let’s do some gay maf here …
there are 8 pipes ( 4 loops ) per twister. an average installation will be about 2 boreholes of 300 feet each. that’s 2 X 300 X 8 = 5,000 feet or almost a mile of pipe …
fuck son …
this can’t be cheap.
let’s also do another calculation …
the twister is 5 inches in diameter so if we treat it as a 5" cylinder rather than separate pipes then two 300 foot boreholes will provide 750 square feet of surface area for heat exchange.
each borehole costs about $6,000 so about $10 per square foot of heat exchange surface.