Yuh Dak SIC-A series - Manual (Page 10)

3. Main Functions
3-2
When the machine is started, compressor (1) starts working. Refrigerant is
compressed into high pressure and high temperature gas in the process from
A to B. In the process from B to C and D, this high pressure and high temp.
gas is cooled when it is passing through the condenser (2) and changed into
liquid. Heat is taken away by the cooling water. In the process from D to E,
the pressure of liquid refrigerant is reduced by expansion valve (4) and a part
of the refrigerant is changed from liquid to gaseous state. In the process from
E to A, refrigerant absorbs the heat of process water in the evaporator (5) and
returns back to the compressor. This heat exchange process repeats until
process water is cooled down to required temperature.