High-precision temperature and humidity control system of metering shelter and operation control method

Abstract

The high-precision temperature and humidity control system comprises a plurality of temperature and humidity sensors, a control unit and executive components, the temperature and humidity sensors collect the temperature and humidity in the cabin in real time, the control unit conducts relevant operation on the executive components according to a control strategy, and the executive components are controlled by the control unit according to the control strategy. Refrigeration, heating, dehumidification and humidification of the cabin are controlled, and the temperature and humidity of the cabin are adjusted; the execution component comprises an air conditioning unit, a plurality of sets of foot heaters, a plurality of air duct heaters and a plurality of humidifiers, and is used for executing a control instruction of the control unit; the air conditioning unit is used for adjusting temperature and humidity, an air duct heater is further arranged at an air supply outlet of the air conditioning unit and used for adjusting the temperature, multiple sets of foot heaters are evenly distributed at multiple positions in the cabin of the metering square cabin and used for adjusting the temperature, and the humidifier is used for adjusting the humidity. A temperature and humidity metering environment close to a laboratory is provided for on-site metering, the working field of metering guarantee can be widened, the metering coverage rate of equipment is improved, and the reliability of calibrated equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature control, and in particular to a high-precision temperature and humidity control system and an operation control method for a metering cabin. Background Art

[0002] In order to deal with various public safety emergencies, it is necessary to solve the major problem of insufficient measurement and testing resources. At present, on-site measurement usually involves transporting standard equipment to the location of the equipment to be calibrated, and then carrying out measurement. However, this service method has certain limitations. For example, the equipment to be calibrated may be in a high-cold area, a high-temperature area, or a seaside area with high humidity. Under such circumstances, the measurement work actually introduces new uncertainties. Therefore, it is necessary to establish a measurement cabin close to the laboratory environment. The design of the measurement cabin for testing has changed the measurement and testing work mode that was mainly based on laboratory testing in the past. The measurement cabin is designed to be portable and vehicle-mounted, which can better meet the needs of on-site measurement and testing. In particular, in cases where the equipment to be calibrated is difficult to disassemble and difficult to transport, it is necessary to use the measurement cabin to achieve on-site measurement. The measurement cabin needs to be designed with a high-precision temperature control system. Therefore, the technical difficulties of the high-precision temperature control system of the measurement cabin need to be overcome urgently. Summary of the invention

[0003] For application scenarios where the equipment to be calibrated is difficult to disassemble and transport, it is necessary to build a metrology cabin close to the laboratory environment so that the equipment to be calibrated can be calibrated in the cabin, which greatly improves the metrology efficiency and coverage. The temperature control system based on high-precision temperature and humidity sensors provides a metrology environment closer to the laboratory for the cabin in the shortest time.

[0004] In the first aspect, an embodiment of the present invention provides a high-precision temperature and humidity control system for a metering cabin, which provides high-precision temperature and humidity control for the metering cabin under extreme outdoor environmental conditions, and realizes the construction of an on-site metering environment that meets the requirements, including multiple groups of temperature and humidity sensors, a control unit, and an execution component. The temperature and humidity sensors collect the temperature and humidity in the cabin in real time. The control unit performs relevant operations on each execution component according to the control strategy to complete the control of cabin cooling, heating, dehumidification, and humidification, and adjust the cabin temperature and humidity; the execution component includes an air-conditioning unit, multiple sets of foot heaters, multiple duct heaters, and multiple humidifiers, which execute the control instructions of the control unit; the air-conditioning unit is used to adjust the temperature and humidity, and an air duct heater is also provided at the air outlet of the air-conditioning unit for adjusting the temperature. Multiple sets of foot heaters are evenly distributed at multiple positions in the cabin of the metering cabin for adjusting the temperature, and the humidifier is used to adjust the humidity.

[0005] In some embodiments, the control unit includes an internal control unit and a display control unit. The display control unit implements local control and includes a display screen and operation buttons. The operation buttons are used to control operations, and the display screen is used to display the operating status of the unit, the cabin temperature, and the cabin humidity information. The internal control unit remotely controls operations according to operating instructions, and specifically performs relevant operations on each execution component according to the control strategy to complete the control of cabin cooling, heating, dehumidification, and humidification.

[0006] In some embodiments, the foot heater and the air duct heater are electric heaters or fuel heaters.

[0007] In some embodiments, the humidifier is an ultrasonic humidifier.

[0008] In some embodiments, the multiple groups of temperature and humidity sensors arranged inside the metering cabin are selected as integrated temperature and humidity sensors, which are covered with a PTFE waterproof and breathable membrane.

