AIREDALE EasiCool Technical Manual page 47

Precision Air Conditioning
Installation
Liquid Sub Cooling
The degree of liquid sub cooling required to prevent flashing of liquid refrigerant can be calculated by the following
method.
Subcooling = Condensing temperature — Saturation temperature (Nett pressure at expansion valve)
Pressure Loss due to Liquid Lift
= H x spl
Total Pressure Loss in Liquid Line
TPL Liquid = PFL + Valves
Nett Pressure at Expansion Valve
= Condensing pressure - Total pressure loss in liquid line
= 34 - 3.01 = 30.99 bar
Sub Cooling Required
=Condensing temperature - Saturation temperature
Given the following as an example:
Where
H = Height (m)
spl = Static pressure loss
= 20 x 0.115 = 2.3 bar
• Refrigerant R410A
• Condensing temperature (54.4°C) equivalent
condensing pressure at 54.4°C = 34 Bar
• Liquid lift 20m
• Piping friction loss 0.21 bar
• Losses through valves and fittings 0.5 Bar
Note:- At normal liquid temperatures
the static pressure loss due to
elevation at the top of a liquid lift
0.115 bar/m.
Where
PFL = Pipe friction loss (0.21Bar)
Valves = Losses through Valves and fittings
= 0.21 +0.5 + 2.3
Total pressure loss in liquid line = 3.01 Bar
Saturation temperature at the nett pressure
at expansion valve (30.99 bar) = 52°C
(from refrigerant tables)
= 54.4 - 52 = 2.4 °C
Therefore liquid sub cooling required to prevent
liquid flashing = 2.4 °C
EasiCool Technical Manual 7525389 V1.8.0_05_2016
EasiCool™
47