Solar Water Heating

There are a few different ways to heat water with solar energy.

Using the summer sun to heat a pool makes perfect sense in the sunny Okanagan. The most economical method of heating a swimming pool is through the use of a floating, transparent, polybubble cover that traps the energy of the sun. Commercial solar swimming pool heaters can further enhance the heating of a pool, however, they are expensive and achieve about the same heating effect as a polybubble cover.

If you travel to the Mediterranean it seems as though every other house has a solar domestic hot water heater, but in Canada they are a rarity. There are two reasons for this: first of all the lack of winter sunshine across most of Canada and the cost of purchasing and installing a heater. Some solar water heaters have a 20 year payback period, after which time the system will probably require replacement!
 The solution could be to build your own heater which sounds difficult but actually is not. While I was teaching at PVSS we built a batch solar water heater out of two oil barrels mounted in a large insulated box that had a glass cover over its sloped south-facing side. In addition, the glass cover was sealed-off at night, by raising a hinged reflective cover. Each barrel was painted with high-heat flat black paint and was 90% filled with water (to allow for expansion and contraction of the contents). A copper pipe carried cold water into a copper spiral in each barrel and then continued into the conventional hot water heater.

This very simple hot water heater, that was mainly constructed from recycled materials, supplied a family of four with about 60% of their annual needs for hot water. A heater of this design could very easily have a payback period of less than two years, which is a very attractive proposition.