Article 40566 of sci.engr.heat-vent-ac: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: sci.engr.heat-vent-ac,alt.home.repair Subject: Re: Still interested in purely-radiant cooling. Date: 16 Aug 2008 11:32:01 -0400 Organization: Villanova University Lines: 27 Message-ID: References: <264fefe7-4fe8-470b-bc53-d43b886ed5a3@w39g2000prb.googlegroups.com> <48a6d4e7$1@news.alcatel.com> NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1218900724 1387 153.104.44.130 (16 Aug 2008 15:32:04 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Sat, 16 Aug 2008 15:32:04 +0000 (UTC) Xref: news.misty.com sci.engr.heat-vent-ac:40566 alt.home.repair:1039632 <.p.jm@see_my_sig_for_address.com> wrote: > A very small percentaqe of the heat you radiate goes in any >one particular direction, and the amount that falls on the 'receiving >/ absorbing surface' will thusly decrease as the square of the >distance from it. Not if the surface completely encloses you. The MRT is solid angles weighted by their temperatures. Multiply each area your body sees by its temp, add the products, and divide by the total area of a reference sphere surrounding you, containing the individual areas. You might radiate 50% to a large close wall. As you walk away from a large wall, the near-field view factor might still be about 50%. And we don't need liquid helium. The MRT graph here: http://heatkit.com/html/guide2.htm#MasonryHeating says we can be comfy in 90 F air with 40 F walls, in a bunny-free room. Some buildings have chilled beams and ceilings for cooling. A chilled floor would make more sense, since warm air rises. A slow ceiling fan with an occupancy sensor and a room temp thermostat could stir up some floor air as needed for comfort. Nick