Dragons and daylight: Maximizing sunlight and climate control with TDDs

by arslan_ahmed | February 17, 2023 11:00 am

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By Benjamin Oman

For four-year-old Nakal and eight-year-old Berani, two Komodo dragons, the comforts of home have been difficult to reproduce where they reside: in the rainy, gray region of the Pacific Northwest. The pair, born in the tropical climate of Indonesia, share a unique set of environmental needs that have challenged the construction of their living space for years. Among the requirements are intense humidity, wild native landscaping, and temperature variances ranging from 21 to 60 C (70 to 140 F). For most, such extreme features would not produce the ideal circumstances for a home environment. However, these conditions are exactly what Komodo dragons need.

A necessary renovation

Nakal and Berani are the wild residents of the Woodland Park Zoo in Seattle, Washington. Recently, with the help of tubular daylighting technology, their home enclosure has been transformed to successfully meet their distinctive health and wellness needs. For years previously, they lived in an aging exhibit space whose inadequacies have proved challenging for their caretaker, Kevin Murphy. As an animal curator at the Woodland Park Zoo, Murphy is responsible for ensuring the two Komodo dragons have everything they need to thrive in their enclosure. So, when it came time to renovate their sub-optimal housing space, he knew the renovation’s success hinged upon one singular facet: the roof.

“This enclosure was originally designed 20 years ago, and it was essentially built inside a greenhouse with an old glass roof,” he says. “We didn’t have enough control over the environment—especially temperature and humidity. So, for this project, the number one goal was to gain complete control over the environmental conditions.”

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For the Komodo dragons, complete control meant producing and efficiently maintaining various temperature zones—ranging from 21 C (70 F) to basking areas of 60 C (140 F)—all within the same space. Murphy and the dragons needed a habitat capable of sustainably insulating and providing these intense heat and moisture conditions, a task made all but impossible by the original glass ceiling. Replacing the glass ceiling with a standard roof seemed the inevitable direction for the renovation; however, the decision would prove more complicated than it appeared.

The glass ceiling’s biggest failure was also its most tremendous success. While the skylight roof proved virtually useless at insulating the space properly, it did an exceptional job of providing substantial amounts of natural daylight, a critical resource for the Komodo dragons.

“In my experience, animals react positively to a natural photoperiod,” said Murphy. “We do reproduce that photoperiod with our light cycles here, but a natural photoperiod is really beneficial.”

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Eliminating the glass ceiling in exchange for an insulated metal roof would mean discontinuing the dragons’ regular exposure to natural daylight. This circumstance would prove devastating to their health and well-being. In addition to considering the daylight’s positive impact on the animals, the illumination from the glass ceiling proved beneficial to the exhibit itself—specifically the natural flora of the space. To Murphy, the daylight and the exhibit features shared a symbiotic relationship that could not be disrupted.

“We also had tremendous lighting needs for our plants, so we wanted it to look like a naturalistic exhibit. So, putting an entire roof on the building could not be attained in this space.”

Soon, the original intent of the renovation grew paradoxical. While updating the enclosure and replacing the glass ceiling would drastically improve the insulation, it would ultimately eliminate access to natural daylight, leaving the animals and the exhibit worse off than before. However, allowing the space to continue existing in its current form was unsustainable. Somehow, the zoo needed to seal off the ceiling space of the exhibit while still maintaining natural daylight illumination for the Komodo dragons and plants.

These contradictory circumstances soon reached Dennis Poon, a Woodland Park Zoo architect heading the renovation project. After much deliberation, Poon determined a new insulated metal roof was ultimately necessary.

“We decided to do a new roof structure, and because we’re doing a new roof structure, we’re losing all the glass skylights we had before where we allowed daylight to come through,” he says. “We were trying to find the best way to give daylight into the exhibit for the animals because we didn’t want to lose that aspect of having that natural light connection they had before.”

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A tubular solution

After extensively researching numerous options, Poon considered the idea of using a tubular daylighting device (TDD), as it could satisfy the contradictory requirements.

