Exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system

Abstract

The present invention discloses an exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system, which relates to the technical field of air-conditioning units; improves a heat recovery system, realizes the fresh air unit to recover exhaust air heat, and the two heat recovery functions of fresh air pre-cooling and reheating heat recovery, and the heat recovery amount can be freely adjusted according to demand to realize the problem of free heat recovery, and the present invention includes a fluorine pump and an exhaust heat recovery coil, a fresh air pre-cooling and preheating coil, and a fresh air reheating coil which are connected in series and parallel through a three-way valve and system pipelines, and there are four operation modes in total; in order to reduce cavitation of the fluorine pump, the present invention switches the three-way valve to ensure that the low-pressure side of the fluorine pump is condensing heat exchange, the refrigerant of the fluorine pump system absorbs heat and evaporates in the exhaust heat recovery coil, and the fresh air pre-cooling and preheating coil releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and preheating fresh air, the refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil, and the exhaust heat recovery coil releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and precooling fresh air.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning units, and in particular to an exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system. Background Art

[0002] Existing technical solutions: The current fresh air units mainly use rotary heat recovery, plate heat recovery, heat pipe gravity heat recovery, glycol coil heat recovery, and fluorine pump heat recovery for exhaust air. The fresh air units use pre-cooling and reheating heat recovery for fresh air in summer, that is, pre-cooling before the refrigeration coil and reheating heat recovery after the refrigeration coil. The types of fresh air pre-cooling and reheating heat recovery include heat pipe gravity heat recovery and glycol coil heat recovery.

[0003] The defects of the existing technology are as follows: the two heat recovery types coexist, requiring two independent systems, which are complex and expensive. The wheel heat recovery, plate heat recovery, and heat pipe gravity heat recovery used by the fresh air unit to recover exhaust air heat can only be used on integral units, not on split units, and the unit structure has poor adaptability. Plate heat recovery and heat pipe gravity heat recovery are passive heat recovery methods, and the heat recovery amount cannot be freely adjusted. Fluorine pump heat recovery is only used for exhaust air heat recovery in the fresh air unit, and does not involve fresh air pre-cooling and reheating heat recovery in the fresh air unit in summer.

[0004] The problem that the patent needs to solve: A heat recovery system that realizes two heat recovery functions: heat recovery of exhaust air by the fresh air unit and heat recovery of fresh air pre-cooling and reheating; the heat recovery amount can be freely adjusted according to demand to realize free heat recovery.

[0005] In response to the above problems, the inventors proposed an exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system to solve the above problems. Summary of the Invention

[0006] In order to solve the problem of free heat recovery in a heat recovery system, the fresh air unit can recover the exhaust air heat, and the fresh air pre-cooling and reheating heat recovery can be realized by two heat recovery functions and the heat recovery amount can be freely adjusted according to demand; the purpose of the present invention is to provide an exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solution: the fluorine pump and the exhaust heat recovery coil, the fresh air pre-cooling and preheating coil, and the fresh air reheating coil are connected in series and parallel through the first three-way valve, the second three-way valve, the third three-way valve, the fourth three-way valve and the system pipeline. There are four operating modes in total. In order to reduce cavitation of the fluorine pump, the three-way valve is switched to ensure that the low-pressure side of the fluorine pump is condensing heat exchange under various operating conditions.

[0008] Preferably, in winter heating operation, the first three-way valve only connects the fluorine pump and the second three-way valve, the second three-way valve only connects the first three-way valve and the first refrigerant pipeline, the third three-way valve only connects the exhaust heat recovery coil and the fresh air pre-cooling and preheating coil, and the fourth three-way valve only connects the second refrigerant pipeline and the fluorine pump; the fluorine pump compresses the refrigerant to flow through the first three-way valve, the second three-way valve, the first refrigerant pipeline, the exhaust heat recovery coil, the third three-way valve, the fresh air pre-cooling and preheating coil, the second refrigerant pipeline, and the fourth three-way valve, and returns to the fluorine pump. Because the fresh air temperature is lower than the exhaust air, there is a temperature difference between the fresh air and the exhaust air. The refrigerant in the fluorine pump system absorbs heat and evaporates in the exhaust heat recovery coil, and releases heat and condenses in the fresh air pre-cooling and preheating coil, thereby achieving the purpose of exhaust heat recovery and preheating fresh air. The temperature after the fresh air pre-cooling and preheating coil can be adjusted by changing the operating frequency of the fluorine pump to achieve free heat recovery.

