Designing (& Testing) A Solar Regenerated Desiccant Air Conditioner for our Passively Heated Solar Home, by Henry Gurr. This is the seventh of a series of nine photos. Please see the first in this series (pix 16/76) for full explanation.

To make this photo, I just stepped back about 12’ from the position from which I took the previous photo. NOTE: Bold font shows added info from caption of previous photo.

Again you see the 4” dia white plastic pipe, angling down from the solar collector. This conducts sunny day hot air from the roof, into the 4’ x 5’ x 6.5’ plywood box, you now fully see at center. This hot air flows through ~250 lb of wood sawdust in this box. The sawdust is the desiccant. The box is raised up ~20”, so an old air conditioner centrifugal blower, can be located, under the box. The blower has sufficient pressure to circulate air through the pipes, sawdust, house, and back. There are two valves, each two way, to switch air flow between night operation and day operation. One of these valves is within the 4” dia white plastic “Tee”, seen at upper left of the photo. The valve is achieved, merely with an up and down sliding (gasket edged) disk, within the “Tee”. To see how it works, you will have to make some sketches. At night, additional pipes bring air from the house, and circulate it thru the desiccant to be dried. Then the air moves into the house by underground 12” culvert pipe, the entrance of which is under the center of the box: This provides for close pipe connection, and keeps rain out of the culvert pipe. The next two photos show more about how the air pipes & valves are connected and how the weight of the box is supported.

Although it is hard to tell it, the box end nearest you is ~6” lower than the far end, thus providing slope for rain run-off the corrugated galvanized sheet steel roofing sections, laid on the top of the box.

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