Well it might work to have the cell immersed behind a glass or fused silica window yes! I notice with veggie oil and even moreso with BD that heating with an immersion heater is much more prone to boiling on the heater surface with BD and oil which leads me to believe that the specific heat capacity is worse (less) than water. Pure water is a good insulator and is ideal with a specific heat capacity of unity but it is hard to keep it pure enough to be insulating especially if it is in contact with metals. Freon would be ideal if not for the environmental issues. :(
Joe Michael Redler wrote: > > As we all know, there are a lot of ways to harvest waste heat but the > one that stands out in my mind is from a message posted about six months > ago. I don't know if this is a solution, but I'm definitely curious to > know one way or the other. > > http://www.mail-archive.com/biofuel@sustainablelists.org/msg59540.html > > 1) Oils are generally non-conductive so, the PV cells can be immersed in > it without shorting. > > 2.) Some oils can come with fairly good optical qualities - important > for passing light to PV and transforming light to electricity. > > Joe: I remember reading your post about experimenting with black bodies > and it looks like you have a background that may be useful here. Maybe > you can chime in (if your reading this thread)? > > > Mike > > > */Zeke Yewdall <[EMAIL PROTECTED]>/* wrote: > > This is basically what I did. kludging would be the word for it, as > about once a week it would have a catestrophic leak and I'd have to > rebuild it. Worked okay to get research data, but obviuosly not long > term.... I found that preheating water for domestic hot water (which > could have final heating done either by real solar thermal collectors, > or gas/electric/etc) seemed to be the best. Try to get it too hot and > the efficiency dropped way off (I had water tubes touching the back of > the PV module, but no front glazing), plus it didn't cool the PV cells > enough to help with electrical efficiency much either. The trick is > to size the storage tank and PV area with the daily draw to still get > the cooling effect and not stagnate the tank. I suppose with a > different collector design you could obtain higher temperatures, and > still probably not damage the PV module (unless the circulation loop > stagnated, then I'm not sure), but I was going more for cooling the > PV, and seeing the collected thermal energy could be useful, rather > than having high quality thermal energy as the primary goal. Given > that typical solar thermal DHW system here in the US don't achieve > 100% solar fraction anyway, I figured that preheat was a decent way to > go. If you wanted to go for 100% solar fraction (which is what we > should be doing long term) cascading it with a higher temp solar > thermal collector might be alot better. > > On 5/15/06, Chip Mefford wrote: > > Zeke Yewdall wrote: > > > This is exactly what I did my master's thesis on. The concept works > > > pretty well from a theoretical perspective. I was just > investigating > > > using water cooling for non-concrentrating PV, but it would > work even > > > better for concentrating PV. You shouldn't really have to deal with > > > 1200F, at least if you are talking about water, because the maximum > > > working temp for a water based fluid is probably about 400F or so?? > > > (assuming antifreeze additives and increased pressure). Depends on > > > how much pressure you are talking about I guess. > > > > > > > l was thinking of kludging up water jackets for PV panels, to feed > > the INFLOW for a small evacuated tube solar heater, preheating the > > inflow by 'cooling' the PVs. > > > > Do you think this makes sense? > > > ------------------------------------------------------------------------ > > _______________________________________________ > Biofuel mailing list > Biofuel@sustainablelists.org > http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org > > Biofuel at Journey to Forever: > http://journeytoforever.org/biofuel.html > > Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): > http://www.mail-archive.com/biofuel@sustainablelists.org/ > _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
