scholarly journals Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

2019 ◽  
Vol 9 (8) ◽  
pp. 1627 ◽  
Author(s):  
Samer Kahwaji ◽  
Mary Anne White

Edible oils could provide more accessible alternatives to other phase change materials (PCMs) for consumers who wish to build a thermal energy storage (TES) system with sustainable materials. Edible oils have good shelf life, can be acquired easily from local stores and can be less expensive than other PCMs. In this work, we explore whether margarine, vegetable shortening, and coconut oil are feasible PCMs, by investigations of their thermal properties and thermal stability. We found that margarine and vegetable shortening are not useful for TES due to their low latent heat of fusion, ΔfusH, and poor thermal stability. In contrast, coconut oil remained thermally stable after 200 melt-freeze cycles, and has a large ΔfusH of 105 ± 11 J g−1, a low degree of supercooling and a transition temperature, Tmpt = 24.5 ± 1.5 °C, that makes it very useful for TES in buildings. We also determined coconut oil’s heat capacity and thermal conductivity as functions of temperature and used the measured properties to evaluate the feasibility of coconut oil for thermal buffering and passive heating of a residential-scale greenhouse.

2014 ◽  
Vol 7 (3) ◽  
pp. 1185-1192 ◽  
Author(s):  
Hengxing Ji ◽  
Daniel P. Sellan ◽  
Michael T. Pettes ◽  
Xianghua Kong ◽  
Junyi Ji ◽  
...  

Embedding continuous ultrathin-graphite foams (UGFs) with volume fractions as low as 0.8–1.2 vol% in a phase change material (PCM) can increase the effective thermal conductivity by up to 18 times, with negligible change in the melting temperature or mass specific heat of fusion.


Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2043 ◽  
Author(s):  
Hai-Chen Zhang ◽  
Ben-hao Kang ◽  
Xinxin Sheng ◽  
Xiang Lu

A series of novel bio-based form stable composite phase-change materials (fs-CPCMs) for solar thermal energy storage and management applications were prepared, using the pomelo peel flour (PPF) as the supporting matrix and poly (ethylene glycol) (PEG) or isocyanate-terminated PEG to induce a phase change. The microscopic structure, crystalline structures and morphologies, phase change properties, thermal stability, light-to-thermal conversion behavior, and thermal management characteristics of the obtained fs-CPCMs were studied. The results indicate that the obtained fs-CPCM-2 presented remarkable phase-change performance and high thermal stability. The melting latent heat and crystallization heat for fs-CPCM-2 are 143.2 J/g and 141.8 J/g, respectively, and its relative enthalpy efficiency ( λ ) is 87.4%, which are higher than most reported values in the related literature. The obtained novel bio-based fs-CPCM-2 demonstrated good potential for applications in solar thermal energy storage and waste heat recovery.


Author(s):  
Song Mengjie ◽  
Liao Liyuan ◽  
Niu Fuxin ◽  
Mao Ning ◽  
Liu Shengchun ◽  
...  

Phase change materials (PCMs) are widely applied in recent decades due to their good thermal performance in energy systems. Their applications are mainly limited by the phase change temperature and latent heat. Many publications are reported around the characteristic improvement of binary organic PCMs. The thermal stability study on organic binary PCMs used in thermal energy storage applications becomes fundamental and meaningful. In this study, thermal stability of three types of organic binary PCMs was experimentally investigated, which are frequently used in building and industry applications. To qualitatively investigate the stability of composite PCMs, differential scanning calorimetry (DSC), and Fourier-transform infrared spectroscopy (FT-IR) spectra testing of samples were also conducted. Experimental results showed that the selected composite PCMs, capric acid (CA), and myristic acid (MA), had the best thermal performances, with its phase change temperature unchanged and heat of fusion decreased only 8.88 J/g, or 4.55%, after 2000 thermal cycles. Furthermore, quality ratio of required PCMs as the variation of operation duration was analyzed to quantitatively prepare the materials. The PCMs can successfully operate about 3125 times when prepared as 1.20 times of its calculated value by starting fusion heat. Conclusions of this research work can also be used for guiding the selection and preparation of other energy storage materials.


2015 ◽  
Vol 787 ◽  
pp. 77-81
Author(s):  
Pasam Bhagyalakshmi ◽  
K. Rajan ◽  
K. Senthil Kumar

Thermal Energy Storage using phase change materials (PCM) has become an interesting area of energy research because of its high energy storage density, isothermal nature of storage process and small volume changes. In the present work paraffin wax (PW) and Palmitic acids(PA) are chosen as phase change materials and mixed in different proportions(40-60% PW-PA, 50-50% PW-PA and 60-40% PW-PA) to prepare eutectic PCMs. And also paraffin is combined with Copper oxide nano powder to prepare composite PCM. Differential Scanning Calorimetric (DSC) Tests have been conducted to find the latent heat capacity of the above combination of PCMs. The results showed that 40-60%PW-PA eutectic mixture is effective in increasing the latent heat of fusion compared to the other combinations.


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