Green Building Primer

The function of these solar energy systems is to convert sunlight to heat that can be used for space heating, space cooling, and domestic hot water. These systems are not an integral part of the building's structure. Solar hot water, heating and cooling systems are the best in terms of design and are the most economical when planned and incorporated into a new structure.

The inititial capital cost of such systems tends to be high, and the larger the heating or cooling load (or the larger the volume of domestic hot water needed), the larger the solar collection system needs to be, and the more expensive. Therefor, every effort should be made to minimize the load on the system through conservation methods. If the system is intended for space heating and cooling, the building should be weatherized and insulated to very high standards. If the system is intended for domestic hot water, hot water piping should be insulated, and water conserving fixtures should be used.

The goal of a solar heating system should never be to provide for 100% of the heating needs of a building, as seasonal variability in available sunlight and heating/cooling needs would lead to a large system that is underutilized in the summer in order to cover all heating needs in the winter. Using a system for multiple functions (such as space heating and domestic hot water) can lead to greater yield year round.

The fundamental requirement for a solar system is to have a sunny location where the solar collectors can be located. Collectors can be oriented as much as 30 degrees off south and still function well. Similarly, the slope of the collectors can vary by ± 15 degrees without significantly harming the performance of the system. However, two basic guidelines are:

• The collectors should have full sun from 9am to 3pm.
• The collectors should face south at approximately the same angle as the latitude.