Testing device for simulating climate environment in free air

Abstract

The invention provides a test device for simulating a climatic environment in free air, and relates to the technical field of climatic condition simulation and automatic control, a CO2 release device is composed of a plurality of air belts, a first stainless steel pipe, a first stainless steel support, a first track wheel and a first winch, the first stainless steel pipe is vertically inserted into the edge of a target crop area, and the first stainless steel support is connected with the first track wheel; the support is hung on the pipe, the gas belt is parallel to the crop area, and the first winch is used for height adjustment to ensure effectiveness of gas spraying. The heating device is composed of an infrared lamp, a second stainless steel pipe, a second stainless steel support, a second track wheel and a second winch, the infrared lamp is fixed to the support, and the second winch adjusts the height of the support. And the control device is connected with the gas supply device and the infrared lamp to realize real-time monitoring and adjustment of the working state, so that set environmental conditions are provided at different growth stages. According to the invention, the control precision of CO2 concentration can be improved, and the working state of gas supply and heating equipment can be monitored and adjusted in real time.

Description

Technical Field

[0001] The invention relates to the technical field of climate condition simulation and automatic control, in particular to a test device for simulating climate environment in free air. Background Art

[0002] In order to predict the impact of increased atmospheric carbon dioxide (CO2) and rising temperatures on ecological ecosystems, a large number of field controlled experiments have been carried out in different regions of the world using open-top chambers (OTCs) and free-air concentration enhancement devices (FACEs) in the past 30 years.

[0003] Compared with OTC, the environmental conditions such as air temperature, humidity, light and wind speed in FACE are close to the natural environment, which can simulate future climate change scenarios more realistically and has been widely used in related research on the impact of global change on ecosystems. The FACE system mainly releases pure CO2 into the air, and uses the diffusion effect driven by natural wind or concentration difference to evenly distribute CO2 to the natural space, thereby increasing the atmospheric CO2 concentration. Since the wind in the natural environment is uncontrollable, it will inevitably cause fluctuations in the CO2 concentration in the FACE system, which may affect plant growth.

[0004] Therefore, it is crucial to improve the control accuracy and reduce the fluctuation of CO2 concentration. In addition, under the conditions of global change, the increase in CO2 concentration and the rise in temperature occur simultaneously. Compared with the change of a single factor, the impact of the interaction of two factors is more in line with the real scenario of global change. Therefore, the device for coupling the increase in CO2 concentration with the temperature rise has become an indispensable experimental platform for related research. However, most of the existing experimental devices can only simulate the change of a single factor. The proportion of time that the deviation of the CO2 concentration control accuracy does not exceed 10% of the target concentration is only about 70%, and the proportion of time that the temperature deviation does not exceed the target value ±0.5℃ is only about 70%. In addition, the level of automation control is low, and the operation process is cumbersome, which is difficult to meet the needs of current research. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the object of the present invention is to provide a test device for simulating a climate environment in free air, which can improve the control accuracy of CO2 concentration and temperature and reduce the fluctuation of CO2 concentration and temperature.

[0006] To achieve the above object, the present invention provides the following solutions: A test device for simulating a climate environment in free air, comprising: a gas supply device, a CO2 release device, a temperature raising device and a control device; the gas supply device is connected to the CO2 release device through a gas pipeline; the CO2 release device is arranged at the edge of a target crop area; the gas supply device is used to transport gaseous CO2 to the CO2 release device; The CO2 release device includes: multiple air belts, a first stainless steel pipe, a first stainless steel bracket, a first rail wheel and a first winch; each of the first stainless steel pipes is vertically inserted into the edge of the target crop area; the first stainless steel bracket is suspended on the first stainless steel pipe; a first winch is arranged on the top of each first stainless steel pipe, and the first winch is connected to the first stainless steel pipe through a steel wire rope; the air belt is fixed on the first stainless steel bracket; the plane where the air belt is located is parallel to the plane where the target crop area is located; the first winch is used to adjust the height of the first stainless steel bracket to drive the air belt to rise and fall; the air belt is used to The target crop area is sprayed with the gaseous CO2; the heating device includes a plurality of infrared lamps, a second stainless steel tube, a second stainless steel bracket, a second track wheel and a second winch; each of the second stainless steel tubes is vertically inserted into the edge of the target crop area; the second stainless steel bracket is suspended on the second stainless steel tube; a second winch is provided on the top of each second stainless steel tube, and the second winch is connected to the second stainless steel tube by a steel wire rope; the infrared lamp is fixed on the second stainless steel bracket; the control device is connected to the gas supply device and the infrared lamp, and the control device is used to control the working status of the gas supply device and the infrared lamp.

