Active solar design is the use of photovoltaic cells to harness light energy and convert it to electricity. That energy can be used for anything, while passive solar design maintains the heating and cooling of buildings. The idea apples to photoelectric effect. The cells capture photons from light and release electrons. The capturing of the electrons creates an electric current. This electricity can be used for multiple activities.
Through practices combining sustainable architecture with landscape architecture, architects can promote limiting water usage through infiltration, storing, and recycling water. A few practices use residential bioswales or bioretention ponds. Bioswales using plants (such as grass,) soils, rocks, and other types of vegetation to infiltrate and treat stormwater runoff. They treat stormwater by reducing the pollutants and contaminants, which increases water quality. Bioswales must be sloped to move water through the system. Bioretention ponds act similarly by using vegetated areas to capture and store stormwater runoff. Rain gardens can use rainfall and stormwater runoff as irrigation in a depressed vegetated area, usually with the use of native plants. By using highly porous plants, 30 percent of the runoff can be filtered into the ground, which is about one inch of rainfall per 4 hours. Residential rain water harvesting if the act of collecting, diverting, and storing rain in a catchment tank. The rainwater can be used for landscape irrigation, because rainwater is collected directly from the sky and avoids many pollutants water collects by flowing streets. The rainwater can also be used for activities like car washing and toilet flushing.
Passive solar design is the use of the sun's energy for the heating and cooling of living spaces. Active solar design is the use of mechanical devices to harness energy. Passive design is cheaper, more sustainable, and can be more efficient than active design. Since it relies on natural energy, it can't break; therefore, it doesn't require any repair costs or any costs to run it, such as the HVAC system. The idea is that buildings should be elongated on a east to west axis in which the southern side of their building is equipped with windows and the appropriate materials to capture the sun's energy for heating. During the winter, the buildings are heated; during the summer, the buildings can be cooled with foliage, awnings, attic fans, and operable windows. This works best in buildings with open floor plans and interior designs that lack carpet, drapes, and fabric covered furniture that can absorb moisture from the air, which causes the HVAC system to work harder. Rooms with carpeting and such should be located on the northern side of the building, along with the rooms that are less used and won't benefit from the sun's heat as much.
There are three types of passive solar design. The first is direct gain which encompasses south facing glass that transfer solar energy into the house, where it directly and indirectly strikes thermal mass materials (thermal mass is the ability of something to absorb heat energy) into the house. Direct gain utilizes 60-75% of suns energy striking the windows. Indirect gain is when thermal mass absorbs the sunlight that strikes it and transfers it to living space by conduction. Indirect gain utilizes 30-45% of sun's energy. It also requires operable vents at the top and bottom of the thermal wall to release energy. The last is isolated gain, which utilizes 15-30% of the sun's energy, by using a sun room that shares it's collected heat with a shared wall to the indoor living. |
Cassie HowardA high school student aspiring to change the world through green technology and sustainability. Archives
April 2015
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