Green Options

A community in Canada has an unusual form of solar power that can provide over 90% of the annual heating and hot water needs for the homes, despite being situated in a cold Alberta location where winter temperatures can reach -33 degrees C (-27 F).

The Drake Landing Solar Community collects solar energy in a heat storage fluid through an array of solar panels on the roof of each home and covering all of the garages at the back of each home. The heated fluid is transferred to a neighborhood energy center, and then into the ground beneath an insulated layer, where the heat is stored in the earth.

Combined together, the 52 home community is able to collect and store enough energy from the sun during the summer that the ground storage temperatures reach 80 degrees C (176 F). This heat is sufficiently insulated beneath the ground that it can be drawn from throughout the winter to provide heat and hot water.

Solar thermal technology provides space heating and hot water and is a frequently forgotten member of the solar family. These highly effective systems are popular in many parts of the globe, from China to Greece to Zimbabwe. They displace the use of the existing hot water heater and heating equipment, typically saving either natural gas or electricity.Solar thermal is a more mature technology than solar photovoltaic systems that produce electricity. It has been used for centuries for water heating. In fact, even Leonardo Da Vinci owned one.

When considering the installation of such a system, it is important to consider the following items.