# Passive and Active Solar Systems in Eco-Architecture and Eco-Urban Planning
## 2 Materials and Methods
### Solar Architecture and Solar Urban Planning: The State of the Art
#### 2.1.3 The Use of the Sun in Urban Planning  
The use of the sun to create better architectural solutions has been echoed in urban design. The emergence of urban concepts in ancient Greece, aimed at making optimal use of the sun, was in part due to the need to protect the forests needed to supply wood for heating homes, building houses and ships. The location of a city and the way it was built were to ensure optimal benefits from solar energy. This was favored by the grid nature of city layout known from the classical period, making use of the sunny southern orientation of buildings and natural ventilation. An example is ancient Priene, where the topography supported \"solar\" solutions, due to which each of the houses in a row were fully open to the sun. Pre-Columbian settlements in southwestern North America are an interesting example of deliberate urban design using optimal sunlight conditions. Housing by the Anasazi was built into the southern walls of cliffs or in open terrain, and a characteristic feature was their compact, terraced buildings open to the south [31]. Acoma, inhabited by the Pueblo since the 12 th century, consists of row buildings in the form of two or three-level houses. Massive external walls acted as accumulation walls, storing heat. The northern walls had only small window openings, serving as a buffer for the residential part, while the protruding horizontal walls covered with boards and branches created a shading zone. Based on the idea of a pre-Columbian \"passive\" house, the town of Taos among others in the Sangre de Cristo Mountains in the north-central region of New Mexico was founded in 1615. In the era of intense industrialization, interest in health-promoting conditions increased in the then polluted, wet and shady cities. An example of a model housing estate that used orientation toward the sun to obtain optimal sunlight is the industrial town of Port Sunlight in England. The French architect [PERSON] proposed two-, four- and six-story buildings for modern working-class housing and at the same time determined the minimum distances between buildings such that they would not shade one another during the winter. [PERSON] also conducted studies on the size of window openings and their influence on interior lighting, as well as the geometry of the ceiling, which would allow better illumination of a room through reflected natural light. In designing _Cite Industrielle_, [PERSON] used the ideal sunny city of Olythmus as a model. The buildings in the modern city faced south, and houses occupied only half of their plots, so as not to shade neighboring buildings during the winter. In the era of modernism, under the influence of the Athens Charter, there was a growing interest in green, sun-oriented city design. After the First World War, solar architecture was used in the design of housing complexes for the working class in the Netherlands, Sweden and Switzerland. Multi-family residential complexes designed in rows were being built, such as Tussendijken and Kifhoek in Rotterdam, or the Heuberg estate in Vienna. As part of the Bauhaus trend in architecture and urban planning, [PERSON] created a large urban complex in 1928, while [PERSON], [PERSON] and Boehm in 1929 designed the [PERSON] estate in Frankfurt am Main, and in 1925 Taut and Wagner, the Britz estate in Berlin. The construction of cheap, new, modernist housing, optimally oriented toward the sun, quickly turned out to be a success. A series of row-type houses, based on the north-south axis of the Siemensstadt housing estate in Berlin, were being planned. With time, however, it was noted that such an orientation of buildings resulted in an insufficient supply of sunlight for most of the day during the winter, a major obstacle to functionality. In the modernist postulates of [PERSON], there were ideas to create horizontal windows running from support to support, due to which interiors were to be evenly illuminated [13]. Horizontal windows illuminate an interior much better than vertical ones.