Reducing construction costs with big fans

July 14, 2016

All photos courtesy Big Ass Fans

By Vicky Broadus
Architects often sell their clients on the promise of large overhead fans based on the argument of long-term energy savings from reduced reliance on HVAC. Architect Antonio Santini and his team at RED Studio persuaded an initially skeptical client by devising an overall plan for a new office building that not only offered long-term savings, but more importantly, was also less expensive in its upfront costs. This resulted in a clean, uncluttered interior that is both a showcase of energy-efficiency and a flexible environment putting employees’ well-being first. The innovative use of large overhead fans also required creative rethinking of the lighting design that earned the studio an award from the Illuminating Engineering Society (IES).

Fans in an office space
RED Studio’s client, Kiewit Corporation, is among the largest construction firms in the world. The Omaha, Nebraska-based corporation wanted a new building for its Toronto office, Peter Kiewit Infrastructure. Santini described his client’s goals for providing thermal comfort as similar to most—a cost-effective system that ran smoothly. Additionally, Kiewit had an environmental mandate. While it was not focused on Leadership in Energy and Environmental Design (LEED) ratings, it still wanted to be mindful of environmental solutions.

“If it was in their budget, then they could make the case to their corporate executives,” Santini said of considering
new solutions.

Santini and RED Studio had conducted research into indoor air quality (IAQ) and distribution through the use of large overhead fans, and were eager to put it to use. They knew that by supplementing conditioned air with cooling airflow, businesses could greatly reduce air conditioning use and cost—from three to six per cent for every degree the thermostat is raised. In winter, the fans efficiently and completely distribute heated air, saving a similar amount.

RED Studio saw the Kiewit project as an opportunity to create a showcase for the large construction company. However, it would take some time to design an innovative plan and persuade Kiewit’s engineers it could do more than save energy costs—that is, it could save money on the front end as well.

“We introduced them to the notion of bringing in the fans and completely rethinking the mechanical strategy,” Santini said. “What we did was essentially go back to the drawing board.”

The design
Due to the nature of the building—open-concept industrial-style with 5.5-m (18-ft) high ceilings—the standard solution for the environment is to, in Santini’s words, “litter the ceilings with ductwork and units and try to capitalize as much as you can on distribution to get to where you need to be.”

This presents various challenges when it comes to design and air quality. Santini’s team of mechanical engineers and their vendor stripped down the mechanical units and distributions to capitalize on the overhead fans—17 in total across the 3000-m2 (33,000-sf) structure.

Executives in the Peter Kiewit Infrastructure office in Toronto were initially skeptical of the high-volume low-speed (HVLS) fans replacing traditional HVAC and ductwork, but ultimately the cost-savings, energy efficiency, and occupant comfort won them over.

Santini said it achieved three things:

“First, it gave us 17 different zones for user control for comfortability,” he explained. “Another thing is by doing the distribution with the fans, it allowed us to cover almost 100 per cent of every square inch of the floorplate so that there wasn’t any pocket of air that was going to be stale. There’s always a lot of air movement in the space. And third, it cleaned up our ceiling dramatically, so that we didn’t have to deal with the ductwork.”

Partly because the rooftop units did not have to push air through maze of ductwork, the team was able to size down its rooftop units to smaller, more energy-efficient models. The fans were a visual boon as they kept the ceiling neat and tidy and contributed to a sleek, utilitarian look in the office.

Kiewit’s executives bought into the design concept, particularly because of the energy efficiency, which Santini said “sealed the deal.” However, the RED team ran into some reluctance from the client’s facility management group, who did not believe the design could work. They wanted it done in a traditional manner with chillers and the typical methods used for a large floorplan.

“They didn’t understand the benefits of having user controls and the air movement produced by the fans,” Santini explained.

Santini and his mechanical engineer spent several evenings collaborating and debating design rationales and philosophies, and then backing them up with hard data to prove their effectiveness.

In terms of ductwork, rooftop units were introduced into the space with a main spine associated with each unit. The function of this main spine is to throw air into the upper strata of the building. This air is then distributed across the space with the help of overhead fans. Essentially, the rooftop unit only produces the air to a specified temperature and it is the fans job to distribute it to the lower strata.

