Heat recovery fresh air conditioning unit and control method

Abstract

The heat recovery fresh air conditioning unit comprises a total heat recovery fresh air conditioning unit body and a control cabinet, the total heat recovery fresh air conditioning unit body is formed by splicing an upper exhaust box body and a lower air supply box body, and an exhaust side bypass electric air valve and a heat recovery device are sequentially arranged in the upper exhaust box body in the flowing direction; a first pressure difference sensor assembly and an exhaust enthalpy value sensor are distributed in the upper exhaust box, a constant air volume device, a heat recovery device, an air supply side bypass electric air valve and an air feeder are arranged in the lower air supply box body in the flowing direction, and a second pressure difference sensor assembly, a fresh air enthalpy value sensor and a fresh air enthalpy value sensor after heat recovery are distributed in the lower box body. And the control cabinet realizes the operation states of the heat recovery device and the bypass electric air valve through judgment according to the pressure difference measured by the pressure difference sensor assembly and the enthalpy value measured by the enthalpy value sensor in combination with the frequency value and the electricity consumption of the fan. Compared with a traditional control method, the method is easier to implement, the energy-saving effect is better, and the indoor air quality is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of heating, ventilation and air conditioning, and in particular to a heat recovery fresh air air conditioning unit and a control method thereof. Background Art

[0002] The energy consumption of building operation accounts for about 20% of the total energy consumption in China. In the context of dual carbon, building energy conservation has attracted more and more attention from the society. In the energy consumption of buildings, HVAC energy consumption accounts for 30-40%, and the energy consumption of air conditioning system for processing fresh air accounts for about 45% of the total energy consumption of air conditioning. Reducing the energy consumption of fresh air system is of great significance to building energy conservation.

[0003] In the fresh air air conditioning system, changing the demand for fresh air system air supply by indoor carbon dioxide concentration is a common energy-saving method. When the number of people in the room decreases, the indoor carbon dioxide concentration decreases, and the fresh air reduces the fresh air volume, which can save a lot of fresh air heating, cooling and fresh air transmission energy. However, the carbon dioxide concentration cannot completely control the indoor air quality. When the fresh air volume is reduced according to the reduction of carbon dioxide concentration, it may cause formaldehyde and total volatile organic compounds to exceed the standard. Sometimes the reduction of fresh air volume will cause the airflow organization to deteriorate, thereby affecting the thermal comfort of personnel. Fresh air-exhaust heat recovery is another common energy-saving method for fresh air air conditioning systems. Using full heat recovery or sensible heat recovery devices (such as heat recovery wheels, heat pipes, and membrane heat exchangers) to recover the cold and heat in the exhaust air to pre-cool or pre-heat the fresh air can save fresh air heating or cooling energy. However, the heat recovery device will bring resistance to the fresh air or exhaust system, increase the fan energy consumption, and the rotation of the wheel will also generate certain energy consumption. Therefore, the fresh air heat recovery device cannot always save energy.

[0004] In the Chinese patent with publication number: CN 116642228 A, it discloses "a dual-cold source fresh air processing system and control method". This method specifically determines whether the fresh air heat recovery system meets the demand under this working condition by the absolute value of the difference between the fresh air outlet temperature and the exhaust air inlet temperature, and controls the opening and closing of the bypass valve by detecting the pressure difference between the inside and outside of the room. This method can achieve energy saving only when the branch of the heat pump is used to assist the fresh air system under a large heat load. However, this method simply uses the difference between the fresh air outlet temperature and the exhaust air inlet temperature and the temperature difference between indoors and outdoors to achieve the use of the branch of the heat pump to assist the fresh air system. Its control structure is simple, and its control accuracy cannot be guaranteed, and it cannot achieve the best energy saving effect.

[0005] It can be seen that how to improve the control accuracy of the heat recovery fresh air air conditioning unit to further achieve energy-saving effects is a problem that needs to be solved in this field. Summary of the invention

[0006] In view of the technical problem of low control accuracy in existing fresh air air-conditioning systems, the purpose of the present invention is to provide a heat recovery fresh air air-conditioning unit, which is easier to implement, has better energy-saving effects and higher indoor air quality than traditional control methods. On this basis, a control method for a heat recovery fresh air air-conditioning unit is also provided, which effectively overcomes the problems existing in the prior art.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a heat recovery fresh air air-conditioning unit, including a full heat recovery fresh air air-conditioning unit and a control cabinet, the full heat recovery fresh air air-conditioning unit and the control cabinet are connected by a communication line and a power line, the full heat recovery fresh air air-conditioning unit includes an air-conditioning unit box body, the air-conditioning unit box body is composed of an upper exhaust air box body and a lower air supply air box body, the upper exhaust air box body is provided with an exhaust side bypass electric air valve and a heat recovery device in sequence according to the flow direction, the upper exhaust air box is provided with a first pressure difference sensor assembly and an exhaust The wind enthalpy sensor interacts with the control cabinet data to collect the pressure difference and enthalpy value in the upper exhaust box and transmits them to the control cabinet. The lower air supply box is provided with a constant air volume device, a heat recovery device, an air supply bypass electric air valve and a blower according to the flow direction. The constant air volume device passes through the air duct to the outdoor atmosphere. The lower box is provided with a second pressure difference sensor assembly, a fresh air enthalpy sensor and a fresh air enthalpy sensor after heat recovery, and interacts with the control cabinet data to collect the pressure difference and enthalpy value in the lower air supply box and transmit them to the control cabinet.

