Passive Solar Design

Table of Contents




What is Passive Design?

The Passive Design method in constructing buildings improves the traditional construction of buildings especially in extreme cold or hot climates. The main improvement of the Passive Design is to eliminate the problem of poor heating and cooling systems within the building which improves the efficiency of the building’s energy. The design supports a cost-effective method and solution to poor quality construction. Conventional buildings consume up to 90% more cooling and heating energy than passive design buildings.

Passive Design [1]



What is Passive Solar Design?

The passive solar design uses sunlight to regulate the heating and cooling systems of living spaces through thermal mass. The method usually uses south-facing windows to reflect, transmit, or absorb the solar radiation. There are several design elements to follow to ensure a successful design:

  • Aperture
  • Thermal mass
  • Distribution
  • Control
Five Elements of Passive Solar Design [2]




Passive Solar Design Elements

Aperture

The aperture is a large glass window area for sunlight to enter the living space and faces within 30 degrees of true south. During the heating season, other buildings or tress should not shade the aperture from 9 a.m. to 3 p.m. everyday. Else wise, the windows should be shaded to prevent overheating.

Thermal Mass

Thermal mass material is typically concrete, brick, stone, and tile which retain or store the heat produced by the sunlight. The thermal mass is located behind the absorber (hard and darkened surface) surface. In the cooling season the material absorbs heat from the warm air in the house while during the heating season the material absorbs heat from the sunlight.

Distribution Mechanisms

The distribution mechanism in the design determines how solar heat circulates from the collection of heat to different points of a building through conduction, convection, and radiation. The appliances of fans, ducts, and blowers can be used to further distribute the heat flow.  

Control Strategies

The use of roof overhangs provides shade to the aperture area during the summer season when the hours of sunlight become longer. There are a number of different methods which include a differential thermostat that signals a fan to turn on; operable vents and dampers that allow or restrict heat flow; low-emissivity blinds; operable insulating shutters; and awnings



Passive Solar Heating

During the periods when the sun is low or absent, the energy captured during the periods of high sunlight within the buildings’ materials is released. The use of the south facing glass window and thermal mass allows absorption, storage, and distribution of heat throughout the building.




Passive Solar Cooling

During summer seasons when the daytime heat becomes intense and longer, there is a need for a cooling system to regulate the building heat flow. The use of shading, thermal mass, and natural ventilation reduces overheating of the building and stores cool night air for regulating temperatures.  The use of overhangs or shades on south facing windows, shade trees, thermal mass, and cross ventilation is common.




References

[1]  “Passive design,” Passive Design | Green Home Technology Center. [Online]. Available: https://greenhome.osu.edu/passive-design. [Accessed: 09-Dec-2021].

[2] “Passive solar design,” Sustainability. [Online]. Available: https://sustainability.williams.edu/green-building-basics/passive-solar-design/. [Accessed: 09-Dec-2021].

[3] N. Norris, “Five principles of passive house design and construction,” Passive House Accelerator, Jan-2019. [Online]. Available: https://passivehouseaccelerator.com/articles/five-principles-of-passive-house-design-and-construction. [Accessed: 09-Dec-2021].


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Lesley Lang 1066 days ago
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