Daikin EWAD620-C17C-SS, Service Manual

Page: 79 / 304

ESIE10-01 General Outline
Part 1 – System Outline 1–73
3
1
4
5
Correction factors
for water and glycol
mixture
How to use the
Correction factors
proposed in the
previous tables?
Q
Mixture Water and Glycol - Evaporator leaving water temperature > 4°C
• Depending on the type and percentage (%) of glycol filled in the circuit (see table "Minimum
glycol percentage for low air temperature" on page 1–72 and table "Correction factors for
water and glycol mixture" on page 1–73).
• Multiply the Cooling Capacity, the Compressor Power Input by the Correction factor of table
"Correction factors for water and glycol mixture" on page 1–73.
• Starting from this new value of Cooling Capacity, calculate the Flow Rate (l/s) and the Evapo-
rator Pressure Drop (kPa).
• Now multiply the new Flow Rate and the new Evaporator Pressure Drop by the Correction
Factors of table "Correction factors for water and glycol mixture" on page 1–73.
Ethylene Glycol (%) 10% 20% 30% 40% 50%
Ethylene Glycol
Cooling Capacity 0.991 0.982 0.972 0.961 0.946
Compressor Power Input 0.996 0.992 0.986 0.976 0.966
Flow Rate (
Δ
t)
1.013 1.040 1.074 1.121 1.178
Evaporator Pressure Drop 1.070 1.129 1.181 1.263 1.308
Propylene Glycol
Cooling Capacity 0.985 0.964 0.932 0.889 0.846
Compressor Power Input 0.993 0.983 0.969 0.948 0.929
Flow Rate (
Δ
t)
1.017 1.032 1.056 1.092 1.139
Evaporator Pressure Drop 1.120 1.272 1.496 1.792 2.128
Example
Unit Size: EWAD650C-SS
Mixture: Water
Working Condition: ELWT 12/7°C – Condenser inlet air temperature 35°C
Cooling capacity: 647 kW
Power Input: 221 kW
Flow Rate (
Δ
t 5°C):
30.90 l/s
Evaporator pressure drop: 79 kPa
Mixture: Water + Ethylene Glycol 30% (for a winter air temperature up to -15°C)
Working Condition: ELWT 12/7°C – Condenser inlet air temperature 35°C
Cooling capacity: 647 x 0.972 = 629 kW
Power Input: 221 x 0.986 = 218 kW
Flow Rate (
Δ
t 5°C):
30.05 (referred to 629 kW) x 1.074 = 32.27 l/s
Evaporator pressure drop: 85 (referred to 32.27 l/s) x 1.181 = 100 kPa