[0009] Preferably, in the summer cooling operation, the heat and humidity load of the treated room is relatively large, and the refrigerator does not need to be reheated or the reheat amount is relatively small after cooling and dehumidification. At this time, the fluorine pump heat recovery system only pre-cools the fresh air, and the specific connection method of the fluorine pump system pipeline is: the first three-way valve only connects the fluorine pump and the third refrigerant pipeline, the second three-way valve only connects the fourth refrigerant pipeline and the first refrigerant pipeline, the third three-way valve only connects the exhaust heat recovery coil and the fresh air pre-cooling and preheating coil, and the fourth three-way valve only connects the fourth refrigerant pipeline and the fluorine pump; the fluorine pump compresses the refrigerant to flow through the first three-way valve, the third three-way valve and the fourth three-way valve. The third refrigerant pipeline, the second refrigerant pipeline, the fresh air pre-cooling and pre-heating coil, the third three-way valve, the exhaust heat recovery coil, the first refrigerant pipeline, the second three-way valve, the fourth refrigerant pipeline, the fourth three-way valve, return to the fluorine pump. Because the fresh air temperature is higher than the exhaust air, there is a temperature difference between the fresh air and the exhaust air. The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and pre-heating coil, and the exhaust heat recovery coil releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and pre-cooling the fresh air. The temperature after the fresh air pre-cooling and pre-heating coil can also be adjusted by changing the operating frequency of the fluorine pump to achieve free heat recovery.

[0010] Preferably, during the transition season, cooling operation is performed when the fresh air temperature is close to or lower than the exhaust air temperature. At this time, the fluorine pump cannot pre-cool the fresh air through the exhaust heat recovery coil. During the transition season, the heat and humidity in the treated rooms are relatively low, that is, the heat load is relatively small and the humidity load is relatively large. The fresh air needs to be reheated after being cooled and dehumidified by the chiller. At this time, the fluorine pump system switches to the fresh air pre-cooling and reheating operation mode. The specific connection method of the fluorine pump system pipeline is: the first three-way valve only connects the fluorine pump and the third refrigerant pipeline, the third three-way valve only connects the fifth refrigerant pipeline and the fresh air pre-cooling and preheating coil, the second three-way valve only connects the fourth refrigerant pipeline and the sixth refrigerant pipeline, and the fourth three-way valve only connects the fourth refrigerant pipeline and the fluorine pump; the fluorine pump compresses the refrigerant to flow through the first three-way valve, the third refrigerant pipeline, the second refrigerant pipeline, the fresh air pre-cooling and preheating coil, the third three-way valve, the third refrigerant pipeline, the fresh air reheat coil, the sixth refrigerant pipeline, the second three-way valve, the fourth refrigerant pipeline, the fourth three-way valve, and returns to the fluorine pump. In order to achieve the control effect of constant temperature and humidity in the room, after the cold machine starts cooling, the temperature after the evaporator is processed to the indoor set temperature Below the dew point temperature, taking the indoor set temperature and humidity of 23℃ / 55% as an example, the temperature after the evaporator needs to be processed to 13℃. At this time, there is a temperature difference before and after the evaporator. The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil, and releases heat and condenses in the fresh air reheat coil, thereby achieving the purpose of fresh air reheat heat recovery and pre-cooling fresh air. If the fluorine pump reheating heat does not meet the requirements of the reheat supply air temperature at this time, the condensing reheat coil can be turned on, and the precise adjustment of the auxiliary heater and humidifier can achieve the control target of constant temperature and humidity. The auxiliary heater can have electric heating, hot water coil, steam coil and other heating types. The humidifier can have electrode humidification, electric heating humidification, dry steam humidification, high-pressure micro-mist, high-pressure spray, wet film and other humidification types.

