How much 'gain' would we get if we sunk a 55 gallon barrel into the
relatively cool ground here in Florida, filled it with calcium free
water, and sprayed the condenser in a closed loop cycle when it is
Any evaporated water would be made up with condensate.
I can imagine two advantages. Evaporative cooling (how humid is your area?
The more humid, the less benefit you'll get). The other advantage is that
some of the heat will be lost to the cool earth.
There must be some reason it isn't yet common practice. Maybe that reason is
not much benefit. And maybe the reason is the equipment and install costs.
Please make a flow-through design, rather than a deisign where water is
collected and stays. If ther is no drain (just evaporation) then eventually
the minerals and solids will concentrate.
Window AC are designed to spray the condensate water on the condensor coils.
Howver, the wet condensors tend to attract dust. And so, window AC need
cleaning every couple years. Wet coils for your outdoor unit will likely
also need cleaning more often.
Save the effort of burying the barrel...
The btus are found in the phase change of the water...
Roughly 970 btu/lb of water. The "relatively cool" water from a buried
barrel will only give you 1btu/dF of the temp difference. 65dF water to 212
dF will yield 147 btu/lb, relatively low compared to that phase change...
it won't involve a shovel.
I'd route the gutters to it & collect the rainwater, filling with tap water
adds too many variables.
You could raise the barrel above the unit & let gravity power the water flow
rather than a pump, although a spray might require a few extra feet of
You'd also make monitoring the water quality easier with an above ground
The idea of spraying coils w/water has been around for years, though most
I've run into are water coils w/prop fans. I'm sure someone makes a
refrigerant type system...
Since most outdoor units are built to handle rain & the like, I don't see
why it would hurt if common sense is also used... I would be very careful to
avoid a heavy spray that would bypass the coil & blow straight on the motor.
It might be more advantages to have a couple "drip tubes" rather than a
spray on the coil, especially with the elevated barrel. Then there's always
the question of what your going to do to drain the base pan.
All in all, I don't think the efficiency increase from such a project would
justify it's cost & maintenance issues.
It'd probably be easier to put the efforts & $$$ in insulation, Programmable
stats, window treatments, etc...
But if you give it a try, we'd all like to hear the results.
You could look here of course;
A new Texas upstart company around 1998 [called AC2] tried to market a
residential evaporative condenser that used water and air. Problem was,
citys and municipalities would not approve because of the excessive water
usage. [We're in a water drought in most western states.] The problem came
due to the 'flushing' of the TDS. The required flush cycle washed out the
TDS as the unit ran. But the water flush was so often and so high [to
prevent TDS build up and copper coil caking] that it became prohibitive in
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.