Planned Community Stores Heat Underground

It just makes sense, doesn’t it? It’s hot in the summer, it’s cold in the winter. So why can’t we just save that hotness until we’re freezing in the wintertime and we want to be warm? If a kid said it we’d laugh. But when a master-planned solar neighborhood springs up based on the idea, we’re going to have to apologize to that brilliant kid. The Drake Landing development in Okotoks, Alberta, is 52 family homes connected to a solar heat storage system that does just that--it stores the summer heat underground. It is the first of its kind and residents move in next month.

Here’s how it works. Solar collectors on the houses’ garage roofs heat glycol that is pumped in a circuit underground to a heat exchanger at the Energy Center housed in its own little building. The hot glycol heats water. The hot water is then injected down into the ground, into a network of boreholes that go as deep as 37 meters down. The hot water heats the earth and the earth holds the heat. In the winter, this thermal mass will take care of 90% of the space heating and water heating needs for the 52 homes in the community (there’s a great animation of how this works on the website). Considering that winter temperatures in Alberta are more than 20 below, this is a pretty serious challenge, and it will take two years for the borehole system to store enough heat to cover the projected heating load.
This is another wonderful example of apparently simple ideas being refined into advanced systems. It’s all coming together, people! :: Drake Landing via Environmental Building News