GeoThermag: A geothermal magnetic refrigerator

• The new concept of GeoThermag has been introduced.
• A test apparatus has been described.
• Gadolinium spheres have been used as refrigerant.
• Experimental results under various conditions have been performed.
• The maximum cooling capacity, the temperature span and the COP have been measured.

Magnetic refrigeration has played an important role in the scientific landscape in recent years and could potentially be an alternative to vapour compression technology. Although new prototypes have recently been developed and new material refrigerants have been tested, there is still no equipment that can be used in the refrigeration industry. In the present work, we demonstrate how magnetic refrigeration can be applied to climate system environments by combining the technology of magnetic refrigeration with that of low temperature geothermal energy. Thus, we introduce the concept of GeoThermag. After describing the GeoThermag system in detail, we report experimental results that demonstrate the validity of this application. These experimental tests were obtained by using a magnetic refrigerator that was connected to a geothermal probe. Using 1.20 kg of gadolinium, we found that the GeoThermag system configured in this manner is capable of providing cold water to feed a radiating panel and to develop a cooling capacity of 190 W with a COP of 2.20.

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