The Dielectric Study of Ethylene Glycol as a Coolant Using Davidson-Cole Relaxation Model

Abstract

In this work, the dielectric properties of ethylene glycol as an additive to heat transfer fluid isstudied. To do this, the Davidson-Cole relaxation equations were derived from Debye equation. The static permittivity(), complex permittivity (∞)and the relaxation time ()of ethylene glycol were substituted in the derived equations. The dielectric constant ′and loss factor ′′of ethylene glycol were computed using Microsoft Excel. The result showed that the dielectric constant is higher at lower frequencies (i.e. 44.30 at 0.01GHz and 10°C) but decreases as the temperature increases. However, at high frequency, the dielectric constant increases as the temperature increases. The loss factor also decreases as temperature increases but increases to its maximum value as the frequency increases. It then decreases steadily after attaining its maximum value at further increase in the frequency. The decrease in the loss factor as the temperature increases showed that ethylene glycol does not generate so much heat when subjected to an applied field.The higher dielectric constant at lower frequencies, on the other hand, suggest that ethylene glycol as a coolant can perform optimally at those frequencies.