In the equinox months of March and September, the sun’s path and angle above the horizon are halfway between the extremes of June and December. Naval Observatory (http://aa. In the summer season (June), the sun rises in the northeast and moves in a clockwise direction around a site until it sets in the northwest. An east-facing slope experiences moderate temperatures, whereas a west-facing slope is the hottest and driest of all slopes during the summer months. Figure 3-13 through 3-15 illustrate the shadow patterns of a two-story house located on a level site in the temperate zone at four seasons of the year. Study Sun and Shadow Patterns
Before being able to effectively design with sun, it is necessary to understand the movement of the sun throughout the day and at different seasons of the year. These events are ever-present and must be incorporated into residential design to make it sustainable, as discussed in the following sections. Figure 3-14
Shadow patterns from a two-story house at different times of the day in March and September. At noon, the sun rises to an angle of 27 degrees above the horizon. Most of these phenomena occur in cyclical patterns that are seasonal and somewhat predictable. navy. All residential environments are exposed to and dependent on a series of natural events, including sun exposure, wind exposure, and precipitation. Shadow patterns can be plotted by using information from sun charts available in many public libraries, some CAD programs, the National
Figure 3-11
Plan direction of the sun at different times of the day and season. Thus, the sun is less intense, restricted in its time of shining, and limited in its direction of exposure in comparison to other seasons of the year. This information can be used to construct shadow patterns around a house on a residential site and to determine where the sunniest and shadiest zones are as well as the associated microclimates. The sun’s relative position in the sky is constantly changing in its plan orientation as well as its angle above the horizon (Figure 3—11). General deductions from these patterns are that:
• all sides of the house receive sun exposure during the summer; similarly, all sides of the house experience shadow as well. The potential for fire and earthquakes impacts the landscapes in certain regions as well. mil/data/docs/AltAz. Figure 3-13
Shadow patterns from a two-story house at different times of the day in June. At the same time, the angle of the sun above the horizon is constantly increasing to a zenith of about 72 degrees from the south at noon (Figure 3-12). The frost is apt to stay in the ground one to two weeks longer on a north-facing slope than on a south-facing slope. • the largest areas of shadow during March and September occur on the east, north, and west sides of the house. • only the south side of the house receives direct sun exposure in the winter; the northern side receives no sun exposure at this time of year. usno. A south-facing slope, like the south side of a house, receives the most sun throughout the year and is the warmest of all during the winter season. A north — facing slope is the coolest of all, especially during the winter.
