Quick question for the group - NorthWestern Energy here in Montana uses a 30-minute demand window instead of the typical 15-minute. Does this change how we should approach HVAC staging? Seems like we'd have more flexibility but also more risk if multiple units cycle during that longer window. Anyone have experience with 30-minute demand billing?
NorthWestern Energy demand window - HVAC timing questions
Marilyn - the 30-minute window is actually more forgiving for short-term spikes but you're right about the cycling risk. MLGW uses 15-minute here in Memphis. With 30 minutes you need to think about the entire half-hour period, not just individual startup events. Staging becomes even more important because units might cycle multiple times in that window.
That makes sense Randy. I'm working with a client who has four heat pumps that seem to short-cycle in shoulder seasons. Even with the longer window, if they're all cycling every 10-15 minutes, we could still hit peak demand multiple times. Might need to look at better zone controls to reduce the cycling frequency.