New Dawn of Daylighting in Industrial Plants

Advanced optical daylighting technology has emerged that expands and improves how daylight can be harvested and eliminates problems with roof leaks, shifting light patterns, and building maintenance.

Manufacturers looking to increase energy efficiency and green their manufacturing facilities need only to look upward. The use of daylight for daytime illumination of industrial buildings can provide significant cost, energy efficiency, and sustainability benefits.

A new optical daylighting technology can banish problems with roof leaks, shifting patterns and levels of illumination, and building maintenance headaches of the past. Furthermore, it radically improves how daylight can be harvested.

Igniting this daylighting revolution is an optical technology and product category—the tubular daylighting device (TDD) (see Figure 1).

How a Tubular Daylighting Device Works

Unlike skylights, TDDs are distributed optical systems with relatively small, highly engineered rooftop apertures designed to selectively capture and deliver daylight into the building. These efficient, high-output systems allow for the overall glazed area to be significantly smaller than skylights for an equivalent interior illumination with improved consistency.

A TDD uses sophisticated refractive and reflective optical technologies that provide a range of controlled light distribution patterns, similar to electric lighting equipment. At the core of the advanced TDDs are unique, highly engineered optical materials and systems that selectively capture, redirect and transport, and then deliver focused or diffused daylight (see Figure 2).

Figure 2
After a TDD collects, or captures, sunlight, its optical materials selectively reflect and redirect the daylight from the rooftop aperture to the interior of the building.

These new technologies increase the effectiveness of how daylight can be applied, and can be very effective in spaces with ceiling and roof heights higher than 60 feet. These small, advanced optical daylight-collection devices on the roof can be designed to maximize the harvesting of the daylight from early morning to late afternoon, even in winter.

Advanced versions of these optical light guide systems are designed to filter out unwanted ultraviolet and infrared (heat) wavelengths of energy, providing only the beneficial wavelengths of light that are used in human vision. TDDs can be designed to reflect overpowering light and heat in the summer, even when the sun is directly overhead at noon.

A TDD’s optical design and lens technologies can shape the light output, placing it precisely where it is needed. Modern TDDs have a wide range of optical daylight-collection fixtures that either diffuse ambient daylight or focus daylight to areas as task lighting.

In addition, complex and convoluted tubing systems and highly engineered daylight fixtures can direct and deliver (transfer) the light over long distances (see Figure 3 )
One improvement in modern TDDs is that they can transfer daylight from one area of the roof to another area in the plant to deliver daylight where it is needed.

The optical devices can redirect daylight around the structural, mechanical, plumbing, and supply systems that typically populate a manufacturing facility’s congested overhead ceiling space and high roof (see Figure 4).

The TDD’s components are designed to work in concert with one another to minimize or eliminate undesirable shifting patterns of daylight.

As a result of these technology improvements, the TDD provides useful and consistent levels of daytime illumination, even under varying sky conditions throughout the year. It can be the primary source of interior illumination during the day, displacing a significant amount of electric lighting equipment in production, warehouse, package/product sorting, quality control and inspection, shipping and receiving, fulfillment, and offices.

Benefits

Substituting electric lighting with sunlight enhances a plant’s sustainability because it is:

• Energy-efficient—Using daylight as the primary daytime source of interior illumination significantly reduces peak load and annual lighting energy consumption.
• Environment-sensitive—Reducing electricity consumption measurably reduces the facility’s carbon footprint.
• A cost-saver—In addition to the savings the reduction in electricity nets, maintenance and associated costs are reduced as well.
• A morale-booster—Increased worker productivity and the potential health benefits associated with the use of daylight as a light source have been documented in many studies, and they contribute financially as well.
• A quality control enhancer—Modern daylighting’s ability to provide consistent, controlled, high levels of focused task lighting, coupled with its unique full-spectral content and color rendering characteristics, has been shown to significantly improve visibility of manufacturing defects, enhancing quality control.
• A code-based technology—Many energy, design, and construction codes and regulations, such as ASHRAE/IES 90.1, ASHRAE/IES/USGBC 189.1, and the ICC’s IgCC, now have adopted daylighting requirements for industrial and large commercial spaces. The threshold for this is constantly being reduced, but most codes currently establish a threshold for open areas larger than 8,000 square feet directly under the roof, with ceiling heights exceeding 15 ft. above the finished floor. In addition, effective daylighting can help manufacturers achieve net-zero-energy design objectives.

To maximize lighting energy savings, it is critical that manufacturers use daylight-harvesting controls that fully integrate daylight with the plant’s electric lighting system. While this had been problematic with traditional daylighting and skylighting systems in the past, advanced optical TDD systems are equipped with optical control of lighting patterns and can provide consistent
output.

New TDD systems have emerged that integrate daylighting with electric lighting, providing seamless, 24-hour illumination from a single combination daylighting/electric lighting fixture.

Modern plants are using TDDs to push the boundaries of sustainable design, employing creativity and innovation in the application of robust and purposeful daylighting applications. Throughout the world, advanced optical daylighting systems are illuminating manufacturing, warehousing, office, and maintenance facilities (see Pushing the Boundaries of Daylighting: Case Examples).

The future of daylighting in sustainable manufacturing plants looks bright.

Pushing the Boundaries of Daylighting: Case Examples

Distributed. The complex roof structure of Camp Lejeune, N.C., required the rooftop apertures of the TDD system to be confined to a small area. Yet, the lighting requirements necessitated that the daylight be distributed throughout the plant.

30-foot Distance. When designing and building an energy-efficient and sustainable tobacco processing facility, the Hangzhou Tobacco Co. in Hangzhou, China, installed tubular daylighting device (TDD) systems to provide critical task illumination for the tobacco drying, processing, and inspection areas of the facility.

The TDDs’ optical light guide systems collect and then “duct” daylight around existing interior obstructions and barriers through the 30-foot vertical distance between the roof system and the suspended ceiling structure in the Hangzhou Tobacco Co.

Daylight Grows Algae. In addition, daylight technology is also being harnessed to support new industrial applications, including manufacturing algae in bioreactors and algae-growth chambers using daylight.

Algae to Omega Holdings Inc., Fort Lauderdale, Fla., produces, markets, and distribute algae-derived products. One of the company’s core practices is using environmentally clean technologies and innovative production methods to cultivate and harvest algae biomass.

The manufacturer supplies organic raw materials for functional foods, nutraceuticals, animal feed, and personal care products such as Astaxanthin and contaminant-free omega-3 oil.

“Solatube International makes great products for bringing daylight indoors, and we use them to grow algae,” said Geronimos Dimitrelos, Algae to Omega’s owner. “Too much light and it will be destroyed; too little and it won’t grow.”