Student uses magnets to cut consumer cooling costs
Earlham College student Justin Vadas is exploring ways to incorporate a magnet (in blue) in refrigeration applications to provide cooling at a low-cost, efficient and environmentally-friendly manner. He is conducting research as part of the Science Undergraduate Laboratory Internship Program at Oak Ridge National Laboratory.
While some magnets hold holiday-themed photographs of family members on a fridge, others detect cancers or help trains reach speeds faster than the strongest tornados on record. So, it is no surprise that magnets continue to attract and keep the attention of researchers like Justin Vadas, an undergraduate student in chemistry and physics at Earlham College, who are discovering ways to capitalize even more on magnets’ expansive potential.
A participant in the DOE Office of Science’s Science Undergraduate Laboratory Internship (SULI) Program at Oak Ridge National Laboratory (ORNL), Vadas is researching how to replace conventional air conditioning systems with magnetic regeneration air conditioning, a more efficient technology. The SULI program, managed by the Oak Ridge Institute for Science and Education, encourages undergraduate students to pursue careers in science, technology, engineering and mathematics (STEM) by providing research experiences at one of the 15 participating U.S. Department of Energy (DOE) laboratories.
“The focus of the research right now is finding a scale at which superconducting magnets become viable as a source for large-scale magnetic refrigeration applications,” said Vadas. “It seems like heating, ventilation and air conditioning (HVAC) systems for buildings could really benefit from this technology.”
Vadas and his team are exploring how superconducting magnets can be used in HVAC systems, as opposed to appliance-scale magnetic refrigeration applications. Vadas’ mentor Dr. Boyd Evans, a mechanical engineer and research scientist at ORNL, said the primary challenge of his team is to optimize a design that reduces energy loss caused by the need for the magnet to be kept at cryogenic—extremely cold—temperatures.
“Keeping the magnet cold using a cyrocooler represents a parasitic energy loss,” he said. “We are focused on reducing operating costs, and whether we can produce substantially more refrigeration power than the power required to run the cyrocooler.”
Vadas tasks mainly included mechanization and regulation of key components of the refrigeration system. According to Vadas, magnetic refrigeration is based on a principle known as the magnetocaloric effect. He explained that when the magnetic poles within a magnetic material align with a magnetic field, the temperature of the material rises. He and his team are employing this concept to raise and lower the temperature of a magnetic refrigerant to provide cooling.
Vadas said the design uses a linear actuator to move the magnetic refrigerant, which is the element gadolinium, in and out of the magnet.
As the temperature of the refrigerant rises, water is pumped over it to cool it down to room temperature. This water then is directed to what is known as a hot bath, or the exhaust. When the linear actuator pushes the refrigerant out of the magnet, the refrigerant cools down to below room temperature, causing the water that flows over it this time to become colder. This cool water is directed to the cold bath.
“As this process is repeated, the hot bath will keep getting hotter, and the cold bath will keep getting colder,” explained Vadas. “The heated air around the hot bath then will be expelled outside by fans, and the cold bath also will use fans to blow the cooled air around it inside.”
Vadas’ task was to develop coding to mechanize the drive shaft, regulate a pump to control the flow direction of the water to go to the appropriate bath at the appropriate time and to acquire temperature measurements of the hot and cold baths. He now needs to perform an integration of all of the individual codes into one program to control the system’s cycle automatically.
“My team and I are almost done with the engineering phase,” said Vadas. “We have been designing the parts and sending in blueprints and specifications to be built.”
The next step is experimentation.
“I am hoping for great results during the experimentation phase,” he said. “We already have taken into account several factors that influence efficiency during the design of the system, and there is still a great deal of optimization to do once the system is built.”
He said he envisions at least a 30 percent increase in efficiency in this technology above the conventional vapor compression fridge.
After Vadas graduates, he said he plans to pursue a graduate degree in either physics or chemistry or a discipline that combines them both, and he eventually hopes to become a professor.
“My biggest dream is to make such a significant breakthrough in science that it is worthy of a Nobel Prize,” he said. “Being able to explain how our world works is what drew me to science, and with the guidance of my professors, I have been able to start on a career in the pursuit of such knowledge. The ability to use this knowledge to do extraordinary things is such a big motivator. After all, science was considered magic until it was discovered.”