We've got an 11,000 square foot maintenance garage for trucks, modeling it under LEED and ASHRAE 90.1-2007. This is a tricky space.

It has more than 15 BTUH/SFT of heat so according to Table 3.1 it is not a "semiheated" space - it is a "heated" space. In the real world, it is heat only, no cooling. They use radiant floor heat.

According to Appendix G Table 3.1 1 B we have to simulate the space as both heated and cooled. We get in a lot of trouble real fast after that.

An automotive repair garage requires a huge (41,000 cfm in this case) exhaust fan. This is a gigantic cooling load. The program (Trace) wants to simulate the exhaust as if it entered through the air conditioning unit.

This is heading down the path of simulating a 41,000 CFM 100% outside air rooftop unit, in a space that in the real world has no air conditioning. Yow!

Now, if I say this is a "process" load, and just add the power for the fan as a process electrical load, without adding the airflow in the energy model, is that the correct way to do this? I see another related question below hinting at the same idea. Not sure I am approaching this correctly.