초임계 이산화탄소를 이용한 Polyester 섬유에의 상전이 물질 함침

Abstract

Latent heat storage is one of the most efficient ways storing thermal energy. Unlike the sensible heat storage method, the latent provides much higher storage density, with a smaller temperature different between storing and releasing heat. There are large numbers of phase change materials(PCMs) that melt and solidify at a wide range of temperature, making them attractive in a number of applications. Paraffin waxes are cheap and have moderate thermal energy storage density but low thermal conductive and, hence, require large surface area. Hydrated salts have larger energy storage density and higher thermal conductivity but supercooling and phase segregation, and hence, their application requires the use of some nucleating and thickening agents. Supercritical fluid(SCF), a fluid above its critical temperature and pressure, is a highly nonideal fluid which has unique features in physical properties like a blending of gas and liquid. SCFs have been established as good solevnts for many nonvolatile and thermally labile compounds and are useful in many chemical processes because the solvent power can be manipulated over a wide range by adjusting temperature and pressure. A new technique preparing polyester fiber impregnated with organic PCMs was proposed and experimentally examined. The impregnation apparatus consisted of a high pressure pump, two consecutive high pressure cylinders and auxiliary facilities. Polyester fiber was bound on cylindrical stainless steel net inside equilibrium cylinder and was impregnated with supercritical solution of PCM. PCMs, paraffin waxes and organic acids, were successfully impregnated into the polyester fiber even at temperature below it’s glass transition temperature(Tg), and the impregnated fibers showed high energy storage and release capacity around the melting point of respective PCMs.