RED Studio utilized large-diameter, low-speed fans to move air through the construction company’s 3000-m2 (33,000-sf) office space. The increased air movement allowed for much smaller rooftop HVAC units that require little ductwork.

System costs
Proving the system’s workability and efficiency was just one step in the process of convincing Kiewit to give the ‘go-ahead.’ The more crucial discussion was the upfront cost. Santini’s team basically designed two mechanical strategies—one with the fans, and the other without.

The mechanical engineer obtained the costs of a system without fans with some help from his contacts in the industry. It was then reverse engineered. They went back to the fans and designed a system that eliminated most of the ductwork and reduced the HVAC tonnage.

“With the price of the 17 fans and the price of the mechanical, it actually came in slightly less than a conventional system—about five to seven per cent less,” Santini concluded.

“We told them there would be no cost implication, that it was cost-neutral. Then we reinforced it with the sustainability aspects, from the point of view of air quality, thermal control, and energy efficiency. We didn’t even factor in energy efficiency in the cost breakdown. Sustainability was the icing on the cake,” Santini said.

Kiewit’s Toronto operates believed in the design, and the company recognized the financial and environmental benefits. The project was given the green light.

Long-term, energy efficiency is where most of the savings are. Initially Kiewit’s facility management group took issue with the fans because they were such an uncommon solution. The budget given to the RED Studio team was divided up differently than it would have been in a traditional system. The management group had trouble comprehending a mechanical cost that was dramatically less than what they expected, due to the reduced ductwork and smaller roof units.

“They also weren’t used to seeing a line item for overhead fans, so it became an education,” Santini said.

When the dust settled, both the RED Studio team and Kiewit’s team were happy with the design, and even their mechanical engineer—who at first was a little reluctant—became a big supporter.

As there are 17 fans, there are 17 separate zones of control, which is highly unusual for a building of its size and type. The zones meant each bay of users would have the ability to get more or less air by speeding or slowing the fan.

The fans make a strong esthetic statement in the building—and fit in perfectly with the nature of Kiewit’s business.

Additional challenges
Lighting was one notable challenge for RED Studio’s design. Typically, lights are suspended from the deck, but the presence of the fans precluded that in some spaces. This meant Santini’s team had to go back to the drawing board yet again, and rethink its lighting strategy for the entire building.

Rather than lighting the work surfaces from above, the team designed a lighting system that illuminates the ceiling from below, providing uniform, reflected light off the white surface. High-efficiency outdoor light-emitting diode (LED) fixtures—which normally light urban areas and roads—were brought inside. The fixtures were mounted at a height of 2.7 m (9 ft) within the structural columns themselves, serving the second purpose of a lighting ‘tree,’ and keeping the ceiling clean and organized. The use of high-efficiency outdoor fixtures is grounded in Kiewit’s involvement in road construction and environmental stewardship. The reduced number of units and LED fixtures’ longevity and proximity to the floor all add up to less maintenance. The approach was also cost-neutral compared with alternatives, and resulted in an IES Section Award of Merit for lighting design.

With the lights mounted onto columns, the only thing that is seen hanging from the ceiling are the fans. The fans performed on several levels—mechanically, esthetically, and as an air quality measure.

“As an architect whose primary function and focus is on health and well-being and environmentalism,
I want to make sure that the people are taken care of. So if I can get a mechanical strategy in there that works better than what people are used to doing, I will repeat this formula as often as I can,” Santini said.

Large-diameter, low-speed ceiling fans have gained acceptance for the comfort, energy efficiency, and long-term savings potential they offer. As the Peter Kiewit Infrastructure project shows, with a little ingenuity, they can also represent an upfront savings over more traditional HVAC systems in offices and other public spaces, with the result being a healthier environment for both workers and the planet.

vicky_broadus_BigAssFansVicky Broadus has nearly 15 years of experience as a journalist and is a writer for Big Ass Solutions, which is the parent company of Big Ass Fans and Big Ass Light. She can be reached via e-mail at[1].


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