Unit Heaters, Infrared Heaters, and Ceiling fans in High Bays oh my!

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I am wondering what the best method is to simulate conditioning high bay
spaces in an automotive repair facility with a unit heater that heats
incoming outside air pulled through a louver by an exhaust fan on the
opposite side of the room. The ventilation air is pushed down to the
occupant level by ceiling fans that I will have to account for
separately due to their impact on destratification. The infrared
heaters will provide the heating to the occupants, equipment, and
surfaces that is not provided by the unit heaters.

I imagine that I could select the heating and ventilation system and
tack on a (wall convector) in the auxiliary heating coil/ fan control
methods section under advanced options. I hesitate to model the unit
heaters as a DOAS since that would require design data on a minimum temp
supply which is not in keeping with their design. All units require
combustion air.

Really what it comes down to is that the only outside air passing
through the system (unit heaters) is the combustion air. The
ventilation air is pulled across the space through a louver that could
be modeled as infiltration I guess (opening.) I can't wait to explain
that to LEED. The Infrared heaters only heat surfaces, people and
equipment through radiation and I have seen this implemented via means
similar to miscellaneous loads and even lights in the rooms served that
have a 100% radiant fraction and are attached to a gas meter. I only
have an inkling about tracking this operation to simulate its control
through a thermostat via the schedule though.

Any help is greatly appreciated.


Nic Fonner | EMIT

Nicholas Fonner
Energy Modeling Group
Henneman Engineering, Inc. | energy. focused.
1605 South State Street, Champaign, IL 61820
V 217.359.1514 | F 217.359.9354 | C
www.henneman.com | nfonner@henneman.com

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