The Lillis Business Complex at the University was given an innovative design to minimize the use of air conditioning and heating to regulate temperature, and after three years the self-sufficient design is going as planned, although with some slight problems keeping the building temperature stable.
The Lillis main building, between Peterson and Gilbert halls, is the only building on campus certified by Leadership in Energy and Environmental Design (LEED) for overall energy efficiency. That is largely because the building’s ventilation system is supposed to route air flow into the atrium and out ceiling vents to keep temperature within a comfortable range without much artificial heating or cooling.
The building earned its LEED certification for its architectural design before it was completed in 2003, but a recent student analysis of the building found that the temperature on the fourth floor was as much as eight to nine degrees higher than the first floor, and a consistent difference of about five degrees. The temperature in all floors also fluctuated rapidly over the course of the study, according to its data.
The study, conducted over four days last spring, was led by four University architecture students who performed the analysis as a class project.
Architect Kent Duffy, who was the main designer of the new building, said Lillis is designed so that air flows into the building from classrooms and outer hallways into the main atrium. After it reaches the atrium and gathers heat, the air rises to the top of the four-floor building and out vents in the ceiling, which can also be encouraged by exhaust fans intended to remove smoke from the building, Duffy said.
The vertical airflow method known as the “stack effect.”
The student case study placed devices in the atrium to collect temperature data for four days in February, then observed air flow in the building.
Architecture student Jeremy Webber said they found that the air flowed into the main atrium from the bottom floors, rose to the top, but then partly moved out to hallways in the upper floors rather than through the vents in the top of the atrium.
Webber said much of the irregular air flow was likely caused by pressure in the building, which also relates to temperature.
“If the atrium is a higher pressure than the hallways that are on the third and fourth floor, then it’s going to down the hallways no matter what the temperature is,” he said.
Webber said some temperature difference between the floors was natural with the “heat stack” structure the atrium uses.
“That’s going to be expected,” he said. “If you’re using a stack system, just in general it’s going to be warmer at the top and cooler at the bottom.”
Duffy said there is naturally some temperature difference to be expected from the first floor to the fourth floor using the vertical airflow method.
“There will certainly be a temperature difference, but … one of the things we’ve heard back is that as a rule in the atrium, it’s remained comfortable for much more of the year than people expected,” he said.
Architecture professor Charlie Brown, who is also director of the Energy Studies in Buildings Laboratory at the University, said the difference should be about two to three degrees with the design.
Duffy said the larger-than-expected temperature discrepancy was fine, as long as it remained within the intended comfort zone of 68 to 78 degrees. He said that the time of year the measurement was taken also affects the limited ventilation through the building.
“In the summertime we want to move a lot of air through the building,” Duffy said. “In the wintertime if we move a lot of air through the building, then the whole building gets cold on the inside, and you have trouble heating it back up. What we want to do is let the least amount of air flow through to create the fresh air requirements that make people comfortable, but not so much to cool the mass of the building off.”
Several professors who work in Lillis said they had not experienced any irregular temperatures in their offices since the building opened.
Duffy said the initial construction plan was to renovate the adjacent Gilbert and Peterson buildings immediately after Lillis’ completion, but the project was delayed because of limited funds. He also said the eventual update of the older buildings would allow the self-regulating ventilation system to work even more efficiently than it does now.
“We really are making something that essentially hasn’t been done before,” he said. “This (University) laboratory is a national resource.”
Contact the business, science and technology reporter at [email protected]