[0008] The control cabinet realizes the operating status of the heat recovery device and the exhaust side bypass electric air valve or the supply side bypass electric air valve by judging the pressure difference and enthalpy values ​​measured by the first pressure difference sensor assembly, the second pressure difference sensor assembly, the exhaust air enthalpy value sensor, the fresh air enthalpy value sensor and the fresh air enthalpy value sensor after heat exchange, as well as the frequency values ​​and power consumption of the exhaust fan and the supply fan.

[0009] Furthermore, the upper exhaust box body is provided with exhaust inlets and exhaust side outlets on both sides, the exhaust inlet is connected to the exhaust duct from the indoor to the unit, the exhaust outlet passes through the air duct to the outdoor atmosphere, and the exhaust air flows from the exhaust inlet to the exhaust side outlet.

[0010] Furthermore, a carbon dioxide sensor and an exhaust side filter are also provided inside the upper exhaust box, which are arranged in sequence according to the flow direction, the carbon dioxide sensor, the exhaust side filter, the exhaust enthalpy sensor, the exhaust side bypass electric air valve, the heat recovery device and the exhaust fan and interact with the control cabinet data.

[0011] Furthermore, the first differential pressure sensor assembly includes an exhaust side heat exchange device differential pressure sensor, an exhaust fan differential pressure sensor, and an exhaust side filter differential pressure sensor, and they are connected to the interior of the upper exhaust box through pressure measuring hoses respectively.

[0012] Furthermore, the lower air supply box is provided with a fresh air inlet and an air supply outlet on both sides. The air supply outlet is connected to the air duct to supply air to the room. The fresh air inlet passes through the air duct to the outdoor atmosphere. The direction of the air supply is from the fresh air inlet to the air supply outlet.

[0013] Furthermore, the lower air supply box is also provided with an air supply filter, an enthalpy sensor after heat exchange on the air supply side, a heat exchange coil and an air supply temperature sensor, which are, in order of flow direction, a fresh air inlet, a constant air volume device, a fresh air enthalpy sensor, an air supply filter, a heat recovery device and an air supply bypass electric air valve, an enthalpy sensor after heat exchange on the air supply side, a heat exchange coil, a air supply fan and an air supply temperature sensor, and interact with the control cabinet data.

[0014] Furthermore, the second differential pressure sensor assembly includes a supply side heat exchange device differential pressure sensor, a blower differential pressure sensor, and a supply side filter differential pressure sensor, and each of them is connected to the interior of the lower air supply box through a pressure measuring hose.

[0015] Furthermore, a water pipe is connected to the heat exchange coil outside the lower air supply box, and an electric regulating valve is arranged on the water pipe.

[0016] Furthermore, the control cabinet includes a cabinet body and a multi-circuit smart meter, a controller, a full heat recovery control relay, a blower frequency converter, and an exhaust fan frequency converter arranged in the cabinet body. The multi-circuit smart meter interacts with the blower and the exhaust fan data respectively, and is used to detect the power consumption of the power supply circuit of the blower and the exhaust fan. The multi-circuit smart meter interacts with the recovery device data, and is used to detect the power consumption of the total heat recovery unit circuit rotor. The multi-circuit smart meter interacts with the controller data, and transmits the above-detected power consumption to the controller. The blower frequency converter interacts with the blower and the controller data respectively, and is used to detect the operating frequency of the blower and transmit it to the controller. The exhaust fan frequency converter interacts with the exhaust fan and the controller data respectively, and is used to detect the operating frequency of the exhaust fan and transmit it to the controller.

[0017] In order to achieve the above object, the present invention provides a control method for a heat recovery fresh air air conditioning unit, characterized in that it is implemented based on the heat recovery fresh air air conditioning unit, and the control method comprises the following steps:

[0018] S1: Setting parameters and built-in equipment performance curves;

[0019] S11: using a constant air volume device controller to set the air volume of the constant air volume device according to the value calculated by the formula, and the constant air volume device controller maintains the air volume of the constant air volume device unchanged;

[0020] S12: Inputting the performance parameter table of the supply fan and the performance parameter table of the exhaust fan into the memory of the controller;

[0021] S13: Input the maximum and minimum concentration setting values ​​of indoor carbon dioxide and the indoor temperature setting value;

[0022] S14: Set the dead zone size of the temperature setting value and the maximum and minimum values ​​of the dew point temperature;

[0023] S2: Control of heat exchange device and bypass electric air valve;

[0024] S21: Detect the fresh air enthalpy value, the fresh air enthalpy value after heat recovery, and the return air enthalpy value respectively and transmit them to the controller; detect the exhaust side resistance of the heat recovery device, the exhaust fan pressure difference, the supply side resistance of the heat recovery device, and the supply fan pressure difference and transmit them to the controller;

