Article 1050663 of alt.home.repair: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: alt.home.repair Subject: Re: Repairing BB Hole in Window Date: 9 Oct 2008 06:56:05 -0400 Organization: Villanova University Lines: 22 Message-ID: References: NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1223549767 23636 153.104.44.130 (9 Oct 2008 10:56:07 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Thu, 9 Oct 2008 10:56:07 +0000 (UTC) Xref: news.misty.com alt.home.repair:1050663 >... How many times do we have to squeeze a bellows to remove 5% of the air >from a window cavity, with a check valve and a vacuum breaker that allow >dry air to replace withdrawn air when the bellows is released, if we want >to lower the cavity dew point from 50 to 10 F? ... 31 times. 10 P=.5*EXP(17.863-9621/(460+70))'initial cavity vapor pressure ("Hg) 20 W=.62198/(29.921/P-1)'initial humidity ratio (#w/#a) 30 PRINT P,W 40 P10=EXP(17.863-9621/(460+10))'vapor pressure at 10 F and 100% RH 50 W10=.62198/(29.921/P10-1)'10 F humidity ratio 60 W=.95*W'squeeze bellows 70 IF W>W10 THEN N=N+1:GOTO 60 80 PRINT N,W,W10 .3741957 7.87707E-03 31 1.525878E-03 1.536647E-03 Nick