[Bldg-sim] Update on Spec Heating decrease with Window Film application

Keith Swartz kswartz at ecw.org
Fri Nov 7 11:32:09 PST 2014


I have also had models with VAV systems where the ventilation air changed rather dramatically if the peak cooling airflow changes, especially if the ventilation calculation uses the Multiple Spaces Equation from ASHRAE 62.1. If the peak airflow changes for each space while the ventilation airflow per space remains the same, the fraction of outside air for each space changes, which affects the system outside air amount.

Keith Swartz, PE, BEMP, LEED AP
Senior Energy Engineer | Energy Center of Wisconsin | Madison.Chicago.Minneapolis
608.210.7123 | www.ecw.org<http://www.ecw.org/>

From: John Aulbach [mailto:jra_sac at yahoo.com]
Sent: Thursday, November 06, 2014 10:37 AM
To: bldg-sim at onebuilding.org
Subject: [Bldg-sim] Update on Spec Heating decrease with Window Film application

I have always believed that when a modeling lesson is learned, the answer should be shared.

>From Joe Huang's suggestion, I found out that the parametric runs had varying supply and return flow, which decrease load. In reality, the supply and return fans remain the same.

I thusly ran my Base case to obtain airflows, then hard wired those flows into the model. Now window film application DOES result in an increase in space heating load.

Word to the wise.

John R. Aulbach, PE
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