[0009] In the second aspect, an embodiment of the present invention provides an operation control method of a high-precision temperature and humidity control system based on the metering cabin. To meet the temperature and humidity requirements of the metering cabin, the control system controls the start and stop of the cooling, heating, dehumidification and humidification processes of the execution components according to the ambient temperature and humidity values ​​detected in real time by multiple groups of temperature and humidity sensors in the metering cabin, as well as the preset target values, and adjusts the compressor speed of the air-conditioning unit and the power of the heater in real time to make the temperature and humidity in the cabin reach the target value range; the operation control method realizes the high-precision temperature and humidity control process of the system according to the actual situation, including:

[0010] According to the actual needs of the metering cabin, two temperature target values ​​a℃ and b℃ and two humidity target values ​​α% and β% are preset to form nine preset target temperature value-target humidity value areas;

[0011] Formulate corresponding temperature and humidity control strategies according to the conditions of each preset target temperature value-target humidity value area;

[0012] Then, the average value is taken according to the ambient temperature and humidity values ​​detected in real time by multiple groups of temperature and humidity sensors in the metering cabin;

[0013] The average value is corresponded to each preset target temperature value-target humidity value area, and a corresponding control strategy is adopted to control the start and stop of the cooling, heating, dehumidification and humidification processes of the execution components so that the temperature and humidity in the cabin reach within the two target value ranges.

[0014] In some embodiments, formulating a corresponding temperature and humidity control strategy according to the situation of each preset target temperature value-target humidity value region includes:

[0015] The two preset temperature target values are a℃ > b℃, and the two preset humidity target values are α% < β%. According to the two preset temperature target values and the two preset humidity target values, it is divided into nine control regions:

[0016] When the ambient temperature ≥ a℃ and the humidity ≤ α%, it is the first region;

[0017] When the ambient temperature ≥ a℃ and β% ≥ humidity > α%, it is the second region;

[0018] When the ambient temperature ≥ a℃ and the humidity > β%, it is the third region;

[0019] When a℃ > ambient temperature ≥ b℃ and the humidity ≤ α%, it is the fourth region;

[0020] When a℃ > ambient temperature ≥ b℃ and β% ≥ humidity > α%, it is the fifth region;

[0021] When a℃ > ambient temperature ≥ b℃ and the humidity > β%, it is the sixth region;

[0022] When the ambient temperature < b℃ and the humidity ≤ α%, it is the seventh region;

[0023] When the ambient temperature < b℃ and β% ≥ humidity > α%, it is the eighth region;

[0024] When the ambient temperature < b℃ and the humidity > β%, it is the ninth region;

[0025] The operation control strategy is as follows:

[0026] The first region is the cooling and humidifying area. When the temperature and humidity in the cabin are in this region, enter the control of the refrigeration function and the humidification function;

[0027] The second region is the cooling area. At this time, the humidity control remains the same as the control of the previous region, that is, according to the control of the previous region, it can be humidifying, dehumidifying, or neither humidifying nor dehumidifying. Enter the refrigeration function control;

[0028] The third region is the cooling and dehumidifying area. At this time, enter the refrigeration function control, and give priority to adjusting the compressor speed according to the temperature to quickly adjust the temperature parameters;

[0029] The fourth region is the humidifying area. At this time, the temperature control remains the same as the control of the previous region, that is, according to the control of the previous region, it can be refrigerating, heating, or neither refrigerating nor heating; enter the humidification function control;

[0030] The fifth region is the target area. At this time, both remain the same as the control of the previous region;

[0031] The sixth region is the dehumidifying area. At this time, the temperature control remains the same as the control of the previous region, that is, according to the control of the previous region, it can be refrigerating, heating, or neither refrigerating nor heating, and enter the dehumidification function control;

[0032] The seventh area is the heating and humidification area, at which point the heating and humidification functions are controlled;

[0033] The eighth zone is the temperature rising zone. At this time, the humidity control maintains the control of the previous zone unchanged, that is, according to the control of the previous zone, it can be humidification, dehumidification, or neither humidification nor dehumidification; enter the heating function control;

[0034] The ninth area is the heating and dehumidification area, which enters the heating and dehumidification function control;

[0035] The control unit controls each execution component to enter the cooling, heating, dehumidification and humidification process according to the above-mentioned areas, including

[0036] Refrigeration control, at this time, the evaporator fan, condenser fan and compressor of the refrigeration system are running, and the compressor speed is controlled according to the difference Δt between the cabin temperature and the target temperature and the temperature difference change rate Δt'; (where Δt = average cabin temperature - average of two preset target temperature values, Δt' = Δt1-Δt2, indicating the temperature difference change rate)

[0037] Heating control: The control system realizes heating through PTC electric heating. The electric heating is steplessly adjusted according to the temperature in the metering cabin using the PID control algorithm. When the temperature in the metering cabin reaches the preset temperature range, the heating is exited and all electric heating is shut down.

