designer's own words:Don't waste the heat. Recycle your urine. An average person releases about one litre of urine per day. Why not use the heat provided by the urine? The new Green is Yellow... The system is based on two boilers. One for hot water and one for central heating. This system, adopted throughout the world, is a more ecological solution than the single boiler system, under two conditions: the hot water boiler only switches on when hot water is required, and the central heating boiler is switched off when not needed (in the summer). The urine is collected with a waterless system to avoid reduction of the heat provided. It is filtered and heated up to 50 degrees (starting from 37 degrees instead of 7 degrees if using normal cold water) in the boiler. The design of the radiator is based on the system of arterials and veins in the human kidneys. But here, the urine is not just the output but the input as well.