[0007] Preferably, the air belt has air jet holes distributed in a zigzag shape on one side facing the center of the target crop area; the air belt is made of PE material; the aperture of the air jet holes is 0.5 mm, and the horizontal interval of the air jet holes is 4 cm.

[0008] Preferably, the number of the air belts is 8; each of the air belts forms an octagonal structure.

[0009] Preferably, it also includes a CO2 concentration analyzer and an anemometer; the CO2 concentration analyzer and the anemometer are connected to the control device; the CO2 concentration analyzer and the anemometer are arranged at the center of the experimental area of ​​the target crop area; the CO2 concentration analyzer and the anemometer are respectively used to obtain the CO2 concentration and wind speed in the center of the experimental area of ​​the target crop area.

[0010] Preferably, the gas supply device includes a proportional regulating valve and a CO2 storage tank, a vaporizer and a pressure regulator connected in sequence; the proportional regulating valve is arranged on the gas transmission pipeline of the CO2 storage tank; the vaporizer is used to gasify the liquid CO2 in the CO2 storage tank to obtain gaseous CO2; the pressure regulator is used to adjust the delivery pressure of the gaseous CO2 so as to deliver the gaseous CO2 to the CO2 release device; the proportional regulating valve is used to adjust the delivery rate of the gaseous CO2.

[0011] Preferably, the control device is connected to the proportional control valve, the CO2 concentration analyzer and the anemometer; the control device is used to perform PID control on the proportional control valve according to the CO2 concentration and the wind speed.

[0012] Preferably, it also includes multiple infrared probes, a third stainless steel tube, a heating belt and a temperature probe; the infrared probes are arranged on the third stainless steel tube in different directions; the heating belt and the temperature probe are both arranged in the water and soil layers of the experimental area of ​​the target crop area; the heating belt is used to heat the water and soil layers; the temperature probe is used to monitor the soil and water temperature of the water and soil layers; the infrared probe is used to monitor the infrared temperature of the crop canopy.

[0013] Preferably, the infrared lamps are evenly distributed on the second stainless steel bracket in a concentric circle or hexagonal manner.

[0014] Preferably, the infrared probe and the temperature probe are also connected to the control device; the control device is used to perform PID control on the infrared lamp through the infrared temperature, and is also used to perform PID control on the heating belt through the soil and water temperature.

[0015] Preferably, it also includes a rain gauge; the rain gauge is arranged in the target crop area; the rain gauge is connected to the control device; the rain gauge is used to obtain rainfall data of the target crop area; the control device is also used to control the working status of the gas supply device and the infrared lamp according to a preset sunrise and sunset schedule and the rainfall data.

[0016] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention provides a test device for simulating a climate environment in free air, comprising: a gas supply device, a CO2 release device, a heating device and a control device; the gas supply device is connected to the CO2 release device through a gas pipeline; the CO2 release device is arranged in a target crop area; the gas supply device is used to transport gaseous CO2 to the CO2 release device; the CO2 release device comprises: a plurality of air belts, a first stainless steel pipe, a first stainless steel bracket, a first rail wheel and a first winch; each of the first stainless steel pipes is vertically inserted into the edge of the target crop area; the first stainless steel bracket is suspended on the first stainless steel pipe; a first winch is arranged on the top of each of the first stainless steel pipes, and the first winch is connected to the first stainless steel pipe through a steel wire rope; the air belt is fixed on the first stainless steel bracket; the air belt The plane where the first stainless steel support is located is parallel to the plane where the target crop area is located; the first winch is used to adjust the height of the first stainless steel support to drive the air belt to rise and fall; the air belt is used to spray the gaseous CO2 to the target crop area; the heating device includes a plurality of infrared lamps, a second stainless steel pipe, a second stainless steel support, a second track wheel and a second winch; each second stainless steel pipe is vertically inserted into the edge of the target crop area; the second stainless steel support is suspended on the second stainless steel pipe; a second winch is arranged on the top of each second stainless steel pipe, and the second winch is connected to the second stainless steel pipe by a steel wire rope; the infrared lamp is fixed on the second stainless steel support; the control device is connected to the gas supply device and the infrared lamp, and the control device is used to control the working state of the gas supply device and the infrared lamp. The present invention makes the adjustment of the air belt extremely convenient through a device that can be quickly raised and lowered, ensuring that there is an ideal diffusion space between the air belt and the crop canopy, and the present invention can monitor and adjust the working state of the gas supply and heating equipment in real time to ensure that suitable environmental conditions are provided at different growth stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram of the structure of a device provided in an embodiment of the present invention; Figure 2 A side view of a device provided by an embodiment of the present invention; Figure 3 A schematic diagram of a proportional control valve opening control equation provided by an embodiment of the present invention; Figure 4 A schematic diagram of CO2 control accuracy provided by an embodiment of the present invention; Figure 5 A schematic diagram of temperature rise control accuracy provided by an embodiment of the present invention; Figure 6 A schematic diagram of soil temperature at different depths provided by an embodiment of the present invention.

