We finally got the ground source heat pump up and running on Thursday. The commissioning took most of the day with the majority of the time taken up getting the antifreeze into the ground loops (the pipes that run underneath the field). There is around 125 gallons of antifreeze (glycol) in the 1800m of ground loops.
The ground source heat pump was powered up around 4pm on Thursday. It took around an hour to heat up the hot water tank (500l). Once the hot water tank was up to temperature, we turned on the underfloor heating. It will probably take until next week before the building is up to full temperature (21c), but the building felt warmer the next morning.
With 125 gallons of anti-freeze installed in the ground loops, we have around 30-35 gallons left over. Not sure what to do with this. Maybe ebay?
Apparently this anti freeze will detriorate if left in the sun for a significant period of time. If you are going to store it outdoors, do make sure that it is under cover.