Does anybody know if having the horizontal collector area 80m from the house is a disadvantage?. I reckon it doesn't matter - after all the pipe is still underground all the way into the heatpump. Any replies (technical preferably!) greatly appreciated
It depends where the heat pump sits. If its out in the garden (80m away) then it certainly effects the efficiency. But if these 80 m of distance are used for the heat exchanging and the flow and return are well seperated by at least 1m distance (i.e. not influencing each other) it wouldn't matter. But if they aren't and are just two pipes thrown into the trench propably touching each other without the apropiate insulation between them then the efficiency would suffer badly.The apropiate insulation would not be the same as the standard interior rubber foam insulation.Check the web at http://www.uponor.de/brecoflex/ for samples of underground pipe insulation material, there are many more manufacturers out there.
Thanks heinbloed,
my plan is to have the collector area (500sq m) located at 80m distance from the house with a trench containing the last 80m of collector pipe running up to the heatpump which will be located in or adjacent to the house. So I Agree with your view that in this case it wouldn't impact efficiency