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Zhenxiang Electromechanical Technology (Shanghai) Co., Ltd
Process principle of temperature and humidity comprehensive test chamber
Date: 2025-04-22Read: 6
The process principle of the temperature and humidity comprehensive test chamber is mainly based on the collaborative operation of temperature and humidity control systems, combined with air circulation and intelligent regulation mechanisms to achieve precise environmental simulation. The following is a detailed explanation of the specific principles:
1、 Temperature control principle
1. Heating mechanism
Use electric heating elements (such as resistance wires and titanium tubes) to increase the temperature inside the box. When the sensor detects a temperature lower than the set value, the controller starts the heating system and dynamically adjusts the power output through PID algorithm.
Some devices are equipped with multi-level heating modules to avoid local overheating and increase the heating rate.
2. Refrigeration mechanism
Cooling is achieved through a cascade compressor refrigeration cycle, which includes components such as compressor, condenser, evaporator, and throttle valve. The reverse Carnot cycle principle (isothermal compression, adiabatic expansion) is used to rapidly reduce temperature.
Low temperature environments (such as below -55 ℃) require a combination of mechanical refrigeration and liquid nitrogen assisted refrigeration to enhance refrigeration efficiency.
2、 Principle of humidity control
1. Humidification method
Steam humidification: Water vapor is generated through an electric heating water tank or ultrasonic atomizer to increase the humidity inside the box.
Spray humidification: In the early days, water was sprayed onto the box wall to increase the partial pressure of water vapor through diffusion. It has gradually been optimized into a closed-loop water circulation system.
2. Dehumidification method
Condensation dehumidification: Utilizing the low-temperature condensation of moisture in the air on the surface of the evaporator of the refrigeration system, and then discharging it through the drainage pipe.
Adsorption dehumidification: Some equipment is equipped with molecular sieves or silica gel desiccants to reduce humidity through physical adsorption.
3、 Air circulation and uniformity guarantee
1. Forced circulation system
Equipped with a built-in centrifugal fan or rotating fan, it pushes air through the air guide plate and diffuser to form a closed-loop flow, ensuring even distribution of insulation and humidity.
The design of top air supply and bottom return air can reduce temperature and humidity gradient fluctuations.
2. Dynamic balance adjustment
Based on the principles of thermodynamics and humid aerodynamics, the system dynamically adjusts the collaborative working status of heating, cooling, humidification/dehumidification modules through real-time monitoring data from sensors, maintaining long-term stability of temperature and humidity.
4、 Core Control Logic
1. Sensor feedback
Use PT100 temperature sensor and capacitive/resistive humidity sensor to collect real-time environmental data inside the box.
2. Intelligent algorithm adjustment
Using PID control algorithm (proportional integral derivative) to process sensor signals, achieving precise matching of heating power, cooling capacity, and humidity regulation.
Support multi-stage programmatic control (such as 120 sets of programs) to adapt to complex temperature and humidity change curve requirements.
5、 Key Process Collaboration Process
1. Heating stage: Start the heating system and close the cooling valve to reduce energy loss.
2. Cooling stage: The refrigeration compressor runs at full power, and the heating module assists in adjusting the cooling rate as needed.
3. Constant temperature and humidity stage: Each subsystem enters fine-tuning mode and achieves dynamic balance through PID algorithm (BTC/BTHC technology).