[0025] S22: Measure the power consumption and operating frequency of the supply fan, the power consumption and operating frequency of the exhaust fan, and the power consumption of the rotor of the full heat recovery unit circuit and transmit them to the controller respectively;

[0026] S23: The controller reads the refrigeration performance coefficient of the refrigeration system or the heating energy efficiency system of the heating system from the building control system or the energy management system;

[0027] S24: Based on the different operating states of the unit, the operating states of the heat recovery device and the bypass electric air valve are controlled in combination with the values ​​collected by S21 to S23;

[0028] S3: Monitor the indoor carbon dioxide concentration through the carbon dioxide sensor and compare it with the carbon dioxide concentration value set in S13 to control the frequency of the supply fan and the exhaust fan;

[0029] S4: According to the operating status of the unit, the operating status of the electric regulating water valve is controlled by detecting the indoor dew point temperature, the air conditioning supply temperature and the indoor set temperature through the enthalpy sensor.

[0030] Compared with the traditional method of using outdoor temperature difference as the control criterion, the heat recovery fresh air air conditioning unit and control method provided by the present invention have higher energy utilization efficiency by directly monitoring the energy consumption and recovered energy of the heat recovery system and directly using them as the criterion for controlling the bypass air valve and the impeller.

[0031] Secondly, the indoor air quality is high by integrating a constant air volume valve in the unit and pre-setting the air volume of the air volume device by considering fixed organic pollutants other than indoor carbon dioxide.

[0032] In addition, various sensors are pre-installed in the unit and control cabinet, and are pre-connected, with pre-set air volume valve air volume, indoor carbon dioxide concentration, dew point temperature, etc., reducing the workload of on-site installation and debugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0034] Figure 1 This is a structural diagram of the full heat recovery fresh air air conditioning system;

[0035] Figure 2 This is a flow chart of the control method of the full heat recovery fresh air air conditioning system;

[0036] Figure 3 This is a flow chart of setting parameters and built-in equipment performance curves in the control method of the full heat recovery fresh air air conditioning system;

[0037] Figure 4 It is a flow chart of the heat exchange device and bypass electric air valve control method in the control method of the full heat recovery fresh air air conditioning system;

[0038] Figure 5 This is a flow chart of a method for controlling a supply fan and an exhaust fan in a method for controlling a full heat recovery fresh air air conditioning system;

[0039] Figure 6 This is a flow chart of the air supply parameter control method in the control method of the full heat recovery fresh air air conditioning system.

[0040] The following is a description of the components in the accompanying drawings:

[0041] 1. Full heat recovery fresh air air conditioning unit 111. Upper exhaust box 10. Exhaust air inlet 12. Exhaust side air outlet 17. Carbon dioxide sensor 52. Exhaust side filter 162. Exhaust enthalpy sensor 72. Exhaust side bypass electric air valve 4. Heat recovery device 22. Exhaust fan 132. Exhaust side heat exchange device pressure difference sensor 142. Exhaust fan pressure difference sensor 152. Exhaust side filter pressure difference sensor

[0042] 112. Lower air supply box 9. Fresh air inlet 8. Constant air volume device 81. Constant air volume device controller 11. Air supply outlet 51. Air supply filter 163. Fresh air enthalpy sensor 4. Heat recovery device 71. Air supply bypass electric air valve 161. Fresh air enthalpy sensor after heat recovery 6. Heat exchange coil 21. Air supply fan 1101. Air supply temperature sensor 131. Air supply side heat exchange device pressure difference sensor 141. Air supply fan pressure difference sensor 151. Air supply side filter pressure difference sensor

[0043] 201. Pressure measuring hose 204. Water pipe 211. Electric regulating valve

[0044] 300. Control cabinet 301. Cabinet 18. Multi-circuit smart meter 19. Controller 41. Relay for full heat recovery control 31. Blower inverter 32. Exhaust fan inverter 202. Communication line 203. Power line DETAILED DESCRIPTION

[0045] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific diagrams.

[0046] The heat recovery fresh air air conditioning unit provided by the present invention is Figure 1 It consists of two parts: a full heat recovery fresh air air conditioning unit 1 and a control cabinet 300. The full heat recovery fresh air air conditioning unit 1 and the control cabinet 300 are connected by a communication line 202 and a power line 203 to realize communication between the full heat recovery fresh air air conditioning unit 1 and the control cabinet 300 as well as transmission of electrical energy and kinetic energy.

[0047] Among them, the full heat recovery fresh air air-conditioning unit 1 includes an air-conditioning unit box, and the air-conditioning unit box is composed of an upper exhaust air box 111 and a lower air supply box 112. The upper exhaust air box 111 and the lower air supply box 112 can preferably be spliced ​​together by multiple functional sections.

[0048] The upper exhaust box 111 is provided with exhaust inlet 10 and exhaust side outlet 12 on both sides. The exhaust inlet 10 is connected to the exhaust duct from the indoor to the unit, and the exhaust outlet 12 passes through the air duct to the outdoor atmosphere. The exhaust air flows from the exhaust inlet 10 to the exhaust side outlet 12.

