Back to Search Start Over

A magnetically-activated thermal switch without moving parts

Authors :
Cátia Rodrigues
La Salete Martins
Alberto M. Pereira
Daniel Silva
J. C. R. E. Oliveira
João P. Araújo
João Ventura
Madalena M. Dias
Source :
Energy Conversion and Management. 197:111881
Publication Year :
2019
Publisher :
Elsevier BV, 2019.

Abstract

With the ever increasing power dissipation in electrical devices, new thermal management solutions are in high demand to maintain an optimal operating temperature and efficient performance. In particular, recently developed magnetically-activated thermal switches (MATSs) provide an alternative to existing devices, using the magnetic and thermal properties of superparamagnetic nanofluids to dissipate heat in a controlled manner. However, the presence of moving parts is a major drawback in these systems that must still be addressed. Herein, we present a compact and automatized MATS composed by an encapsulated superparamagnetic nanofluid and an electromagnet allowing to activate the MATS without any moving part. We investigate the effect of different temperature gradients ( 10 , 26 and 40 °C) and powers applied to the coil (6.5, 15, 25 and 39 W) on the performance of this novel MATS. The results show that the highest ( 44.4 % ) and fastest ( 0.6 °C/s) temperature variation occur for the highest studied temperature gradient. On the other hand, with increasing power, there is also an increase in the efficiency of the heat exchange process between the two surfaces. These results remove one of the main barriers preventing the actual application of magnetic thermal switches and opens new venues for the design of efficient thermal management devices.

Details

ISSN :
01968904
Volume :
197
Database :
OpenAIRE
Journal :
Energy Conversion and Management
Accession number :
edsair.doi...........a4fa397d78d9f4a3f0a5f21740dd9a8c
Full Text :
https://doi.org/10.1016/j.enconman.2019.111881