1, Refrigeration system and compressor: in order to ensure the cooling rate and minimum temperature requirements of the test chamber, we choose a set of two yuan cascade water cooling system consisting of imported German Valley wheel semi closed compressor. Cascade refrigeration system comprises a high temperature refrigeration cycle and a low temperature refrigeration cycle, the connecting container for evaporative condenser, evaporator condenser is also to the role of the energy transfer, the studio heat energy to transmit through the two stage refrigeration system, to achieve the purpose of temperature. Refrigeration system design and application of energy regulation technology, an effective approach which can guarantee the normal operation of the refrigeration unit in the case and the energy consumption of the refrigeration system and refrigeration capacity effectively regulated, the refrigeration system operation cost and the failure rate dropped to more economic status.

2,The principle of refrigeration work: the reverse card cycle is selected for the high and low refrigeration cycle, which consists of two isothermal processes and two adiabatic processes. The process is as follows: the refrigerant is compressed by adiabatic compressor to a higher pressure, which consumes power and increases exhaust temperature. After that, the refrigerant exchanges heat with the surrounding medium through the condenser to heat the surrounding medium. After the cooling agent is adiabatic expansion of the valve, the refrigerant temperature is reduced. Finally, the refrigerant absorbs the heat from the higher temperature by the evaporator, so that the temperature of the cooled object is reduced. This cycle goes round to achieve the purpose of cooling.

3, Refrigerant: DUPONT company R502 (high temperature cycle), R23 (low temperature cycle);

4, Auxiliaries: expansion valve (US SPORLAN), solenoid valve (Italy CASTEL), filter (American SPORLAN), pressure controller (British and American RANCO), oil separator (Europe and America ALCO) and other refrigeration accessories are imported.