Synthesis and Study of Microcapsules with Beeswax Core and Phenol-Formaldehyde Shell Using the Taguchi Method

2021 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Tejashree Amberkar ◽  
Prakash Mahanwar
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Taguchi Method ◽  
Phase Change ◽  
Phase Change Material ◽  
Surfactant Concentration ◽  
Phenol Formaldehyde ◽  
Processing Parameters ◽  
Agitation Speed ◽  
Change Material

Phenol-formaldehyde shelled phase change material microcapsules (MPCMs) were fabricated and their processing parameters were analyzed with the Taguchi method. Core to shell ratio, surfactant concentration and speed of mixing are the parameters that were optimized in five levels. The optimized values for the surfactant concentration, core to shell ratio and agitation speed were 3%, 1:1 and 800 rpm, respectively. The obtained microcapsules were spherical in shape. The melting enthalpy of the MPCMs synthesized with optimized processing parameters was 148.93 J/g in 35–62 °C. The obtained temperature range of phase transition temperature can be used for storing different food articles such as chocolate and hot served foods.

Preparation of RHA-Paraffin Phase Change Materials

2011 ◽  
Vol 399-401 ◽  
pp. 1156-1159
Author(s):  
Jun Wang ◽  
Bao Guo Ma ◽  
Jian Liang Zhang ◽  
Wen Yang
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Material ◽  
Rice Husk ◽  
Absorption Rate ◽  
Phase Change Materials ◽  
Rice Husk Ash ◽  
Dsc Analysis ◽  
Change Material ◽  
Enthalpy Of Phase Transition

In this paper, a kind of RHA-paraffin phase change material was prepared, and the SEM was used for observing its internal morphologies, DSC analysis was carried out for detecting its temperature and enthalpy of phase transition. The results showed that rice husk ash have a greater absorption rate for paraffin; a large number of pores of the RHA were filled by paraffin in the RHA-paraffin phase change material, and the absorption rate can reach 53.5%.

Analysis on Thermal Characteristics of Phase Change Roof and Insulation Roof

2011 ◽  
Vol 99-100 ◽  
pp. 1128-1136
Author(s):  
Guo Zhong Wu ◽  
Yan Zhao ◽  
Jing Wang ◽  
Dong Li
Keyword(s):  
Phase Transition ◽  
Heat Flux ◽  
Transition Temperature ◽  
Phase Change ◽  
Thermal Characteristics ◽  
Bottom Surface ◽  
Average Heat ◽  
Average Temperature ◽  
Steady Stage ◽  
Change Material

The two-dimensional unsteady heat transfer models of common roof, insulation roof and phase change roof were established, and the thermal characteristics of common roof, insulation roof and phase change roof with different phase transition temperature were analyzed based on CFD software, the hourly average temperature distribution of their top and bottom surface from initial stage to steady stage and 24-hour hourly average temperature distribution of and average heat flux of bottom surface in steady stage were also attained. The results show that, under air conditioning constant temperature mode, addition of insulation material and phase change material observably improve the heat insulation performance of roof structures, the cooling and energy saving effect of roof more obviously, the attenuation multiple and delay time of roof more obviously, and make the hourly distribution of average temperature and average heat flux of roof bottom surface much gentler. In addition, choosing a phase change material with suitable phase transition temperature according to outside air comprehensive temperature is the key to utilize its latent heat more effectively.

Thermally switchable terahertz metasurface absorber composed of H-fractal and enabled by phase-change material of vanadium dioxide

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hassan Divdel ◽  
Hamed Taghipour-Farshi ◽  
Hassan Rasooli Saghai ◽  
Mohammad-Ali Tavakoli Ghazi Jahani
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Material ◽  
Vanadium Dioxide ◽  
Ground Plane ◽  
Terahertz Range ◽  
Metallic State ◽  
Level 1 ◽  
Change Material ◽  
Level 2

Abstract A terahertz metasurface absorber with actively switchable bandwidth enabled by vanadium dioxide (VO2) is presented and investigated numerically. The VO2 is a phase-change material and its conductivity in the terahertz range changes by several orders of magnitude upon phase-transition. The metasurface consists of an H-shaped fractal resonator placed on top of a polyimide spacer and a ground-plane of gold. The resonator is composed of an H-shaped level-1 fractal of gold and VO2 strips that converts it to a level-2 fractal. At room temperatures, the VO2 is in the insulator state and the resonator reduces to a level-1 fractal offering narrowband absorption at 8.08 THz reaching 0.98 absorption. At higher temperatures, the VO2 is in the metallic state and the resonator is effectively a level-2 fractal with an absorption higher than 0.9 in a bandwidth of 6.63–9.89 THz.

scholarly journals A Parametric Investigation on Energy-Saving Effect of Solar Building Based on Double Phase Change Material Layer Wallboard

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaoxiao Tong ◽  
Xingyao Xiong
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Material ◽  
Wall Temperature ◽  
Parametric Investigation ◽  
Double Phase ◽  
Phase Transition Temperatures ◽  
Saving Effect ◽  
Change Material ◽  
Inside Wall

In order to further understand the thermal performance of the double phase change material (PCM) layer wallboard, the wallboard model was established and a comprehensively numerical parametric investigation was carried out. The variation laws of inner wall temperature rise and the heat flux transferred under different phase transition temperatures and thermal conductivities are presented in detail. The main results show that the temperature of the inside wall for case 2 can be reduced by about 1.5 K further compared to that for case 1. About 83% of the heat transferred from the outside is absorbed by the PCM layer in case 2. Reducing the phase transition temperature of the PCM layer can decrease the inside wall temperature to a certain extent in the period of high temperature. The utilization of double PCM layers shows much more performance compared to that of the single PCM layer case, and the temperature of the inside wall can be reduced by 2 K further.

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