Using Passive Solar enrgy os a great way to design a new home or use in a remodeling project. If you have no plans for doing any major remodeling or building a new home you can still use the passive approach to help heat and cool your home.
Though using passive techniques in an exhisting home without making structure changes is definetely possibble. To use it without making major changes to your home takes watching and learning how your home reacts during the year. Our home has a great cross breeze if we keep the first window in our living room open and the one in the bath open. This is true no matter how hot and stuffy it is outside as our house juts out from the other homes and is angled just right to catch the breeze coming up the road. In the winter our sliding glass door helps to keep the dining room around 70 when the sun is shining. We have learned these things by living in our home. Though our living room has over 80% of it’s exterior wall in windows or doors, which makes us keep our east facing windows shaded till the sun passes. So now we have made changes to help keep us comfortable without using our central air or furnance as much. We introduced a low enegy window fan to boost the air flow and are looking into adding stone or tile to the dining room to help retain the heat longer after the sun goes down. In the living room we needed light dampening shades and curtains to keep the heat of the sun out during summer months. These are just examples of what you can do as you start understanding the strenths and weaknesses of your home. Making them work for you can save you big on heating and cooling cost.
To use passive solar in your home you need to understand that it is based on the principal that heat moves from warmer materials to cooler ones until there is no longer a temperature difference between the two. Using heat-movement and heat-storage mechanisms you can move heat to different parts of your home. There are five types of mechanisims you can use, they are:
- Conduction -The way heat moves through materials by vibrating the molecules to spread the warmth. An example would be the hot cup of coffee you use to warn your hands in the winter.
- Convection -The way heat moves through liquids and gases by being lighter then cooler so always rising, while cooler sinks. An example would be the warm water at the top of the pool while freezing in the deep end.
- Radiation -The process of heat transferring from warm object to cooler ones. 2 types of radiation are important to passive solar design and use, they are solar and infrared radiation. Depending on properties of each object this radiation can be absorbed, reflected or transmitted.
- Thermal capacitance – Is the ability of materials to store heat. Thermal mass is the term often heard but that is referring to the actual object storing the heat, not it’s ability.
Understanding the principals being applied to passive solar design and use is an important aspect of using this type of heating and cooling. Once the principals are understood then trying different arrangements to make them all work together and not against each other will increase their effectiveness. We will be going in depth about passive solar over the next couple articles as it touches so many different areas in your home.
Buy our book - OFF THE GRID - a tour of American off-grid places and people written by Nick Rosen, editor of the off-grid.net web site
Leave a Reply