Quote:
Originally Posted by Geo NR Gee
I appreciate the information gentlemen. That is what I was looking for.
What would be a good distance between sensors down the borehole? If I drill a 4" borehole 100', and drop the sensors down 10' apart, would that be enough sensors to pick up the temperature differences from a water bearing (heat removing) layer?
That also brings me to another question. After the test hole shows the data needed, why wouldn't I put two loops down one hole? One for the solar flat plate collector loop and the other for the heat exchange loop?
Thanks,
Geo
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That depends on a lot of factors. If you are just using the heat pump for heating, the second (solar) loop can help boost efficiency. If the heat pump will be used for cooling too, the solar loop can fight the heat pump, reducing efficiency. Also, two loops will require a larger borehole, increasing drilling costs. The heat transfer into and out of the ground also suffers somewhat versus separate boreholes, since the two loops will almost never be at the same temperature while any liquid is flowing. On a hot summer day, in cooling mode, you would probably not want to pump piping hot solar water down the same hole you are using to dump heat pump heat into.
An aquifer throws another twist into the method. Not bad for the heat pump, not good for storage. How much flow, how thick the layer, etc. makes a world of difference. Ten feet may not be close enough together for fine measurements.