Design of a fuzzy logic controlled thermoelectric brain hypothermia system

Authors: ABDULLAH HAKAN YAVUZ

Abstract: Brain cooling in medicine is the most effective method in protecting brain cells during strokes, heart attacks, and brain traumas. This method, called brain hypothermia, is based on the principle that the brain is superficially cooled under controlled conditions in order to minimize cell death. In this study a helmet was designed to locally cool the brain and an effective controller was designed and tested using fuzzy logic in order to test the effectiveness of the helmet for brain hypothermia. For testing the cooling and heating performances of the helmet, currents between 0 and 60 A were applied to the helmet and its characteristic shape. In considering that the helmet could be exposed to external thermal loads, its maximum cooling capacity at different currents was calculated and found to be 153 W. Two applications were made for the performance test of the controller. Data were recorded for 24 h by setting the inner surface temperature of the helmet to -2 $^{\circ}$C and 30 $^{\circ}$C. The temperature of the helmet went to -1 $^{\circ}$C from 20 $^{\circ}$C in 4 min, to 30 $^{\circ}$C in 1 min and the temperature remained the same for 24 h. While the system was under balance, a balloon at 20 $^{\circ}$C was placed inside and the time the system took to re-balance itself was measured. It was observed that this controller design for a thermoelectric brain cooler can be an alternative method for brain hypothermia thanks to its performance. It was determined that it has advantages over other similar systems thanks to features like it is electrically controllable, has a direct connection to the surface to be cooled and thereby provides faster cooling and heating, its balancing of the thermal loads rapidly applied to the system, and that it is easy to set the cooling and heating speeds via software.

Keywords: Brain cooler, hypothermia, thermoelectric

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