Article 1035304 of alt.home.repair: Path: news.misty.com!not-for-mail From: nicksanspam@ece.villanova.edu Newsgroups: alt.home.repair Subject: Re: Evaporative Cooler putting too much humidity into my house Date: 26 Jul 2008 06:05:03 -0400 Organization: Villanova University Lines: 29 Message-ID: References: <6de4a4bc-7ecd-4110-b85a-54af47484e31@h1g2000prh.googlegroups.com> NNTP-Posting-Host: acadia.ece.villanova.edu X-Trace: max.inside.misty.com 1217062975 3707 153.104.44.130 (26 Jul 2008 09:02:55 GMT) X-Complaints-To: abuse@misty.com NNTP-Posting-Date: Sat, 26 Jul 2008 09:02:55 +0000 (UTC) Xref: news.misty.com alt.home.repair:1035304 Wayne Boatwright wrote: >>>... what they can't do is keep my house at an even 68-70°F >> >> Sure they can, with suitable weather and a thermostat and a humidistat. >> >> How many gph would you need to evaporate and how many cfm would you need >> to ventilate to provide 5000 Btu/h of net cooling in Prescott AZ in June, >> with 70 F indoor air and 85 F outdoor air with a 0.0047 humidity ratio? > >I wasn't talking about Prescott; I was talking about Phoenix. >So, "suitable weather" is the issue... Sure. There are times when evaporative cooling can keep your house exactly 70 F, and times when won't work, when your computer might AC instead. How many gph would you need to evaporate and how many cfm would you need to ventilate to provide 5000 Btu/h of net cooling in Phoenix in May, with 70 F indoor air at 50% RH and 75 F outdoor air with a 0.0045 humidity ratio? If 1000P = 5000 + (75-70)C with P lb/h of water and C cfm and P = 60C0.075(wi-wo) with indoor humidity ratio wi = 0.00787, C = 66P, so 1000P = 5000 + 330P, ie P = 7.5 lb/h (0.9 gph) and C = 492 cfm. >And...any amount of added humidity to the air in my house is more than I want. Philosophy vs comfort? :-) Sounds irrational... Nick