[0019] Description of reference numerals: 1-gas supply device; 2-gas pipeline; 3-first stainless steel pipe; 4-gas belt; 5-first rail wheel; 6-first capstan; 7-heating belt; 8-infrared lamp; 9-second stainless steel bracket; 10-second stainless steel pipe; 11-second rail wheel; 12-second capstan. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The purpose of the present invention is to provide a test device for simulating a climatic environment in free air. The device can be quickly raised and lowered to facilitate the adjustment of the air belt, thereby ensuring an ideal diffusion space between the air belt and the crop canopy. The present invention can also monitor and adjust the working status of the gas supply and heating equipment in real time, thereby ensuring that specific environmental conditions are provided at different growth stages.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 and Figure 2 They are respectively a schematic diagram and a side view of the device structure provided by an embodiment of the present invention, such as Figure 1 and Figure 2 As shown, the present invention provides a test device for simulating a climate environment in free air, comprising: a gas supply device 1, a CO2 release device, a temperature raising device and a control device; the gas supply device 1 is connected to the CO2 release device through a gas pipeline 2; the CO2 release device is arranged in a target crop area; the gas supply device 1 is used to transport gaseous CO2 to the CO2 release device; The CO2 release device includes: multiple air belts 4, a first stainless steel pipe 3, a first stainless steel bracket, a first rail wheel 5 and a first winch 6; each of the first stainless steel pipes 3 is vertically inserted into the edge of the target crop area; the first stainless steel bracket is suspended on the first stainless steel pipe 3; a first rail wheel 5 is arranged on the top of each first stainless steel pipe 3, and a first winch 6 is arranged at an appropriate height on the ground, and the first winch 6 is connected to the first stainless steel pipe 3 through a steel wire rope and the first rail wheel 5; the air belt 4 is fixed on the first stainless steel bracket; the plane where the air belt 4 is located is parallel to the plane where the target crop area is located; the first winch 6 adjusts the height of the first stainless steel bracket by retracting and releasing the steel wire rope to drive the air belt 4 to rise and fall; the air belt 4 is used to move the target The gaseous CO2 is sprayed on the crop area; the heating device includes a plurality of infrared lamps 8, a second stainless steel pipe 10, a second stainless steel bracket 9, a second track wheel 11 and a second winch 12; each of the second stainless steel pipes 10 is vertically inserted into the edge of the target crop area; the second stainless steel bracket 9 is suspended on the second stainless steel pipe 10; a second track wheel 11 is arranged on the top of each second stainless steel pipe 10, and a second winch 12 is arranged at a proper height from the ground, and the second winch 12 is connected to the second stainless steel pipe 10 through the second track wheel 11 and a steel wire rope; the infrared lamp 8 is fixed on the second stainless steel bracket 9; the control device is connected to the gas supply device 1 and the infrared lamp 8, and the control device is used to control the working status of the gas supply device 1 and the infrared lamp 8. The gas supply device 1 includes a proportional regulating valve and a CO2 storage tank, a vaporizer and a pressure regulator connected in sequence; the proportional regulating valve is arranged on the gas transmission pipeline 2 of the CO2 storage tank; the vaporizer is used to gasify the liquid CO2 in the CO2 storage tank to obtain gaseous CO2; the pressure regulator is used to adjust the delivery pressure of the gaseous CO2 so as to deliver the gaseous CO2 to the CO2 release device; the proportional regulating valve is used to adjust the delivery rate of the gaseous CO2.

[0024] Preferably, the air belt 4 has jet holes distributed in a zigzag shape on one side facing the center of the target crop area; the air belt 4 is made of PE material; the aperture of the jet hole is 0.5 mm, the horizontal interval of the jet hole is 4 cm, the number of the air belts 4 is 8; each of the air belts 4 forms an octagonal structure.

[0025] Preferably, it further comprises a CO2 concentration analyzer and an anemometer; the CO2 concentration analyzer and an anemometer are connected to the control device; the CO2 concentration analyzer and an anemometer are arranged in the center of the target crop area; the CO2 concentration analyzer and an anemometer are used to obtain the CO2 concentration and wind speed in the center of the target crop area, respectively. The control device is connected to the proportional control valve, the CO2 concentration analyzer and the anemometer; the control device is used to perform PID control on the proportional control valve according to the CO2 concentration and the wind speed.

