UVM students engineer cleaner air for Vermont cheese cave

by Casey Hurlburt
Jasper Hill Farm is a small family farm in Greensboro, VT. Andy Kehler, a University of Vermont graduate, began Jasper Hill farm with his brother, Mateo, in the summer of 1998. They wanted to create a successful dairy farm model that can be replicated, to help preserve the ever-disappearing Vermont dairy farms that “keep Vermont beautiful,” as stated on their home page.
In 2007, the Kehlers opened seven underground cheese caves, buried at the perfect depth for aging cheese naturally. The Jasper Hill Farm cheese caves age cheese for 14 cheese-makers across the state.
Andy explained that aging cheese creates ammonia, which can compromise the quality of the cheese and is also unhealthy for the workers. The HVAC system created to clear the air of ammonia was not suitable for the cheese aging facility. The system interrupted the natural process that took place, changing the temperature and humidity of the environment.
After two years of trying to fix the problem without success, Andy Kehler went to the University of Vermont’s College of Engineering and Mathematical Sciences and presented his problem to senior college students looking for a capstone design project.
“Our project started with a thorough assessment of the existing HVAC equipment being used at Jasper Hill. From this assessment we concluded that removing the ammonia from the cave air was necessary to maintain the efficiency of the heating and cooling systems and take full advantage of the caves underground construction,” said Dave McClosky.
Evan Johanson, Dave McClosky, Eric Adam Wood, and Paul Veselka, from UVM’s College of Engineering and Mathematical Sciences, took on the challenge and designed an application after a system coal plants use, running emissions through water.
“Once we identified the ammonia as a key problem in the facility, we decided to focus our efforts on a simple yet effective way to remove it from the air. Through research and knowledge of basic chemistry and physics, we developed an idea and an apparatus to go along with it that would test our hypothesis,” McClosky said.
The system which would be used for the cheese cave would be completely different from the tested system used to clean the air of coal plants, “None of the group members were certain that it would work but the theory was sound enough to further pursue it and build our air scrubber,” he said.
The four students created a prototype ammonia filter to represent the cave and tested it for months to determine which variables worked best together, “Once we built the unit we started testing and were pleasantly surprised with how well it worked in our application.”
In April, they traveled to Jasper Hill Farms to test their design. They ran the filter in the cheese cave, testing the water for ammonia, and found that their design was successful. McClosky added, “It felt good to show ourselves we knew what we were talking about.”
The students not only solved Andy’s problem at Jasper Hill Farm; they may have also made a breakthrough in ammonia problems at cheese aging facilities around the world.
Evan Johanson said the biggest issue was the removal of ammonia in the cave. They needed an HVAC system to run more efficiently than the one that was in place. He said they had to deal with a situation in which the cave was too hot in the summer and too cold in the winter. The key was to be able to dissolve ammonia in water.
Johanson, who graduated in May with a degree in mechanical engineering and is working outside Boston, said, “It was the first real chance to get hands-on experience working with a real company. Otherwise we’re just in the lab on campus.
They are now working on a full scale system.