valve (11); a ninth pipeline (L9), the two ends of which are respectively connected to the h end of the second four-way valve (3) and the reheat heat exchanger (8); a tenth pipeline (L10), the two ends of which are respectively connected to the e end of the second four-way valve (3) and the other end of the first one-way valve (11); an eleventh pipeline (L11), wherein both ends of the eleventh pipeline (L11) are respectively connected to the third throttle valve (9) and the reheat heat exchanger (8); A twelfth pipeline (L12), wherein both ends of the twelfth pipeline (L2) are respectively connected to a third throttle valve (9) and an air supply heat exchanger (10); A thirteenth pipeline (L13, both ends of which are connected to the g end of the second four-way valve (3) and the air supply heat exchanger (10); a fourteenth pipeline (L14), the two ends of which are respectively connected to one end of the compressor (1) and the f end of the second four-way valve (3); A fifteenth pipeline (L15), the two ends of which are respectively connected to the second one-way valve (12) and one end of the first throttle valve (5); A first one-way valve (11), wherein a cut-off end of the first one-way valve (11) is connected to an exhaust port (101) of the compressor (1), and a pass end is connected to an end e of a second four-way valve (3); A second one-way valve (12), wherein the cut-off end of the second one-way valve (12) is connected to the first throttle valve (5) and one end of the second throttle valve (6), and the through end is connected to the e end of the third throttle valve (9).

3. The energy-saving primary return air conditioning system based on heat pump heat recovery according to claim 1, characterized in that: The wind circulation system also includes An exhaust regulating valve (13), the exhaust regulating valve (13) being arranged outside the exhaust heat exchanger (4), the exhaust regulating valve (13) being used to control the return air at a part of the return air section of the air conditioner cabinet to pass through the exhaust heat exchanger (4) for heat exchange; A return air regulating valve (14), the return air regulating valve (14) being arranged outside the exhaust air regulating valve (13), the return air regulating valve (14) 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 (15), the fresh air regulating valve (15) being arranged on the outside of the fresh air heat exchanger (7), the fresh air regulating valve (15) being 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; An exhaust fan (16), the exhaust fan (16) being arranged outside the exhaust heat exchanger (4), and the exhaust fan (16) being used to exhaust part of the return air into the outdoor environment; A heat exchange coil (17), wherein the heat exchange coil (17) is arranged outside the return air regulating valve (14) and the fresh air regulating valve (15); a humidifier (18), wherein the humidifier (18) is arranged outside the reheat heat exchanger (8); An air supply fan (19), wherein the air supply fan (19) is arranged outside the humidifier (18).

4. An energy-saving primary return air conditioning system based on heat pump heat recovery as described in any one of claims 1 to 3, characterized in that: When the exhaust air heat exchanger (4) and the reheat heat exchanger (8) are condensers, the fresh air heat exchanger (7) and the supply air heat exchanger (10) are evaporators.

5. An energy-saving primary return air conditioning system based on heat pump heat recovery as described in any one of claims 1 to 3, characterized in that: When the fresh air heat exchanger (7), the reheat heat exchanger (8) and the supply air heat exchanger (10) are condensers, the exhaust air heat exchanger (4) is an evaporator.

6. An energy-saving primary return air conditioning system based on heat pump heat recovery as claimed in any one of claims 1 to 3, characterized in that: The first throttle valve (5), the second throttle valve (6) and the third throttle valve (9) are preferably solenoid valves when they have a throttling effect.

7. An energy-saving primary return air conditioning system based on heat pump heat recovery according to any one of claims 1 to 3, characterized in that: The exhaust air heat exchanger (4), the fresh air heat exchanger (7), the reheat heat exchanger (8) and the supply air heat exchanger (10) can be external cold or heat source circulation coils for indirect heat exchange with the air or refrigerant circulation equipment for direct heat exchange with the air, preferably the refrigerant circulation equipment for direct heat exchange with the air.

8. An energy-saving primary return air conditioning system based on heat pump heat recovery according to any one of claims 1 to 3, characterized in that: The exhaust fan (16) is a device inside the air conditioning cabinet or a fan of an external exhaust pipe; the air supply fan (19) is a device inside the air conditioning cabinet or a fan of an external supply pipe.

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