[0026] The gas supply device 1 is composed of a CO2 storage tank, a vaporizer and a pressure regulator. Liquid CO2 is vaporized from the storage tank through the vaporizer to become gaseous CO2, which is then transported to the CO2 release device at a stable pressure through the pressure regulator.

[0027] Specifically, the air belt 4 of the CO2 release device of this embodiment is an octagonal structure, and CO2 gas is released into the circle through 8 air belts 4 arranged at the edge of the target area. The air belt 4 is made of PE material, and there are small holes distributed in a "Z" shape on the side facing the circle, with a hole diameter of 0.5mm, a horizontal interval of 4cm, and a vertical interval of 2cm. The 8 air belts 4 are fixed on a first stainless steel bracket that can be freely raised and lowered. The first stainless steel bracket is suspended on several first stainless steel pipes 3 that are vertically inserted into the edge of the experimental area. The first stainless steel pipe 3 has a total length of 3 to 5m, inserted into the soil for 1 to 1.5m, and a first track wheel 5 is installed on the top. A first winch 6 is installed on the outside of the first stainless steel bracket at a height of 0.5 to 1m from the ground, and the first stainless steel bracket is connected to the first winch 6 by a high-strength steel wire rope. The height of the air belt 4 can be adjusted by manually or by driving the first winch 6 with a motor, so that it can be suspended at any height above the crop canopy.

[0028] Furthermore, in this embodiment, the experimental area is circular, and a CO2 concentration analyzer and anemometer are installed at the center point to measure the CO2 concentration and wind speed. At the same time, the atmospheric CO2 concentration background value is measured in the area with an interval of more than 75m, and the average of the CO2 concentration and wind speed for 5 seconds is used as the control parameter. The CO2 release amount is controlled through the PID control equation so that the CO2 concentration in the experimental area is always higher than the atmospheric background value. The value is higher than the specified value.

[0029] Furthermore, the PID control process of this embodiment is as follows: The PID control process is as follows: The atmospheric background value and the average value of CO2 concentration in the experimental area in the last 5 seconds are taken as control parameters, and the atmospheric background value + the set concentration difference is taken as the set concentration; 1. Calculate the difference between the actual CO2 concentration and the set concentration: dCO2_n=Set_CO2-CO2_5s_C', where dCO2_n represents the difference between the actual CO2 concentration in the experimental area and the set value, Set_CO2 represents the CO2 concentration value set in the experimental area, and CO2_5s_C' represents the measured CO2 concentration value in the experimental area.

[0030] 2. Determine the trend of the two most recent concentration changes dd=dCO2_n_1-dCO2_n', where dCO2_n_1 represents the difference between the actual CO2 concentration in the previous experimental area and the set value, and dCO2_n represents the difference between the actual CO2 concentration in the current experimental area and the set value.

[0031] 3. According to the difference in concentration, the opening of the electrical proportional control valve is calculated by the PID equation and converted into a voltage value. The calculation formula is as follows: Mtr_P_CO2=Coeff_P_CO2*dCO2_n'Coeff_P_CO2=0.2~0.4 Mtr_I_CO2=Coeff_I_CO2*dCO2_1min'Coeff_I_CO2=0.09~0.15 Mtr_D_CO2=Coeff_D_CO2*dd'Coeff_D_CO2=0.06~0.12 dif_mV_CO2=Mtr_P_CO2+Mtr_I_CO2+Mtr_D_CO2 Output_mV_CO2=Mtr_mV_n_CO2+dif_mV_CO2, where the initial value range of Mtr_mV_n_CO2 is 600-900.

[0032] 4. Send the calculated voltage value to the control device, which will open the proportional control valve. 5. End this PID and record the current PID output value as the base value for the next calculation: Mtr_mV_n_CO2=Output_mV_CO2. Execute PID control every 5 seconds.

[0033] PID completes an adjustment every 5 seconds. It takes a certain amount of time from the opening of the proportional control valve, the release of CO2 from the jet belt 4, the sampling at the center point, to the final detection of the increase in CO2 concentration by the gas analyzer. This time is closely related to the wind speed. When the wind speed is low, the required time will be greater than 5 seconds. The time lag will cause misjudgment of PID control, causing fluctuations in the CO2 concentration of the FACE circle and affecting the control accuracy. In order to avoid this influence, this embodiment uses the average wind speed value of 5 minutes as the control parameter to limit the valve opening of the proportional control valve.