[0038] Humidification control: the control system humidifies through an electric humidifier. When the humidification function is started, the humidifier is turned on. When the humidity in the metering cabin reaches the preset temperature range, the humidification is exited and the humidifier is turned off.

[0039] Dehumidification control, the control system performs dehumidification through the operation of the refrigeration system of the air-conditioning unit. During dehumidification, the compressor speed is controlled according to the difference ΔRH between the humidity in the metering cabin and the target humidity and the humidity difference change rate ΔRH'. When the humidity in the metering cabin reaches the preset humidity range, the dehumidification is exited and the humidifier is turned off.

[0040] In some embodiments, the temperature is balanced by dividing the space in the metering cabin, that is, placing electric heaters at different positions to achieve balanced control, respectively adopting electric heating regulation, air supply volume regulation, and electric heating compensation regulation control for each space area, setting multiple groups of electric heating, respectively arranged at the air supply duct outlets of each space area, and each group of electric heating power is steplessly regulated;

[0041] Several sets of foot heaters are also arranged in the metering cabin;

[0042] During cooling, the compressor speed is adjusted according to the highest temperature collected in the metering cabin, so that the highest temperature is stabilized at the average of the two preset temperature values. If other temperature values ​​are lower than the lower of the two preset temperature values, the corresponding electric heating is appropriately turned on for compensation;

[0043] During heating, the power output of each electric heater is adjusted independently so that each temperature point reaches the target value range.

[0044] The present invention has the advantages that:

[0045] The laboratory measurement environment is usually required to be: temperature (15-25)℃, humidity ≤80%. The high-precision temperature and humidity control system of the present invention mainly includes cooling and cooling / dehumidification, heating and humidification functions, which are used to quickly provide a suitable measurement environment for the measurement cabin. At + (40-46)℃, the cabin measurement environment can be reduced to the measurement environment within (40-60)min; at -41℃, the temperature can be raised to 20℃±2℃ within 1h.

[0046] In short, based on the current development needs of on-site measurement, on-site measurement is an extension and supplement to the measurement assurance system. It provides a temperature and humidity measurement environment close to that of the laboratory for on-site measurement, which can broaden the scope of measurement assurance work, increase the measurement coverage of equipment, better ensure the quality of measurement work, and improve the reliability of the calibrated equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the installation layout of the air-conditioning unit in the metering cabin;

[0048] Figure 2 This is a schematic diagram of the nine control area divisions;

[0049] Figure 3 It is the pressure-enthalpy diagram of the refrigeration system;

[0050] Figure 4 It is a schematic diagram of the appearance structure of the parallel flow heat exchanger;

[0051] Figure 5 It is a schematic diagram of the flat tube and fin structure of a parallel flow heat exchanger;

[0052] Figure 6 It is a schematic diagram of the performance curve of the condensing fan;

[0053] Figure 7 It is a schematic diagram of the performance curve of the evaporation fan;

[0054] In the figure: 100-air conditioning unit, 101-air conditioning supply outlet, 102-air conditioning return outlet, ①-first area, ②-second area, ③-third area, ④-fourth area, ⑤-fifth area, ⑥-sixth area, ⑦-seventh area, ⑧-eighth area, ⑨-ninth area, 103-air inlet direction, 104-air outlet direction, 105-louver fins. DETAILED DESCRIPTION

[0055] The technical solution of the present invention is further described below in conjunction with specific implementation methods.

[0056] In the first aspect, an embodiment of the present invention provides a high-precision temperature and humidity control system for a metering cabin, including six groups of temperature and humidity sensors, a control unit, and an execution component. The temperature and humidity sensors collect the cabin temperature and humidity in real time. The control unit performs relevant operations on each execution component according to the control strategy to complete the control of cabin cooling, heating, dehumidification, and humidification, and adjust the cabin temperature and humidity. The control unit includes an internal control unit and a display control unit. The display control unit realizes local control, including a display screen and operation buttons. The operation buttons are used to control operations, and the display screen is used to display the unit operation status, cabin temperature, and cabin humidity information; the internal control unit remotely controls operations according to operation instructions, specifically According to the control strategy, relevant operations are performed on each execution component to complete the control of cabin cooling, heating, dehumidification and humidification. At the same time, relevant information such as cabin environment information and air conditioning system operation status can be reported to facilitate detection and fault maintenance; the execution components include air conditioning units, four sets of foot heaters, six duct heaters, and six humidifiers. The foot heaters and duct heaters are both electric heaters that execute the control instructions of the control unit; the air conditioning unit is used to adjust the temperature and humidity. The air outlet of the air conditioning unit is also equipped with a duct heater for adjusting the temperature. Multiple sets of foot heaters are evenly distributed at four locations in the cabin of the metering cabin for adjusting the temperature, and humidifiers are used to adjust the humidity. The foot heater can be an electric heater or a fuel heater, and the duct heater can be an electric heater or a fuel heater. Specifically, in order to meet the requirements of unit temperature control at 20℃±1℃ and humidity at 60%±15%, the system has an automatic control function. In automatic mode, after startup, the system automatically controls the start and stop of cooling, heating, dehumidification, humidification and other functions according to the cabin temperature, humidity and set target values, and can adjust the compressor speed and electric heating power in real time to make the cabin temperature and humidity reach the control target range.

