LCP
RG66006889-Rev.01
23
Warning: the refrigerant R410A requires “POE” polyolester oil of a type approved by the
compressor manufacturer.
For no reason should a mineral oil be introduced into the oil circuit.
-
The difference between the Dew Point and Bubble Point is known as “GLIDE” and this is a
characteristic property of refrigerant mixtures. If pure fluids are used, the phase change
occurs at a constant T and thus the glide is equal to zero. If HFC R410A [
50%-50% blend of
R32/R125
] is used, the glide will be negligible (0.2°C) and the fluid can be considered like a
pure fluid.
7.5
EXPANSION VALVE (OPTIONAL)
An electronically controlled expansion valve is installed as a
standard feature on all LCP units. If correctly parameterised and
controlled by the software, this device has the ability to render the
operation of the cooling circuit highly efficient and this will have the
ultimate effect of decreasing the power intake of the system
when a sudden change occurs in the thermal load. With a traditional
expansion valve there is a transient time of 2 to 3 minutes before a
condition of equilibrium is reached.
Example:
A compressor switches off
The evaporation temperature increases
Superheating decreases
The valve closes
The refrigerant flow rate decreases
The cooling capacity decreases
The evaporation temperature decreases
…and so on...
Average T
(T1+T2)/2
T1 (start of condensation)
DEW POINT
T2 (end of condensation)
BUBBLE POINT
Enthalpy h
P
Compressor
discharge
real P
R410A