[0011] Preferably, in the summer cooling operation, the fresh air temperature is higher than the exhaust air temperature. At this time, the fluorine pump system can pre-cool the fresh air through the exhaust heat recovery coil; the treated room has a certain heat and humidity load, and the fresh air needs to be reheated after being cooled and dehumidified by the chiller. At this time, the fluorine pump system can perform fresh air pre-cooling and reheating operation. At this time, both heat recovery modes can be operated, with fresh air pre-cooling and reheating heat recovery operation being prioritized. When the reheating heat recovery amount reaches the requirement, a portion of the refrigerant can be bypassed to the exhaust heat recovery coil through the three-way valve and the three-way valve to achieve free heat recovery of energy. The specific connection method of the fluorine pump system pipeline is: the first three-way valve only connects the fluorine pump and the third refrigerant pipeline, the third three-way valve connects the fifth refrigerant pipeline, the exhaust heat recovery coil and the fresh air pre-cooling and preheating coil, the second three-way valve connects the first refrigerant pipeline, the sixth refrigerant pipeline and the fourth refrigerant pipeline, and the fourth three-way valve only connects the fourth refrigerant pipeline and the fluorine pump; the fluorine pump compresses the refrigerant to flow through the first three-way valve, the third refrigerant pipeline, the second refrigerant pipeline, the fresh air pre-cooling and preheating coil, and the third three-way valve. The refrigerant is divided into two paths through the third three-way valve. One path of refrigerant passes through the fifth refrigerant pipeline, the fresh air reheat coil, the sixth refrigerant pipeline, the second three-way valve, and the fourth three-way valve. The refrigerant pipeline and the fourth three-way valve return to the fluorine pump. The other refrigerant passes through the exhaust heat recovery coil, the first refrigerant pipeline, the second three-way valve, the fourth refrigerant pipeline, and the fourth three-way valve and returns to the fluorine pump. In order to achieve the control effect of constant temperature and humidity in the room, after the refrigerator starts cooling, the temperature after the evaporator is treated to below the dew point temperature of the indoor set temperature. Taking the indoor set temperature and humidity of 23℃ / 55% as an example, the temperature after the evaporator must be treated to 13℃. At this time, there is a temperature difference before and after the evaporator. The refrigerant in the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil, and releases heat and condenses in the fresh air reheat coil, thereby achieving the purpose of fresh air reheat heat recovery and pre-cooling fresh air. If the fluorine pump reheat exceeds the reheat supply air temperature requirement at this time, a part of the refrigerant can be bypassed to the exhaust heat recovery coil through the three-way valve and the three-way valve to achieve free heat recovery of energy, and then supplemented by precise adjustment of the heater and humidifier to achieve the control target of constant temperature and humidity.

[0012] Preferably, the fluorine pump adopts a variable frequency fluorine pump with adjustable flow; the three-way valve adopts an analog refrigerant three-way valve with adjustable flow; a temperature point is set after the fresh air pre-cooling and preheating coil to collect the temperature; a temperature point is set after the fresh air reheating coil to collect the temperature, and the fluorine pump frequency and the opening of the three-way valve are adjusted according to the temperature after the fresh air pre-cooling and preheating coil, the temperature after the fresh air reheating coil and the control target.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. Through the setting of the three-way valve, in order to reduce the cavitation of the fluorine pump, the three-way valve is switched to ensure that in various operating states, the low-pressure side of the fluorine pump is condensing heat exchange, the fluorine pump system refrigerant absorbs heat and evaporates in the exhaust heat recovery coil, and the fresh air pre-cooling and preheating coil releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and preheating fresh air. The fluorine pump system refrigerant absorbs heat and evaporates in the fresh air pre-cooling and preheating coil, and the exhaust heat recovery coil releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and pre-cooling fresh air. The fresh air pre-cooling and reheating heat recovery operation, when the reheat heat recovery amount reaches the requirement, a part of the refrigerant can be bypassed to the exhaust heat recovery coil through the three-way valve 6 and the three-way valve 8 to achieve free heat recovery of energy;

[0015] 2. Through the setting of fresh air pre-cooling and preheating coils and fresh air reheating coils, according to the temperature after the fresh air pre-cooling and preheating coils, the temperature after the fresh air reheating coils and the control target, the frequency of the fluorine pump and the opening of the three-way valve are adjusted, so that the heat recovery amount can be freely adjusted according to demand, thereby realizing free heat recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a schematic diagram of the system of the fluorine pump free heat recovery fresh air variable frequency condensation reheat constant temperature and humidity air conditioning unit of the present invention.