[0049] A carbon dioxide sensor 17, an exhaust-side filter 52, an exhaust enthalpy sensor 162, an exhaust-side bypass electric air valve 72, a heat recovery device 4 and an exhaust fan 22 are arranged in sequence inside the upper exhaust box 111 according to the flow direction.

[0050] The carbon dioxide sensor 17 interacts with the control cabinet data to monitor the indoor carbon dioxide concentration and transmit the detected data to the control cabinet.

[0051] The exhaust-side filter 52 is used to protect the heat recovery device 4 and extend the service life of the heat recovery device 4 .

[0052] The exhaust air enthalpy sensor 162 interacts with the control cabinet 300 to determine the indoor air state and transmit the detected data to the control cabinet 300. The data is used as a basis for adjusting the electric regulating valve 211 to ensure that the indoor air remains in a comfortable state.

[0053] The electric air valve 72 on the exhaust side cooperates with the heat recovery device 4. When the enthalpy difference between indoor and outdoor air is small and heat recovery is not economical, the exhaust air bypasses the heat recovery device 4. The heat recovery device 4 is used to recover heat or cold in the exhaust air to solve the energy consumption of fresh air processing.

[0054] The exhaust fan 22 is used to exhaust outdoor dirty air. A first differential pressure sensor assembly is placed on the wall of the upper exhaust box 111, and the first differential pressure sensor assembly includes an exhaust side heat exchange device differential pressure sensor 132, an exhaust fan differential pressure sensor 142, and an exhaust side filter differential pressure sensor 152. The above differential pressure sensors are connected to the interior of the upper exhaust box 111 through a pressure measuring hose 201.

[0055] Among them, the exhaust side heat exchange device pressure difference sensor 132 and the exhaust fan pressure difference sensor 142 are used to measure the exhaust side resistance and exhaust fan pressure difference of the heat recovery device 4 respectively, and combined with the multi-channel electric meter 18 in the control cabinet, they are used in the controller 19 to calculate the exhaust fan power consumed by the heat recovery exhaust side resistance.

[0056] The exhaust side filter pressure difference sensor 152 is located on both sides of the exhaust side filter 52 and cooperates with the exhaust side filter 52 to determine the degree of dirtiness and blockage of the filter and whether the filter needs to be replaced and cleaned.

[0057] The lower air supply box 112 is provided with a fresh air inlet 9, a constant air volume device 8 and an air supply outlet 11 on both sides. The air supply outlet 11 is connected to the air duct to supply air to the indoor room. The fresh air inlet 9 and the constant air volume device 8 are connected to the air duct to the outdoor atmosphere. The direction of the air supply is from the fresh air inlet 9 and the constant air volume device 8 to the air supply outlet 11.

[0058] In the lower air supply box, according to the flow direction, there are fresh air inlet 9, constant air volume device 8, fresh air enthalpy sensor 163, air supply filter 51, heat recovery device 4 and air supply bypass electric air valve 71, enthalpy sensor 161 after heat exchange on the air supply side, heat exchange coil 6, air supply fan 21 and air supply temperature sensor 1101.

[0059] The fresh air enthalpy sensor 163 and the enthalpy sensor 161 after heat recovery on the air supply side interact with the control cabinet 300 respectively, and are used to measure the enthalpy values ​​of the fresh air and the fresh air after heat recovery respectively and transmit them to the control cabinet 300. The difference between the two is calculated by the controller to calculate the energy saving benefit of heat recovery.

[0060] The heat recovery device 4 is used to recover the heat or cold in the exhaust air to solve the energy consumption of fresh air processing;

[0061] The air supply bypass electric air valve 71 cooperates with the heat recovery device 4 to allow fresh air to bypass the heat recovery device 4 when the enthalpy difference between indoor and outdoor air is small and heat recovery is not economical.

[0062] The heat exchange coil 6 cooperates with the heat recovery device 4 to further heat or cool and dehumidify the air when the heat recovery device 4 cannot fully meet the air heat and humidity treatment requirements.

[0063] The blower 21 is used to deliver outdoor fresh air into the room to dilute the indoor dirty air.

[0064] The air supply temperature sensor 1101 exchanges data with the control cabinet 300 , and is used to monitor the temperature of the air supplied to the room, which is used as a basis for determining whether to adjust the electric regulating valve 211 .

[0065] The air supply filter 51 is used to filter particulate matter in the outdoor fresh air, protect the heat recovery device 4 and ensure the indoor air quality.

[0066] A second differential pressure sensor assembly is placed on the wall of the lower air supply box 112, and the second differential pressure sensor assembly includes a differential pressure sensor 131 of the heat exchange device on the air supply side, a differential pressure sensor 141 of the blower, and a differential pressure sensor 151 of the filter on the air supply side. The above-mentioned differential pressure sensors are connected to the interior of the lower air supply box 112 through a pressure measuring hose 201.

