Sub-purlins were installed perpendicular to the stand- ing seams on the existing roof, which created a cavity in which to place polyiso insulation board material.
inch of board thickness. In the case of the Goodfellow AFB demonstration project, the rigid insulation board has a foil facing on one surface, acting as a radiant barrier to further improve energy effi ciency. The ESTCP demonstration project at
Goodfellow AFB used THERMAX insulation from Dow Building Solutions, a business unit of The Dow Chemical Co., Midland, Mich. The glass-fi ber-reinforced polyisocy- anurate foam core, which is laminated be- tween smooth facers, was seamlessly inte- grated into the fi nal assembly. At R-6.5 per 1 inch of material thickness, plus the added R-value from the refl ective facing and air space, the thermal level of insulation was increased by more than 250 percent. The projected energy savings of $11,750
per 10 KSF building includes the annual energy savings from insulation (heating and cooling energy), solar hot water, space heating, solar electricity and water con-
servation from rainwater harvesting. The portion of the total energy savings from the insulation alone is estimated to be $2,500 per 10 KSF building, or more than 20 percent in the Goodfellow AFB demonstra- tion building. In addition, the reinforcing material
used in THERMAX insulation, along with a patented chemical formula, enhances the fi re resistance and dimensional stability of the insulation. These were important prod- uct attributes for the DoD demonstration project because of the high temperatures possible from the performance of the solar- energy-collection systems.
Air Infi ltration When looking at energy savings, high
R-value is only part of the equation. The building also must be sealed from air leakage or the insulation’s value can be short-circuited. When used in conjunction
Circle No. 16 March-April 2013 // RETROFIT 33
Stackable and integrated roofing technologies that produce electricity, heat and hot water – for new and retrofit installations.
Is your roof ready? Ask for “Building Integrated PV–Thermal”!
Pfister Energy is a Goodfellow AFB ESTCP
integrated metal roofing technology project partner. Project info and video are at www.pfisterenergy.com.