Originally Posted by malconium
When the weather improves around here I would be willing to do some more tests. I still have the panels and the temperature guage. I would love to hear from more people about whether or not they feel more tests are in order and what they would like to have tested. Perhaps those of us that are interested in this topic could colaborate a bit and come up with some testing scenarios?
Wow, I never thought of the "inside of the car" greenhouse effect. Very possible, but it seems that would have heated the top panel, too. I need to think about how we'd design the unassailable experiment.
I think if I use my data logger to watch the temperature profile throughout the day, and build the box you mentioned but connect it tightly to the earth (cut out the bottom of the box and bury the edges a little--good thermal sink, the earth), we could infer quite a bit. Here's a full description:
1. Build said box (box to be insulated with 3/4" foam on all sides and painted white outside) and tie it to the earth-- provide suitable standard hole in top to fit the various panels. Provide temperature sensor in dirt, in the air inside the box, and two more for bottom and top temperatures of the panel. Provide a wind shield around the test site that doesn't shade the box.
2. Provide a "standard plate" that is black and is horizontal, on a pole next to box. Put a sensor on the plate and some small distance under the plate to get air ambient temp.
3. Record and graph the temperatures for 24 hours.
4. Install new panel and repeat.
5. Take a standard reading (24 hrs) on the box with a single sheet of unpolished aluminum to cover the "test hole."
I recognize that day-to-day ambient conditions won't be constant, but by graphing the results (and maybe doing this test for a week, then repeating for all panels) you will quickly see the delta temperatures. I think a lot can be inferred from that.
I will do all the above. Need to have someone else build and provide test panels. I suggest about 16" square--how big were the panels that Andy built? I'd like to see a panel with a rib in the middle. I think we ought to also see what happens if you make the panel sandwich without ribs (use foam and glue on the edges) and with ribs (one side, two sides, four sides) to get an idea of what the thermal conductivity of the ribs is compared to the larger area between the ribs.
Yo! This is a lot of little pesky panels!! I guess you'd only have to do the rib variations on one panel design, say with fiberglass batts as the standard, since that's what the standard AS comes with. We'll need to establish a standard size and thickness (1-1/2", right?) if there is a lot of interest.