Article 31318 of alt.solar.thermal: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: alt.solar.thermal Subject: Re: poor man's trombe wall Date: 22 Sep 2008 05:10:45 -0400 Organization: Villanova University Lines: 36 Message-ID: References: <8cb951f7-2d4d-479f-bc33-8bf24c2c5ad6@z11g2000prl.googlegroups.com> <48d58d31$0$33226$815e3792@news.qwest.net> <2311580c-7614-4d83-a805-f893a534f3e4@a29g2000pra.googlegroups.com> NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1222074647 12021 153.104.44.130 (22 Sep 2008 09:10:47 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Mon, 22 Sep 2008 09:10:47 +0000 (UTC) Xref: news.misty.com alt.solar.thermal:31318 wrote: >> It might be more interesting to turn some of the windows into air heaters >> that lose little heat at night by pushing in a tight-fitting piece of dark- >> painted foil-foamboard insulation with an air gap at the top. > > ... Would I put holes or air gap at both the top and bottom to get some > convection ailflow going A 3' tall window might have a 3" gap between the foamboard and the window, with a slot at the top but no slot at the bottom, so warm air can rise out of the top slot during the day, with no airflow at night. With more thought, we can make a foamboard insert with a flow organizer at the top that lets cool room air flow down between a screen and the cool glass and lets solar- warmed air rise up and out in another gap north of the screen. >> Or make a "heat storage counter" a 4'x2'x30" tall box with insulation on >> 4 sides and a 4'x30" glazed south wall (eg discarded windows) south of >> a light-colored floor with lots of 2-liter water or soda bottles inside >> the box stacked in a horizontal hexagonal pattern. We might let room air flow through the box on a cool day. This could work well with phase-change materials. >> Water can store 2-3X more heat by volume than masonry (about 4.4 Btu/F for >> a 4" diam x 1' tall 2-liter bottle, vs 5 Btu/F for an 8"x8"x16" hollow >> concrete block), and glazing can make the box warmer than the room temp, >> so the water can store more heat. > >This is suprising to me. Hollow cinder blocks I can believe, but how >about a solid block? Concrete stores about 25 Btu/F-ft^3, so 8x8x16" would store about 15 Btu/F. Nick