Date:         Wed, 12 May 1999 22:58:19 -0500
Reply-To:     Joshua Van Tol <jjvantol@USWEST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Joshua Van Tol <jjvantol@USWEST.NET>
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>The vw bus needs, at a guess, 20,000 BTU's of cooling, perhaps more. A very
>high efficiency air conditioner uses about 1 watt of power for each 12
>watts of
>heat removal. So, you'd need 20,000 Watts/12 = 1.666 KW to power the system.

I made a goof here. My thermo teacher would have flayed me alive for this.
The numbers are right, however, I should have said "A very high efficiency
air conditioner uses about 1 watt of power for each 12 BTUs of heat
removed."

>Now, the sun beats down with an intensity of about 1 KW/m^2, very good solar
>cells are 22 % efficient. Such solar cells are EXTREMELY expensive. 10-15%
>efficiency is more common. I.e. you can get 220 W per square meter of solar
>cell area. So, you'd need 1.666 KW/220 W/m^2 = 7.6 m^2.
>
>So, in short, with everything stacked on your side, there's still not enough
>area on top of the bus to supply the energy to run an air conditioner.

Joshua Van Tol -- jjvantol@uswest.net