[0067] The air supply side heat exchange device pressure difference sensor 131 and the blower pressure difference sensor 141 are used to measure the air supply side resistance and the blower pressure difference of the heat recovery device 4 respectively, and are combined with the multi-channel electric meter 18 to calculate the blower power consumed by the heat recovery air supply side resistance in the controller 19.

[0068] The air supply side filter pressure difference sensor 151 is used to determine the degree of dirtiness and blockage of the air supply filter 51 and whether the filter needs to be replaced and cleaned; a water pipe 204 is connected to the heat exchange coil 6 on the outside of the lower air supply box 112, and cold water or hot water is transported to the heat exchange coil 6 through the water pipe to further heat and humidity treat the air.

[0069] There is an electric regulating valve 211 on the water pipe 204, which is used to control the degree of heat and humidity treatment of the air to meet the requirements of the indoor heat and humidity environment.

[0070] It should be noted here that the constant air volume device 8 is equipped with a constant air volume device controller 81, through which the air volume of the constant air volume device 8 can be set. The constant air volume device 8 can preferably be a pressure-independent type to avoid the influence of the variable frequency operation of the blower 21 on the constant air volume device 8.

[0071] It should be noted here that the heat recovery device 4 can preferably be a rotary full heat recovery device in order to achieve higher heat recovery efficiency and lower resistance.

[0072] The control cabinet 300 includes a cabinet body 301 , and a multi-circuit smart meter 18 , a controller 19 , a full heat recovery control relay 41 , a blower inverter 31 , and an exhaust fan inverter 32 arranged in the cabinet body.

[0073] The multi-circuit smart meter 18 interacts with the air supply fan 21 and the exhaust fan 22 for data detection.

[0074] At the same time, the multi-circuit smart meter 18 interacts with the full heat recovery device 4 to detect the power consumption of the full heat recovery unit circuit wheel.

[0075] Secondly, the multi-circuit smart meter 18 interacts with the controller 19 and transmits the detected power consumption to the controller 19 .

[0076] The blower inverter 31 exchanges data with the blower 21 and the controller 19 respectively. The blower inverter 31 is used to detect the operating frequency of the blower 21 and transmit it to the controller 19 .

[0077] The exhaust fan inverter 32 exchanges data with the exhaust fan 22 and the controller 19 respectively. The exhaust fan inverter 32 is used to detect the operating frequency of the exhaust fan 22 and transmit it to the controller 19.

[0078] Based on the heat recovery fresh air air conditioning unit formed by the above scheme, this scheme also provides a control method for the heat recovery fresh air air conditioning unit, see Figure 2 , the control method comprises the following steps:

[0079] S1: Set parameters and built-in device performance curves (such as Figure 3 );

[0080] S11: using the constant air volume device controller 81 to set the air volume of the constant air volume device 8 according to the calculated value of formula (1), and the constant air volume device controller 81 maintains the air volume of the constant air volume device unchanged;

[0081] V min =Max(V dilute 、V pressure 、V moist ) (1)

[0082] Among them, V min is the set air volume of the constant air volume device 8, m3 / h;

[0083] V diluteIt is the air volume required to dilute the fixed controlled pollutants in the room, m3 / h; fixed pollutants are pollutants brought by the decoration panels, furniture or other process equipment in the room; the scenarios already in ANSI / ASHRAE62.1 or other similar standards can be obtained by looking up the table in the standard or by simple company; the scenarios not in the standard can be calculated by the room pollutant ventilation dilution formula;

[0084] V pressure The minimum fresh air volume required to maintain room pressurization, m3 / h; can be calculated by the building gap infiltration wind calculation formula according to the indoor and outdoor pressure difference of 5Pa;

[0085] V moist It refers to the air volume required to dilute the fixed moisture source in the room, m3 / h; it can be obtained from the room moisture balance equation.

[0086] S12: Inputting the performance parameter table of the supply fan 21 and the performance parameter table of the exhaust fan 22 into the memory of the controller 19, the fan performance parameter table being a relationship table among fan power, fan pressure head, fan air volume, and fan frequency;

[0087] S13: Input the maximum and minimum indoor carbon dioxide concentration setting values ​​Cset,max, Cset,min; input the indoor temperature setting value Tset; the maximum indoor carbon dioxide concentration can be preferably set to 800ppm;

[0088] S14: Set the dead zone size ΔTdead of the temperature setting value, the maximum and minimum values ​​of the dew point temperature Td,max, Td,min;

[0089] S2: Control of heat exchange device and bypass electric air valve (such as Figure 4 );

[0090] S21: the enthalpy value H0 measured by the fresh air enthalpy value sensor 163 is transmitted to the controller, the enthalpy value H1 of the fresh air after heat recovery measured by the fresh air enthalpy value sensor 161 after heat recovery is transmitted to the controller, the enthalpy value H3 measured by the return air enthalpy value sensor 162 is transmitted to the controller 19, and the pressure difference sensor 132, the pressure difference sensor 142, the pressure difference sensor 131, and the pressure difference sensor 141 respectively detect the exhaust side resistance of the heat recovery device, the exhaust fan pressure difference, the supply side resistance of the heat recovery device, and the supply fan pressure difference and transmit them to the controller;

