Magnetic Refrigeration

Magnetic Refrigeration

Aims of the project

Many magnetic refrigeration prototypes with different designs and software models have been built in different parts of the world; nevertheless, there are still challenges in the way of commercialization of magnetic refrigerators. The obstacles hindering commercial production of room temperature magnetic refrigeration are both economic and technical. In this project, the possibilities with and the potentials of magnetic refrigeration system are investigated to find the most suited application for commercializing the technology.

This Project is a part of EFFSYS EXPAND, a program established by The Swedish Energy Agency, Energimyndigheten

Publications

The articles (full text) can be downloaded by clicking on their titles:

MAGNETIC VS. VAPOR-COMPRESSION HOUSEHOLD REFRIGERATORS: A PRELIMINARY COMPARATIVE LIFE CYCLE ASSESSMENT

Monfared, B., Furberg, R., and Palm, B., 2014, "Magnetic vs. vapor-compression household refrigerators: A preliminary comparative life cycle assessment," International Journal of Refrigeration, 42(0), pp. 69-76. doi: 10.1016/j.ijrefrig.2014.02.013.

OPTIMIZATION OF LAYERED REGENERATOR OF A MAGNETIC REFRIGERATION DEVICE (pdf 3.1 MB)

Monfared, B., and Palm, B., 2015, "Optimization of layered regenerator of a magnetic refrigeration device," International Journal of Refrigeration, 57, pp. 103-111. doi: 10.1016/j.ijrefrig.2015.04.019.

SIMULATION OF SOLID-STATE MAGNETOCALORIC REFRIGERATION SYSTEMS WITH PELTIER ELEMENTS AS THERMAL DIODES (pdf 1.3 MB)

Monfared, B., 2017. "Simulation of solid-state magnetocaloric refrigeration systems with Peltier elements as thermal diodes." International Journal of Refrigeration, 74, pp. 322-330. doi: 10.1016/j.ijrefrig.2016.11.007.

DESIGN AND OPTIMIZATION OF REGENERATORS OF A ROTARY MAGNETIC REFRIGERATION DEVICE USING A DETAILED SIMULATION MODEL (pdf 2.0 MB)

Behzad Monfared, Design and optimization of regenerators of a rotary magnetic refrigeration device using a detailed simulation model, International Journal of Refrigeration (2018), doi: 10.1016/j.ijrefrig.2018.01.011.

Background information

Although Magnetic refrigeration is a well-known method in cryogenics, it has not been commercially used at room-temperature. Brown built the first prototype magnetic refrigeration device working at room temperature in 1976. Since Brown’s successful experiments, an increasing number of prototypes have been built. Currently an increasing number of researchers are working on developing prototypes, models predicting the performance of the magnetic refrigerators, and materials used as refrigerant in magnetic refrigerators.

 Working principle

The working principle of magnetic refrigerators is based on magnetocaloric effect, perceived as adiabatic temperature change or isothermal entropy change. Some materials show a significant temperature change when they are exposed to an external magnetic field. When the process of magnetizing is done adiabatically the magnetocaloric effect is observable as adiabatic temperature change, ∆Tad. However, if the heat is removed from the material to keep the temperature constant while the external magnetic field increases, the effect is seen as entropy change. 

For a magnetocaloric material at thermal equilibrium with its surroundings, the increase in the external magnetic field in an adiabatic process results in an increase in the temperature of the material. Because of being at higher temperature, the magnetocaloric material can exchange heat with its surroundings to approach the surroundings’ temperature. After the heat transfer process, if the external magnetic field is reduced the temperature of the magnetocaloric material will drop below the temperature of the surroundings, and therefore, the cooling effect can be used for refrigeration purposes. There is an analogy between the magnetic refrigeration cycle and conventional cycles, esp. Joule-Brayton cycle. The analogy is shown graphically in the diagram.

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