Smart Windows Offer Modern Solution for Middle Tennessee State University

2/9/2023

With a nickname like “The Glass House,” windows are a serious business in the Murphy Center, Middle Tennessee State University’s (MTSU) basketball and event center. The facility is home to the largest installation of smart windows in higher education with a 33,000-square-foot glass curtain. 

The update to the 50-year-old facility in Murfreesboro was unveiled in October 2022 and is expected to result in significant energy savings as well as greatly improve the thermal comfort and brightness/glare levels for occupants. Replacing the original windows, the building’s upgraded windows use glass from SageGlass that automatically tint and clear based on the sun and weather outside.  

This was an important factor when considering a new window solution for the building, which is home to the MTSU men’s and women’s basketball programs and the university’s primary indoor facility for concerts, commencement ceremonies, and numerous other large events. 

Replacing an antiquated system 

Previously, the Murphy Center was using a glazing system that was original to the facility when it was built in 1970. The old structural silicone gasket type system was starting to fail in multiple locations around the building, leading to structural problems, says Bill Waits, assistant vice president for MTSU Campus Planning. 

“We were having a situation where the glass was cracking … certainly the glazing, wood panels would be falling out," Waits says. “The sealant on the insulated glass assemblies had been compromised in a lot of places, and we had condensation occurring on the inside of those glazing assemblies.” 

This meant the facilities and maintenance staff was constantly replacing and servicing the area to make do, and because of the age of the system, the gaskets used to hold the windows in place were no longer made anymore.  

“Ultimately, I think we're looking at a system that probably should have been replaced many years ago but was still there,” says Waits.  

Another major issue was the amount of solar glare caused by the large number of windows that make up the facility. This was specifically challenging during basketball games when the solar glare on the playing surface interfered with the university’s ability to televise games.   

Prior to upgrading the windows, a temporary solution was to install mechanical shades throughout the building, which needed to be manually lowered to block the sun. Not only was this a tedious task, but it simply did not look good. 

“One thing we liked about the smaller windows and SageGlass was we could kind of lose the need to have that secondary mechanical shade system that at the end of the day was really left down it seemed like 24/7,” Waits says. “I think right now we have a kind of a cleaner result and with the electrochromic glass.” 

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Ron Malone, assistant vice president for events and transportation services, says that if there was any type of a large event on the main floor during the day glare was a significant problem.  

For example, before installing the mechanical shades, they used black plastic to block the windows. When hosting a large Easter celebration years ago, they had to take black plastic and tape it all the way around on the east and south side of the building to get the building dark enough to host that event.  

And while the shades were certainly an improvement, they still had their problems. 

“Every time you had to do that (lower the shades), you kind of had to hold your breath to make sure that when you've lowered it, everything goes down to where it's supposed to. And when you're done and you're raising them, that everything goes back without fail,” says Malone, adding that what once was a tense situation at the facility, now can be done with the click of a button.  

“It's like transition lenses, they just darken and lighten as you tell them to.”    

And beyond the maintenance and safety of the window system, atheistically, the facility was long overdue for a facelift.  

“Even if you weren't overly concerned about whether or not there was a structural integrity that might allow the window to fall and create a safety issue at one time or another, we also had these clouding issues that really made the building look its age,” says Malone. 

A solution  

Selecting a new window system came down to several factors, including comfort, sustainability and budget.  

“At the end of the day, one of the biggest obstacles is we needed a new system that would certainly control that glare … and we looked at several systems and options that may take care of it,” Waits says. 

The university did a handful of solar studies and look at several different solutions, such as a multiwall polycarbonate type system, before finally making a selection.  

“We looked at polycarbonate, which is of course a plastic, and certainly would have been a better economical choice than where we landed with electrical permit glazing. But, given the name of the building is ‘The Glass House,’ we didn't really want to go back with plastic. ‘The Plastic House’ didn't quite have the same ring to it,” Waits says. 

Another option was fritted glass, a more traditional curtain wall, which still didn’t yield the glare control the facility required.  

“What the smart windows provided was a system that would control the glare without having to add additional other moves to control glare,” Waits says.

The windows use solar sensors to detect current light levels and direction of lighting to automatically control the necessary tint. Based on the solar conditions, the windows can go from completely clear glass to a very dark tint in a matter of seconds.  

For example, if it's midday, sun may be coming in at a certain direction. The window’s sensors are able to block out the sun where needed while keeping the east and west facades completely clear. 

“You kind of have the option to be hands off and let the system determine what areas need to be tinted and what level of tint that it goes to,” Waits says. “Or you can come in and manually override that system and then tint as you see fit.” 

The windows also have the ability to make patterns in the glass with different levels of tint to create graphic patterns.  

A modernized facility  

Not only have the windows given the facility a major facelift, but they ensure the building remains comfortable throughout the year. Waits says it is too early to really see the energy impact, but he expects the smart windows will go a long way in blocking the sun on hot days and harnessing its heat on cool days, ultimately leading to energy savings and sustainability improvements. 

“The new system certainly will have an increased level of thermal insulation and thermal breaks to the system that should give us some savings as far as energy usage, just in heating and cooling the building,” Waits says. “Certainly, from a cooling standpoint, being able to control the glare, the solar glare will be a benefit. And then, at the same time, if there's no glare present, having the glass clear allows more natural light and things into the space versus having to be as reliant on electrical lighting inside the arena there.”  

Malone says that it while it is still too early to calculate any type of energy savings, he did notice that the heating and cooling system did not turn on as much during some the hotter days during the fall. He credits this to the windows sensors, which automatically shade the building to keep it cool when the sun’s solar glare is brightest.  

He also notes that to increase those energy savings they could manually darken all four sides of the building, and they may be something they look into in the future.  

“We're going to see some savings. It's still a little early for that, but we do anticipate that being a big benefit,” he adds. 

Amy Wunderlin is a freelance writer from Fort Atkinson, Wisconsin.