He’s known as “the apostle of geothermal.” At least that’s the nickname given to Mark Nussbaum of Oak Park’s Architectural Consulting Engineers by Frank Lipo, executive director of the Historical Society of Oak Park-River Forest. To Lipo, Nussbaum’s expertise in designing geothermal heating and cooling systems for some of the more notable historic structures in Oak Park and the Chicago area is nothing short of awe-inspiring.
Lipo cites Nussbaum’s recent works as evidence. There’s Oak Park’s Unity Temple, the Glessner House in Chicago, the Dawes Mansion in Evanston and Lipo’s own pet project, the Cicero Township Firehouse, soon to be headquarters to the Historical Society. He is also installing geothermal in the Park District of Oak Park’s new nature center in Austin Gardens.
Nussbaum may be too modest to call himself an apostle, but his engineering skills have made his input sought after throughout Chicago.
What is geothermal?
Geothermal replaces traditional furnace and air-conditioning systems. Using the Earth as a heat source, deep pipes are dug into the ground to take advantage of the underground’s near constant temperature, to heat and cool a building.
According to Nussbaum, geothermal systems are nothing new.
“It’s been around since at least the 1940s,” Nussbaum said. “Geothermal as a concept was popularized in the ’70s and ’80s. It’s not new technology; it’s just a refrigeration system.”
Nussbaum said the Department of Energy calls geothermal the most efficient heating and cooling system available, but he acknowledges there are upfront costs. “It’s more expensive to install, but you usually see energy savings set off the cost of installation in about 10 years. Over the life of the system, they are actually lower in cost than traditional heating and cooling systems.”
An added benefit is that most of the materials involved in geothermal systems have a longer life-span than traditional systems, resulting in less frequent maintenance. Nussbaum notes that a traditional, residential furnace might have a lifespan of fifteen to eighteen years. “Because a geothermal system doesn’t have outside equipment, it can last twenty or more years, but the underground piping is good for at least fifty years. You just have to replace the interior heat pump, which is about the same cost as replacing a furnace.”
Nussbaum, who is careful to specify that he is a design engineer and not an installer of geothermal systems, has been involved with Unity Temple restoration work for almost a decade.
“We began working with them in 2004 on ideas for reworking the system,” Nussbaum said. “Last year or the year before, they received a large foundation grant, so we did a redesign of the system and worked with the architect to integrate our plans into the entire restoration project.”
Part of his appeal is experience dealing with significant buildings.
“Our firm specializes in historic buildings,” he said, “and the whole goal is to not tear up what makes a historic building so valuable.”
Nussbaum noted there are numerous ways to approach geothermal installation — from using a pond and drain system to installing vertical piping.
“Vertical piping is the only way to go on a site like the Unity Temple,” he noted. “It’s the most ecological and the best for our urban environment. The pipes at Unity go down about 500 feet. In this area 150 to 500 feet is typical.”
The Unity Temple project is representative of many of his most recent works.
“The dominant reason people put in geothermal is because of the environmental savings,” said Nussbaum. “People have that desire, and I can tell them if it’s viable. The Unity Temple congregation really wanted the most efficient system they could get there. The building presented some unique challenges because it is all concrete construction, so this was really a collaborative project with Harboe Architects.”
As the restoration of the Historical Society’s new Lake Street headquarters continues, Executive Director Frank Lipo said the appeal of a geothermal system was part environmental and partly practical.
“For historical materials such as papers and photographs,” he explained, “humidity is best when it’s not fluctuating. Geothermal is ideal for constant humidity levels without spikes.”
As the 500-foot wells for pipes were installed on the Lake Street lawn of the building in late September, Nussbaum’s specifications had already been used for the interior system’s installation. The pipes enter the building through the basement, which houses an air handling unit for supply and return. Two units on other levels of the building facilitate the necessary air exchanges.
For Lipo, using the latest technology for temperature and humidity control fits neatly with the rest of the Historical Society new building’s restoration efforts. On the first floor, original Georgia pine walls and ceilings are being brought back to life and the original hole for the fire pole in the 1898 firehouse has been restored. Throughout the structure, where possible, historic details such as a soapstone sink and brick walls are being maintained. Ductwork from the new geothermal, plumbing and electrical systems will remain exposed in areas to allow for high ceiling heights.
Lipo says the materials all fit into the history of the building. “From the start, this was a sort of industrial space. We want the rooms to have some of that original feel.”
He points to the second floor space, once used as meeting hall for the Grand Army of the Republic, a Civil War veterans group, will be used as a meeting place, and the first floor will have a rotating gallery with room for exhibitions and much improved accessibility for all.
“It’s a 19th-century building with a 21st-century museum,” Lipo said, “so we’re combining elements of different eras. The new geothermal system is very much a link to the 21st-century. We now have this state of the art system that should keep our monthly bills lower. We’re in a public building and being an educational institution, we’re trying to tell stories. We can tell the story of geothermal, too, using our actual systems as an instructional tool.
“People may think history is further back,” he added, “but it keeps going. This building is old, but we also have contemporary spaces.”