PROPANE ENERGY CASE STUDY

Project: Andes Central High School
Location: Lake Andes, South Dakota
Architect/Engineer: TSP

The Project: Located in a rural agricultural community in south central South Dakota, the Andes Central school project united the district’s 350 students on a single campus by adding to the existing 25,000-square-foot elementary and middle school. With a modest budget, the team from TSP had to manage upfront costs while also meeting ambitious sustainability goals and allowing for future adaptability.

The Challenges: “Being in South Dakota, we get some -20°F and -30°F wind chills,” says Mel Tschumper, head of maintenance and custodians for the Andes Central School District. He has two priorities for the heating system at the Central High School: reliability and efficiency. In addition, project architect Chase Kramer says the team was seeking LEED-like performance. “One of the things was ensuring that we had a really strong thermal envelope, whether that was more than the basic requirement for insulation in the walls or making sure that there were high quality windows on the project,” Kramer says.

The Architectural Design: The TSP team built flexibility into the way the building and its rooms were designed. Classrooms can be adapted for multiple seating arrangements ranging from a circle to a more traditional setup, and breakout spaces in between the classrooms can accommodate quiet work or meetings. The science labs were designed as “classatories,” where the desks can be set up in a traditional lecture arrangement but then slide and lock into place to form peninsulas connected to the lab equipment, which includes sinks and propane connections for Bunsen burners.

The architects were also thoughtful about the way the high school integrated with the existing elementary and middle schools. To provide access to the cafeteria for the high school without disrupting the younger grades, the designers added a corridor along the north side that provides a separate entrance to the cafeteria while also forming an interior courtyard that could be used for outdoor classes in the future.

Mechanical Heating Design: For the mechanical systems, the design team originally considered a geothermal system, but it became clear early on that it wouldn’t fit in the budget without sacrificing other project priorities. Senior mechanical engineer Roger Nikolas points out “Drilling wells is expensive and those costs, they’re just prohibitive.” Adding a new well field also would have taken up valuable land that was earmarked for future expansions. “So that would have limited their ability to construct additions to this facility in the future” says Nikolas. Instead, he was confident the project could meet comfort and efficiency goals with the “tried and true” approach of propane boilers. Not only would these provide the needed heat for normal operation, but the on-site underground storage of the propane heating fuel would also allow the building to keep running in case of emergency situations.

In the final design, two 2,500 MBH condensing propane boilers supply a 160°F-heating loop to provide perimeter radiant heat in the classrooms as well as hydronic coils in the air-handling system. “With a propane boiler system, we’re able to ratchet that temperature up on that heating loop at times when we need it,” he says. “So when you get -20°F temperatures — and we get that every winter — we really want to make sure that that skin of the building is warm.”

Water Heating and Cooking Design: For domestic hot water, Nikolas specified two 95-percent-efficient propane water heaters with internal storage. “There’s quite a bit of usage for the building because we have athletic areas and showers, so we chose to use separate systems for that because it allows them to turn that boiler plant down or even shut it off in the summer,” he says. Although the design team looked at electric water-heating options, they would have required a larger amount of hot-water storage, resulting in much higher energy costs for the school district.

The propane water heaters’ ability to provide large amounts of hot water is particularly useful in the kitchen, where the staff use it constantly for dishwashing, Tschumper says. The cooks also rely on propane cooking equipment, including two convection ovens, a six-burner stove, a kettle, a steamer, and bread makers. “I don’t think they could be as efficient with electricity as they would with propane,” Tschumper says.

The Results: For Tschumper, who attended the original high school in Lake Andes, graduating in the 1970s, the successful project is a source of pride. Compared with the old building, where students frequently wore coats in the winter when the fuel oil heating system couldn’t keep up, the new building is more comfortable for students and easier to maintain. “It’s a beautiful building in a beautiful location, and the school is much more efficient,” Tschumper says. “And all winter long, I have never had one complaint from any of the teachers or students about being cold. The propane system is smooth; the heat is reliable. All the rooms are consistent day by day.”

The performance and flexibility that the propane heating system provides helped to earn the school and its designers at TSP recognition, winning the grand prize in the 2019 Propane Project of the Year awards.

RESILIENT EXPANSION JOINT CASE STUDY

Project: Justice Center
Location: Christchurch, New Zealand

The Project: The Christchurch Justice and Emergency Services Precinct (the Precinct) was a $400 million project in Christchurch, New Zealand, the nation’s capital. This location is no stranger to earthquake activity, with a magnitude 6.2 earthquake occurring there in 2011 that took 185 lives. Preparedness for future events like this was topmost on the minds of the designers of the new Justice Center, particularly since it was the first major public building to be built and opened in Christchurch by the government since the earthquake of 2011.

The Design: The new precinct building was designed and constructed to rest on base isolators intended to help it withstand the most severe earthquakes. Notable related details on this project included the installation of a new type of seismic expansion joint. This fabricated system uses ceramic magnets to hold metal panels in place while stronger, braided-metal arresting cables connect them to the structure. The magnetic retention system allows for generous daily thermal movement and minor lateral shear allowances without disengagement from the wall. During heavy seismic cycles the panel disengages, and the arresting cables take over to ensure the panels remain against walls or ceilings. In this way, corridor egress widths and heights are not impaired while the building is enduring the earthquake. From an aesthetic standpoint, the infill pan is engineered to accept many common infill materials to minimize the surface appearance of the seismic expansion joint.

Resiliency Results: After an earthquake, disengaged panels can be repositioned and put back into place by engaging the ceramic magnets. The building is thus enabled to move as needed during the seismic activity but maintains its ability to function and be restored to a normal appearance afterword quite quickly.