SID66

Thanks for that - interesting when you put things in the air for others to comment. In the coastal regions of South Africa it rarely goes below 15 deg C so freezing is not likely. Not sure on the relevance of your first danger point (surface area) - I will be using the standard 200l/44gal drum as a reservoir with garden refuse around it and the sun shining on the exposed sections. Thus making your danger point 3 moot as there will be no connections within the "compost". For info - I am using a stainless steel drum (I believe was origionally used to supply syrup to Coca Cola) and have had it standing full of water for a few days to dissolve any remaining syrup, I will empty it before I pipe it into the closed system. The water coming out the ground is approx 19 deg C, My geyser is set at 55 deg C. My aim it to increase the t of the water entering the geyser to 25 deg C or higher. I will obviously have to paint the drum black and will put a wire "cage" around it for the grass cuttings. The drum will stand in the sun for approx 8 hours of the day. I have done some calcs to get the resultant t of the mixed water after using half the hot water but am short the formula to work out how much electricity it will take to heat up 200l of water by 1 degree C - help on this would be greatly appreciated. ( have forgotten my high school science)

This is where the word "Truce" comes in.

Good day all, I was looking into this topic and found this site, I have obviously regiatered and look forward to new ideas. Here is one to mull over- Interupt the cold water suppy to the geyser (at ground level) and run a pipe into a 200l (44Gallon) drum, run another pipe(outlet) from the drum back to the origional feed to the geyser. Firstly the water (in this country) is colder coming out the ground than the air above the ground. Thus the water now housed in the drum will warm up to ambient temperature and saving you having to pay to heat it by those few degrees. Secondly- as you cut the grass, pile the cuttings around the drum. The "rotting" cuttings will generate heat that will save you even more. Any comments?