Article 40617 of sci.engr.heat-vent-ac: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: alt.hvac,sci.engr.heat-vent-ac Subject: Re: Why is hot dry air impossible/impractical? Date: 30 Sep 2008 07:56:23 -0400 Organization: Villanova University Lines: 20 Message-ID: References: NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1222775786 10825 153.104.44.130 (30 Sep 2008 11:56:26 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Tue, 30 Sep 2008 11:56:26 +0000 (UTC) Xref: news.misty.com alt.hvac:413516 sci.engr.heat-vent-ac:40617 Green Xenon [Radium] wrote: >> >The overwhelming majority of heat emitted from a fire, is convective >> >heat, not radiant heat. There is some radiant heat but it is very >> >small compared to the convective heat. > >> What fire temperature makes them equal? > >Huh? The formulas are well-known. If a room is 70 F and the fire is Tf, the room gains Qc = 0.19(Tf-70)^1.33 Btu/h-ft^2 by convectiion and Qr = 0.1714x10^-8((460+Tf)^4-(460+70)^4) Btu/h-ft^2 by radiation. What are Qc and Qr when Tf = 100, 1000, and 10,000 F? If Qc = Qr, what's Tf? Nick