How to achieve precise coordinated control of temperature, humidity, and irradiance in the solar radiation test chamber? The solar radiation test chamber integrates high-precision sensors, intelligent control systems, and multi parameter collaborative algorithms to achieve precise collaborative control of temperature, humidity, and irradiance, meeting the stringent requirements of material weather resistance testing (such as ISO 4892, ASTM G154, and other standards). The following is the implementation path of its core technology:
1、 Multi parameter independent control and dynamic compensation
Temperature control:
Adopting PID temperature control algorithm, combined with heating tube and refrigeration compressor (or semiconductor refrigeration chip) to achieve fast response. For example, when the temperature is set to 60 ℃, the system provides real-time feedback data through temperature sensors and automatically adjusts the heating power or cooling capacity to ensure temperature fluctuations of ≤± 0.5 ℃.
The built-in circulating fan promotes uniform air flow inside the box, eliminates local temperature differences, and achieves temperature uniformity of ± 2 ℃.
Humidity control:
Independently regulate humidity through steam humidification and dehumidification modules (such as condensation dehumidification). For example, when testing in a high humidity environment (85% RH), the system controls the amount of water sprayed by the humidifier based on the humidity sensor signal; When testing in a low humidity environment (10% RH), activate the dehumidification module to reduce the air moisture content.
The humidity control accuracy can reach ± 2% RH, and it is compensated in conjunction with temperature (such as when the humidity naturally decreases at high temperatures, the system automatically increases the humidification amount).
Irradiance control:
Using xenon arc lamp or metal halide lamp as the light source, coupled with a filter to simulate the solar spectrum (such as 290-800nm band).
Real time monitoring of irradiance intensity through light feedback sensors, combined with PWM dimming technology to dynamically adjust light power, ensuring irradiance fluctuations of ≤ ± 5% (such as setting 550W/m ², the actual value remains stable at 522.5~577.5W/m ²).
2、 Multi parameter collaborative control algorithm
Model Predictive Control (MPC):
Establish a dynamic coupling model for temperature, humidity, and irradiance to predict the trend of parameter changes. For example, when the irradiance increases, the model calculates the temperature rise inside the box in advance and starts the refrigeration module to pre cool down to avoid overshoot.
Expert system optimization:
Built in material testing experience library, automatically adjusts parameter coordination strategies based on the weather resistance characteristics of different materials (such as plastics, coatings, rubber). For example, when testing photovoltaic modules, priority should be given to ensuring irradiance stability while dynamically adjusting temperature to simulate actual day night cycles.
3、 Environmental simulation and anti-interference design
Insulation and shielding:
The box is insulated with double-layer vacuum glass or high-density polyurethane foam to reduce external temperature interference; Spray black light absorbing coating on the inner wall to reduce the impact of light reflection on irradiance measurement.
Compensation algorithm:
In response to light aging (such as the decrease in irradiance caused by the decay of xenon lamp life), the system automatically records the usage duration and dynamically adjusts the dimming parameters to extend the service life of the light source while ensuring stable irradiance.
4、 Calibration and Verification
Regular traceability:
Temperature and humidity sensors need to be calibrated by a metrology institution every year, and irradiance meters need to be compared with standard light sources (such as F1 irradiance meters) every six months to ensure measurement accuracy.
Uniformity test:
Arrange multiple testing points inside the box (such as the 9-point method) to verify the spatial uniformity of temperature, humidity, and irradiance, ensuring that all samples are under the same testing conditions.
Through the above technology, the solar radiation test chamber can achieve precise collaborative control of temperature (-40 ℃~+100 ℃), humidity (10%~98% RH), and irradiance (300~1200W/m ²), providing a reliable experimental environment for material weather resistance research.