Panasonic PAW-160MAH2L Installation Instructions Manual page 38

Product description
Calculation example for total additional refrigerant charge (R410A)
Unit: U-60PE2E5A
Pipe length: 40 meter
AHU DX coil (supplied by AHU manufacturer): 1,7 dm
Refrigerant charge at shipment fi tted for pipe length within 30 m
Pipes additional refrigerant charge: 0,04 kg/m
AHU DX coil additional refrigerant charge: 0,9 kg/dm
Refrigerant charge at shipment is suffi cient for AHU DX coil volume up to 1,4 dm
Total additional refrigerant charge calculation
((1.7 dm
Calculation example for number of passes in the heat exchanger
The minimum number of passes in the AHU heat exchanger is restricted. The limit is calculated
by the formula:
Minimum number of passes
= Number of steps × Distance between tube sheets × Number of rows × 1.5 × 10
The calculated value must then be rounded up to the next integer number.
Example
Number of steps: 12
Distance between tube sheets: 1,000 mm
Number of row: 3
Minimum number of passes = 12 × 1,000 x 3 × 1.5 × 10
This value must be rounded up to 6.
This means that the minimum number of passes is 6 passes.
36
– 1.4 dm ) x 0.9 kg/dm
3 3
3
3
) + (10 m x 0.04 kg/m) = 0.27 kg + 0.40 kg = 0.67 kg
3
= 5.4
–4
3
–4