[Equest-users] Increase in roof insulation increases cooling load.

[Cyrus Grimes]

This is a school and 70% of the rooms have about 25 kids. I was skeptical at first I guess I will concede. I just don't have the confidence in Equest yet. I guess I can play around with the insulation and fin the preferred insulative value for the roof, do you suppose such a prediction would be valid?

               Cyrus Grimes, LEED(r) AP               .
                    Mechanical Engineer
Phone (614) 443-1178 ext. 274

From: Eric O'Neill [mailto:elo at MichaelsEngineering.com]
Sent: Friday, December 19, 2008 11:03 AM
To: Cyrus Grimes
Cc: equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Increase in roof insulation increases cooling load.

Cyrus,

Depending on your internal gains, the increased levels of roofing insulation may make it more difficult for the system to reject the heat. I generally find this response when modeling auditoriums or rooms with high levels of internal gains. The system ends up working overtime to displace the heat that would normally have escaped after the internal loads subsided and/or ambient conditions cooled off. For instance, on a 45 degree day, the building might break even with a high internal gain and low roof insulation, but with the higher roof insulation, the internal gains dominate and cooling is required. It really depends on the scenario, but without more information, I can only say that it's plausible.

Eric
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Cyrus Grimes
Sent: Friday, December 19, 2008 9:34 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Increase in roof insulation increases cooling load.

In a parametric run the roofing insulation was increased from U= 0.063 to U=0.033. by increasing the thickness of the "Insul Bd 2in (HF-B3)" of the built up roof from 0.28 to 0.64.

In my results the HVAC cooling load increased by 4% and my heating load decreased by 4%. Overall the net change was -1% energy savings.

Is this reasonable?
 Any suggestions?

thanks

                  Cyrus Grimes, LEED(r) AP               .
                    Mechanical Engineer

Corporate Office
1108 City Park Avenue, 3rd Floor
Columbus, Ohio 43206

Phone (614) 443-1178 ext. 274
Fax: (614) 443-1594
e-mail: cgrimes at dynamix-ltd.com

 www.dynamix-ltd.com
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