Direct sunlight is of critical importance in architecture — for reasons of aesthetics, experience, and comfort, as well as energy performance. Direct sunlight can reduce winter heating, but can dramatically increase summer cooling. Direct sunlight can provide warmth and dynamism to a space, but can also mean visual or thermal discomfort for occupants as diverse as office workers and athletes. And access to direct sunlight is increasingly regulated on both the building and urban scale.
However, until now there hasn’t been a good way for designers to evaluate direct sunlight in a quick, quantifiable way. The architect’s traditional tools — sun angle charts and shadow studies — show only points in time, making it time-consuming to aggregate results across hours, days, or seasons. Sefaira’s new Direct Sunlight simulation makes these types of studies straightforward — and, in doing so, makes it easier for architects to consider the elemental impact of the sun on their buildings.
Here are a handful of design questions that can be answered — and insights that can be gained — from Direct Sunlight analysis:
1. Detailed shading design: Sefaira’s Response Curves already helps users optimize shading lengths. But Direct Sunlight analysis helps take it a step further: it can show precisely where direct sunlight hits the floorplate during cooling months, enabling designers to fine-tune shading devices to keep out bad gains, and to balance the aesthetics of shading devices with performance in real-time.
2. Passive solar design: Direct Sunlight is a powerful tool for passive solar design. Users can compare direct sunlight during heating seasons versus cooling seasons, designing to maximize the former and minimize the latter. Energy analysis can reveal which months are heating- and cooling-dominated for a specific design, and this information can be used to determine the time periods for Direct Sunlight analysis.
3. Exterior solar access: What is the impact of a proposed building on its surroundings, in terms of access to sunlight? Will an exterior courtyard receive enough sunlight in winter months? Performing Direct Sunlight analysis on the exterior ground plane can illuminate these questions.
4. Prevent sunlight in light-sensitive spaces: Some spaces need to specifically exclude direct sunlight, even though indirect daylighting may be important. This is can be true of museums, athletic facilities such as gymnasiums and natatoriums, or work environments such as offices and libraries (in which it’s beneficial to keep sunlight off computer screens). In these cases, pairing daylighting analysis with direct sunlight analysis enables designers to design for great daylight without risk of direct exposure.
5. Meeting certifications requirements. A growing number of building certifications address direct sunlight. SEPP 65 Solar and Daylight Access requirements in Australia require a minimum amount of direct sunlight during winter months. (For more on how Sefaira can be used to meet SEPP 65 requirements, see our blog post on the topic.) The B3 Guidelines in Minnesota limits the amount of direct sunlight a space can receive. And the LEED v4 Daylight requirements include a maximum Annual Sunlight Exposure (ASE) for regularly occupied spaces. (ASE doesn’t directly correspond to sunlight, but areas of high direct sunlight likely have a high ASE; so direct sunlight analysis provides a handy way to diagnose and mitigate ASE problems.)
Direct Sunlight analysis is the latest in a series of innovative daylighting features from Sefaira. Other visualizations include “Overlit and Underlit” analysis, aligned with the LEED v4 daylighting requirements, and an “Annual” (Daylight Autonomy) analysis, which aggregates daylighting performance over an entire year — as well as more traditional Time of Day and Daylight Factor analyses. Taken together, these metrics allow designers to consider daylight and sunlight like never before: developing an intuitive understanding of the sun’s effects and shaping their designs according to its orbit.