[0018] In the figure: 1. Fluorine pump; 2. Exhaust air heat recovery coil; 3. Fresh air pre-cooling and preheating coil; 4. Fresh air reheat coil; 5. First three-way valve; 6. Second three-way valve; 7. First refrigerant pipeline; 8. Third three-way valve; 9. Second refrigerant pipeline; 10. Fourth three-way valve; 11. Third refrigerant pipeline; 12. Fourth refrigerant pipeline; 13. Fifth refrigerant pipeline; 14. Sixth refrigerant pipeline; 15. Variable frequency compressor; 16. Oil separator; 17. Four-way valve; 18. Fifth three-way valve; 19. Condenser; 20. Economizer; 21. Heating electronic expansion valve; 22. One-way valve; 23. Compressor air supply circuit electronic expansion valve; 24. Condenser reheat condenser; 25. Condenser reheat throttling electronic expansion valve; 26. Refrigeration electronic expansion valve; 27. Evaporator; 28. Gas-liquid separator; 29. ​​Auxiliary heater; 30. Humidifier. DETAILED DESCRIPTION

[0019] 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.

[0020] like Figure 1 As shown, the present invention provides an exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system, which is characterized in that the fluorine pump 1 and the exhaust heat recovery coil 2, the fresh air pre-cooling and preheating coil 3, and the fresh air reheating coil 4 are connected in series and parallel through the first three-way valve 5, the second three-way valve 6, the third three-way valve 8, the fourth three-way valve 10 and the system pipeline, and there are four operating modes in total.

[0021] Method 1, used for fresh air exhaust heat recovery preheating operation, includes the following steps:

[0022] S1. The specific connection method of the fluorine pump system pipeline is as follows: the first three-way valve 5 only connects the fluorine pump 1 and the second three-way valve 6, the second three-way valve 6 only connects the first three-way valve 5 and the first refrigerant pipeline 7, the third three-way valve 8 only connects the exhaust heat recovery coil 2 and the fresh air pre-cooling and preheating coil 3, and the fourth three-way valve 10 only connects the second refrigerant pipeline 9 and the fluorine pump 1;

[0023] S2, the refrigerant compressed by the fluorine pump 1 flows through the first three-way valve 5, the second three-way valve 6, the first refrigerant pipeline 7, the exhaust heat recovery coil 2, the third three-way valve 8, the fresh air pre-cooling and pre-heating coil 3, the second refrigerant pipeline 9, the fourth three-way valve 10, and returns to the fluorine pump 1.

[0024] By adopting the above technical solution, in winter heating operation, the fluorine pump heat recovery system preheats the fresh air. Since the fresh air temperature is lower than the exhaust air, there is a temperature difference between the fresh air and the exhaust air. The fluorine pump system refrigerant absorbs heat and evaporates in the exhaust heat recovery coil 2, and the fresh air precooling and preheating coil 3 releases heat and condenses, thereby achieving the purpose of exhaust heat recovery and preheating fresh air. The temperature after the fresh air precooling and preheating coil can be adjusted by changing the fluorine pump operation frequency to achieve free heat recovery.

[0025] Method 2, used for fresh air exhaust heat recovery pre-cooling operation, includes the following steps:

[0026] S1. The specific connection method of the fluorine pump system pipeline is as follows: the first three-way valve 5 only connects the fluorine pump 1 and the third refrigerant pipeline 11, the second three-way valve 6 only connects the fourth refrigerant pipeline 12 and the first refrigerant pipeline 7, the third three-way valve 8 only connects the exhaust air heat recovery coil 2 and the fresh air pre-cooling and preheating coil 3, and the fourth three-way valve 10 only connects the fourth refrigerant pipeline 12 and the fluorine pump 1;

[0027] S2, the refrigerant compressed by the fluorine pump 1 flows through the first three-way valve 5, the third refrigerant pipeline 11, the second refrigerant pipeline 9, the fresh air pre-cooling and preheating coil 3, the third three-way valve 8, the exhaust heat recovery coil 2, the first refrigerant pipeline 7, the second three-way valve 6, the fourth refrigerant pipeline 12, the fourth three-way valve 10, and returns to the fluorine pump 1.

