[RE-wrenches] offgrid system question

[Peter Parrish]

There are two figures of merit that can be used to make the conversion. The
simplist is EER. 

First, how many "tons" the AC is rated at? Multiply that number by 12,000
BTU/hr per ton, to get the number of BTU/hr the AC system can pump out of
the house.

Second, EER is the ration of the BTU/hr to electrical power the AC consumes.
Divide the BTU/hr by EER and you get the power consumption.

There is a second figure of merit called SEER, it is similar to EER but
takes a seasonal average. All ACs have a SEER rating.

Example: 3 ton AC rated at a SEER of 10. 3 ton equals 36,000 BTU/hr and
consumes 3.6 kW (15 A at 240 VAC). If you run the AC for four hours a day,
the energy consumed is14.4 kWh.

- Peter  

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of jay peltz
Sent: Friday, August 22, 2008 7:23 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] offgrid system question

Can someone tell me how to convert AC "tons" to rough electrical load?
or is there a way?

I've got a customer who is wanting to install a AC unit and they tell  
me its a 2.5 ton and uses 9000 watts.
( they haven't given me make or model yet)

thanks,
jay

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