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Beijing Pusanda Instrument Technology Co., Ltd
The cyclic test of alternating temperature and humidity: how to achieve complex climate simulation in the alternating test chamber
Date: 2025-12-19Read: 0
Alternating test chamber is an environmental testing equipment that can perform periodic or arbitrary changes between high and low temperatures and humidity according to a preset program. It is mainly used to assess the performance stability and durability of products under complex climatic conditions. It is widely used in electronic appliances, automotive components, coatings, packaging, photovoltaics and other fields.
1、 Working principle
Alternating test chamberThe foundation is high and low temperature humidity control technology, combined with programmable time temperature humidity change curves. The workflow generally includes:
Temperature control: Heating and cooling are achieved through electric heating and compressor cooling, combined with air duct circulation to ensure uniform temperature inside the box.
Humidity control: The relative humidity is regulated by a humidification system (such as electrode humidifiers, steam generators) and a dehumidification system (refrigeration dehumidification or rotary dehumidification) to achieve a wide range of changes from low humidity to high humidity.
Loop control: Users can write multiple programs in the controller, such as "25 ℃/60% RH hold for 2 hours → increase to 60 ℃/95% RH hold for 4 hours → decrease to -20 ℃/30% RH hold for 2 hours". The device automatically executes in sequence and can set the number of cycles and total duration.
2、 Key structures for achieving complex climate simulations
Temperature and humidity sensors: high-precision platinum resistance thermometers and capacitive humidity sensors provide real-time feedback data and closed-loop control of temperature and humidity fluctuations.
Humidification and dehumidification module: The humidifier quickly increases humidity, and the dehumidification system uses cooling coils to condense water vapor or adsorb materials to remove moisture, achieving rapid humidity switching.
Refrigeration and heating system: Similar to high and low temperature test chambers, but requires anti condensation design during humidity control to avoid water vapor frosting on low temperature surfaces affecting humidity measurement.
Air duct and diversion system: Ensure even distribution of insulation and humidity inside the box, especially to prevent local condensation or dry areas during humidity changes.
Control system: supports multi-stage programming, slope control (adjustable temperature and humidity change rate), data storage and curve display, and some models can be remotely monitored through networking.
3、 Typical Applications of Complex Climate Simulation
Electronic products: Simulate temperature differences between day and night and humid environments to test the moisture resistance, mold resistance, and solder fatigue performance of circuit boards.
Automotive components: Reproduce the high temperature and high humidity summer rainy season and the low temperature and dry winter climate, evaluate the durability of seals, coatings, and plastic parts.
Photovoltaic modules: Test the output stability and insulation withstand voltage changes under long-term temperature and humidity cycling.
Packaging materials: Verify the ability to maintain deformation and strength in alternating humid and dry environments.
4、 Key points of operation and maintenance
According to the testing standards (such as IEC, GB, ASTM), set a reasonable temperature and humidity change rate and residence time to avoid rapid changes that may cause uncontrolled condensation.
Regularly check the quality of the humidification water source to prevent scale or microorganisms from affecting the accuracy of the humidity sensor.
Clean the condensate discharge channel and filter screen to maintain good dehumidification efficiency.
Calibrate temperature and humidity sensors to ensure reliable data.
5、 Summary
Alternating test chamberThrough temperature and humidity dual variable programmable loop control, a high degree of simulation of complex climate environments has been achieved. Mastering its working principle and structural characteristics can not only help with correct selection and programming, but also reveal potential defects in product environment adaptability testing, and improve the efficiency and reliability of research and quality control.