[0028] By adopting the above technical solution, in the summer cooling operation, the heat and humidity load of the treated room is relatively large, and the refrigeration unit does not need to reheat or the reheat amount is relatively small after cooling and dehumidification. At this time, the fluorine pump heat recovery system only pre-cools the fresh air. Because the fresh air temperature is higher than the exhaust air, there is a temperature difference between the fresh air and the exhaust air. The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil 3, and releases heat and condenses in the exhaust air heat recovery coil 2, thereby achieving the purpose of exhaust heat recovery and pre-cooling the fresh air. The temperature after the fresh air pre-cooling and preheating coil can also be adjusted by changing the fluorine pump operation frequency to achieve free heat recovery.

[0029] Method 3, used for fresh air pre-cooling and reheating operation, includes the following steps:

[0030] S1. The specific connection method of the fluorine pump system pipeline is as follows: the first three-way valve 5 only connects the fluorine pump 1 and the third refrigerant pipeline 11, the third three-way valve 8 only connects the fifth refrigerant pipeline 13 and the fresh air pre-cooling and preheating coil 3, the second three-way valve 6 only connects the fourth refrigerant pipeline 12 and the sixth refrigerant pipeline 14, and the fourth three-way valve 10 only connects the fourth refrigerant pipeline 12 and the fluorine pump 1;

[0031] S2, the refrigerant compressed by the fluorine pump 1 flows through the first three-way valve 5, the third refrigerant pipeline 11, the second refrigerant pipeline 9, the fresh air pre-cooling and preheating coil 3, the third three-way valve 8, the third refrigerant pipeline 13, the fresh air reheat coil 4, the sixth refrigerant pipeline 14, the second three-way valve 6, the fourth refrigerant pipeline 12, the fourth three-way valve 10, and returns to the fluorine pump 1.

[0032] By adopting the above technical solution, in the transition season, cooling operation is carried out, and the fresh air temperature is close to or lower than the exhaust air temperature. At this time, the fluorine pump cannot pre-cool the fresh air through the exhaust heat recovery coil 2; in the transition season, the heat and humidity in the treated room are relatively small, that is, the heat load is relatively small and the wet load is relatively large. The fresh air needs to be reheated after being cooled and dehumidified by the chiller. At this time, the fluorine pump system switches to the fresh air pre-cooling and reheating operation mode.

[0033] Method 4, used for fresh air exhaust heat recovery pre-cooling, fresh air pre-cooling and reheating mixed operation, includes the following steps:

[0034] S1. The specific connection method of the fluorine pump system pipeline is as follows: the first three-way valve 5 only connects the fluorine pump 1 and the third refrigerant pipeline 11; the third three-way valve 8 connects the fifth refrigerant pipeline 13, the exhaust heat recovery coil 2 and the fresh air pre-cooling and preheating coil 3; the second three-way valve 6 connects the first refrigerant pipeline 7, the sixth refrigerant pipeline 14 and the fourth refrigerant pipeline 12; the fourth three-way valve 10 only connects the fourth refrigerant pipeline 12 and the fluorine pump 1;

[0035] S2, the refrigerant compressed by the fluorine pump 1 flows through the first three-way valve 5, the third refrigerant pipeline 11, the second refrigerant pipeline 9, the fresh air pre-cooling and preheating coil 3, and the third three-way valve 8. The refrigerant is divided into two paths through the third three-way valve 8. One path of refrigerant passes through the fifth refrigerant pipeline 13, the fresh air reheat coil 4, the sixth refrigerant pipeline 14, the second three-way valve 6, the fourth refrigerant pipeline 12, and the fourth three-way valve 10, and returns to the fluorine pump 1. The other path of refrigerant passes through the exhaust heat recovery coil 2, the first refrigerant pipeline 7, the second three-way valve 6, the fourth refrigerant pipeline 12, and the fourth three-way valve 10 and returns to the fluorine pump 1.

