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Benefits of Passive Solar Heating
Solar energy is one of the most efficient forms of energy in the world. Solar energy makes use of the energy supplied by the sun to provide energy for a building. It can be used to run an entire household. Solar heating uses solar energy to heat a building. There are two kinds of solar heating–active and passive solar heating. Passive solar heating collects the heat of the sun without using any mechanical heating device. Active solar heating, on the other hand, uses mechanical devices to trap, store and distribute the heat. Active solar heating systems supply more heat than passive solar heating systems, but they also have a higher initial cost for equipment and installation and cost more to maintain.
Passive solar heating is a part of passive solar building design. It uses the features of the building to absorb and release heat. These features are called thermal mass. Thermal mass includes windows, masonry and other architectural features in the building. With passive solar heating, the actual design of the structure is created to trap the heat of the sun and distribute it slowly over time. For example, large windows are often placed along the south facing walls of the structure because this is the sunniest part of a building year round. The sun would shine through those windows and be absorbed by thermal mass such as a brick wall. The brick wall would store that heat inside it naturally and when it is no longer sunny, the brick wall will radiate that heat and help warm the room. Occasionally, a mechanical device like a fan will be needed to help distribute the heat stored in the thermal mass throughout the building.
There are three kinds of passive solar heating – direct gain, indirect gain and isolated gain. Direct gain is the purest and simplest form of passive solar heating. Sunlight enters through south facing windows; it is absorbed by thermal mass and then reradiated when needed to reach a comfortable temperature. Direct gain depends heavily on architectural design and materials as well as the location and orientation of the building. With indirect gain, thermal mass is placed between the sun and the room to be heated. The sun does not directly heat the room. Instead, the sun heats the thermal mass, often either a masonry wall or a water wall, and the thermal mass distributes the heat to the home. Isolated gain is probably the most complex form of passive solar heating, and it involves heating either water or air in a convection loop. The water or air is cycled from the collector to the storage bin and back.
Passive solar heating is best when incorporated into a newly constructed building as opposed to being added on to an existing structure. So much of passive solar heating is derived from the positioning of the windows, the insulation in the building, the type and placement of various building materials and the location of the building itself. These features would be hard to change after the fact and would also be cost inefficient.
Cost efficiency is the primary reason to design a home with a passive heating system. While a passive heating system may not be able to satisfy the heating needs of a home completely, it will dramatically save on energy costs. Passive solar heating costs little or nothing to operate. The main cost is generated during the building of the home or office, but that cost is often negligible when working with an experienced architect and contractor.
Another benefit of passive solar heating is that it has no negative impact on the environment. Passive solar heating systems do not emit greenhouse gases and does not depend on the use of fossil fuels. This form of heating is completely renewable and clean. The design of passive solar heating buildings (particularly with direct gain) also affords a lot of natural light creating a delightful living or working environment. The heat emitted by these systems is often even and constant adding to the comfort level in the building. Moreover, unlike forced air heating systems, passive solar heating produces no noise, another feature that adds to the comfort level of the space.
If you’re interested in employing a passive solar heating design into your next home or office, be sure to work with an architect with experience in passive solar energy. While the principles and “rules of thumb” of passive solar energy are easy to understand, if they are not implemented correctly, there’s not point in having them at all.