Ground Source trenches

[Two Cylinder]

Hello All, newbie here.
I am building a new home on a spacious plot and considering a ground source heat pump instead of air source.
I understand trenches need to be 1.2m deep, 1m wide, and 5m apart.
But how level does the overall site have to be?
My site is on the side of a hill and the trenches would need to go to and fro up and down the hill.
Is there is a maximum gradient for such a system to work efficiently?
Thanks
Darren

 

[ShaunCorbs]

I would go bore hole much better than a slinky