[0057] The humidity in this embodiment is relative humidity.

[0058] like Figure 1 The figure shows the installation layout of the air-conditioning unit in the metering cabin.

[0059] The laboratory measurement environment is usually required to be: temperature (15-25)℃, humidity ≤80%. The main functions of the high-precision temperature control system include cooling and cooling / dehumidification, heating and humidification, which are used to quickly provide a suitable measurement environment for the measurement cabin. At +(40-46)℃, the cabin measurement environment can drop to the measurement environment within (40-60)min; at -41℃, the temperature can rise to 20℃±2℃ within 1h. The specific working principle is as follows:

[0060] Refrigeration and cooling / dehumidification: When the air conditioner is in refrigeration or dehumidification operation, the low-temperature and low-pressure refrigerant gas is sucked into the compressor, compressed into high-temperature and high-pressure gas and then discharged. The gas is cooled into high-pressure saturated liquid in the condenser. The liquid enters the evaporator after throttling and reducing pressure through the expansion throttling mechanism. The liquid refrigerant evaporates and absorbs heat in the evaporator, which reduces the surface temperature of the evaporator. The air in the cabin is cooled by the evaporator surface under the action of the centrifugal fan and then sent to the cabin occupants. The water vapor in the air is cooled to saturation on the evaporator surface, producing condensed water. The liquid refrigerant evaporates and absorbs heat to become superheated gas, which is sucked in and compressed by the compressor again through the pipeline. This cycle is repeated to achieve the purpose of reducing the temperature and humidity in the cabin.

[0061] For heating, this solution uses fuel heater and electric heating. The heating capacity of the fuel heater is 15000W and that of the electric heater is 14000W. The electric heater can be steplessly adjusted according to the temperature in the cabin to achieve stable temperature control and energy saving.

[0062] For humidification, an ultrasonic humidifier is used in this embodiment.

[0063] The control system based on high-precision temperature and humidity sensors includes the selection and arrangement of temperature and humidity sensors. A total of six groups of temperature and humidity sensors are arranged inside the metering cabin to detect the temperature and humidity data in the cabin in real time. The sensors are commercially available integrated temperature and humidity sensors, which are covered with a carefully selected PTFE waterproof and breathable membrane to effectively prevent the sensor openings from contacting water vapor and dust, ensuring that the sensors are not contaminated, maintaining high sensitivity, and obtaining more lasting high-precision measurements. They can adapt to more harsh environments such as high temperature, low temperature, and humidity. The specific performance indicators are shown in Table 1.

[0064] Table 1 Technical indicators of temperature and humidity sensors

[0065] Supply voltage 2.2V~5.5V Humidity range 0~100%RH Temperature range -40℃～85℃ Humidity accuracy ±2%RH(25℃) Temperature accuracy ±0.3℃ Resolution Temperature: 0.01℃; Humidity: 0.024%RH Repeatability ±0.1%RH, ±0.1℃ Response time Humidity: ≤8s; Temperature: 5~30s

[0066] In the second aspect, an embodiment of the present invention provides an operation control method of a high-precision temperature and humidity control system based on the metering cabin. To meet the temperature and humidity requirements of the metering cabin, the control system controls the start and stop of the cooling, heating, dehumidification and humidification processes of the execution components according to the ambient temperature and humidity values ​​detected in real time by multiple groups of temperature and humidity sensors in the metering cabin, as well as the preset target values, and adjusts the compressor speed of the air-conditioning unit and the power of the heater in real time to make the temperature and humidity in the cabin reach the target value range; the operation control method realizes the high-precision temperature and humidity control process of the system according to the actual situation, including:

[0067] According to the actual needs of the metering cabin, two temperature target values ​​a℃ and b℃ and two humidity target values ​​α% and β% are preset to form nine preset target temperature value-target humidity value areas;

[0068] Develop corresponding temperature and humidity control strategies according to the situation of each preset target temperature - target humidity value area;

[0069] Then, according to the environmental temperature and humidity values detected in real time by multiple groups of temperature and humidity sensors in the metering cabin, take their average value;

[0070] Correspond the average value to each preset target temperature - target humidity value area, adopt corresponding control strategies, and control the start and stop of the refrigeration, heating, dehumidification, and humidification processes of the execution components, so that the temperature and humidity in the cabin reach within the range of the two target values.

