The refrigeration system of the three comprehensive test chambers adopts a refrigeration system composed of enclosed industrial compressor units produced by France's "Taikang" or Germany's Gulun. This model of compressor has a large refrigeration capacity, low noise, low energy consumption, high efficiency, and can operate stably and reliably for a long time; The refrigeration system also adopts PLC control and energy regulation cold end output method, surpassing the traditional cold and hot balance control method. PID regulation is used to meet the requirements, greatly reducing user costs, extending the service life of the equipment, and improving the economic efficiency of equipment use; It is beneficial for reducing equipment noise and improving the working environment of the laboratory. The refrigeration evaporator, refrigeration evaporator, and light tube dehumidifier of the three comprehensive test boxes are equipped with complete sets of equipment from the United States, with single side welding and cold expansion; Cooling method: air cooling or water cooling (when using water cooling, the water temperature is ≤ 25 ℃, and the water supply pressure should be between 0.15MPa and 0.3Mpa); Main refrigeration accessories: solenoid valves, globe valves, filters, pressure controllers, oil separators, plate heat exchangers, etc. are all imported products. Refrigerant: Using environmentally friendly refrigerants R404A and R23. The heating system of the three comprehensive test standards, including high-quality oxygen free copper pipes and nitrogen filled welding process (traditional method uses ordinary copper pipes, direct welding method, which can easily generate oxides on the inner wall of the copper pipes, cause blockage of the refrigeration system, and prevent or slow cooling of the test chamber), is composed of multiple sets of nickel chromium alloy threaded electric heaters and polytetrafluoroethylene aviation silver plated protective wires in the air conditioning room. The humidification system is located within the air duct system and consists of a stainless steel humidifier.