Development of sunlight-driven eutectic phase change material nanocomposite for applications in solar water heating

Organic phase change materials (PCMs) have been utilized as latent heat energy storage medium for effective thermal management. In this work, a PCM nanocomposite, consisting of a mixture of two organic PCMs (referred to as eutectic gel PCM) and minimal amount (0.5 wt%) of nanographite (NG) as a supporting material, was prepared. Differential scanning calorimeter was used to determine the melting temperature and latent heat of pristine PCM, paraffin (61.5 °C and 161.5 J/g), eutectic gel PCM (54 °C and 158 J/g) and eutectic gel PCM nanocomposite (53.5 °C and 155 J/g). The prepared PCM nanocomposites exhibited enhanced thermal conductivity and ultrafast thermal charging characteristics. The nanocomposites were employed for two different applications: (i) providing hot water using an indigenously fabricated solar water heating (SWH) system and (ii) solar rechargeable glove that can be rapidly warmed and used. Experimental results on SWH system show that the use of PCM nanocomposites helps to increase the charging rate of PCM while reducing the discharging rate of heat by PCM to water, thus enhancing the maximum utilization of solar energy and hence improving the efficiency of the SWH system. The experimental results on solar rechargeable glove revealed that the glove has the ability to retain the temperature up to 3 hours

Improvement in the luminous efficiency of MEH-PPV based light emitting diodes using zinc oxide nanorods grown by the electrochemical deposition technique on ITO substrates

Zinc oxide (ZnO) nanorods grown by the electrochemical technique have been used to enhance the luminance of poly[2-methoxy-5-(2'-ethylhexoxy)-1,4-phenylenevinylene] (MEH-PPV)-based polymer light-emitting diodes. The luminance of the device with ZnO nanorods is found to increase by more than two times as compared with the device without ZnO nanorods. The diameter of the nanorods used in device fabrication was ~145 nm. The size of the nanorods was estimated from field emission scanning electron microscope images. Optical and structural characterizations of the nanorods were also performed by using absorption, photoluminescence and x-ray diffraction, confirming the formation of ZnO nanorods