Influence of additives on thermal conductivity of shape-stabilized phase change material

Abstract Shape-stabilized phase change material (PCM) is a kind of novel thermal energy storage material. Its thermal conductivity is low, which limits its application in many conditions. In this paper, additives with high thermal conductivities were doped in it to improve its thermal conductivity. The thermal conductivity was measured by a thermal probe at room temperature. The experimental results show that the thermal conductivity of the shape-stabilized PCM can be improved greatly by adding exfoliated graphite. An empirical equation was developed for calculating the effective thermal conductivity of the shape-stabilized PCM with different mass fraction of graphite additive. By using the so-called numerical element method, a theoretical equation was obtained for predicting the effective thermal conductivity, which agrees well with the experimental results. The empirical equation and the theoretical prediction are useful for “designing” and controlling the thermal conductivity of the shape-stabilized PCM.

[1]  Xin-Gang Liang,et al.  The boundary induced error on the measurement of thermal conductivity by transient hot wire method , 1995 .

[2]  Xu Xu,et al.  Experimental study of under-floor electric heating system with shape-stabilized PCM plates , 2005 .

[3]  Xu Xu,et al.  Modeling and simulation of under-floor electric heating system with shape-stabilized PCM plates , 2004 .

[4]  Min Xiao,et al.  Preparation and performance of shape stabilized phase change thermal storage materials with high thermal conductivity , 2002 .

[5]  Xu Xu,et al.  Modeling and simulation on the thermal performance of shape-stabilized phase change material floor used in passive solar buildings , 2005 .

[6]  Richard Griffiths,et al.  Analysis of thermal-probe measurements using an iterative method to give sample conductivity and diffusivity data , 2004 .

[7]  Amar M. Khudhair,et al.  A review on phase change energy storage: materials and applications , 2004 .

[8]  A. Nagashima,et al.  ABSOLUTE MEASUREMENT OF THE THERMAL CONDUCTIVITY OF ELECTRICALLY CONDUCTING LIQUIDS BY THE TRANSIENT HOT-WIRE METHOD (THERMAL CONDUCTIVITY OF AN AQUEOUS NaCl SOLUTION AT HIGH PRESSURE). , 1981 .

[9]  X. Py,et al.  Paraffin/porous-graphite-matrix composite as a high and constant power thermal storage material , 2001 .

[10]  Yong Jiang,et al.  Study on transition characteristics of PEG/CDA solid–solid phase change materials , 2002 .

[11]  X G Liang,et al.  A convenient method of measuring the thermal conductivity of biological tissue. , 1991, Physics in medicine and biology.

[12]  J. Blackwell.  A Transient-Flow Method for Determination of Thermal Constants of Insulating Materials in Bulk Part I—Theory , 1954 .

[13]  X. Ge,et al.  The measurement of thermal conductivities of solid fruits and vegetables , 1999 .

[14]  R. Lehtiniemi,et al.  Numerical and experimental investigation of melting and freezing processes in phase change material storage , 2004 .

[15]  Luisa F. Cabeza,et al.  Heat transfer enhancement in water when used as PCM in thermal energy storage , 2002 .

[16]  Ye Hong,et al.  Preparation of polyethylene–paraffin compound as a form-stable solid-liquid phase change material , 2000 .

[17]  J. Fukai,et al.  Improvement of thermal characteristics of latent heat thermal energy storage units using carbon-fiber brushes: experiments and modeling , 2003 .

[18]  Adrian Bejan,et al.  Designed porous media: maximal heat transfer density at decreasing length scales , 2004 .

[19]  Shuxia Cheng,et al.  A fine needle probe for determining the thermal conductivity of penetrable materials , 2001 .