[0036] By adopting the above technical solution, in the summer cooling operation, the fresh air temperature is higher than the exhaust air temperature. At this time, the fluorine pump system can pre-cool the fresh air through the exhaust heat recovery coil 2; the treated room has a certain heat and humidity load, and the fresh air needs to be reheated after cooling and dehumidification by the chiller. At this time, the fluorine pump system can perform fresh air pre-cooling and reheating operation. At this time, both heat recovery modes can be operated, and fresh air pre-cooling and reheating heat recovery operation is given priority. When the reheat heat recovery amount reaches the requirement, a part of the refrigerant can be bypassed to the exhaust heat recovery coil 2 through the three-way valve 6 and the three-way valve 8 to realize free heat recovery of energy.

[0037] The fluorine pump 1 adopts a variable frequency fluorine pump with adjustable flow. The three-way valve adopts an analog refrigerant three-way valve with adjustable flow. A temperature point is set after the fresh air pre-cooling and preheating coil 3 to collect the temperature; a temperature point is set after the fresh air reheating coil 4 to collect the temperature.

[0038] By adopting the above technical solution, the frequency of the fluorine pump and the opening of the three-way valve are adjusted according to the temperature after the fresh air pre-cooling and preheating coil, the temperature after the fresh air reheating coil and the control target, so that the heat recovery amount can be freely adjusted according to demand to achieve free heat recovery.

[0039] To achieve the control effect of constant temperature and humidity indoors, the following steps are included:

[0040] S1. After the cooling machine starts cooling, the temperature after the evaporator 27 is processed to below the dew point temperature of the indoor set temperature. Taking the indoor set temperature and humidity of 23°C / 55% as an example, the temperature after the evaporator 27 needs to be processed to 13°C. At this time, there is a temperature difference before and after the evaporator 27. The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil 3, and releases heat and condenses in the fresh air reheating coil 4, thereby achieving the purpose of fresh air reheating heat recovery and pre-cooling the fresh air;

[0041] S2. If the reheating capacity of the fluorine pump does not meet the reheating air supply temperature requirement, the condensing reheating coil 24 can be turned on and regulated by the auxiliary heater 29 and the humidifier 30.

[0042] By adopting the above technical solution, the control target of constant temperature and humidity can be achieved through precise adjustment of the auxiliary heater 29 and the humidifier 30.

[0043] To achieve the control effect of constant temperature and humidity indoors, the following steps are included:

[0044] S1. After the cold machine starts cooling, the temperature after the evaporator 27 is processed to below the dew point temperature of the indoor set temperature. Taking the indoor set temperature and humidity of 23℃ / 55% as an example, the temperature after the evaporator 27 needs to be processed to 13℃. At this time, there is a temperature difference before and after the evaporator 27. The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil 3, and releases heat and condenses in the fresh air reheating coil 4, thereby achieving the purpose of recovering the fresh air reheat heat and pre-cooling the fresh air.

[0045] S2. If the reheating amount of the fluorine pump exceeds the reheat supply air temperature requirement, a portion of the refrigerant can be bypassed to the exhaust heat recovery coil 2 through the second three-way valve 6 and the third three-way valve 8.

[0046] By adopting the above technical solution, free heat recovery of energy can be achieved, and then supplemented by precise adjustment of heaters and humidifiers to achieve the control goal of constant temperature and humidity.

[0047] The auxiliary heater 29 can be of a heating type such as electric heating, hot water coil, steam coil, etc., and the humidifier 30 can be of a humidification type such as electrode humidification, electric heating humidification, dry steam humidification, high-pressure mist, high-pressure spray, wet film, etc.

[0048] By adopting the above technical solution, the normal operation of the system is guaranteed.

