In a Passive Solar System by What Is the Energy Collected?

Glass

• One of the key components of a passive solar system is using large areas of glass. Glass allows solar radiation to pass through it but acts as an insulator against conducted or convected heat. For this reason sunlight can pass through a glass window and warm the room inside, but the heat cannot escape out through the window. This means that a house can be warmed by sunlight even on a cool day.

Thermal Mass

• Once the heat has been trapped, the next important component is thermal mass. Thermal mass is a large, thick volume of material that heats up and cools down very slowly. Concrete, stone or masonry walls are positioned in front of the glass to absorb the heat. The rest of the walls in the room are insulated to prevent heat fluctuations.

Water as Thermal Mass

• As an alternative to heavyweight building materials, water can act as thermal mass. Glass bottle walls are a popular way of creating a heat sink on the outside of a house. The bottles are filled with dark-colored fluids and mounted in a cement wall. The bottles make up the bulk of the wall. The water absorbs and radiates the heat in the same way as masonry or concrete.

Building Design

• For passive systems to be effective, the house must be planned out correctly. The heat-harvesting wall must face toward the south with a window in the wall that is the maximum size possible. The most commonly used rooms should be on the south side of the building while rooms like bathrooms and storage rooms should be on the north side of the building and have small windows to minimize heat loss.