[0034] like Figure 3 As shown, the X-axis represents the wind speed, with a value range of 0 to 10 m / s, and the Y-axis represents the valve opening, with a value range of 0 to 2000 mv. When the wind speed is less than X1, the middle value of the valve is Y1, when X1 < wind speed < X2, the middle value of the valve is (Y2-Y1) / (X2-X1), and when the wind speed > X2, the middle value of the valve is Y2. The Y1 value determines the fluctuation range of the valve opening. By adjusting X2 and Y2, the slope of the control equation can be changed to obtain the most appropriate empirical value and achieve the best control accuracy. In this implementation case, X1 is 0.68, X2 is 4.2, Y1 is 440, and Y2 is 1150.

[0035] After the proportional regulating valve is opened, CO2 gas enters the air belt 4 and is released into the atmosphere through the small holes of the air belt 4. The jetting sequence of the 8 air belts 4 is determined according to the wind speed and wind direction. -1 When the 8 air bands are divided into two groups, odd and even, they take turns to spray at intervals of 10 seconds. -1 ≤Wind speed<5 ms -1 When the wind speed is ≥5m s -1 Stop spraying when

[0036] Preferably, it also includes multiple infrared probes, a third stainless steel tube, a heating belt 7 and a temperature probe; the infrared probes are arranged on the third stainless steel tube in different directions; the heating belt 7 and the temperature probe are both arranged in the water and soil layers of the experimental area of ​​the target crop area; the heating belt 7 is used to heat the water and soil layers; the temperature probe is used to monitor the soil and water temperature of the water and soil layers; the infrared probe is used to monitor the infrared temperature of the crop canopy.

[0037] Preferably, the infrared lamps 8 are evenly distributed on the second stainless steel bracket 9 in a concentric circle or hexagonal manner.

[0038] Preferably, the infrared probe and the temperature probe are also connected to the control device; the control device is used to perform PID control on the infrared lamp 8 through the infrared temperature, and is also used to perform PID control on the heating belt 7 through the soil and water temperature.

[0039] Preferably, it also includes a rain gauge; the rain gauge is arranged in the target crop area; the rain gauge is connected to the control device; the rain gauge is used to obtain rainfall data of the target crop area; the control device is also used to control the working status of the gas supply device 1 and the infrared lamp 8 according to a preset sunrise and sunset schedule and the rainfall data.

[0040] Specifically, in this embodiment, the canopy is warmed by infrared lamps 8 made of ceramic materials. The infrared lamps 8 are installed in a stainless steel waterproof housing, and the number of infrared lamps 8 is determined according to the area of ​​the experimental area and the temperature rise range. A 1kw power is required to increase the temperature by 2°C per square meter as a basis for calculation. The infrared lamps 8 are arranged in concentric circles or hexagons and evenly distributed in the heating area to ensure that each experimental area is heated by no less than 6 lamps. The infrared lamps 8 are fixed on a bracket made of stainless steel. In order to minimize the shading rate as much as possible and to have sufficient strength to support the weight of the infrared lamps 8, a double-layer structure is adopted, that is, the bracket is composed of an upper and lower two-layer steel structure, and a high-strength stainless steel round steel (diameter 8mm) is used as the skeleton to enhance the supporting force of the bracket.

[0041] The second stainless steel bracket 9 is suspended on several second stainless steel pipes 10 (50 mm in diameter) vertically inserted into the edge of the experimental area. The second stainless steel pipe 10 has a total length of 4 to 6 m and is inserted into the soil for 1 to 1.5 m. A second track wheel 11 is installed on the top. A second winch 12 is installed 1 m above the soil surface. The second stainless steel bracket 9 is connected to the second winch 12 by a high-strength steel wire rope. The infrared lamp 8 can be suspended above the crop canopy by shaking the second winch 12. The infrared lamp 8 is powered by a special circuit to minimize the mutual influence of circuit failures on the infrared lamp 8.

[0042] Three infrared probes were installed in the experimental area and the non-experimental area to monitor the infrared temperature of the canopy. The infrared probe was installed on a third stainless steel pipe (20 mm in diameter) with a total height of 2 m and vertically inserted into the soil 0.5 m. The infrared probe was adjusted as the crop grew taller and was always located at a height of 0.6-0.8 m in the canopy. The three infrared probes monitored the infrared temperature of the crop canopy in the same area from three different directions, and the middle value was taken to represent the actual measured value of the area. The real-time infrared temperature of the canopy in the non-experimental area was taken as the control value, and the infrared lamp 8 was turned on by PID control so that the infrared temperature of the crop canopy in the experimental area was always higher than the control by a specified value.

