It consists of the condenser chamber, which simulates the outside environment, and the evaporator chamber, which simulates the carriage environment. We can provide single-layer or double-layer structure according to customer requirements and the limitation of construction site. Double-layer structure can simulate the bus/train air conditioning system operation situation more closely, which has higher testing precision, easier installation, but the height of the construction site should be 7.5m above. The evaporator chamber is equipped with one or two enthalpy difference test apparatus which are used to measure the air volume and ability of the air conditioning.