[0091] S22: The multi-circuit electric meter 18 measures the power consumption E1 of the power supply circuit of the blower 21, the power consumption E2 of the power supply circuit of the exhaust fan 22, and the power consumption E3 of the rotor of the full heat recovery unit circuit, and transmits them to the controller 19 respectively; the operating frequencies of the blower and the exhaust fan are transmitted to the controller 19 respectively through the blower frequency converter 31 and the exhaust fan frequency converter 32;

[0092] S23: The controller 19 reads the cooling coefficient of performance EER of the refrigeration system or the heating energy efficiency system COP of the heating system from the building control system or the energy management system;

[0093] S24: Determine the operating status of the unit;

[0094] If the unit is not running, the exhaust side bypass electric air valve 72 is closed, the supply side bypass electric air valve 71 is closed, and the relay 41 of the heat recovery device 4 is disconnected;

[0095] If the unit is in cooling state, and H0>H3, the fan total pressure ΔP1 and AP2 measured by the supply fan differential pressure sensor 141 and the exhaust fan differential pressure sensor 142, the fan frequency values ​​f1 and f2 fed back by the supply fan inverter 31 and the exhaust fan inverter 32, and the fan performance parameter table input in step S1 are used to find out the air volume Vs and Vp of the supply fan 21 and the exhaust fan 22. According to the pressure differences ΔPr1 and ΔPr2 measured by the supply side heat exchange device differential pressure sensor 131 and the exhaust side heat exchange device differential pressure sensor 132, the heat recovery power consumption is calculated using formula 2:

[0096] E R =E1×(ΔP r1 / ΔP1)+E1×(ΔP r2 / ΔP2)+E3 (2)

[0097] If V s ×1.2×(H0-H1)>1.1×E R × COP, the exhaust side bypass electric air valve 72 is closed, the supply side bypass electric air valve 71 is closed, and the relay 41 of the heat recovery device 4 is closed;

[0098] If V s ×1.2×(H0-H1)≤1.1×E R × COP, the exhaust air side bypass electric air valve 72 is opened, the supply air side bypass electric air valve 71 is opened, and the relay 41 of the heat recovery device 4 is disconnected;

[0099] If the unit is in cooling state and H0≤H3, the exhaust side bypass electric air valve 72 is opened, the supply side bypass electric air valve 71 is opened, and the relay 41 of the heat recovery device 4 is disconnected;

[0100] If the unit is in ventilation state, the exhaust side bypass electric air valve 72 is opened, the supply side bypass electric air valve 71 is opened, and the relay 41 of the heat recovery device 4 is disconnected;

[0101] If the unit is in the heating state and H0 < H3, the total fan pressure ΔP1 and AP2 are measured using the supply fan differential pressure sensor 141 and the exhaust fan differential pressure sensor 142, and the fan frequency values f1 and f2 feedback by the supply fan frequency converter 31 and the exhaust fan frequency converter 32. According to the fan performance parameter table input in step S1, the air volumes Vs and Vp of the fans 21 and 22 are found. Based on the differential pressures ΔPr1 and ΔPr2 measured by the supply-side heat exchange device differential pressure sensor 131 and the exhaust-side heat exchange device differential pressure sensor 132, the heat recovery power consumption is calculated using formula 3:

[0102] E R = E1×(ΔP r1 / ΔP1)+E1×(ΔP r2 / ΔP2)+E3 (3)

[0103] If V s ×1.2×(H1 - H0)>1.1×E R ×COP, the exhaust-side bypass electric air valve 72 is closed, the supply-side bypass electric air valve 71 is closed, and the relay 41 of the heat recovery device 4 is closed;

[0104] If V s ×1.2×(H1 - H0)≤1.1×E R ×COP, the exhaust-side bypass electric air valve 72 is opened, the supply-side bypass electric air valve 71 is opened, and the relay 41 of the heat recovery device 4 is disconnected;

[0105] S25: Return to step S21, loop;

[0106] S3: Control of the supply fan 21 and the exhaust fan 22 (such as Figure 5 );

[0107] S31: Monitor the indoor carbon dioxide concentration Cin by the carbon dioxide sensor 17;

[0108] S32: If C set,max > C in > C set,min , keep the frequency of the supply fan 21 unchanged at f1, and keep the frequency value f2 of the exhaust fan 22 unchanged;

[0109] If C in ≥C set,max , increase the operating frequency f1 of the supply fan 21 and increase the operating frequency f2 of the exhaust fan 22 to make Vs - Vp a fixed value;

[0110] If C in ≤C set,max , decrease the operating frequency f1 of the supply fan 21 and decrease the operating frequency f2 of the exhaust fan 22 to make Vs - Vp a fixed value;

[0111] S33: Return to S31 loop

[0112] S4: Indoor air parameter control (such as Figure 6 ).

