Power of the weather

Rain, frost & sun have destroyed the old wooden building but on the roof of the new house, warm water is being generated by the sun. The old brick building behind the tree is under a protection order and I think was a lime kiln but I have to research this. Apparently, the kiln or oven is still intact & it was planned to have the building moved to a historic building museum but the high cost made it unrealisable, at least for the moment.
When we had a new wood pellet central heating installed in our house in 2005, I wanted to include a solar water heating panel but all the heating engineers said it would not be cost effective and so we didn't. Annoys me every day the sun shines but maybe one day I will try fitting a panel myself. At least we had the foresight to have the new boiler equipped with solar piping connections. The next step would then be Photovoltaic panels but our house roof line runs north>south not exactly ideal. Bavaria & particularly our area is inundated with PV roofing which given the events in Japan is of course very welcome & the initial "architectural" concerns some years ago have now been forgotten.
We do have some solar water heating - for our 40-year-old concrete swimming pool which I am currently trying to repair. Droughts & floods have taken their toll on the structure & the cracks now need substantial work. Heating simply consists of loads of black 1" pipes on a garden shed roof but it is amazing how quickly they heat up the 35,000-litre pool. In June/July we often get up to 30°C.