Since ancient times, humans have been harnessing energy from the sun. Through evolving technologies, we have learned how to use that energy in more efficient ways, either through solar panels or with the use of passive solar techniques.
We can use passive solar energy in a number of different ways. By designing and situating a home with larger windows facing south, we can collect the suns energy to warm our house during the colder months of the year. We can also use materials within our home that will soak up that energy and slowly radiate it over time. These heat absorbing materials are called a thermal mass and can keep our home’s heating and cooling costs down.
Thermal mass materials such as concrete, stone, brick or water have the ability to store energy and release that energy back into the living space. In the winter months, the house is designed to allow the maximum sun into the home. The sun's energy heats the home and the thermal mass absorbs the heat. In the evening when the sun is gone, the thermal mass radiates the heat back into the home. In the summer, the home is designed to work the opposite. Window shadings keep the sun out of the home. At night the thermal mass cools down and during the day it absorbs heat to keep the home cool. A passive solar thermal mass should be well designed and installed balancing glazing with the thermal storage mass. As a rule, you will need your south facing window area to be about 10% of your floor area.
The VerEco Home on exhibit at the Western Development Museum uses concrete blocks as the thermal mass. Each block measure 12” x 24” and is 1 1/4” thick. The concrete blocks are located in the kitchen, dining room, living room and the south bedroom/office. Weighing 15 lbs/square foot with a total space off 600 square feet, the VerEco house has over 10,000 lbs. of thermal mass.
A well designed solar home can hold an interior temperature between 20 and 21 degrees Celsius balancing the square footage of glass (solar collectors) and the right amount of effective thermal storage mass. In the summer, a shaded thermal mass will keep rooms cool.
Learning more about solar thermal mass and passive solar design is as easy as logging on to the internet and doing a google search.