[0049] Working Principle: The attached figure shows a schematic diagram of a fluorine pump free heat recovery fresh air variable frequency condensation reheat constant temperature and humidity air conditioning unit system. The unit contains two refrigerant systems, one is a fluorine pump refrigerant system, and the other is a vapor compression condensation reheat refrigerant system;

[0050] The fluorine pump refrigerant system includes a variable frequency fluorine pump 1, an exhaust heat recovery coil 2, a fresh air pre-cooling and preheating coil 3, a fresh air reheating coil 4, a first three-way valve 5, a second three-way valve 6, a first refrigerant pipeline 7, a third three-way valve 8, a second refrigerant pipeline 9, a fourth three-way valve 10, a third refrigerant pipeline 11, a fourth refrigerant pipeline 12, a fifth refrigerant pipeline 13, a sixth refrigerant pipeline 14, etc., which constitute a fluorine pump refrigerant system;

[0051] The vapor compression condensation reheat refrigerant system includes a variable frequency compressor 15, an oil separator 16, a four-way valve 17, a fifth three-way valve 18, a condenser 19, an economizer 20, a heating electronic expansion valve 21, a one-way valve 22, a compressor air supply circuit electronic expansion valve 23, a condensation reheat condenser 24, a condensation reheat throttling electronic expansion valve 25, a refrigeration electronic expansion valve 26, an evaporator 27, a gas-liquid separator 28, etc., which constitute a vapor compression condensation reheat refrigerant system.

[0052] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. An exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system, characterized by: The fluorine pump (1) and the exhaust heat recovery coil (2), the fresh air pre-cooling and pre-heating coil (3), and the fresh air reheating coil (4) are connected in series or in parallel via a first three-way valve (5), a second three-way valve (6), a third three-way valve (8), a fourth three-way valve (10), and system pipelines, and there are four operating modes in total; Method 1, used for fresh air exhaust heat recovery preheating operation, includes the following steps: S1. The specific connection mode of the fluorine pump system pipeline is as follows: the first three-way valve (5) only conducts the fluorine pump (1) and the second three-way valve (6); the second three-way valve (6) only conducts the first three-way valve (5) and the first refrigerant pipeline (7); the third three-way valve (8) only conducts the exhaust heat recovery coil (2) and the fresh air pre-cooling and pre-heating coil (3); the fourth three-way valve (10) only conducts the second refrigerant pipeline (9) and the fluorine pump (1); S2, the refrigerant compressed by the fluorine pump (1) flows through the first three-way valve (5), the second three-way valve (6), the first refrigerant pipeline (7), the exhaust heat recovery coil (2), the third three-way valve (8), the fresh air pre-cooling and pre-heating coil (3), the second refrigerant pipeline (9), the fourth three-way valve (10), and returns to the fluorine pump (1); Method 2, used for fresh air exhaust heat recovery pre-cooling operation, includes the following steps: S1. The specific connection mode of the fluorine pump system pipeline is as follows: the first three-way valve (5) only conducts the fluorine pump (1) and the third refrigerant pipeline (11); the second three-way valve (6) only conducts the fourth refrigerant pipeline (12) and the first refrigerant pipeline (7); the third three-way valve (8) only conducts the exhaust heat recovery coil (2) and the fresh air pre-cooling and pre-heating coil (3); and the fourth three-way valve (10) only conducts the fourth refrigerant pipeline (12) and the fluorine pump (1); S2, the refrigerant compressed by the fluorine pump (1) flows through the first three-way valve (5), the third refrigerant pipeline (11), the second refrigerant pipeline (9), the fresh air pre-cooling and pre-heating coil (3), the third three-way valve (8), the exhaust heat recovery coil (2), the first refrigerant pipeline (7), the second three-way valve (6), the fourth refrigerant pipeline (12), the fourth three-way valve (10), and returns to the fluorine pump (1); Method 3, used for fresh air pre-cooling and reheating operation, includes the following steps: S1. The specific connection mode of the fluorine pump system pipeline is as follows: the first three-way valve (5) only conducts the fluorine pump (1) and the third refrigerant pipeline (11); the third three-way valve (8) only conducts the fifth refrigerant pipeline (13) and the fresh air pre-cooling and pre-heating coil (3); the second three-way valve (6) only conducts the fourth refrigerant pipeline (12) and the sixth refrigerant pipeline (14); and the fourth three-way valve (10) only conducts the fourth refrigerant pipeline (12) and the fluorine pump (1); S2, the refrigerant compressed by the fluorine pump (1) flows through the first three-way valve (5), the third refrigerant pipeline (11), the second refrigerant pipeline (9), the fresh air pre-cooling and preheating coil (3), the third three-way valve (8), the fifth refrigerant pipeline (13), the fresh air reheating coil (4), the sixth refrigerant pipeline (14), the second three-way valve (6), the fourth refrigerant pipeline (12), the fourth three-way valve (10), and returns to the fluorine pump (1); Method 4, used for fresh air exhaust heat recovery pre-cooling, fresh air pre-cooling and reheating mixed operation, includes the following steps: S1. The specific connection method of the fluorine pump system pipeline is as follows: the first three-way valve (5) only conducts the fluorine pump (1) and the third refrigerant pipeline (11); the third three-way valve (8) conducts the fifth refrigerant pipeline (13), the exhaust heat recovery coil (2) and the fresh air pre-cooling and pre-heating coil (3); the second three-way valve (6) conducts the first refrigerant pipeline (7), the sixth refrigerant pipeline (14) and the fourth refrigerant pipeline (12); the fourth three-way valve (10) only conducts the fourth refrigerant pipeline (12) and the fluorine pump (1); S2, the fluorine pump (1) compresses the refrigerant and flows through the first three-way valve (5), the third refrigerant pipeline (11), the second refrigerant pipeline (9), the fresh air pre-cooling and pre-heating coil (3), and the third three-way valve (8). The refrigerant is divided into two paths through the third three-way valve (8). One path of refrigerant passes through the fifth refrigerant pipeline (13), the fresh air reheating coil (4), the sixth refrigerant pipeline (14), the second three-way valve (6), the fourth refrigerant pipeline (12), and the fourth three-way valve (10), and returns to the fluorine pump (1). The other path of refrigerant passes through the exhaust heat recovery coil (2), the first refrigerant pipeline (7), the second three-way valve (6), the fourth refrigerant pipeline (12), and the fourth three-way valve (10), and returns to the fluorine pump (1).

