How can a constant temperature and humidity test chamber maintain high precision in both temperature and humidity control over a wide temperature and humidity range?

Publish Time: 2026-02-12

As a core piece of equipment for environmental reliability testing, the constant temperature and humidity test chamber is widely used in industries such as electronics, materials, pharmaceuticals, and automotive to simulate product performance under different climatic conditions. Its core value lies in its ability to maintain high precision and stability in temperature and humidity control over an extremely wide range. However, temperature and humidity are physically coupled—temperature changes directly affect the saturated water vapor pressure, thus altering relative humidity; while humidification or dehumidification processes introduce thermal effects, interfering with the temperature field.

1. High-Precision Sensors and Fast-Response Feedback Systems

The prerequisite for achieving high-precision control is accurate measurement. Constant temperature and humidity test chambers commonly employ industrial-grade platinum resistance temperature sensors and high-stability capacitive humidity sensors, achieving measurement accuracy of ±0.1℃ and ±1%RH. These sensors are rigorously calibrated and positioned at multiple key locations inside the chamber to collect temperature and humidity data in real time. Meanwhile, the control system reads feedback signals at millisecond-level frequencies, forming a closed-loop regulation circuit to ensure that any minute deviations can be quickly captured and corrected, laying a perceptual foundation for precise control.

2. Independent and Cooperative Temperature and Humidity Control Units

To decouple the strong correlation between temperature and humidity, the constant temperature and humidity test chamber adopts a "zoned independent + intelligent linkage" control architecture. The refrigeration system is typically equipped with a cascade compressor and electronic expansion valve, while heating uses PID-controlled stainless steel electric heating tubes; humidification often uses shallow-tank steam humidification or ultrasonic atomization, and dehumidification is achieved through refrigeration dehumidification or rotary dehumidification. The key is that each execution unit does not work in isolation, but is dynamically coordinated by the central controller based on the current temperature and humidity status, target setpoint, and rate of change, adjusting the start-stop sequence and output power. For example, under high temperature and high humidity conditions, the system will prioritize stabilizing the temperature before fine-tuning the humidification amount; while under low temperature and low humidity conditions, it is necessary to avoid excessive cooling that could lead to frost formation and affect humidity response.

3. Advanced Control Algorithms and Adaptive Adjustment

Traditional PID control is prone to overshoot or oscillation under complex operating conditions. To address this, high-end constant temperature and humidity chambers incorporate intelligent algorithms such as fuzzy control, feedforward compensation, and even model predictive control. The system can predict temperature and humidity trends and adjust outputs in advance, reducing hysteresis. Simultaneously, some units possess a "self-learning" function, optimizing control parameters based on historical operating data to adapt to different loads, door opening disturbances, or environmental changes, ensuring long-term consistency and repeatability.

4. Optimized Chamber Structure and Airflow Organization

Beyond hardware and algorithms, the physical structure is equally crucial. The inner chamber uses mirror-finished stainless steel to reduce heat radiation interference; the insulation layer uses high-density polyurethane foam with a thickness exceeding 80mm, effectively isolating external heat exchange. More importantly, the air duct design employs a forced circulation air supply system, combined with multi-blade centrifugal fans and baffles, ensuring uniform temperature and humidity distribution within the chamber. This uniform environmental field not only improves testing accuracy but also reduces energy consumption and fluctuations caused by localized over-control.

In summary, the constant temperature and humidity test chamber achieves high-precision control over a wide temperature and humidity range, representing a systematic engineering project integrating precision sensing, intelligent algorithms, collaborative execution, and structural optimization. It is this pursuit of perfection in details that enables the equipment to "give customers peace of mind" in rigorous scientific research and industrial testing, truly becoming a reliable cornerstone for product quality verification.