Working with climatic conditions instead of against them is essential to crafting a sustainable approach to design. Using sunlight to heat, power, light the spaces we use brings synergies and benefits that will extend beyond today and well into the future.
Passive solar strategies can have significantly positive impacts on human well-being and the environment. Providing people with well-lit and visually appealing surroundings can help to create more effective, efficient, and healthy spaces while reducing energy costs and improving indoor air quality. Incorporating natural daylight into architectural design ensures that people will have the best possible environment and health outcomes from the spaces they experience. Access to sunlight benefits health in various ways such as improved vision, increased wakefulness and improved sleep, vitamin D deficiency prevention, lowered blood pressure, and, simply stated, it makes people feel good.
Architects can bring the positive impacts of sunlight to people by making smart choices in their designs that optimize access to natural daylight. To illustrate how passive sustainable principles can be integrated into a space, we have created a prototype for a Poolhouse + Fitness Pavilion with passive solar strategies that can be integrated into various typologies and forms. This year-round Poolhouse + Fitness Pavilion harnesses energy from the sun and responds to seasonal conditions through its envelope design. The pavilion is a simple space with a versatile enclosure that can adjust to temperature swings and solar variations throughout the year to minimize overall energy use and maximize human comfort. Passive sustainable strategies illustrated by this prototype include:
• Horizontal shading devices
• Cross ventilation
• Sunspace + thermal heat mass
• Top daylighting + louvered shading
• Photovoltaic shading system
• Green roof
The building’s façade features a horizontal shading system along the perimeter of the structure that covers the building from excessive light and glare. Intercepting sunlight before it reaches the pavilion’s glazing dramatically reduces heat gain during the summer. External shading devices can reduce solar heat gain through glazing by up to 80%. By designing shading devices according to the sun’s seasonal path, both summer shading and winter solar gain are achieved. The adjustable shading devices can be repositioned to allow for temperature variations or occupant preferences during unusually warm or cool periods.
Operable glass walls around the pool area create a year-round space that can comfortably adjust to seasonal fluctuations. While the glass walls are likely to be closed during the winter, their ability to retract in the summer allows for natural ventilation and passive cooling from naturally occurring winds. Some best-practices to maximize the benefits of cross-ventilation are: to locate openings perpendicular to prevailing winds; to size outlet openings to be equal to or larger in size than inlet openings; to locate openings on opposite sides of a space; maintain an unobstructed path between inlet and outlet openings for adequate air flow; and to enjoy!
Another benefit of the retractable glazing system is that it creates a sunspace that is heated naturally throughout the day. In the winter months when the glazing is closed, the space is warmed by solar heat gain from the south. Heat is then stored in the floor’s thermal mass and in the thermal wall that divides the two areas. Heat obtained from the sun in the space around the pool is transferred to the adjacent fitness area through a thermal storage wall. A thermal storage wall is a mass wall, usually masonry, stone, or concrete, that faces the equator and has high thermal storage capacity, high density, and high thermal inertia - or the ability to resist temperature swings. It is this material property that tampers heat gain and loss, facilitating continued warmth in the winter and cooling in the summer.
One of the most effective daylighting strategies to implement in a space is the use of top-lighting, which allows natural light to enter a building from above providing even illumination to the entire space. This type of lighting is ideal for human health, as it provides an evenly well-lit space and reduces the need for artificial light. Top-lighting is provided at the pool area in the form of a glass canopy with integrated adjustable shading louvers. The advantage of this top-lighting is access to the entire sky, consistent distribution of daylight, and the daylighting of the entire pool area as desired for leisure. Louvered shading controls act as direct sunlight diffusers, reducing glare and creating softer, uniform daylighting levels. These louvers also shade the top-facing glazing from direct sunlight in summer to reduce solar heat gain.
The photovoltaic system over the pool area brings multiple synergies that benefit the pavilion. By integrating photovoltaics with the shading louvers on single-tilt axes, the panels respond to changes in the sun’s azimuth throughout the year. Since solar panels produce the most electricity when they are placed exactly perpendicular to the sun, the panels face south at a 55-degree angle from the horizon in the winter and at 25-degrees from the horizon in the summer. The seasonal position of the shades correlates with a need for more shade in the summer and less shade in the winter: optimal directionality equals optimal shading. For structures that do not have adjustable-tilt panels, the best practice is to tilt the panels between 30-45 degrees all year round - the higher the latitude, the higher the tilt. The photovoltaic louvered panel system paired with ample natural daylighting designed into the pavilion envelope, means that the lighting of the entire structure can come from the sun.
The extensive green roof over the indoor fitness area brings multiple benefits to the pavilion. Vegetation and soil placed on waterproofing membrane with drainage, increase the insulative qualities of the roof and tamper ambient air temperature swings. Additionally, the green roof reduces overall building energy consumption used for heating and cooling and combats the heat island-effect created by roofing and hardscapes. By integrating an organic thermal mass on the roof, the structure retains rainfall, reduces noise, filters pollutants, and cools the fitness area during Utah’s’ hot summers. The green roof also provides a comfortable rooftop space with a great view to enjoy.
Working with climatic conditions instead of against them is essential to crafting a sustainable approach to design. Using sunlight to heat, power, light the spaces we use brings synergies and benefits that will extend beyond today and well into the future. Whether a building is used for recreation and leisure or for learning, healing, or working, harnessing the power of the sun to enhance our experiences and minimize energy use is key to creating better built environments that foster social, environmental, and economic well-being.