From: "Timm Simpkins" 
Newsgroups: misc.consumers.house sci.physics alt.home.repair sci.engr.heat-vent-ac
Subject: Re: Efficient use of Air conditioner
Date: Thu, 22 Jul 2004 13:06:54 -0600


 wrote in message
news:cdo6fh$a0q@acadia.ece.villanova.edu...
>  wrote:
>
> >> Joseph Meehan  wrote re:
> >
> >> >...the very high cost of removing the moisture that comes in from
outside.
> >
> >> That's a low cost, unless water vapor condenses inside the house.
>
> We were talking about a) ventilating a house at night vs b) keeping an AC
> running. I'm thinking a) is better, as long as we don't have condensation
> inside the house.
>
> >Take a given volume of air at 90 F and 40%.
>
> Why 90 F and 40%?
>
> >How much energy does it take to cool the air to say 72 F?
>
> Depends on the volume :-)
>
> >How much energy does it take to cool and condense enough water to get
down
> >to 40% at 72 F?
>
> Why 40%? Standard ASHRAE humans are comfy at 56% and 80.2 F.
>
> >...Without running through the math, I would think getting the water
vapor
> >out is the energy expensive part.
>
> Try math! If your 32x32x8' house has 6K Btu/F of fast capacitance and 400
> Btu/h-F of thermal conductance, including 200 cfm of air leaks, and it's
> 78% and 71 F in the morning, and the outdoor temp hits 92 in the
afternoon,
> with the morning humidity ratio, which is better, a) or b)?

If you walk out on your back porch and don't have enough pancakes to build a
fence True or False?

False because bicycles don't have hotdogs with flat sidewalks.