Ok so check out Jake's (memphis91) thread. He pulled a good one off, then switched it up to get even better results.
https://ecorenovator.org/forum/geoth...er-heater.html
Also, start reading the homemade heat pump manifesto. AC hacker's quest started out with good intentions and grew as he documented his efforts. His thread attracted many ambitious people and hit critical mass. The explosion of information has educated and motivated a huge crowd. It's a massive thread, but absolutely worth reading.