(2-3) Calculating the Load and Selecting a Model
38
1
Load (in the summer with air-conditioning)
2
Necessary Air Circulation
3
Model Selection
< Sensible Heat > SH
< Latent Heat > LH
Total load is 28.8kW
Computer
Lighting
Number of people in the room
Infiltration draft
Outer wall (heat transmission)
Windows (radiation)
Windows (heat transmission)
Inner wall(heat transmission)
Outside air
1,800W
5 persons
✕
64 (U)
(0.2 times/h) 39.6m
3
✕
0.336
✕
8
8.5m
2
✕
3.6
✕
8
13.5m
2
✕
0.65
✕
188
13.5
✕
5.93
✕
8
61.6
✕
2.05
✕
4
125m
3
✕
0.336
✕
8
20.9 kW
1.8 kW
0.32 kW
0.11 kW
0.25 kW
1.91 kW
0.64 kW
0.5 kW
0.34 kW
26.8 kW
Total
Infiltration draft
Number of people in the room
Outside air
39.6
✕
834
✕
0.0117
5 persons
✕
82
125m
3
✕
834
✕
0.0117
0.39 kW
0.41 kW
1.22 kW
2.0 kW
Total
26800
0.336
✕
(24 -18)
V =
÷
60 = 221m
3
/min
Calculate the temperature difference by setting the outdoor temperature; then, calculate hourly loads.
The chart shows the result of a calculation, supposing that the system reaches its highest load at 12 o'clock.
Outdoor temperatures in this example Summer : 32˚CDB relative humidity 60%
Winter
: -2˚CDB relative humidity 42%
PUY-P250YMF-C
✕
2, PFD-P500VM-A type
Indoor ˚CDB 24˚C / Indoor ˚CWB 17˚C outdoor ˚CDB 32˚C
Capacity of the Moment 51.5kW SHF = 0.92
Capacity of Sensible Heat 51.5
✕
0.92 = 47.4/kW
Standard Air-Flow Volume: 320m
3
/min can be accommodated with PUY-P250YMF-C
✕
2 and PFD-P500VM-A.