I?m running an office building with three different energy programs (Trane Trace, Carrier HAP, and DOE?s eQUEST to compare and contrast each energy modeling programs output. Two of my programs Trane Trace and Carrier HAP have similar rooftop unit sizing, however, my eQUEST model is producing rooftop unit sizes (RTU-1 & RTU-2) that greatly exceeds the other two programs. I believe that this difference is the ventilation load. CFM?s and building sensible loads are similar, however. There is a large discrepancy between the total cooling capacity (defined by ?cooling capacity? in eQUEST?s SV-A reports. My eQuest model is reporting a much higher than expected total ?Cooling Capacity? for my rooftop units. All models have two VAV rooftop units (one for each floor of a two story office building). The ventilation rates, internal loads and envelope are identical between my models. The models have air side economizers w/integrated dry bulb with an upper cutoff of 75 deg. F with the non-economizer outside air turned off during unoccupied hours. All programs are using KC, MO TMY2 weather data.

Can anyone explain, or find my error, in the eQUEST modeling that is causing the unusual load in ventilation? It seems obvious that the three programs would produce similar outputs, however, there must be an eQUEST modeling error that I?ve created.

Also, does eQUEST have a load breakdown that describes (lists) the values that make-up the ?SV-A cooling capacity??

I?ve attached the Carrier RTU-1 (1st floor office load) system report and the eQUEST model.

Thanks,

Michael Schaefer - P.E.*, LEED AP

Licensed in Kansas, Missouri, and Colorado