[Equest-users] Return Air Reset Control

[Bishop, Bill]

Lyle,

 

Each zone in eQUEST will be modeled as having a single, uniform temperature each hour. In cooling mode, the return air temperature should be the thermostat setpoint from the COOL-TEMP-SCH (assuming the system can meet the loads), or a little hotter from duct/plenum heat gains. You can consider using the system COOL-CONTROL strategies to modulate supply air temperature and/or flow rate. WARMEST is the only value that resets the supply air based on zone loads.

 

I think you would need CFD software if you wanted to optimize data center HVAC design.

 

My approach in eQUEST would be to model this as I would any other system - entering known system capacities, flow rates etc., and entering the expected equipment loads into the space. (My experience with a few server rooms is that data center equipment loads are nearly constant 24/7/365. I'd be interested to hear others' experiences.) Even if the actual data center is controlled by hot aisle temperature instead of a wall-mounted thermostat, I would create the thermostat schedule based on a typical data center room setpoint, such as 75°F.

 

Regards,

Bill

 

 

 

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Lyle Keck
Sent: Wednesday, May 11, 2011 7:46 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Return Air Reset Control

 

Does anyone have experience modeling return air temperature reset in equest? 

I am modeling a data center that resets the supply airflow based on a max return air temperature of 95 degF coming off the hot server aisles.

 

I searched the archives and the only thread I found on this topic did not have any useful modeling input or guidelines. 

 

Any experience or suggestions are appreciated. Thank you for your time, 

 

Lyle Keck  

 

 

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