The maker now has a large solar thermal collector running on a flat roof, rated at 1600 Watts and labeled as the second panel in a series. Rather than making electricity directly, the panel is a heat collector, and it feeds a loop of antifreeze fluid that circulates through flexible hoses to a plate heat exchanger. The maker says it is part of a solar steam engine project intended to generate electricity in the end.
The construction looks nicely thought through. The absorber is an aluminum sheet carrying copper pipes, screwed down onto foam supports with a cordless drill, after grooves were routed and PVC foam strips were cut on a table saw. The collector plate was degreased with silicone remover and then coated in black heat-resistant paint. Rigid insulation was trimmed to fit inside an aluminum enclosure frame, and clear polycarbonate glazing was laid over sponge tape around the frame and sealed, with Bostik Seal 'N Bond H750 caulk finishing the glazing edges.
A few details stand out to me. Before the vent ports were sealed shut, the enclosure was flushed with compressed air passed through a silica gel desiccant tube to drive out moisture. The loop is monitored with an in-line pressure gauge and an automatic air vent, and a hot tub filtration pump drives the fluid around. On the roof, wooden support legs on caster wheels allow the angle to be adjusted, and ratchet straps anchored into the brick wall with chemical anchors hold the panel in place.
Two things remain open. On-screen captions show the polycarbonate bulging when the panel was under test pressure, so the glazing strength seems worth watching. The maker has also asked how the design could be turned into a solar hot water heater, and that question has not been answered yet.
Project by The DIY Science Guy. Watch it on their YouTube channel: