14 Sept 2011: John and Rachel are making progress with the sustainable building project, which includes this idea to solar charge the slab to their new conservatory. They sent me some photos.
Now that the pipes are down, the decision of how much to heat it can be tuned based on performance. If there is an array of evacuated tubes, it would get too hot in summer, so Chris Wood and I have suggested that the tubes are primarily heating a water tank, and that some of that spare heat is drawn off to provide warmth to the slab - using a time clock and thermostat to manage it. There is no thermal link to the larger ground below, the heat is entirely contained within the 300mm slab.
|Underslab and slab edge insulation in place.|
|Blinded hardcore and membrane under the insulation|
Reinforcing mesh laid and approx 100 metres
of underfloor heating pipes cable tied to reinforcing mesh
|Concrete now laid, pipes coming up to surface|