[0043] Furthermore, the PID control procedure of this embodiment is as follows: 1. Read the average temperature of the three infrared thermometers in the non-experimental area and the experimental area for one second respectively, and take the middle value as the current real-time infrared temperature value Temp_T=Middle_hw_temp. Temp_T represents the current real-time infrared temperature, and Middle_hw_temp represents the middle value of the three infrared thermometers.

[0044] 2. The real-time infrared temperature of the non-experimental area + the set temperature rise value is taken as the target infrared temperature set_kqtemp=KZ_DZ_hw_wd+value. Where set_kqtemp represents the target infrared temperature; KZ_DZ_hw_wd represents the real-time infrared temperature of the non-experimental area; value represents the set temperature rise value.

[0045] 3. Calculate the difference between the real-time infrared temperature of the experimental area and the target infrared temperature dtemp_n = set_kqtemp-Temp_T. dtemp_n represents the difference between the real-time infrared temperature of the experimental area and the target infrared temperature; set_kqtemp represents the target infrared temperature; Temp_T represents the measured infrared temperature of the experimental area.

[0046] 4. Determine the trend of the last two infrared temperature changes in the experimental area, and calculate the temperature difference within 1 minute dT = dtemp_n-dtemp_n-1. Among them, dT represents the difference between the last two infrared temperatures, dtemp_n represents the current infrared temperature value; dtemp_n-1 represents the previous infrared temperature value; 5. If the real-time infrared temperature of the experimental area is higher than the target infrared temperature, the difference (dT) ≥ 0.5°C, the heating is turned off.

[0047] 6. If the real-time infrared temperature of the experimental area is lower than the target infrared temperature, and the difference (dT) is less than 0.4°C, the heating will not be turned on. If the difference (dT) is greater than 0.4°C, the difference (ΔT) of the infrared temperature change in the last 1 minute will be judged. If ΔT ≥ 0.2°C, the heating will not be turned on. If ΔT < 0.2°C, the heating will be turned on until ΔT ≥ 0.2°C, and the real-time infrared temperature of the experimental area is ≥ 0.5°C higher than the target infrared temperature, the heating will be turned off.

[0048] The heating belt 7 is used to increase the temperature of the water and soil layer in the experimental area. The heating belt 7 is 8mm wide and 3mm thick. It is made of PTC heating material inside and wrapped with polyolefin material. The power is 35w / m, and the maximum temperature in the water is 50℃. The heating belt 7 is evenly laid on the soil surface with an interval of 15 to 30cm. For safety reasons, the power supply voltage of the heating belt 7 is not higher than 36V. Three temperature probes are arranged on the soil surface of the non-experimental area and the experimental area, and the middle value is taken to represent the measured value. The opening of the heating belt 7 is controlled by PID so that the soil and water temperature in the experimental area is always higher than the temperature in the control area by a specified value.

[0049] Further, the PID control procedure is as follows: 1. Read the average temperature of the three thermometers in the non-experimental area and the experimental area for one second, and take the middle value as the current real-time field water temperature Temp_W_T=Middle_W_temp. Temp_W_T represents the current real-time field water temperature, and Middle_W_temp represents the middle value of the three thermometers.

[0050] 2. The real-time temperature of the non-experimental area + the set temperature rise value is taken as the target temperature set_wtemp=KZ_Temp_W_T+value. Where set_Wtemp represents the target temperature; KZ_Temp_W_T represents the field surface water temperature of the non-experimental area; value represents the set temperature rise value.

[0051] 3. Calculate the difference between the real-time temperature and the target temperature in the experimental area: dtemp_n = set_wtemp - Temp_T. Where dtemp_n represents the difference between the real-time field surface water temperature and the target temperature in the experimental area; set_wtemp represents the target field surface water temperature; and Temp_T represents the measured field surface water temperature in the experimental area.

[0052] 4. Determine the trend of the last two field water temperature changes in the experimental area, and calculate the temperature change value within 30 seconds dT = dwtemp_n-dwtemp_n-1. Among them, dT represents the difference between the last two field water temperatures, dwtemp_n represents the current field water temperature value; dwtemp_n-1 represents the previous field water temperature value 5. If the real-time field surface water temperature in the experimental area is ≥ the target temperature, the heating will be turned off.

[0053] 6. If the real-time field water temperature in the experimental area is lower than the target temperature and the difference is less than 0.3℃, the heating will not be turned on. If the difference is greater than 0.3℃, the temperature change difference (ΔT) within the last 30s will be judged. If ΔT≥0.1℃, the heating will not be turned on. If ΔT<0.1℃, the heating will be turned on until ΔT≥0.1℃, and the difference between the real-time temperature in the experimental area and the target temperature is less than 0.3℃, and the heating will be turned off.

