Monday, September 18 2006
The experience with my homebrewed solar panel has given me the experience I need to hook up my newfangled high-tech vacuum-tube collector. In particular, I needed to know how to insulate and connect hoses. For my homebrewed panel, I ended up using rubber hoses covered with, foam pipe insulation, protected from the destroying ultraviolet of the sun by an accordion-shaped piece of aluminized dryer vent. For the hoses to the new collector, I've opted to run the foam-insulated hoses inside two inch wide PVC, the grey ultraviolet-resistant kind used for running electrical conduit. Since this sort of PVC isn't generally used in plumbing applications, there are no fittings for getting around plumbing errata like elbow joints and pressure release valves, which hang off either side of the collector. I've had to improvise the insulation and UV protection for these parts using things like spray foam, a part of a gallon antifreeze bottle, pieces of old caulking tubes, and lots of duct tape. I'd use a lot of duct tape on my homebrewed solar panel and know, after a year, that it doesn't hold up in the sun. The plastic is already brittle and flaking away, leaving just the formerly-embedded fiberglass strings. So I'm trying a different method of solar-proofing. I'm coating materials in roofing cement and then laying down a layer of aluminum foil. For surfaces that won't experience any sort of abrasion, this should be adequate; aluminum doesn't degrade at all in sunlight, and asphalt is happy as long as it has something UV-resistant to hide behind.
After I'd solar-proofed the least-accessible end of the new collector's plumbing manifold (where the evacuated tubes deliver their heat using a proprietary heat transport fluid), I took it up to the roof and placed it on a pair of temporary brackets so it would be in place for the rest of the frame that came with it. Those temporary brackets quickly dissolved under the weight of the manifold (about thirty pounds), but they successfully held it in an approximation of where it needed to be. The approximation was perfect for one of the two hinges I installed at the foot of the frame, but for the other it was off by an annoying two inches. Forcing the frame into the right place with one hand while sinking the screws with a drill in the other (and balancing in a precarious spacewalk with the rest of my body) proved difficult. I tried multiple times, using ropes to force the manifold somewhat higher towards the end. I was so frustrated at one point I jabbed powerfully at the frame with the fingertips of my free left hand, and this seemed to work momentarily. But then I struck the frame at the worst possible way, ripping the fingernail of the middle finger of my left hand and causing an angry blood blister to seize control further down beneath the nail. At this point I had to be really careful, because frustrating accidents like this can lead to worse ones, the kind that send you falling to your death. I backed off and took a break.
In getting the collector's frame into position, I'd had to carefully manipulate multiple nuts and bolts, doing my best not to let them drop into oblivion below. By oblivion, I mean bouncing down the shingled roof into a hillside covered with brush. (I've recovered tools from here using a powerful rare-earth hard drive magnet taped to the end of a stick, but it's not easy.)
I have lots of strange habits when talking to myself, particularly in stressful situations such as installing stuff on a roof. Today I kept using the word "nutdropperman" as an ironic way to describe what I was doing today. I was, of course, hoping not to be a nutdropperman. And in general I succeeded. I only dropped two nuts today, one of which I recovered as an unexpected boon when I went down to recover a dropped wrench.
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