Solar architecture is a new way of integrating of solar cells technology with modern building techniques. It can be incorporated in new buildings and also can be adapted to the built ones.
Solar panels can be used as conventional materials for the external building with the advantage of the generation of electricity or thermal energy. The use of thin film photovoltaic modules provides an integration with steel roofing profiles that enhances the building’s design. Orienting a building to the Sun, selecting materials with favourable properties, and designing spaces that circulate air, is also solar architecture. Solar panel systems also offer an economically competitive alternative to conventional building materials since it costs only slightly more than some metal facades (as aluminum), they repay the additional cost by generating their own revenue. PV panels can be considered as a building material and are available in colors like blue or black. Solar panels help to reduce carbon emissions and demonstrate a strong commitment to the environment.
The seasonal variations in the sun’s path throughout the day are the key of study of solar architecture. This occurs as a result of the inclination of the Earth’s axis of rotation in relation to its orbit. The sun path is unique for any given latitude.
The 47-degree difference (between winter and summer) in the altitude of the sun at solar noon forms the basis of passive solar design. This information is combined with local climatic data heating and cooling requirements to determine at what time of the year solar gains will be beneficial for thermal comfort, and when it should be blocked with shading. By strategic placement of items such as glazing and shading devices, the average solar gain entering a building can be controlled throughout the year.
Heat transfer in buildings occurs through convection, conduction, and thermal radiation through building elements like roofs, walls, floor and windows. Windows are predictable for thermal radiation. Energy from radiation can move into a window in during the day , and out at night. Solar heat gain can be significant even on cold clear days. Solar heat gain through windows can be reduced by insulated glazing, shading, and orientation. When shading windows, external shading is more effective at reducing heat gain than internal window converings The sunlight can be easily shaded with appropriate length overhangs or angled louvres during summer and leaf bearing summer shade trees which shed their leaves in the fall. The amount of radiant (in addition to the solar angle) heat received is related to the location. latitude, altitude and cloud cover.
Another passive solar design principle is that thermal energy can be stored in certain building materials and released again when heat gain eases to stabilize diurnal temperature variations.
The efficiency of passive solar heating depends mainly on latitude, sun path and sunshine; seasonal variations in solar gain, diurnal variations of temperature; microclimate related to breezes, humidity and vegetation.
Direct gain attempts to control the amount of direct solar radiation reaching the building. This direct solar gain is almost the most important part of passive solar house designation as it imparts to a direct gain. The cost effectiveness of these configurations is currently being investigated in great detail and is demonstrating promising results.
Indirect gain tries to control solar radiation reaching an area adjacent but not part of the living space. Heat enters the building through windows and is captured and stored in thermal mass (for example in water tanks) and then is slowly transmitted indirectly to the building through conduction and convention.
Isolated gain involves utilizing solar energy to passively move heat from or to the living space using a fluid, such as water or air. Measures should be taken to reduce heat loss at night e.g. window coverings or movable window insulation. Examples of these configurations are thermosiphon, double envelope house, thermal buffer zone, solar space heating system and solar chimney.
Heat storage, or thermal mass, keeps the building warm when the sun can’t heat it. A thermal mass includes a trombe wall, a ventilated concrete floor, a cistern, water wall or roof pond. There is an experimental technique to use the ground as thermal mass large enough for annualized heat storage.