Trane trg-trc001-en Air Conditioner User Manual


  Open as PDF
of 73
 
34 TRG-TRC001-EN
notes
period four
Air Quantity
With the supply air conditions known, the next step is to calculate the specific
quantity of air (cfm or cubic feet per minute) needed to satisfy the room heat
gains. The required supply airflow is determined using the following formula,
where the sensible heat gain is expressed in Btu/hr and the two temperatures
are in °F.
Realize that 1.085 is not a constant! It is the product of density, the specific heat
of air and the conversion factor of 60 minutes per hour. These properties of air
at “standard” conditions (69.5°F DB dry air at sea level) result in the value
1.085. Air at other conditions and elevations will cause this factor to change.
6HQVLEOH+HDW*DLQ
Õ5RRP'%¤6XSSO\'%
6XSSO\
$LUIORZ
67(36ROYHWKHVXSSO\DLUIORZHTXDWLRQ
'HWHUPLQLQJ6XSSO\$LUIORZ
Figure 55
Supply Airflow (cfm)
Sensible Heat Gain
1.085 Room DB Supply DB–()×

=
Density 0.075 lb/ft
3
=
Specific Heat 0.24 Btu/lb°F=
0.075 0.24× 60 min/hr× 1.085=
 previous next