Waste materials as the potential phase change material substitute in thermal energy storage system: A review

Phase change material (PCM) has been recognized as one of the important element in the energy storage and conservation management. PCM and its combination has been widely used in many applications and significant number of literatures has been published to highlight the potential use of PCM as thermal energy storage (TES) material. However, although the information is quantitatively enormous and the application of waste has becoming a trending subject nowadays, documented researches on PCM material derived from waste material are still very scarce. Therefore, in this paper, in-depth reviews on the implementation of potential waste materials in PCM considering its purposes in improving the TES performance, economic values and environment were reviewed and elaborated. Overall, this review shows potential utilization of waste materials as a new material substitute to produce an efficient, cost-effective and environmentally friendly PCM in the future TES system

Synthesis and characterization of stearic acid/waste filler materials as composite phase change material in thermal energy storage application

This paper investigates the potential of waste materials, i.e. recycled aluminum cans and carbon biochar (carbon BC) wastes as fillers in stearic acid as PCM supporting matrix material. Using recycled aluminum powder (recycled Al powder) and carbon BC, a new invention of composites phase change material (C-PCM) was established. These C-PCM, which has been was incorporated with different waste fillers, were prepared at different waste mass loading and further characterized using scanning electron microscope (SEM), Fourier infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), pycnometer density analysis, and thermal thermogravimetric analysis (TGA). The result showed that both C-PCM were uniformly dispersed into stearic acid (SA) and portrayed a good contact surface area. The C-PCM with recycled Al powder filler results in higher melting and freezing latent heat than C-PCM with carbon BC filler. Thermal cycle test analysis of selected C-PCM exhibited good thermal stability, reliability, and effective latent heat storage. From the thermal evaluation test, the storage performance of C-PCM was found to perform better compared to lone SA as PCM (SA-PCM). Despite having low latent heat compared to lone PCM, the addition of waste materials into SA has increased C-PCM's thermal stability. Al/SA C-PCM is identified as the most effective TES medium since it gives the best thermal stability and latent heat values

Night Flying Insect Density and Activity Pattern in Bau, Lundu & Serian, Sarawak.

Many researches have been conducted to address the impacts of urbanisation on diversity and density of insects in temperate regions but not in tropical regions. This study was conducted from October 2014 until April 2015 in order to determine the insect density and activity pattern of night flying insects in Bau, Lundu and Serian. Insect sampling was conducted by towing a trap with 1 m2 opening using a vehicle over a distance of 1000 m. A total of 1372 individuals were captured during the sampling period. The density of night flying insects in Bau, Lundu and Serian was 0.423 individuals/m3, 0.600 individuals/m3 and 0.349 individuals/m3 respectively. The main orders of insects sampled are Diptera followed by Coleoptera, Hymenoptera, Herniptera, Lepidoptera and Orthoptera. Peak time of those insects' activities is between 1830-1930 hours. This study also showed that there is a significant difference between Bau, Lundu and Serian in term of density but no difference in the activity pattern

Development of paraffin wax incorporated with aluminium waste as phase change material for thermal energy storage

In this paper, an investigation of a new innovation of heat storage properties of thermal conductivity enhancement via a newly formulated composite consists of paraffin wax incorporated with waste aluminum can from solid municipal waste as the potential PCM composite was studied. The samples composite were synthesized at different percentage of waste aluminum powder mass loading ranging from 0wt% until 100wt% into the paraffin wax and characterized. From differential scanning calorimetry (DSC) analysis, the rate of heat flow has been has found to be increased as more mass loading of waste aluminum was added. However, the latent heat during melting and freezing of DSC data has reduced. This is due to the high amount filler which has reduced the amount of PCM, whereby latent heat is only absorbed/released by the PCM; not the filler/additive. Besides that, the thermal stability has improved strongly when waste filler is added rather than lone paraffin PCM. The density of waste composite PCM materials has also be found to be higher and thus, has increased the heat flow between the materials and improves the energy storage process. From the addition of filler, the smooth surface of lone paraffin has improved as the surface area has becoming to be rougher and shinier, thus resulted with higher contact surface area. Therefore, the new formulated waste PCM composite of paraffin wax incorporated with aluminum waste ranging from 60wt% and above could become a promising material for TES medium

Review on the utilization of waste material as a potential substitute for the phase change material used in thermal energy storage system

Recently, great attention has been focused on the application of thermal energy storage (TES) as one of the key solution towards the most effective heat and energy storage system. TES in a form of phase change material (PCM) has been recognized as one of the efficient method for energy management and conservation system. PCM has been widely used in many applications and significant number of literatures has been published to highlight the potential use of PCM as TES material. In the last few decades, various combination of materials has been used to improve the quality and performance of PCM. However, although the information is quantitatively enormous and the application of waste has becoming a trending subject nowadays, documented researches on PCM material derived from waste material are still very scarce. Therefore, in this paper, in-depth reviews on the implementation of potential waste materials in PCM considering its purposes in improving the TES performance, economic values and environment were explored, investigated and reviewed. Overall, this review shows a potential utilization of waste materials as a new substitute to produce an efficient, cost-effective and environmentally friendly PCM in the future TES system

Studies on free fatty acid esterification of used cooking oil: investigation on the performance of sulphonated cation exchange resins

Used cooking oil (UCO) is one of the potential substitutes for conventional biodiesel feedstock. In this study, different types of macroporous cation exchange resins, namely RCP160M, RCP145H, PK228LH, PK216LH, PK208LH, SK104H and SK1BH, were used as catalysts in the UCO esterification process. These resins were characterised using Fourier transform infrared spectroscopy (FT-IR), nitrogen physisorption, scanning electron microscopy (SEM), an elemental analyser (CHNS), titration and a particle size distribution (PSD) analyser to determine their physicochemical properties. These catalysts were screened and RCP160M resin was found to give the best catalytic performance. RCP160M was used in subsequent studies focusing on the effect of different esterification variables. A conversion rate of 95% of free fatty acid (FFA) was achieved at the optimum condition with catalyst loading of 4 wt. %, reaction temperature of 60°C, and methanol-to-oil mass ratio of 18:1. RCP160M shows great potential as a catalyst in the biodiesel pre-treatment process as it outperformed the other catalysts and yielded maximum FFA conversion. This may be attributed to its higher specific surface area and total pore volume. The kinetic results revealed that the experimental data was best fitted to the Eley-Rideal model (Case II) with the activation energy of 37.2 kJ mol−1