[0054] Optionally, this embodiment is also provided with an automatic operation control process: A rain gauge is installed in the experimental area to record rainfall information. At the same time, the local sunrise and sunset schedule is added to the control system. The CO2 release device automatically turns on after sunrise and automatically turns off after sunset. During the operation time, if the rainfall in 10 minutes is greater than 0.2mm or the average wind speed in 5 minutes is greater than 5m s-1, the CO2 release device will automatically turn off and automatically turn on after the rain stops or the wind decreases. If the rainfall in 10 minutes is greater than 0.2mm, the heating system will be turned off and automatically turned on after the rain stops.

[0055] As an optional implementation, this embodiment establishes a high-precision CO2 concentration increase and temperature increase device with a diameter of 12m in the rice field planting area, wherein the CO2 concentration is 200 ppm higher than the control (natural environment atmospheric background value), and the temperature is 2°C higher than the control (natural environment). CO2 release began on July 5th, and the rice harvest was completed on November 2nd, and the jet was stopped. It ran for 120 days. Infrared warming started on July 25th and ended on November 1st, with a total operation of 99 days. Soil and water warming started on July 25th, and heating stopped from August 10th to 25th due to mid-term field baking. Reheating began on the 26th, and heating was stopped on October 14th due to the need to drain water in advance to prepare for rice harvesting. It ran for a total of 65 days.

[0056] like Figure 4 As shown in the graph, the background value of CO2 concentration during operation was 326.0-821.6ppm, and high concentration values ​​mainly appeared in the early morning. Then, as the photosynthesis of crops increased, the CO2 concentration dropped rapidly. The average CO2 concentration in the control circle during the entire rice season was 418.6ppm, and the CO2 concentration increase in the FACE circle was 204.0±22.3ppm. The CO2 concentration control accuracy deviation was within 20% for 96% of the time, and within 10% for 90% of the time.

[0057] like Figure 5 As shown in the figure, based on the 1-minute temperature average, the infrared temperature value of the crop canopy in the control circle ranged from 7.8 to 34.6°C, with an average of 21.88°C. The average temperature of the canopy warming in the experimental area was 23.64°C, 1.76°C higher than that in the control area. The temperature difference between the experimental area and the control area ranged from 0.50 to 2.72°C, and the time within the range of 1.5 to 2.5°C accounted for 90%.

[0058] like Figure 6 As shown in the figure, calculated by the 1-minute temperature mean, the field surface water temperature in the non-experimental area during the experiment was 14.4-36.5℃, with an average of 24.02℃. The field surface water temperature in the experimental area during the rice season was 26.16℃, 2.09℃ higher than that in the control area. The temperature difference between the experimental area and the control area was 1.10-2.66℃, and the time in the range of 1.5-2.5℃ accounted for 92%. The average soil values ​​at 5cm, 10cm and 20cm in the control area were 24.76, 24.35 and 24.38℃, respectively. The average temperatures at 5cm, 10cm and 20cm in the experimental area were 26.60, 26.03 and 25.92℃, respectively, which were 1.84, 1.68 and 1.54℃ higher than those in the control area, respectively, and the time in the range of 1.5-2.5℃ accounted for 95%.

[0059] The beneficial effects of the present invention are as follows: 1) The present invention uses a 1.5-inch diameter air belt as the jet system. Compared with the PVC pipe, it has a large capacity and can effectively buffer the pressure of CO2 when the valve is opened. After many tests, it is determined that the diameter of the air outlet is 0.5mm and the interval is 4cm, which makes the release of CO2 more stable. The small holes are arranged in a "Z" shape, and CO2 can be released at multiple heights at the same time, quickly forming a three-dimensional high CO2 concentration area with better uniformity.

[0060] 2) Through many attempts, the optimal PID control parameters were obtained, and the equation for limiting the opening range of the proportional control valve was added, which effectively improved the problem of low accuracy under low wind speed conditions.

[0061] 3) The device that can be quickly raised and lowered makes the adjustment of the jet belt extremely convenient, ensuring an ideal diffusion space between the jet belt and the crop canopy.

[0062] 4) The light is turned on and off by PID instead of simply "ON-OFF". After many attempts, the optimal parameters are determined, which effectively eliminates the influence of the "lag effect" when the infrared light is turned on and the "tailing effect" after it is turned off on the control accuracy.

[0063] 5) All temperatures used for control are derived from the median value of the three probes to reduce the impact of sudden equipment failure.

