How Passive Solar Heating Works
Passive Solar Heating uses intelligent building design to take advantage of the natural processes of heating. This type of solar heating takes advantage of radiation, natural convention and conduction in order to heat a building. Passive solar heating does not use mechanical technology to harvest solar energy. When the light from the sun hits the building you can take advantage of the energy by installing building materials that allow you to reflect, transmit or absorb the useful radiation from the sun. You can also utilize the airflow in your building that is created by the heat produced by the sun. The system allows you to store and utilize the energy from the sun when it is not shining.
Building Design
You should design the building to be elongated on an east to west axis. To make the most of your passive solar heating system, design the building or home with an open floor look. On the south facing portion of the building you want a substantial amount of glass and you want to utilize thermal mass in order to absorb and then store and distribute the heat you have accumulated.
Direct Gain
The living space of the building serves as the solar collector and it absorbs the heat and it acts as the distribution system. Solar energy enters the house through the glass and then hits the walls and floors which serve as thermal mass materials. Experts believe that you will capture about sixty to seventy-five percent of the energy from the sun that has hit the windows. You can also use containers filled with water to store the heat you have captured from the sun.
Indirect Gain
In this version of a passive solar heating system the thermal mass is above the living space. After the thermal mass has captured the sunlight, conduction moves the energy to the interior of the building. This type of passive solar heating system will use about 30% to 45% of the sun's energy that contacts the glass of your building. The indirect gain system utilizes either a roof pond system or a thermal storage wall system. With the thermal storage wall variation the thermal mass is placed closely behind the glass in the building which faces south. If you decide to use the roof ponds system you will need a flat roof and very large plastic or fiberglass containers in order to store water. The space situated below the pond system receives heat from the warm water situated in the containers.
Isolated Gain
The main feature of this type of passive solar heating is placing the main parts of the system away from the living space of the building. For example, a sunroom uses a specific device to capture the air and send it to a storage system. This type of system will make use of about fifteen to thirty percent of the sunlight which hits the south facing glass. Passive solar heating systems can allow you to take advantage of the energy provided by the sun.
