The constant temperature and humidity test chamber is widely used in product testing in fields such as electronics, automotive, and chemical engineering by precisely regulating temperature and humidity, simulating environmental conditions. Its working principle and core system can be summarized as follows:

working principle

The core principle of the constant temperature and humidity test chamber is based on dynamic balance control of temperature and humidity. Temperature regulation is achieved through the coordination of a heating system (electric heating tube or resistance wire) and a refrigeration system (vapor compression refrigeration): when the temperature is below the set value, the heating system starts; When the temperature is higher than the set value, the refrigeration system reduces the temperature through components such as compressors, condensers, evaporators, etc. Humidity regulation relies on humidification and dehumidification systems: humidification systems increase humidity by heating and evaporating through a water tank or injecting steam; The dehumidification system adopts mechanical refrigeration dehumidification, which cools the air below the dew point to precipitate moisture, or circulates dehumidification through a dryer.

core system

Control system: As the "brain", the control system adopts PID algorithm or a combination of PID and fuzzy control to collect real-time temperature and humidity sensor data, compare it with the set value, and automatically adjust the operating status of heating, cooling, humidification, and dehumidification components to ensure stable environmental parameters.

Refrigeration system: using vapor compression refrigeration, consisting of a compressor, condenser, throttling mechanism, and evaporator. For low temperature requirements below -40 ℃, cascade refrigeration technology is usually used to improve refrigeration efficiency by working together with high and low temperature refrigeration systems.

Heating system: composed of high-power resistance wires or electric heating tubes, with power matching the temperature rise and fall requirements. Some test chambers add heaters to the bottom plate to enhance temperature uniformity.

Humidity system: Humidification is achieved through steam humidification method, which involves direct injection of low-pressure steam or evaporation from a water tank; Dehumidification is mainly based on mechanical refrigeration, and some models are equipped with dryers for dehumidification to meet special needs.

Air circulation system: composed of centrifugal fans and air ducts, it ensures uniform distribution of temperature and humidity inside the box through forced convection, avoiding local deviations from affecting test results.