Freezing cycle type absorbs heat inside the panel by evaporator of freezing cycle and releases heat outside the panel by condenser. Inside of the panel is cooled by repeating this.
Freezing cycle has following structure. In this, high temperature high pressure cooling medium (gas) given out from compressor releases heat by condenser and cools up to normal temperature and undergoes condensation(liquid). This normal temperature high pressure cooling medium(liquid) becomes low temperature fixed pressure by expansion valve and absorbs heat by evaporator, undergoes evaporation to become gas. Vaporization heat at this time is absorbed from surrounding and evaporator gets cooled. Thus, this is the device in which evaporator and condenser are combined and evaporation and condensation of cooling medium is repeated.