[0113] S41: Determine whether the unit's operating state is cooling, heating, or ventilation;

[0114] S42: If the unit operation state is cooling, the return air enthalpy sensor 162 detects the indoor dew point temperature Td, in;

[0115] If T d，in >T d,max , open the electric regulating water valve 211; if T d，min ≤T d，in ≤T d,max , maintain the valve position of the electric regulating water valve 211 unchanged; if T d，in <T d，min , close the opening of the electric regulating water valve 211;

[0116] If the operating state is ventilation, close the electric regulating water valve 211;

[0117] If the unit is in heating mode, detect the air supply temperature Ts and the indoor set temperature Tset; if T s <T set -ΔT dead , open the electric regulating water valve 211; if T set -ΔT dead ≤T s ≤T set +ΔT dead , keep the electric regulating water valve opening unchanged; if T s >T set +ΔT dead , turn down the electric regulating water valve opening;

[0118] S43: Return to step S41;

[0119] The heat recovery fresh air air conditioning unit and control method composed of the above scheme, when implemented specifically, if the full heat recovery fresh air air conditioning unit with a fresh air supply volume of 5000m3 / h serves an office of 1000m2, the room is set with a summer design dry bulb temperature of 25°C and a relative humidity of 50%, and a winter indoor dry bulb temperature of 22°C, the supply fan has a design operating air volume of 5000m3 / h, an external full pressure of 500Pa, and a power of 4kW; the exhaust fan has a design operating air volume of 4500m3 / h, an external full pressure of 250Pa, and a power of 3kW; the rotary motor has a power of 200W.

[0120] When setting the parameters initially, the air volume of the constant air volume device is set to 1080m3 / h, the maximum and minimum values ​​of the dew point temperature in summer Td,max, Td,min are 16.7℃, 8.5℃ respectively, the indoor dry bulb temperature in winter Tset is 22℃, the temperature dead zone ΔTdead is 0.5℃, and the maximum and minimum indoor carbon dioxide concentration setting values ​​Cset,max, Cset,min are 800ppm and 400ppm respectively.

[0121] According to the control and calculation of steps S1-S4, it can actually save about 9.3% of energy consumption compared with the control of bypass and rotor based on the indoor and outdoor temperature difference. Therefore, compared with the traditional method of using outdoor temperature difference as the control criterion, the enthalpy difference between the two sides of the heat recovery rotor or heat exchanger, the actual power consumption of the heat recovery system and the real-time cooling and heating efficiency of the system are used to determine whether to perform heat recovery and directly use them as the criterion for controlling the bypass damper and rotor. This can more accurately determine the operating mode, adaptively operate with variable air volume, and save more heating or cooling energy.

[0122] At the same time, this solution integrates a constant air volume valve in the unit to divide the fresh air volume demand into area demand fresh air volume and personnel demand fresh air volume. The area demand fresh air volume is used to solve the air pollution problem of building materials, and the personnel demand fresh air volume is used to dilute carbon dioxide and solve the problem of adding formaldehyde and total volatile organic compound sensors. In addition, the air volume of the air volume device is preset by considering the fixed organic pollutants other than indoor carbon dioxide, so the indoor air quality is high.

[0123] In addition, various sensors are pre-installed in the unit and control cabinet, and are pre-connected, with pre-set air volume valve air volume, indoor carbon dioxide concentration, dew point temperature, etc., reducing the workload of on-site installation and debugging.

[0124] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A heat recovery fresh air air conditioning unit, characterized in that: The air conditioning unit comprises a full heat recovery fresh air air conditioning unit and a control cabinet, wherein the full heat recovery fresh air air conditioning unit and the control cabinet are connected by a communication line and a power line, wherein the full heat recovery fresh air air conditioning unit comprises an air conditioning unit box body, wherein the air conditioning unit box body is composed of an upper exhaust air box body and a lower air supply air box body, wherein an exhaust side bypass electric air valve and a heat recovery device are sequentially arranged inside the upper exhaust air box body according to the flow direction, wherein the upper exhaust air box is provided with a first pressure difference sensor assembly and an exhaust air enthalpy sensor, and is connected to the control cabinet data The data is exchanged with the control cabinet to collect the pressure difference and enthalpy value in the upper exhaust box and transmit them to the control cabinet. The lower air supply box is provided with a constant air volume device, a heat recovery device, an air supply bypass electric air valve and a blower according to the flow direction. The constant air volume device passes through the air duct to the outdoor atmosphere. The lower box is provided with a second pressure difference sensor assembly, a fresh air enthalpy value sensor and a fresh air enthalpy value sensor after heat recovery, and interacts with the control cabinet data to collect the pressure difference and enthalpy value in the lower air supply box and transmit them to the control cabinet. The control cabinet realizes the operating status of the heat recovery device and the exhaust side bypass electric air valve or the supply side bypass electric air valve by judging the pressure difference and enthalpy values ​​measured by the first pressure difference sensor assembly, the second pressure difference sensor assembly, the exhaust air enthalpy value sensor, the fresh air enthalpy value sensor and the fresh air enthalpy value sensor after heat exchange, as well as the frequency values ​​and power consumption of the exhaust fan and the supply fan.

