Retrotec USACE - Manual (Page 155)

Appendix D D25
D.2.1.12 Air Supply Outlets Are Located Close to Exhaust Grilles
(Ineffi ciency)
Figure D41. Vehicle maintenance facility with air supply grilles located close to the roof along
the short side of the bay and air exhaust inlet at the roof level in the middle of the bay.
When an air exhaust is located in proximity to the air supply grilles, ventila-
tion air will have a neutral buoyancy or, when slightly heated in winter, will not
reach the occupied zone. This results in a poor ventilation effi ciency, a waste of
energy, and inferior indoor air quality (Figure D41).
D.2.2 Heating and Cooling Systems
D.2.2.1 Use of Forced Air Heating in Large High Bay Areas
(Ineffi ciency)
Figure D42. Unit heaters used for heating
in high bay machining area. Most of heat
from heaters rises, adding to temperature
stratifi cation.
Human occupancy and storage of materials rarely occurs above 3.7 m (12 ft)
from the fl oor. Using forced air heating requires heated air to be conveyed to
the space and discharged above the heated area. The resulting heated air even-
tually rises to the underside of the ceiling or roof assembly above the occupant
or stored material. The “loss” of heated air up and away from the heat require-
ment results in energy loss (Figure D42). Forced air heating can be replaced
with radiant heating that can be directed to the occupant or stored material