Application of solar energy systems in building design saves money and conserves energy, in addition to attractive architectural designs and improving environmental conditions surrounding the building. Passive solar technologies and PV systems can be effectively used in a building in several ways.
Passive Solar Design
Passive solar technologies directly take advantage of the sun’s light and heat without using any mechanical or electrical devices. Also termed as ‘daylight’, this method is used for floors, window and walls to capture sunlight from high heat zone and relay it to low heat zone For example, we can capture sun’s heat from outside and transfer it to a room during winter and vice versa during summer. Use of building structure to capture sunlight and store heat alone can save upto 50% of the energy used at home. Window placement, use of thermal mass and appropriate solar orientation of building are key aspects of solar passive design. Some major design considerations are discussed below:
- South facing windows have maximum exposure to sunlight, window placed should be south facing
- Interior spaces must be open, as open interiors allow sunlight to travel inside.
- Proper orientation, window placement and summer rooftop shading can allow optimum sunlight to enter into space depending on specific season.
- Trombe walls – sun facing wall absorb solar energy and release it to the interior
Thermal mass is a solid or liquid material that store hotness or coolness according to the need within a space. It includes bricks, tile, concrete, clay and adobe. Addition of energy absorbing material as a thermal mass that can store and release heat, can maximize the use of sunlight inside the house. For example, slab floors can be used as a thermal mass, acting as zero to low cost thermal mass options. It is to be noted that thermal mass option requires careful design and analysis to promote adequate distribution of the solar heat.
Incorporating Solar in Buildings
Specific components are also designed into building’s shell or interior to capture and redistribute the solar heat. Glazed mass walls, which are capable of storing sun’s heat energy are oriented towards south for maximum capturing of sunlight. Isolated glazed rooms on south side of the building absorb solar heat and distribute it to the house by natural means.
Rooftops sites are very important and most commonly used source of generating electricity in buildings. Photovoltaic cells are insulated on rooftops to generate own heat and electricity. In past typical barriers included high cost, low efficiency and ugly looking solar panels. Things have massively improved in PV technology in the past few years with steep improvement in efficiency and decent edge to the building, making it cheaper, more efficient and most importantly much better looking.
When a number of solar-powered green buildings are located in proximity, they would create a green zone, providing healthy environment and thus minimizing urban heat island (UHI) effect. The ultimate aim will then be to create many such areas, which would help modern towns and cities to drastically reduce total energy requirement as well as carbon footprint.
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