I haven’t actually done it, but have some knowledge … i think 
Most of the plans that i’ve seen include wells. The deeper you go, the more heat you will access. Also, i don’t know where the frost line is up there. Here, people bury water lines at least 6 feet deep to keep them from freezing so if the pipelines are not at least 6 feet deep here, you would be building a refrigerator (LOL) not a heater!
I’m in the mountains of southern CO US.
My advice, ask some old fart (a farmer or house builder) how deep to bury a water line, then plan on going much deeper.
Come to think about it, i’m sorry, but i really think you will need wells … to get your heat collection stuff 10 meters or more below ground.