In an earlier blog this month, we talked about rooftop solar systems integrated with standing seam roofs. We noted that the most widely employed rooftop solar technology isn’t electric, it’s solar thermal for heating air and hot water. We discussed four different systems, including an under the roof technology that takes heat from the metal roofing components and heats a water/glycol mixture that is circulated through cross-linked polyethylene tubing attached to a structure of purlins that are laid down piece by piece across the roof sheathing.Image may be NSFW.
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Well, since our blog appeared, a new under the roof technology has been emerging that uses the same heat principal but eliminates a lot of the manual labor, time and cost using the old system.
Known informally as the thermal lock module, this new under-the roof-system replaces complex 300 to 500 foot warrens of interlocking components of purlins, tubing, insulation material and aluminum foil with four by eight foot modules factory-fabricated and ready to install. Each module is 1 ½-inch thick and is connected to another by a simple coupling, eliminating a lot of the components and labor needed to install older systems.
The modules are installed as quickly as you would install a piece of plywood sheathing on a roof. It takes less than five minutes to couple them together.
There’s no need for the foil or foam and the system’s creator contends the new glycol system harvests two to three times more BTUs than the older glycol-based ones. In a recent in-plant test with 40 gallons of water, the creators say a single module was able to heat the temperature of the water from 50 degrees F in the morning to 105 degrees F in the afternoon. The new system must still undergo testing at the SRCC™, the non-profit organization which provides authoritative performance ratings, certifications and standards for solar thermal products required in most government and many commercial solar contracts. And its producer will only provide the factory made modules with plans to connect them to a manifold. But a certified solar installer must hook it up to the heating system.
Nonetheless, it appears to be a major step forward in under the roof solar thermal technology and one worth watching for architects, contractors and builders interested in marrying standing seam metal roofs with solar thermal installations.
