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Solar access

Solar access is the ability of one property to continue to receive sunlight across property lines without obstruction from another’s property (buildings, foliage or other impediment). Solar access is calculated using a sun path diagram. Sun is the source of our vision and energy. Its movements inform our perception of time and space. Access to sun is essential to energy conservation and to the quality of our lives. Solar access is the ability of one property to continue to receive sunlight across property lines without obstruction from another’s property (buildings, foliage or other impediment). Solar access is calculated using a sun path diagram. Sun is the source of our vision and energy. Its movements inform our perception of time and space. Access to sun is essential to energy conservation and to the quality of our lives. Solar access is differentiated from solar rights or solar easement, which is specifically meant for direct sunlight for solar energy systems, whereas solar access is a right to sunlight upon certain building façades regardless of the presence of active or passive solar energy systems. A historical example of Solar access is Ancient Lights, a doctrine based on English law that refers to a negative easement that prevents the owner or occupier of an adjoining structure from building or placing on his own land anything that has the effect of obstructing the light of the dominant tenement. In common law, a person's window on his property receiving flow of light that passed through it for so long a time as to constitute immemorial usage in law, the flow of light became an “ancient light” that the law protected from disturbance. The Prescription Act 1832 created a statutory prescription for light. It provided that: The goal of using solar access in urban planning is to create well-designed urban districts that assure exposure of buildings' elevations and public spaces to the sun during a desired period of the year. Urban areas that do not consider solar access may cause discomfort inside buildings and on the street, as well as increase energy consumption for lighting and heating, due to the lack of passive solar energy. On the other hand, as a result, buildings without solar access may also have less solar heat gain and thus reduced cooling load. The solar envelope is a space-time construct. Its spatial limits are defined by the characteristics of land size, shape, orientation, topography, latitude, and its surroundings. Its time limits are defined by the hours of the day, season of the year, and the time interval. In 1976, solar envelope was first proposed by Ralph L. Knowles as a zoning device. It guarantees solar access to properties by regulating construction limits derived from the sun’s relative motion. Buildings within the solar envelope would not shadow adjacent properties during a predefined period of time, usually critical energy-receiving periods during the year. The solar envelope presents the maximum heights of buildings that do not violate the solar access of any existing buildings during a given period of the year. The solar envelope is a way to assure urban solar access for both energy and life quality. The concept of solar envelope was first developed in 1969. It was developed as a framework for architecture and urban design at the University of Southern California. The goal of that study was to improve the quality of the urban environment by designing buildings that pay attentions to orientations. In 1976, a research was carried out by Ralph L. Knowles to further develop the concept of solar envelope as a public zoning policy. Assisted by planning department of the city of Los Angeles, the results of this research were first published in an article called Solar Energy, Building, and the Law. In 1977, to tests the solar envelope concept as a zoning mechanism, Richard D. Berry joined with Knowles to direct undergraduate architecture students in designing buildings within solar envelopes based on a presumption of solar zoning on real urban sites in Los Angeles. The first implementation of the idea of solar access was in the United States around 10th century. In Acoma, 50 miles west of modern Albuquerque, New Mexico, its rows of house are stepped down to the south. Those houses were built for the high-desert climate. The low angle sun in the winter is welcomed and the high angle summer sun is not wanted. During the winter time, houses do not shadow one another. It is this critical relationship of building-height to shadow-area that gave rise to the solar-envelope concept. The most commonly cited law outside the United States is the English Doctrine of Ancient Lights, but there were problems with its application in modern society. Roughly, the doctrine states that if in 20 years no one has overshadowed your property, they cannot now do so. However, this doctrine has been repeatedly disavowed in U.S. courts. Prior appropriation principle was used for the United States water law, which was developed during the west settlement. Similar to the Ancient Lights doctrine, prior appropriation water rights states that the first person to take water for 'beneficial use,' such as agricultural or household use, has the right to continue use the same amount of water for the same purpose. Simply put, “He who gets there first, gets the most”.

[ "Solar energy", "Solar easement" ]
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