Daikin JEHBSCU0200M1, Technical Manual

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T-CU01-MAR21-3 24
9.5 Pipe Size Selection (For EVI unit Only)
Sizing of liquid and suction lines for EVI model will be different from standard scroll models. Piping sizes of this
model need to follow the recommended correction coefficient of cooling capacity. This is vital as if the pipework
selected is oversized, especially for the suction pipe, the gas velocity will be decreased at low mass flow rate /
low evaporating temperature, causing oil return problems. Undersized suction lines will also cause decreased
capacity due to increased pressure drop.
The correction factor of refrigerant R404A is shown as below table:
For instance,
At condition of Te -35°C, Ta +32°C
Refrigerant R404A
Published cooling capacity = 5.9kW.
Cooling capacity = Correction factor x Published cooling capacity
= 0.63 x 5.9 kW
= 3.707kW
Therefore, the pipe sizes should be selected against the
corrected capacity of 3.71kW.
9.6 Insulation Selection (For EVI unit Only)
The liquid pipe connecting CCU service valve to the evaporator must be well insulated with recommended wall
thickness of minimum ¾’’.
9.7 Expansion Valve Selection (For EVI unit Only)
The lower liquid temperature of the EVI unit can increase evaporator expansion valve capacities . Selection of the
expansion valve needs to be done based on the expected amount of sub-cooling shown in below tables:
R404A
Amount of Sub-cooling (K)
Ta\Te -40 -35 -30 -25 -20
27 39.9 36.9 33.9 30.9 27.9
32 40.9 37.9 34.9 31.9 28.9
35 41.5 38.5 35.5 32.5 29.5
38 42.1 39.1 36.1 33.1 30.1
43 43.1 40.1 37.1 34.1 31.1
Ta Te (Watts) -40 -35 -30 -25 -20
27 CF 0.64 0.66 0.68 0.70 0.72
32 CF 0.61 0.63 0.65 0.67 0.69
35 CF 0.59 0.61 0.63 0.65 0.67
38 CF 0.57 0.59 0.61 0.63 0.65
43 CF 0.54 0.55 0.57 0.58 0.60