[0071] In some embodiments, the developing corresponding temperature and humidity control strategies according to the situation of each preset target temperature - target humidity value area includes:

[0072] As Figure 2 shown, the preset two temperature target values are a℃ > b℃, a = 21 and b = 19, a can also be 19, 25, and b can also be 17, 23. The preset two target humidity values are α% < β%, α = 50, β = 70, α can also be 40, 60, and β can also be 60, 80. Divide into nine control areas according to the preset two temperature target values and the preset two target humidity values:

[0073] Environmental temperature ≥ a℃ and humidity ≤ α% is the first area;

[0074] Environmental temperature ≥ a℃ and β% ≥ humidity > α% is the second area;

[0075] Environmental temperature ≥ a℃ and humidity > β% is the third area;

[0076] a℃ > environmental temperature ≥ b℃ and humidity ≤ α% is the fourth area;

[0077] a℃ > environmental temperature ≥ b℃ and β% ≥ humidity > α% is the fifth area;

[0078] a℃ > environmental temperature ≥ b℃ and humidity > β% is the sixth area;

[0079] Environmental temperature < b℃ and humidity ≤ α% is the seventh area;

[0080] Environmental temperature < b℃ and β% ≥ humidity > α% is the eighth area;

[0081] Environmental temperature < b℃ and humidity > β% is the ninth area;

[0082] The operation control strategies are as follows:

[0083] The first area is the cooling and humidification area. When the temperature and humidity in the cabin are in this area, the cooling and humidification functions are controlled. Both manual and automatic control are possible.

[0084] The second area is the cooling area. At this time, the humidity control maintains the control of the previous area unchanged, that is, according to the control of the previous area, it can be humidification, dehumidification, or neither humidification nor dehumidification. Enter the cooling function control;

[0085] The third area is the cooling and dehumidification area. At this time, the refrigeration function control is entered, and the compressor speed is adjusted according to the temperature first to quickly adjust the temperature parameters;

[0086] The fourth area is the humidification area. At this time, the temperature control maintains the control of the previous area unchanged, that is, according to the control of the previous area, it can be cooling, heating, or neither cooling nor heating; enter the humidification function control;

[0087] The fifth area is the target area, and the control of the previous area remains unchanged at this time;

[0088] The sixth area is the dehumidification area. At this time, the temperature control maintains the control of the previous area unchanged, that is, according to the control of the previous area, it can be cooling, heating, or neither cooling nor heating, and enters the dehumidification function control;

[0089] The seventh area is the heating and humidification area, at which point the heating and humidification functions are controlled;

[0090] The eighth zone is the temperature rising zone. At this time, the humidity control maintains the control of the previous zone unchanged, that is, according to the control of the previous zone, it can be humidification, dehumidification, or neither humidification nor dehumidification; enter the heating function control;

[0091] The ninth area is the heating and dehumidification area, which enters the heating and dehumidification function control;

[0092] The control unit controls each execution component to enter the cooling, heating, dehumidification and humidification process according to the above-mentioned areas, including

[0093] Refrigeration control, at this time, the evaporator fan, condenser fan and compressor of the refrigeration system are running, and the compressor speed is controlled according to the difference Δt between the cabin temperature and the target temperature and the temperature difference change rate Δt'; where Δt = the average cabin temperature - the average of the two preset target temperature values ​​((a+b) / 2℃=20℃), Δt' = Δt1-Δt2, which represents the temperature difference change rate;

[0094] It is best to adjust the compressor speed according to the highest temperature collected in the metering cabin, so that the highest temperature is stabilized at the average of the two preset temperature values. If other temperature values ​​are lower than the lower of the two preset temperature values, the corresponding electric heating is appropriately turned on for compensation.

[0095] The compressor speed control is shown in Table 2;

[0096] Table 2 Compressor speed control

[0097]

[0098] like Figure 3 The pressure-enthalpy diagram of the refrigeration system is obtained by simulation. The pressure-enthalpy diagram simulation software used is Coolpack;

[0099] The thermal calculation of the refrigeration system cycle is shown in Table 3.

