Retrotec USACE - Manual (Page 364)

H4 ENERGY & PROCESS ASSESSMENT PROTOCOL
Heat transfer through the building envelope due to warmer outside air ■
Infi ltration due to wind and a stack effect (gravity forces) ■
Ventilation airfl ow rate ■
Internal factors:
Industrial processes such as machining, welding, heat treatment, etc. ■
Electrical motors ■
Process equipment with a high surface temperature ■
Steam or hot water pipes, hot water tanks, etc. ■
Lighting ■
People ■
Computers, vending machines. ■
H.5.2 Cooling Load of HVAC System
If cooling is provided by HVAC system with a cooling coil, cooling load is cal-
culated using the following equation:
Q
cool
= ␳
* q
vent
* (h
s
−
h
out
)
where
Q
cool
= cooling load of ventilation, kW
␳ = air density, kg/m 3
q
vent
= ventilation airfl ow rate, m 3 /s
h
s
= supply air enthalpy, kJ/kg
h
out
= outside air enthalpy, kJ/kg
H.5.3 Heating Energy Consumption
Generally, the heating energy consumption of a building can be calculated
using the following equation:
Q
=
(Q
loss
+
Q
inf
+
Q
vent
+
Q
hv
−
Q
int. load
/
␩
where
Q = heating energy consumption, kWh
Q
loss
= losses of heat through the building envelope, kWh
Q
inf
= heat losses due to infi ltration, kWh