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Church Nianing in Senegal by IN SITU Architecture closes in the north to protect itself from the hot and dry winds of the Harmattan, and opens towards the west to let in cooling trade winds from the sea.
Passive solar design is one key to sustainable building, producing structures with low energy costs and minimal maintenance. Practiced throughout the world, the design method can reduce temperature fluctuations, improve indoor air quality, and minimize greenhouse gas emissions.
Churches can be ideal candidates for passive solar design, and its techniques can be applied to new and existing buildings.
“Passive solar design utilizes the sun’s energy for heating and cooling of interior building spaces without excessive use of mechanical and electrical devices,” says James Theimer, AIA, founder and director of design of Trilogy Architecture in Redding, Calif. “Its primary benefit is substantial savings in operating costs from active mechanical and heating systems ... and cooling systems.”
Theimer notes that passive solar design requires the successful integration of five distinct elements of design:
1-Aperture -- the glass area separating interior from exterior of the building through which sunlight enters.
2-Absorber -- the surface of the element within the interior of the building which the sunlight strikes. The surface sits in the direct path of sunlight.
3-Thermal Mass -- material behind the absorber surface that stores the heat generated from the sunlight.
4-Distribution -- a method used to circulate the stored solar heat throughout the building’s interior spaces.
5-Control -- the means used to adjust the amount of sunlight allowed into the building as well as escape of excess hot air from the building.
Benefits of solar for religious institutions
Church.Design asked Theimer to expand on the promise of passive solar design for churches and other buildings in the United States.
According to Theimer, because passive solar design depends on sunlight, it is not a one-size fits-all solution. The United States is incredibly diverse in its range of different climate conditions. A building in Maine where heating is far more important than cooling will look completely different from the same building in southern Florida, where the reverse is true.
Designers must be creative in adapting to local conditions. To illustrate this idea, almost a decade ago Trilogy Architecture created a series of Climate Comfort Maps based on the different regions of the country and how design could be affected by location. The maps identify three zones of comfort: The Extreme Zone, where heating is most important; the Favorable Zone, where cooling is paramount; and the Marginal Zone, where both are equally important.
Thoughtful architecture is “climate-centric,” taking into consideration factors beyond annual temperature. For example, annual rainfall, sunlight intensity, and wind must be considered, as well.
Regardless of the climate zone where a church will be located, the building form is critical to success. The tall, soaring interior spaces often found in religious designs are well-suited to passive solar design when combined with some mechanical ventilation. Deep overhangs to protect from harsh summer sun are common features in faith-based design and oriented correctly, can greatly enhance the interior environment in both summer and winter months.
Faith-based institutions often employ heavy mass materials, such as granite, for aesthetic purposes, and these can work extremely well as collectors of solar energy. Combined with large glass areas oriented toward the winter sun, a solar-based design has the ability to potentially generate all the necessary heating for a large religious assembly, even in an extremely cold winter climate. In a warmer climate, however, where cooling is more important, solar design must be adapted to allow for nighttime cooling to avoid overheating an interior space.
Given that religious gathering spaces can be so challenging to heat and cool – not to mention costly – it is surprising that there are not more examples of churches utilizing these ideas.
With religious architecture, passive design need not be an all-or-nothing approach. If employed properly, utilizing the benefits of outdoor fresh air and the sun’s energy can greatly enhance the inspirational interior spaces architects work to create in every project.
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Church Nianing's bell tower functions as a wind tower, using natural convection to bring the trade winds into the building to create natural ventilation.
Architecture Masterprize 2019: Winner in Architectural Design / Misc. Architecture
Architect: IN SITU Architecture, Nicolas Vernoux-Thélot
Location: Senegal
Client: Archdiocese of Dakar
Learn more at: Architecture Masterprize, Church Nianing
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Church Nianing's design takes the shape of a shell as its starting point and develops it architecturally, in accordance with the constraints of the site and the bioclimatic context.
[Editor's note: Originally published in May 2020.]
