# Re: Shielding an A/C Compressor/Condenser Unit

On Sat 01 Aug 2009 06:46:53a, DT told us...

In article <Xns9C5899982DB28wayneboatwrightatari@xxxxxxxxxxxxx>,
wayneboatwright@xxxxxxxxxxxxxxx says...
Our A/C Compressor/Condenser is only shaded by the shadow of our house
until about mid-morning. The rest of the day it sits in direct
sunlight. We live in the AZ desert where our summer temperatures are
typically 110°F and above by early afternoon.

Natural shade from trees or shrubs are not a practical solution, both
due to the location of the unit and the time it would take for the
plants to grow to a useful size.

I would like to construct something that would shield the unit from the
intense sun, yet also provide adequate air flow for the unit.

This comes up every year on various HVAC sites, the consensus is that it
does very little. To put some math to it:

The maximum heat gain from a surface directly facing the sun is about
1000 BTUs per square meter. The condenser has maybe a half meter of
surface facing the sun at any time, probably not even that since the sun
is overhead during the hottest weather.

You didn't say how large your HVAC is, but let's look at a 4 ton unit.
That provides 48,000 BTUs of cooling, and depending on the efficiency,
has to transfer approximately 55,000 BTUs of heat into the air. The
solar gain of 500 BTUs amounts to less than one percent. So all it does
is slightly reduce the amount of subcooling, probably not even
measurable with typical instruments.

Thanks, Dennis. This is very interesting information that I didn't know.
However, I am less concerned in improving performance (it is more than
adequate), than I am in wanting to minimize deterioration from the constant
sun exposure.

The house and A/C are both 3 years old. The A/C is a 13 seer 3-1/2 ton
unit. It appears to be properly sized for the house.

--
Wayne Boatwright
------------------------------------------------------------------------
I feel a recipe is only a theme, which an intelligent cook can play
each time with a variation. Madam Benoit

.

• References:

## Relevant Pages

• Re: Shielding an A/C Compressor/Condenser Unit
... The rest of the day it sits in direct sunlight. ... The maximum heat gain from a surface directly facing the sun is about 1000 ... BTUs per square meter. ... BTUs amounts to less than one percent. ...
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• Re: Shielding an A/C Compressor/Condenser Unit
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