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

[Eric O'Neill]

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

P Please consider the environment before printing this e-mail note

 

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