Liquid crystal based active electrocaloric regenerator

Abstract

The active electrocaloric (EC) regenerator exploiting electric conversion into thermal energy has recently become important for developing a new generation of heat-management devices. We analyze an active EC regenerator numerically. We establish a temperature span across the regenerator ΔT by commuting a liquid crystalline (LC) unit between regions with and without an external electric field E. In modelling, we use Landau-de Gennes mesoscopic approach, focusing on the temperature regime where isotropic (paranematic) and nematic phase order compete. We determined conditions enabling a large enough value of ΔT suitable for potential applications. In particular, (i) the vicinity of the paranematic-nematic (P–N) phase transition, (ii) large enough latent heat of the transition, (iii) strong enough applied external field (exceeding the critical field Ec at which the P–N transition becomes gradual), and (iv) relatively short contact times between LC unit and heat sink and heat source reservoirs are advantageous. Our analysis reveals that ΔT≫1K could be achieved using appropriate LC material.

Keywords

• Liquid crystals
• Phase behavior
• Electro-caloric effect