Magnetic Refrigeration: An Old Technology Offering a Green Application

The typical refrigerator creates a cooling effect by harnessing the energy difference between liquid and gas, and capturing the resulting cooling forces from the expansion and contraction of the refrigerant. A similar, exciting technology is magnetic refrigeration: this process uses the energy variance between the different magnetic states in specific refrigerants through magnetization and demagnetization—a process called the magnetocaloric effect. This technology produces extremely low to home-refrigerator-appropriate temperatures. In contrast to conventional gas-compression refrigeration, this method results in greener, cleaner refrigeration that uses no ozone-damaging coolant gases and has higher efficiency ratings.

The Physics Behind the Process

Long before refrigeration courses taught magnetic physics in HVAC schools, Swiss physicist Auguste Piccard and French physicist Pierre Weiss observed the magnetocaloric effect in 1917. The first working models of magnetic refrigerators date back to 1933 and the first magnetic refrigeration systems were developed for creating temperatures as low as -459.13 Fahrenheit.

The magnetocaloric effect is the result of a magnetic-thermodynamic occurrence involving the exposure/removal of ferromagnetic materials to a magnetic field. Exposure causes the atomic lattice within the materials to become disordered, increasing the temperature. Removal, on the other hand, results in the atomic lattice getting ordered and the temperature decreasing. Lowering temperature via controlling magnetic materials is called adiabatic demagnetization. Currently, the most common magnetocaloric materials utilized in the construction of magnetic refrigeration systems are dysprosium and gadolinium alloys, as well as germanium, erbium, and aluminum.

Finding Practical, Cost-Effective Applications

Recently, scientists have observed rotational magnetocaloric results on a scale large enough to be used for the design and manufacturing of magnetic refrigerators and air conditioners for home use. This progress can bring these advanced and environmentally friendly appliances within reach of the average homeowner.

With more products that use magnetic refrigeration becoming commonplace, the benefits of a system that uses no harmful compounds will grow significantly, and the magnetic refrigeration marketplace is expected to grow. Magnetocaloric refrigeration offers several distinct advantages over conventional appliances, such as larger temperature ranges, sustainability, higher efficiency, and environmental benefits.

Growth of Career Opportunities

P&S Market Research expects Western Europe to be the first fully developed marketplace for magnetic refrigeration to expand. North America is expected to be the second largest market by 2017, while other major growth will come from Germany, Canada, the U.K., France, Japan, Italy, Brazil, India, and China.

The advancements this green technology will likely become more applicable to home appliances, especially if the cost of magnetic refrigeration drops as its availability grows. Industries with in the need of cost-effective, large-scale refrigeration include healthcare, grocery, food and beverage processing, refrigerated transportation, commercial refrigeration, database centers, computer chip manufacturing, and more. Individual applications that could benefit from magnetic refrigeration include icemakers, display cases, cryogenic refrigerators, air conditioners and chillers.

Although it has taken over 100 years for designers to find practical applications for the magnetocaloric cooling process, the technology is on the cusp of being implemented in appliances and machines across different settings—whether in a commercial structure or in a family home. Refrigeration technicians with the skills and training to install, maintain, and repair these systems will likely be in great demand.