Have you used a sizing period object? In that case, the extreme temperatures used for sizing could be lower than the temperatures for the weather file used for running the annual simulation, so the boiler load do not need to reach the sized capacity.
Ignacio Gomks
Dear group,
I'm trying to autosize a boiler and chiller for a medium-sized commercial building. Everything is set to autosize with a sizing factor of 1.0 and coincident loads. But the HVAC equipment (e.g., boiler) seems to be given a nominal size that is 20-30% larger than the maximum value in the annual timestep results. I'd have hoped and expected to have the nominal sizes match the peak demand during the sizing days. I'm simulating and reporting the sizing period. I'm also allowing 10 HVAC sizing simulation passes (though this does not change results relative to 1 pass)
Any insights as to what is going on would be greatly appreciated.
Thank you,
Liam