Daylighting with Roof Skylights for Energy Saving and Human Benefits
Energy waste has become one of the most concerns for modern industrial manufacturing facilities, office sites, and commercial buildings. Recent environmental guidelines are pushing commercial and industrial buildings to make their companies greener by reducing energy consumption. Couple that with increasing energy costs, businesses have no other option but to search for greener and better ways to save energy that still keeps the quality and the productivity of the workplace at a high level. Natural daylighting is the answer. Natural light is one of the most important elements in architecture, helping to transform spaces and save energy.
In a world newly concerned about carbon emissions, global warming, and sustainable design, the planned use of natural light in non-residential buildings has become an important strategy to improve energy efficiency by minimizing lighting, heating, and cooling loads. The introduction of innovative, advanced daylighting strategies and systems can considerably reduce a building's electricity consumption and also significantly improve the quality of light in an indoor environment.
Daylighting is the practice of placing skylights or windows on a building so during the day, natural light provides effective internal lighting. This strategy allows natural sunlight to illuminate the interior space of a building without the need to rely exclusively on electrical lighting during the day. Electrical lighting can account for as much as 40 percent of power consumption in many commercial buildings, meaning reducing such loads can significantly lower energy usage. One means to lowering energy use is to install skylights to increase natural daylighting. Although there are many myths surrounding skylights, evidence shows they not only improve energy efficiency, they also provide multiple benefits to people living and working within daylight facilities.
Skylights are roof opening covered with translucent or transparent glass or plastic designed to admit daylight. Skylights have found wide application admitting steady, even light in industrial, commercial, and residential buildings. Installations range from purely functional daylighting to elaborate aesthetic forms. Flat-roofed buildings may have domed skylights; in others the skylight follows the slope of the roof. Often the skylight, or a portion of it, functions as an operating window to admit air.
There are a number of different skylight categories, available in a variety of shapes and sizes, on the market today, each with their own advantages and disadvantages. They can be flat, domed, fixed, or vented. Fixed skylights cannot be opened, unlike vented skylights, either manually or remotely. Prismatic skylights are the most widely used because they allow for the most diffused and evenly distributed light. Other, non-diffused skylights can create hotspots within the building and tend to have poor U-values with high solar-heat-gain coefficients that decrease the thermal efficiency of the skylight.
The materials used for skylights also vary. Polycarbonates have the best impact resistance and are the most hurricane and burglar proof. Some acrylic diffusers can yellow with age. Lastly, glass skylights are commonly used in residential applications and large, custom jobs that vary widely depending upon the customer's specifications.
Different skylight manufacturers offer various alternative designs to achieve improved daylighting. One such alternate design is a tubular skylight or “light pipe”. Tubular designs capture sunlight using a rooftop dome, and then transfer it indoors through a reflective tube that runs from the roof to the ceiling. From there, the light is evenly dispersed into the interior space using a diffuser.
Daylighting strategy benefits can be maximized by combining new skylights with new interior lighting controls. Photo-sensor technology incorporated with skylights can further conserve energy by actively sensing when artificial lighting is not needed.
Environmentally, daylighting reduces the load on power plants, lowers greenhouse-gas emissions and lessens air and water pollution resulting from byproducts of electricity generation. The benefits of skylights extend beyond our environment to our own personal well-being. The increase in natural light that a skylight provides can have a variety of physical and psychological benefits. Skylights help to not only bring new life to a room, but also improve our health and happiness as well. Natural lighting can also be an important tool in attaining sustainability.
Reduced energy consumption: The lessened dependency on artificial lighting can help reduce the use of electricity by as much as 10% and lower heating bills.
Reduction of mildew or mold buildup: Most diseases, especially chronic respiratory problems, are often associated with bacterial and fungal buildup in damp areas such as basements and bathrooms. Natural lighting can naturally lessen the production of harmful organisms. Sunlight is considered to be one of the best natural disinfectants.
Healthy dose of vitamin D: Ample amounts of sunlight can prevent vitamin D and B1 deficiencies that may cause diseases such as rickets and beriberi.
Improved performance due to change in working environment: Many case studies have been conducted that shows significant improvements in employee performances where natural lighting has been introduced into their work environment.
Increased visual appeal to interiors: Natural illumination is still the best type of lighting system used in interior design. It can be a challenging, yet rewarding task to successfully incorporate natural light into a structure or building. Daylight provides better aesthetics, better colour, better definition of space, and highlights architectural details.
There are also some myth related to skylights that they are expensive and increases the chances of roof leaks. However, it has a fast payback period due to energy saving and reduction of electricity use. As for roof leaks, prismatic skylights have a thermal break with flashing details around the curb. If water gets in the skylight, it is diverted around the skylight and not through the roof as a leak. Another myth is that with natural sunlight from the skylights, the building will be too hot. That's not true because there is a reflective lens on top and an opaque lens on bottom. Light is brought in from all different angles and mitigates heat transfer into the building.