Epoxy–PCM Composites with Nanocarbons or Multidimensional Boron Nitride as Heat Flow Enhancers

Abstract

The need for affordable systems that are capable of regulating the temperature of living or storage spaces has increased the interest in exploring phase change materials (PCMs) for latent heat thermal energy storage (LHTES). This study investigates n-nonadecane (C19H40) and n-eicosane (C20H42) as alkane hydrocarbons/paraffins for LHTES applications. An epoxy resin is used as the support matrix medium to mitigate paraffin leakage, and a thickening agent is utilized to suppress phase separation during the curing process. In order to enhance the thermal conductivity of the epoxy–paraffin composite, conductive agents including carbon nanofibers (CNFs), carbon nanotubes (CNTs), boron nitride (BN) microparticles, or boron nitride nanotubes (BNNTs) are incorporated in different gravimetric ratios. Enhancements in latent heat, thermal conductivity, and heat transfer are realized with the addition of the thermal fillers. The sample composition with 10 wt.% BN shows excellent reversibility upon extended heating–cooling cycles and adequate viscosity for template casting as well as direct three-dimensional (3D) printing on fabrics, demonstrating the feasibility for facile integration onto liners/containers for thermal regulation purposes.

Modeling of Energy Demand and Savings Associated with the Use of Epoxy-Phase Change Material Formulations

“…The fabrication steps for the formulations employed and the rationale for their use can be found elsewhere [8]. The PCM (n-Nonadecane, Sigma-Aldrich, St. Louis, MO, United States) was melted using a water bath and then mixed with Part A (resin) of EpoFix (Struers Inc., Cleveland, OH, United States) using a dual asymmetric speed mixer (Flacktek, Landrum, SC, United States).…”

“…However, one of the shortcomings of paraffins is their low thermal conductivity, which can adversely affect their energy absorption/release rates. In order to improve the thermal conductivity, conductive fillers inducing metals [6], metallic foams [7], nanostructured carbon including carbon nanofibers (CNFs) [8], carbon nanotubes (CNTs) [8], boron nitride (BN) [8], as well as boron nitride nanotubes (BNNTs) [8] have been investigated. CNFs are especially attractive owing to their high aspect ratios, which can offer significant improvement in conductivity [9], whereas BN is electrically insulating and thermally conducting [10].…”

“…For the present work, n-nonadecane (C 19 H 40 ) was utilized as the organic PCM material given its melting and solidification temperatures being close to environmental conditions [8]. CNFs and BN were incorporated as the thermal conductivity enhancers as established in our previous work [8].…”

“…For the present work, n-nonadecane (C 19 H 40 ) was utilized as the organic PCM material given its melting and solidification temperatures being close to environmental conditions [8]. CNFs and BN were incorporated as the thermal conductivity enhancers as established in our previous work [8]. To prevent paraffin leakage, an epoxy resin was utilized as the support matrix material [6,8], and a thickening agent, Carbopol, was used to mitigate phase separation during sample formulation [8].…”

“…CNFs and BN were incorporated as the thermal conductivity enhancers as established in our previous work [8]. To prevent paraffin leakage, an epoxy resin was utilized as the support matrix material [6,8], and a thickening agent, Carbopol, was used to mitigate phase separation during sample formulation [8]. A study of energy savings in EnergyPlus [26] was carried out, in which different insulation alternatives were evaluated.…”