Wednesday, August 15, 2012

Using Your Lawn Sprinkling Water to Cool the House

This is a unique way of providing some free space cooling for your house.

Rick runs the water that he is using for lawn watering through a heat exchanger first and extracts some "coolth" from it before it goes out to the yard.

Rick's current test setup.
His current test setup uses a 20 by 20 inch water to air heat exchanger with a fan that blows air through the heat exchanger to cool it.  In this current test setup, it cools the airstream about 10F and provides about 5000 BTU/hr of cooling -- about a half ton of cooling.

The energy use is very low -- the COP appears to be about 29 (SEER 125!).

Side of HX with water connections.

All the details on lawn water for cooling here...

Thanks very much to Rick for sending this in.



  1. Very nice. I've wondered about building a tank like in your $1000 heating system and passing all of a houses water feed through a pex heat exchanger to cool the tank down. The cool water could then be circulated through a device like Rick's water to air heat exchanger with a fan.

    This tank could also be switched over during the heating season to circulate water from the solar panels through the tank to add more heat storage.

  2. Hi Mike,
    Interesting idea.
    I guess you would have to look carefully at what the tank size should be compared to the amount of cold water that will be passing through the pex HX. That is, if you have a (say) 400 gallon tank, and only use (say) 100 gallons of water a day, then it won't be able to cool the tank a lot. But, if you were using more water (say or irrigation), then you could get a better temperature drop on the tank.
    Another thing to look at to cool the tank:
    This has been pretty effective in our climate, and its cheap. If we had more really hot days in the summer, I would be using it routinely.



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