How To Use Passive Solar Heating

Passive solar heating is the most effective way of heating a building. This is because, very often, the total amount of solar heat that reaches your home or office is greater than the amount of energy consumed in the building.
Unlike mechanical methods of heating, passive solar heating is actually built right into the building as an integral part of the structure. This very often adds little or nothing to the initial construction cost. It also adds real value to the home, needs little or no maintenance, and is very reliable.
With passive solar heating you can greatly reduce your heating costs and still be very comfortable, with no extra work. You still need a primary/secondary heat source, but your heating bills will fall dramatically.
The building itself collects and distributes the heat, making it highly efficient. The walls, windows, floors and other features absorb solar heat and release it during the night. Experience has taught us how to maximize the benefits by adapting the construction to fit the angle of the sun, the orientation of the house, etc.
Solar heating requirements
You need a south facing exposure, at least in the Northern Hemisphere, so the heat can be collected. The building must have a clear line to the sun to receive maximum absorption.
The other main requirement is a material to absorb the heat for later distribution. The material can be the actual building itself, or additional structures placed in the path of the sunlight.
How To design a passive solar heating system
Just because one particular method works one place does not mean that it will succeed somewhere else. It is necessary to evaluate the site and climate of you own place. For example: what works in New Mexico will be much different that in Oregon!
Direct Gain of solar heat
This is the simplest form of heating. In this case the solar heat is absorbed by the walls, floors, etc. The heat will naturally be stored in the core of the structures, and released at night as heat loss. This heat loss is what keeps you warm at night.
A good direct gain system will be able to heat the house for several days in the event of cloudy days. Your system needs to allow a lot of heat in and little heat out in order to be efficient. Good windows and window covering are recommended.
Additional structures, such as extra walls, barrels of water, etc., can be used to collect more solar heat. This heat is also released at night, providing free heat.
Indirect Gain
This interesting system uses structures such as walls or water barrels that are placed between the living area and the sun. Because they are in a rather confined area the room temperatures can climb substantially. This extra heat is circulated by means of natural convection.
The air flow from hot to cold naturally causes the heat to circulate throughout the living area. During the night the vents can be closed so the process is not reversed. In this way the heat is kept where you want it instead of returning to the area outside the room. The absorbing wall also radiates heat into the living area.
Isolated Gain of solar heat
This system of passive solar heating uses an external solar panel to collect heat. The heat is transferred by natural convection into a storage area. This storage area, or heat sink, later radiates heat into the living area.
In order to attain the natural convection, the space to be heated must be higher than the storage heat sink, which must be higher than the solar panel. You could always use pumps or fans, but then you do not have a true passive solar heating system.
Conclusion
Passive solar heat can be an effective and inexpensive way to supplement or primarily heat your living space. It just takes some careful planning, especially in the building stage.
Randy Hough, Jon Arnett and company have been involved with energy saving programs for many years in such places as Alaska, Wisconsin, Norway and Croatia. Recently they constructed a passive and active solar heated villa in Croatia, which is beautiful and efficient at the same time (plus it is right on the Adriadic Sea). Check out their website: http://www.SolarOnYourOwn.com to help you in your quest for reducing your energy dependence. Find out how you can save money, save energy, and save the earth!