[0064] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0065] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A test device for simulating a climatic environment in free air, characterized in that: include: A gas supply device, a CO2 release device, a temperature increasing device and a control device; the gas supply device is connected to the CO2 release device through a gas pipeline; the CO2 release device is suspended at the edge of the target crop area; the gas supply device is used to transport gaseous CO2 to the CO2 release device; The CO2 release device includes: multiple air belts, a first stainless steel pipe, a first stainless steel bracket, a first rail wheel and a first winch; each of the first stainless steel pipes is vertically inserted into the edge of the target crop area; the first stainless steel bracket is suspended on the first stainless steel pipe; a first winch is arranged on the top of each first stainless steel pipe, and the first winch is connected to the first stainless steel pipe through a steel wire rope; the air belt is fixed on the first stainless steel bracket; the plane where the air belt is located is parallel to the plane where the target crop area is located; the first winch is used to adjust the height of the first stainless steel bracket to drive the air belt to rise and fall; the air belt is used to The target crop area is sprayed with the gaseous CO2; the heating device includes a plurality of infrared lamps, a second stainless steel tube, a second stainless steel bracket, a second track wheel and a second winch; each of the second stainless steel tubes is vertically inserted into the edge of the target crop area; the second stainless steel bracket is suspended on the second stainless steel tube; a second winch is provided on the top of each second stainless steel tube, and the second winch is connected to the second stainless steel tube by a steel wire rope; the infrared lamp is fixed on the second stainless steel bracket; the control device is connected to the gas supply device and the infrared lamp, and the control device is used to control the working status of the gas supply device and the infrared lamp.

2. The test device for simulating a climatic environment in free air according to claim 1, characterized in that: The air belt has jet holes distributed in a zigzag shape on one side facing the center of the target crop area; the air belt is made of PE material; the aperture of the jet holes is 0.5 mm, the horizontal interval of the jet holes is 4 cm, and the vertical interval is 2 cm.

3. The test device for simulating a climatic environment in free air according to claim 1, characterized in that: The number of the air belts is 8; each of the air belts forms an octagonal structure.

4. The test device for simulating a climatic environment in free air according to claim 3, characterized in that: It also includes a CO2 concentration analyzer and an anemometer; the CO2 concentration analyzer and the anemometer are connected to the control device; the CO2 concentration analyzer and the anemometer are arranged at the center of the experimental area of ​​the target crop area; the CO2 concentration analyzer and the anemometer are respectively used to obtain the CO2 concentration and wind speed at the center of the experimental area of ​​the target crop area.

5. The test device for simulating a climatic environment in free air according to claim 4, characterized in that: The gas supply device comprises a proportional regulating valve and a CO2 storage tank, a vaporizer and a pressure regulator connected in sequence; the proportional regulating valve is arranged on the gas transmission pipeline of the CO2 storage tank; the vaporizer is used to gasify the liquid CO2 in the CO2 storage tank to obtain gaseous CO2; the pressure regulator is used to adjust the transmission pressure of the gaseous CO2 to transport the gaseous CO2 to the CO2 release device; The proportional regulating valve is used to adjust the delivery rate of the gaseous CO2.

6. The test device for simulating a climatic environment in free air according to claim 5, characterized in that: The control device is connected to the proportional control valve, the CO2 concentration analyzer and the anemometer; the control device is used to perform PID control on the proportional control valve according to the CO2 concentration and the wind speed.

7. The test device for simulating a climatic environment in free air according to claim 1, characterized in that: It also includes multiple infrared probes, a third stainless steel tube, a heating belt and a temperature probe; the infrared probes are arranged on the third stainless steel tube in different directions; the heating belt and the temperature probe are both arranged in the water and soil layer of the target crop area; the heating belt is used to heat the water and soil layer; the temperature probe is used to monitor the soil and water temperature of the water and soil layer; the infrared probe is used to monitor the infrared temperature of the crop canopy.

8. The test device for simulating a climate environment in free air according to claim 1, characterized in that: The infrared lamps are evenly distributed on the second stainless steel bracket in a concentric circle or hexagonal manner.

9. The test device for simulating a climatic environment in free air according to claim 7, characterized in that: The infrared probe and the temperature probe are also connected to the control device; the control device is used to perform PID control on the infrared lamp through the infrared temperature, and is also used to perform PID control on the heating belt through the soil and water temperature.

10. The test device for simulating a climate environment in free air according to claim 1, characterized in that: It also includes a rain gauge; the rain gauge is arranged in the target crop area; the rain gauge is connected to the control device; the rain gauge is used to obtain rainfall data in the target crop area; the control device is also used to control the working status of the gas supply device and the infrared lamp according to a preset sunrise and sunset schedule and the rainfall data.

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