Passive solar design uses energy from the sun to heat and cool living spaces by exposing them to the sun. Three things can happen when the sun hits a building. Building materials can either reflect, transmit, or absorb energy. Apart from that, the sun produces heat which causes air to move within living spaces. Understanding these basic solar principles has led to specific design elements, material choices, and placements that provide heating and cooling effects in homes.
How a Passive Solar Home Design Works
A passive solar home gathers heat from the sun through south-facing windows. This heat is then retained in thermal mass, or simply materials that store heat. This heat will meet a share of the home’s heating demands known as passive solar fraction.
Properly designed passive solar homes provide daylight all year. The home will also be highly comfortable during the cooling season through the use of nighttime ventilation. Passive solar home design first lowers heating and cooling loads by making use of energy-efficiency strategies. These reduced loads are then met entirely or partly with solar energy.
It’s crucial when implementing passive solar home designs to limit the size of south-facing glass. The designer should also ensure that any south-facing glass is adequately shaded to prevent overheating and increased cooling loads in the fall and spring.
Energy Efficiency First
When implementing passive solar home design, it is vital to keep in mind that efficiency is the most cost-effective means for lowering heating and cooling loads. Therefore, it’s best to work with building professionals who have enough experience designing energy-efficient houses. For house remodeling projects, it would be best to have a home energy audit.
Site Selection
With passive solar home designs, a section of the south side of a property should have an unobstructed “view” of the sun. Consider how the land to the south of your construction site is going to be utilized. Young trees will grow tall, and any multi-story structures built there will end up blocking your home’s access to the sun.
Essential Elements Needed for an Efficient Passive Solar Design
To be efficient, a passive solar home design should incorporate some essential elements that function together:
Properly oriented windows.
Windows or devices collecting solar energy must face 30 degrees of true south and be kept clean at all times. They must not be shaded during the heating season.
Thermal mass.
Usually, concrete, brick, stone, and tiles are used to absorb heat from the sun during the heating season. They also absorb heat from warm air in the home during the cooling season.
Distribution mechanisms.
Transferring heat from where it is collected to where it is stored happens through conduction, convection, and radiation. Designers also use small fans and blowers to help spread the heat.
Control strategies.
Roof overhangs can be used to shade vertical south windows in summer. Some other control approaches are available, like using electronic sensing devices like differential thermostats, which signal fans to turn or off. Other designers also use operable vents and dampers to control heat flow, low-emissivity blinds, and operable insulating shutters.
While seeming conceptually simple, passive solar home design is a complicated mix of details and variables that must be balanced. Experienced designers use computer models to simulate the details until the design fits the site well.
For the best results, passive solar home designs should be used in combination with real solar systems. This would be the most inexpensive way to heat and cool your home. By combining these two, you will effectively reduce your bills by meeting the reduced energy loads with a solar system.