TDDs are domed devices installed on the roof of a building that use special lenses to capture lower-angle sunlight and reflect it into an interior space through flexible, reflectively coated tubes. The selected TDDs for the project offer 99.7 percent reflectivity; the tubes can be angled to fit almost any space and still provide bright ambient light to hard-to-reach areas. A variety of diffusers, made of modified acrylics, would allow Poon to shape and direct the light coming into the space while maintaining efficient insulation and eliminating unwanted solar glare. With this ideal solution identified, he got to work planning the integration of the device into the new roof and exhibit designs.

He started by identifying which TDD could accomplish the project’s goals.

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“We wanted to find a system that would work with our roof system easily and efficiently, and we came to 736.6-mm (29-in.), round TDDs,” says Poon. Ultimately, they chose a TDD featuring a unique bottom assembly component capable of delivering maximum daylight in high-ceiling applications.

Since most daylighting applications do not want damaging rays, all ultraviolet A and ultraviolet B (UVA and UVB) are removed at the roof dome level. For reptiles and amphibians that require UVA and UVB, it can be easily added back into the environment with electric lights.

The device also featured a prismatic diffuser and optional amplifier, which was key in helping focus sunlight down to specific areas in the enclosure. With the use of a daylight design software, the changes in light distribution can be seen. The amplifier significantly improves the delivery of daylight in high bay and high ceiling areas by reorienting the daylight to the visual task plane. It converts inefficient daylight angles into efficient angles.

In addition to its powerful channeling of daylight, the TDD selected was dual-glazed, providing significant insulation capable of maintaining the intense climate the dragons need. As far has high humidity is concerned, the entire system is sealed to prevent interior air/humidity from entering the optical system. The system is built in such a manner that it cannot “breath” at the roof level to equalize air expansion.

While the illumination output was of crucial importance in the redesign, another concern loomed: exhibit visibility. The design team needed to preserve the exhibit’s rugged natural appearance, keeping the zoo’s many visitors from seeing any infrastructural components that could shatter the immersive viewing experience.

The future renovation’s large observation area had to offer wide, unobstructed views into the enclosure, allowing guests to walk up to the glass to see the dragons. While most electrical and structural elements could be easily hidden or incorporated into the exhibit’s layout, the TDDs needed to operate unobstructed. However, their very functionality proved effective in mitigating this challenge.

TDDs are designed to allow flexibility, leading daylight to unconventional and hard-to-reach places. The reflective tubes are made with materials that can be easily adjusted on-site so the diffusers can be installed where needed. Using this feature, Poon could design the tubes to be hidden from view while still leading daylight to the desired locations.

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For this project, a daylighting software was used to determine the newly arranged outputs. The design calculator is a web-based daylighting tool designed to help users evaluate daylighting solutions faster and accurately, and it is easily accessible. By combining the product photometry with typical meteorological year (TMY) data, the tool measured the distribution of light from a product based on actual weather at a specific project site. This allowed for the project to move forward by minimizing the time it takes to perform a comprehensive analysis.

Poon and his team determined the exhibit would require 13 devices, all directing light to different targeted areas in the building below.

Conclusion

In September 2021, the long-awaited exhibit reopened to eager visitors. Walking up the large glass observatory windows, viewers are now presented with a jungle-like interior; the meticulous details of the construction are tucked out of sight. For Nakel and Berani, the stars of the attraction, their new home has been warmly received. Since the relocation into their new enclosures, the pair have thrived in the cultivated conditions reminiscent of their native Indonesian habitat.

By including an optional thermal insulation panel, dual pane clear windows, which enhanced the thermal performance, the renovation proved a true success for Poon and Murphy.

“We can control all the lighting, temperature, humidity, and ventilation conditions throughout the Komodo spaces, so we can effectively manage the environment to meet the needs of Nakel and Berani,” says Murphy. “As the science of animal care continues to evolve, we strive to continue to learn, change, and improve, so all our animals receive the best possible care throughout their lives.

Author

Benjamin Oman is an Emmy-award-winning creative director and digital communications specialist who is passionate about sustainability, technology, and design. He is the creative and communications manager for lumenomics, a natural daylighting company based in Seattle, Washington. As a construction and design business dedicated to maximizing natural daylight in designed spaces, lumenomics is the commercial distributor of Solatube Tubular Daylighting Devices in Washington and Oregon.

 

 

Source URL: https://www.constructionspecifier.com/dragons-and-daylight-maximizing-sunlight-and-climate-control-with-tdds/

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