Hello all,

I am attempting to model a data center in eQuest for LEED. This will be a first attempt at modelling a data center for me and I am in hopes someone could provide some sage advice on the subject.

My understanding is that the data center will be a standard hot/cold aisle configuration with underfloor cooling (UFAD). The CRACs are on CHW and the CHW plant consists of multiple chillers, as well as, dedicated chillers for ice storage.

Recognizing that eQuest doesn't consider fluid air dynamics or temperature stratification resultant from UFAD, I am considering using the UFAD modelling guidance in the EDR Design Guidelines: HVAC Simulation Guidance (http://www.energydesignresources.com/resources/publications/design-guidelines/design-guidelines-hvac-simulation-guidelines.aspx)

This document addresses UFAD, but not specific to data center or hot/cold aisle. What Ive gotten out of the guidance is that for comfort UFAD applications, the upper portion of a room (non occupied ) space is defined as plenum and the internal loadings for the room are apportioned between the occupied zone and plenum. It seems to me that this method could be appropriate for hot/cold aisle scenarios as well, with the hot aisle as the plenum and cold as space. From the guidance equipments loads are suggested to be apportioned 67% space 33% plenum for comfort applications.

My understanding of hot/cold aisle configurations is that cold air is supplied on the front side of the server racks, pulled through the racks by the server internal cooling fans, and exhausted in to the hot aisle. Following from this logic it seems to me that the equip load should apportioned mostly to the plenum (hot aisle).

Does anyone have a better suggestion for load proportioning for a datacenter? Am I over complicating this?

My next challenge is modelling the Ice storage. I have 6 chillers of which 2 are dual mode CHW and Ice making. My guess is that I will have to model the dual mode units as 4 chillers (2 for CHW and 2 for ice) because of the different efficiencies and supply temps, while somehow using to the equip controls to make sure the chillers are not operating simultaneously.

This will be another first attempt for me. If anyone knows of any useful modelling guidance docs or has any advice on this it would be highly appreciated.

Thank you in advance and regards,

Shuichi Hendrickson, LEED AP