Why the cooling electricity usage increase a lot after install pump VFD
There is very interesting output of cooling electricity usage after changing from constant volume to variable volume for chilled water pump by using OpenStudio modeling. The output showed that the cooling electricity peak demand increased a lot on May compared with the baseline model. At the same time, the heating peak demand also increased a lot on the same month. Does anyone know why it happens like that?
More information will be required to find the root cause. For example, what kind of valves do you have on your chilled water coils. Did you put the VFD on the primary or secondary chilled water pump? The results could potentially be entirely reasonable depending on your inputs and what you're trying to model. As with most energy modeling tasks - the devil is in the details.
@Lincoln Thanks for your comments. Actually, this is a very complicated model with both secondary and primary CHW and HHW loops there. There are a lot of chilled water coils in the model and it is hard to show all the values for clarifying my question. I'll focus on the details to find the answer.