Design Concept
Sunday, July 26th, 2009Passive heating and cooling of buildings is a fascinating topic. Ever since I worked on a coop term at Natural Resources Canada it has interested me.
Today’s idea has two parts: a natural cool air intake and a solar chimney.
A solar chimney is a dark coloured, sun-facing wall. It should be able to conduct heat through it quite easily. For passive cooling, it should have duct work connecting it to all the rooms which are to be cooled. It should also have an opening at the top.
As the sun shines on the dark surface, energy is absorbed. The energy is transferred to the air inside the solar chimney, which rises and leaves through the top openings. This forms a low pressure area, which draws in air from the rooms connected to it.
What is needed next is an air intake which naturally cools the air. Persians have for centuries drawn in air over a covered pool of water, who’s very high heat capacity lowers the temperature of the air and adds a small amount of humidity to it.
This added humidity is undesirable in Waterloo. An alternate intake takes advantage of the fact that under the soil, the temperature is always somewhat cooler. Drawing air through holes in the ground can also lower the temperature of the incoming air.
Adding these two components together and placing the solar chimney vents near the tops of rooms, you can make very efficient, passively powered ventilation systems.