[0100] Table 3 Calculation of thermodynamic cycle of refrigeration system

[0101]

[0102]

[0103] According to calculations, the required compressor air volume for the refrigeration system is 0.0049m 3 / s, the refrigeration system of this scheme uses two high-efficiency variable frequency compressors with a displacement of 50ml / r and a rated speed of 3600 rpm. The compressor gas output is 100×3600 / 60 / 1000 / 1000=0.006m 3 / s>0.0052m 3 / s, meeting the design calculation requirements,

[0104] This system uses Shanghai Haili ATH550 compressor, which adopts DC frequency conversion technology. It can adjust the cooling output of the compressor according to the real-time detected cabin temperature and match it with the cabin heat load in real time. Compared with conventional fixed frequency compressors, it has the advantages of stepless speed adjustment, avoiding frequent start and stop, and precise temperature control.

[0105] The selection and design of the condenser and condensing fan, according to the above calculation, the condenser heat load is about 31kW. The condenser of this scheme adopts two high-efficiency microchannel parallel flow heat exchangers, which have the characteristics of small size, light weight and high heat exchange efficiency. In air conditioners with the same cooling capacity, the micro-microchannel metal round tube heat exchanger can reduce the volume by more than 50%, reduce the weight by more than 40%, and reduce the refrigerant charge by about 50% compared with the fin-type heat exchanger. The overall dimensions of a single condenser are L×H×D: 1100mm×340×25, and the heat exchanger structure is as follows Figure 4 Parallel flow heat exchanger structure diagram, Figure 5 Schematic diagram of the flat tube and fin structure of the parallel flow heat exchanger;

[0106] The heat exchange air volume of the condenser of a single refrigeration system is set according to the condensation inlet and outlet temperature difference of 9°C. According to Va=3.6Q / (ρa*Cpa*Δt), the condensation air volume is about 9800m 3 / h, total wind resistance is about 100Pa. The condensing fan uses a high-efficiency axial flow fan. The rated voltage of the fan is AC220V, the ambient temperature of the fan is -40℃~75℃, and the noise is 68db. Under a static pressure of 120Pa, the air volume is about 5700m 3 / h, this unit uses 2 such fans. It meets the heat exchange requirements of the condenser. Considering the high temperature working condition performance, the condenser size and the condenser fan air volume selection are both left with a large margin. The condenser fan performance curve is shown as follows Figure 6 ;

[0107] Evaporator and evaporating fan selection. The evaporator also adopts a microchannel structure. This temperature control system uses two evaporators with a single size of 350mm×255mm×58mm. The single cooling capacity is about 12kW, and the heat exchange capacity of the two evaporators is 24kW.

[0108] Since precision air conditioning requires low enthalpy difference between inlet and outlet air, the air volume must be increased. Generally, the evaporation fan is selected according to 190m3 / kW. Therefore, according to the design cooling capacity of a single evaporator matching 11000W, the single evaporation air volume is about 2000m3 / h, and 2 sets of fans are selected for a single refrigeration system. Each fan can be steplessly adjusted. The performance curve of the evaporation fan is as follows: Figure 7 shown.

[0109] When the cabin temperature is lower than 19.5℃, the refrigeration function is exited, and the compressor and condensing fan are shut down.

[0110] Heating control, the control system achieves heating through PTC electric heating. The electric heating is steplessly adjusted according to the temperature in the metering cabin using the PID control algorithm. When the temperature in the metering cabin reaches the preset temperature range, specifically greater than 20.5°C, the heating is exited and all electric heating is shut down. Specifically, in order to speed up the temperature rise and reduce the heating time, PTC electric heating is adopted. The PTC heating power is 14000W, and the heating amount can be adjusted steplessly according to the temperature in the metering cabin. At the same time, in order to increase the temperature in the lower part of the cabin, four independent heaters are set on the floor of the metering cabin, with a total of 2000W. The remaining 12000W electric heaters are arranged in the air supply duct in the cabin, and the hot air is sent into the cabin through the evaporating fan.

[0111] In order to control the temperature balance in the metering cabin, the metering cabin is divided into space areas, and six groups of electric heating or / and fuel heater adjustment, air supply volume adjustment, electric heating or / and fuel heating compensation adjustment control are arranged in different space areas. Six groups of electric heating or / and fuel heating are set, which are arranged at the air supply duct openings of each space area, and the power of each group of electric heating or / and fuel heating is steplessly adjusted;

[0112] Preferably, the power output of each electric heater and / or fuel heater is independently adjusted so that each temperature point is within the target value range.

[0113] Humidification control, the control system humidifies through an electric humidifier. When the humidification function is started, the humidifier is turned on. When the humidity in the metering cabin reaches the preset temperature range, specifically greater than 65%, the humidification is exited and the humidifier is turned off. Specifically, the humidifier used by the control system is integrated inside the air-conditioning unit, and the humidification port is connected to the rear opening of the evaporator. When in use, the humidified air is sent into the metering cabin through the evaporating fan to achieve the purpose of humidification in the metering cabin. The humidifier is connected to the external vehicle-mounted water tank through the side wall interface of the air-conditioning unit to supply water to the humidifier.

