Hello eQuesters,

I have a chilled water plant with 3 chillers, 3 cooling towers, and a water side economizer that cool a data center space via Computer Room Air Handlers in the Chicago, IL area. My intent is to accurately model the existing site and then implement some energy savings such as VFD fans and and VFD pumps to see how much energy can be saved.  The existing CRAH fans are constant speed and are controlled based off of maintaining a 70 degree F room temperature set point. The existing chilled water pumps are constant speed and are controlled based off of maintaining a 44 degree F chilled water temperature. I have modeled my baseline and 2 parametric runs with the variable speed fans and variable speed pumps and I am not seeing any energy savings. I should be expecting to have maybe around 10% ventilation fan energy savings and about the same for pump energy savings, but I am not. Can anyone lend any insight as to what my problem is?

Thanks so much for any help or advice you can offer! :)

-Ben