Facilities (Campus Spaces)
Is It Hot In Here?
- By Amy Milshtein
- October 1st, 2014
PHOTO © CHRISTIAN COLUMBRES ARCHITECTURAL PHOTOGRAPHY
When it comes to energy savings, all of the low-hanging fruit has been picked. With their less expensive, high-tech LED lighting in place, institutions now want to save more while still keeping their indoor environmental quality high. It’s time to look at HVAC. What are some strategies schools are using and where is the new cutting edge?
Lane Community College — On the Razor’s Edge
Completed in 2012, the LEED Platinum-certified Lane Community College Downtown Campus in Eugene, OR, stands as a laboratory and teaching tool for the Energy Management program that it houses. The 91,818-square-foot, four-story, L-shaped structure, seen above, features classrooms and living space and is admittedly “complex, but that’s what the school wanted,” according to Marc P. Brune, PE, senior associate, PAE Consulting Engineers, Inc.
Some of the features of this state-of-the-art structure include a high-performance building envelope that provides superior barrier to weather changes; triple-glazed, solar-resistant, operable windows with insulated shades and a vegetated roof over the meeting rooms between the academic and housing buildings. Passive ventilation takes advantage of natural airflow and keeps the building cool. An automated control system regulates temperature, ventilation and lights in each room.
Most striking is the solar-thermal array above the main entrance of the academic building. A set of 35 or so water pipes enclosed in vacuum tubes provides visual impact and non-potable hot water for the building. “I was hesitant about the array at first because the orientation is far from optimal,” admits Brune about the south-facing array that is even shaded part of the day. Still, the building has operated with flying colors. While Brune doesn’t have energy-savings numbers yet, he reports that the school did exceedingly well during an unusual cold snap last winter. “We don’t need to design to peak cooling requirements,” he says. “If we make all of those systems smaller we can put more money into the building envelope.”
Men are From Mars; Women Think It’s Cold in Here
Not every school has the opportunity or drive to go as far as Lane Community College did. Yet schools still aim to cut energy use and keep people happy. To meet that goal, colleges are changing tactics. Instead of programming their air conditioning to meet the highest load on the hottest days, facility departments are realizing that thermal comfort is more than just air temperature.
Thermal comfort takes six factors into account: air temperature, humidity, radiant temperature, air speed, clothing level and metabolic rate. All of these very individual elements come together to create comfort on a personal level. They also mean that schools can turn down the AC, if the conditions are right.
The Center for the Built Environment (CBE) has developed a web-based tool to predict thermal comfort according to ASHRAE Standard-55. This is significant because an “advanced understanding of human comfort presents opportunities to save energy and increase thermal comfort,” according to the CBE’s website. “Using the tools with ASHRAE Standard-55 as a guide, designers may find that a wider temperature band will provide adequate comfort and save a significant amount of energy.”
One way in which organizations are gathering information is by just asking. “We are conducting a comfort survey at Harvard, and we have to ask ‘are you dressed appropriately for the weather?’” reports Brian Barmmer, vice president of technology solutions and sustainability, DTZ. “If they’re wearing shorts and a t-shirt in the summer they will be comfortable in a 75°F room.”
Of course thermal comfort remains a personal issue; even a gender-based one. While science is having mixed reviews proving it, observational data shows that men and women have different perceptions of hot and cold. The answers for why range from bodyfat composition to hormones to physical size, but when you get down to it, it’s freezing in here (am I right, ladies?).
The Variable Solution
With the science of thermal comfort at hand, institutions and manufacturers find solutions. Variable-speed technology, for instance, allows air temperatures to run higher and save energy because humidity is controlled. “The first function of air conditioning is humidity control,” says Eric Walthall, marketing manager, North America, Danfoss. Walthall goes on to comment on the damage that excess humidity can wreak; condensation on windows, water stains and the development of a perfect environment for mold to grow are all related to humidity.
Variable-speed technology allows air conditioners to remove dangerous moisture and move air around as needed. “Most air conditioners are set for the highest load on the hottest day,” says Greg Polk, business development manager, Danfoss. “Variable speed lets you remove the humidity and set the thermostat higher.”
Variable-speed technology can provide between 30-45 percent energy savings. A typical return on investment is between two to three years, according to Polk and Walthall.
The cost of wireless building automation systems has come down over the years, making them an attractive option for schools. “The cost of monitoring has come down so much that we can really get down to the granular level,” says DTZ’s Barmmer of this once-prohibitive technology. “A wireless temperature monitor costs about $100. You could put one in every room to find hot spots.”
Card-swipe data can be used to control temperature as well. “It used to be that you turned on a building at 7:00 in the morning. A close look at data shows that only a handful of people come in between 7:00 and 8:30,” says Barmmer. “We can get to a truly granular level to create a responsive building.”
Some schools that made the early leap to controls may now find themselves with an outdated, expensive system, one that doesn’t play nice with the latest Windows platform or web-based solutions. One company’s specialty is updating old proprietary systems, taking 2008 technology and “squeezing five or more years out of them,” according to Brad Pappal, general manager, Tustin Energy Solutions.
Building controls, no matter the age, need constant monitoring and updating. “We are going into existing buildings right now and assessing their control sequences,” reports Ian Hadden, director of energy management, University of Arkansas at Little Rock. “What was perfect five years ago might not hold true today.”
Hadden’s university is also leaning toward cool roofs and paying attention to daylight modeling when designing new buildings. “Everyone wants more windows to get natural light and stay connected to the outdoors,” he says. “But we have to balance that with heat gain.”
Small steps at the University of Arkansas at Little Rock add up to substantial energy savings. While they’re not the cutting-edge solutions found at Lane County Community College, both schools — and probably yours too — can find ways to keep energy bills low and satisfaction high.
This article originally appeared in the October 2014 issue of College Planning & Management.