[0114] The humidifier uses an ultrasonic humidifier with a humidification capacity of 3kg / h. It mainly uses high-frequency oscillation, and then through the high-frequency vibration of the atomizer, the water in the humidifier is thrown off the water surface to produce a floating mist to achieve the humidification effect. Compared with other types of humidifiers, ultrasonic humidifiers have the following characteristics: high humidification efficiency (close to 100%), high humidification intensity, small and uniform mist particles, and can quickly reach the required humidity per unit time, saving water; low energy consumption per unit humidification, and at the same time has the characteristics of small volume and uniform humidification; the atomization component adopts an integrated atomization core, and the fully sealed structure design achieves the purpose of waterproofing, and is easy to replace; the integrated atomization core has a water protection device, which can effectively ensure that the atomization core automatically stops working when the water level is low; the humidifier adopts multiple protections, such as current overload protection, anti-dry burning protection, water temperature protection, etc., which can ensure the long-term continuous and stable operation of the machine.

[0115] Dehumidification control, the control system performs dehumidification through the operation of the refrigeration system of the air-conditioning unit. During dehumidification, the compressor speed is controlled according to the difference ΔRH between the humidity in the metering cabin and the target humidity and the humidity difference change rate ΔRH'. When the humidity in the metering cabin reaches the preset humidity range, the dehumidification is exited and the humidifier is turned off.

Claims

1. A high-precision temperature and humidity control system for a metering cabin, which provides high-precision temperature and humidity control for the metering cabin under extreme outdoor environmental conditions, and realizes the construction of an on-site metering environment that meets the requirements, characterized in that: It includes multiple groups of temperature and humidity sensors, a control unit and an execution component. The temperature and humidity sensors collect the cabin temperature and humidity in real time. The control unit performs relevant operations on each execution component according to the control strategy to complete the control of cabin cooling, heating, dehumidification and humidification, and adjust the cabin temperature and humidity; the execution component includes an air-conditioning unit, multiple sets of foot heaters, multiple duct heaters, and multiple humidifiers, which execute the control instructions of the control unit; the air-conditioning unit is used to adjust the temperature and humidity, and the air supply port of the air-conditioning unit is also provided with an air duct heater for adjusting the temperature. Multiple sets of foot heaters are evenly distributed at multiple positions in the cabin of the metering cabin for adjusting the temperature, and the humidifier is used to adjust the humidity.

2. The high-precision temperature and humidity control system of the metering cabin according to claim 1 is characterized in that: The control unit includes an internal control unit and a display control unit. The display control unit realizes local control and includes a display screen and operation buttons. The operation buttons are used to control operations, and the display screen is used to display the unit operating status, cabin temperature, and cabin humidity information. The internal control unit remotely controls operations according to operating instructions, and specifically performs relevant operations on each execution component according to the control logic to complete the control of cabin cooling, heating, dehumidification, and humidification.

3. The high-precision temperature and humidity control system of the metering cabin according to claim 2 is characterized in that: The foot heater and the air duct heater are electric heaters or fuel heaters.

4. The high-precision temperature and humidity control system of the metering cabin according to claim 3 is characterized in that: The humidifier is an ultrasonic humidifier.

5. The high-precision temperature and humidity control system of the metering cabin according to claim 4 is characterized in that: The multiple groups of temperature and humidity sensors arranged inside the metering cabin are selected as integrated temperature and humidity sensors, which are covered with a PTFE waterproof and breathable membrane.

6. An operation control method for a high-precision temperature and humidity control system of a metering cabin according to any one of claims 1 to 5, characterized in that: In order to meet the temperature and humidity requirements of the metering cabin, the control system controls the start and stop of the cooling, heating, dehumidification and humidification processes of the actuators according to the ambient temperature and humidity values ​​detected in real time by multiple groups of temperature and humidity sensors in the metering cabin, as well as the preset target values, and adjusts the compressor speed of the air-conditioning unit and the power of the heater in real time to make the temperature and humidity in the cabin reach the target value range; The operation control method realizes the high-precision temperature and humidity control process of the system according to the actual situation, including: According to the actual needs of the metering cabin, two temperature target values ​​a℃ and b℃ and two humidity target values ​​α% and β% are preset to form nine preset target temperature value-target humidity value areas; Formulate corresponding temperature and humidity control strategies according to the conditions of each preset target temperature value-target humidity value area; Then, the average value is taken according to the ambient temperature and humidity values ​​detected in real time by multiple groups of temperature and humidity sensors in the metering cabin; The average value is corresponded to each preset target temperature value-target humidity value area, and a corresponding control strategy is adopted to control the start and stop of the cooling, heating, dehumidification and humidification processes of the execution components so that the temperature and humidity in the cabin reach within the two target value ranges.