2. The exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system according to claim 1, characterized in that: The fluorine pump (1) adopts a variable frequency fluorine pump with adjustable flow rate, the three-way valve adopts an analog refrigerant three-way valve with adjustable flow rate, a temperature point is set behind the fresh air pre-cooling and pre-heating coil (3) to collect temperature, and a temperature point is set behind the fresh air reheating coil (4) to collect temperature.

3. The exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system according to claim 1, characterized in that: To achieve the control effect of constant temperature and humidity indoors, the following steps are included: S1. After the cold machine is turned on for cooling, the temperature after the evaporator (27) is processed to be below the dew point temperature of the indoor set temperature. Taking the indoor set temperature and humidity of 23°C / 55% as an example, the temperature after the evaporator (27) needs to be processed to 13°C. At this time, there is a temperature difference before and after the evaporator (27). The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil (3), and releases heat and condenses in the fresh air reheating coil (4), thereby achieving the purpose of fresh air reheating heat recovery and pre-cooling fresh air; S2. If the reheating capacity of the fluorine pump does not meet the reheating air supply temperature requirement, the condensing reheating coil (24) is turned on and the auxiliary heater (29) and humidifier (30) are used for adjustment.

4. The exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system according to claim 3, characterized in that: To achieve the control effect of constant temperature and humidity indoors, the following steps are included: S1. After the cold machine is turned on for cooling, the temperature after the evaporator (27) is processed to be below the dew point temperature of the indoor set temperature. Taking the indoor set temperature and humidity of 23°C / 55% as an example, the temperature after the evaporator (27) needs to be processed to 13°C. At this time, there is a temperature difference before and after the evaporator (27). The refrigerant of the fluorine pump system absorbs heat and evaporates in the fresh air pre-cooling and preheating coil (3), and releases heat and condenses in the fresh air reheating coil (4), thereby achieving the purpose of fresh air reheating heat recovery and pre-cooling fresh air; S2. If the reheating amount of the fluorine pump exceeds the reheating air supply temperature requirement, a portion of the refrigerant is bypassed to the exhaust heat recovery coil (2) through the second three-way valve (6) and the third three-way valve (8).

5. The exhaust heat recovery and fresh air pre-cooling and reheating heat recovery system according to claim 4, characterized in that: The auxiliary heater (29) has electric heating, hot water coil, and steam coil heating types, and the humidifier (30) has electrode humidification, electric heating humidification, dry steam humidification, high-pressure micro-mist, high-pressure spray, and wet film humidification types.

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