Heat load calculations with heated air changes

Question

I am working on a building project that requires a high ventilation rate for fire safety: 6 air changes per hour (ACH). The winter design temperature is -14, so moving that much air through the system will obviously impact the total building heat load significantly with a 200,000 ft³area.

When I run the analysis with the Revit loads tool before setting the ACH, it returns a heat load of 103,000 Btu/hr. If I set the zone ventilation to 6 ACH, it returns a heat load of 1,662,000 Btu/hr. From a simple heat transfer standpoint, it would make sense that the heating load would skyrocket when you are pumping that much cold air into the building. However, during the winter, part of that makeup air will be infiltrating the building through a heater, so the delta T will not be the difference between the -14 degrees F, and the 50 degree F setpoint, but, rather the heater output temperature and the setpoint.

Does anybody know of a way to account for this within Revit?

Answer 1

I know it is not what you asked, but you could take the intake air below ground, 2m down for example, and benefit from the ground temperature compared to the ambient air temperature - called a "puit canadien" and i did this for a 4 bedroom house in Switzerland - needed 30m of pipe 2m down plus a heat exchanger as @Brian Drummond . Helps in summer to reduce air T and winter to increase air T. Several references can be found online - just make sure that you have a constant slope and get rid of any moisture...