7. The operation control method of the high-precision temperature and humidity control system of the metering cabin according to claim 6 is characterized in that: The formulating of a corresponding temperature and humidity control strategy according to the situation of each preset target temperature value-target humidity value area includes: The two preset temperature target values ​​a℃>b℃, the two preset target humidity values ​​α%<β%, are divided into nine control areas according to the two preset temperature target values ​​and the two preset target humidity values: The first zone is when the ambient temperature is ≥a℃ and the humidity is ≤α%; The environment temperature is ≥a℃, and β% ≥ humidity > α% is the second area; The ambient temperature ≥ a °C and the humidity > β% is the third region; a °C > the ambient temperature ≥ b °C and the humidity ≤ α% is the fourth region; a °C > the ambient temperature ≥ b °C and β% ≥ the humidity > α% is the fifth region; a °C > the ambient temperature ≥ b °C and the humidity > β% is the sixth region; The ambient temperature < b °C and the humidity ≤ α% is the seventh region; The ambient temperature < b °C and β% ≥ the humidity > α% is the eighth region; The ambient temperature < b °C and the humidity > β% is the ninth region; The operation control strategy is as follows: The first region is the cooling and humidifying area. When the temperature and humidity in the cabin are in this region, the cooling function and humidifying function controls are entered; The second region is the cooling area. At this time, the humidity control remains the same as the control in the previous region, that is, according to the control in the previous region, it can be humidifying, dehumidifying, or neither humidifying nor dehumidifying, and the cooling function control is entered; The third region is the cooling and dehumidifying area. At this time, the cooling function control is entered, and the compressor speed is preferentially adjusted according to the temperature to quickly adjust the temperature parameters; The fourth region is the humidifying area. At this time, the temperature control remains the same as the control in the previous region, that is, according to the control in the previous region, it can be cooling, heating, or neither cooling nor heating; the humidifying function control is entered; The fifth region is the target area. At this time, both remain the same as the control in the previous region; The sixth region is the dehumidifying area. At this time, the temperature control remains the same as the control in the previous region, that is, according to the control in the previous region, it can be cooling, heating, or neither cooling nor heating, and the dehumidifying function control is entered; The seventh region is the heating and humidifying area. At this time, the heating function and humidifying function controls are entered; The eighth region is the heating area. At this time, the humidity control remains the same as the control in the previous region, that is, according to the control in the previous region, it can be humidifying, dehumidifying, or neither humidifying nor dehumidifying; the heating function control is entered; The ninth region is the heating and dehumidifying area. At this time, the heating and dehumidifying function controls are entered; The control unit controls each execution component to enter the cooling, heating, dehumidifying, and humidifying processes according to the judgment of each of the above regions, including Cooling control. At this time, the evaporation fan, condenser fan, and compressor of the refrigeration system operate, and the compressor speed is controlled according to the temperature difference Δt between the cabin temperature and the target temperature and the temperature difference change rate Δt'; Heating control. The control system realizes heating through PTC electric heating. The electric heating is steplessly adjusted according to the temperature in the metering cabin using the PID control algorithm. When the temperature in the metering cabin reaches the preset temperature range, the heating is exited and all electric heating stops; Humidifying control. The control system humidifies through an electrode humidifier. The humidifier is turned on when the humidifying function is started. When the humidity in the metering cabin reaches the preset temperature range, the humidifying is exited and the humidifier is turned off; Dehumidifying control. The control system dehumidifies through the operation of the refrigeration system of the air-conditioning unit. When dehumidifying, the compressor speed is controlled according to the humidity difference ΔRH between the humidity in the metering cabin and the target humidity and the humidity difference change rate ΔRH'. When the humidity in the metering cabin reaches the preset humidity range, the dehumidifying is exited and the humidifier is turned off.

8. The operation control method of the high-precision temperature and humidity control system of the metering cabin according to claim 7 is characterized in that: The temperature balance control is carried out by dividing the space area in the metering cabin, and the electric heating regulation, air supply volume regulation and electric heating compensation regulation control are adopted respectively. Multiple groups of electric heating are set up and arranged at the air supply duct openings of each space area. The power of each group of electric heating is steplessly adjusted. Several sets of foot heaters are also arranged in the metering cabin; During cooling, the compressor speed is adjusted according to the highest temperature collected in the metering cabin, so that the highest temperature is stabilized at the average of the two preset temperature values. If other temperature values ​​are lower than the lower of the two preset temperature values, the corresponding electric heating is appropriately turned on for compensation; During heating, the power output of each electric heater is adjusted independently so that each temperature point reaches the target value range.

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