2. A heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The upper exhaust box body is provided with exhaust inlet and exhaust side outlet on both sides. The exhaust inlet is connected to the exhaust duct from the indoor to the unit, and the exhaust outlet passes through the duct to the outdoor atmosphere. The exhaust air flows from the exhaust inlet to the exhaust side outlet.

3. A heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The upper exhaust box is also provided with a carbon dioxide sensor and an exhaust side filter. The carbon dioxide sensor, the exhaust side filter, the exhaust enthalpy sensor, the exhaust side bypass electric air valve, the heat recovery device and the exhaust fan are arranged in sequence according to the flow direction and interact with the control cabinet data.

4. A heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The first differential pressure sensor assembly includes a differential pressure sensor for the heat exchange device on the exhaust side, a differential pressure sensor for the exhaust fan, and a differential pressure sensor for the filter on the exhaust side, and they are connected to the interior of the upper exhaust box through pressure measuring hoses respectively.

5. The heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The lower air supply box is provided with a fresh air inlet and an air supply outlet on both sides. The air supply outlet is connected to the air duct to supply air to the room. The fresh air inlet passes through the air duct to the outdoor atmosphere. The direction of the air supply is from the fresh air inlet to the air supply outlet.

6. A heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The lower air supply box is also provided with an air supply filter, an enthalpy sensor after heat exchange on the air supply side, a heat exchange coil and an air supply temperature sensor, which are, in order of flow direction, a fresh air inlet, a constant air volume device, a fresh air enthalpy sensor, an air supply filter, a heat recovery device and an air supply bypass electric air valve, an enthalpy sensor after heat exchange on the air supply side, a heat exchange coil, a air supply fan and an air supply temperature sensor, and interact with the control cabinet data.

7. A heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The second differential pressure sensor assembly includes a differential pressure sensor for a heat exchange device on the air supply side, a differential pressure sensor for a blower, and a differential pressure sensor for a filter on the air supply side, and each of them is connected to the interior of the lower air supply box through a pressure measuring hose.

8. The heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The lower air supply box is externally provided with a water pipe connected to a heat exchange coil, and the water pipe is provided with an electric regulating valve.

9. The heat recovery fresh air air conditioning unit according to claim 1, characterized in that: The control cabinet includes a cabinet body and a multi-circuit smart meter, a controller, a full heat recovery control relay, a blower frequency converter, and an exhaust fan frequency converter arranged in the cabinet body. The multi-circuit smart meter interacts with the blower and the exhaust fan data respectively, and is used to detect the power consumption of the power supply circuit of the blower and the exhaust fan. The multi-circuit smart meter interacts with the recovery device data, and is used to detect the power consumption of the total heat recovery unit circuit rotor. The multi-circuit smart meter interacts with the controller data, and transmits the above-detected power consumption to the controller. The blower frequency converter interacts with the blower and the controller data respectively, and is used to detect the operating frequency of the blower and transmit it to the controller. The exhaust fan frequency converter interacts with the exhaust fan and the controller data respectively, and is used to detect the operating frequency of the exhaust fan and transmit it to the controller.

10. A control method for a heat recovery fresh air air conditioning unit, characterized in that: It is implemented based on the heat recovery fresh air air conditioning unit according to any one of claims 1 to 9 above, and the control method comprises the following steps: S1: Setting parameters and built-in equipment performance curves; S11: using a constant air volume device controller to set the air volume of the constant air volume device according to the value calculated by the formula, and the constant air volume device controller maintains the air volume of the constant air volume device unchanged; S12: Inputting the performance parameter table of the supply fan and the performance parameter table of the exhaust fan into the memory of the controller; S13: Input the maximum and minimum concentration setting values ​​of indoor carbon dioxide and the indoor temperature setting value; S14: Set the dead zone size of the temperature setting value and the maximum and minimum values ​​of the dew point temperature; S2: Control of heat exchange device and bypass electric air valve; S21: Detect the fresh air enthalpy value, the fresh air enthalpy value after heat recovery, and the return air enthalpy value respectively and transmit them to the controller; detect the exhaust side resistance of the heat recovery device, the exhaust fan pressure difference, the supply side resistance of the heat recovery device, and the supply fan pressure difference and transmit them to the controller; S22: Measure the power consumption and operating frequency of the supply fan, the power consumption and operating frequency of the exhaust fan, and the power consumption of the rotor of the full heat recovery unit circuit and transmit them to the controller respectively; S23: The controller reads the refrigeration performance coefficient of the refrigeration system or the heating energy efficiency system of the heating system from the building control system or the energy management system; S24: Based on the different operating states of the unit, the operating states of the heat recovery device and the bypass electric air valve are controlled in combination with the values ​​collected by S21 to S23; S3: Monitor the indoor carbon dioxide concentration through the carbon dioxide sensor and compare it with the carbon dioxide concentration value set in S13 to control the frequency of the supply fan and the exhaust fan; S4: According to the operating status of the unit, the operating status of the electric regulating water valve is controlled by detecting the indoor dew point temperature, the air conditioning supply temperature and the indoor set temperature through the enthalpy sensor.

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