Quantitative Assessment of Phase Change Material Utilization for Building Cooling Load Abatement in Composite Climatic Condition

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Rajat Saxena ◽  
Kumar Biplab ◽  
Dibakar Rakshit
Keyword(s):  
Mathematical Modeling ◽  
Phase Change ◽  
Data Sheet ◽  
New Delhi ◽  
Load Reduction ◽  
Cooling Load ◽  
Solidification Temperature ◽  
Technical Data ◽  
Advanced Technologies ◽  
Change Material

The global trend of energy consumption shows that buildings consume around 48% of the total energy, of which, over 50% is for heating and cooling applications. This study elucidates on cooling load reduction with phase change material (PCM) incorporation in a building envelope. PCM provides thermal shielding due to isothermal heat storage during phase change. PCM selection depends upon its phase change temperature, thermal capacity, and thermal conductivity, as they play a vital role in assessing their impact on energy conservation in buildings. The uniqueness of this study underlies in the fact that it focuses on the utilization of PCM for New Delhi (28.54°N, 77.19°E) climatic conditions and adjudges the suitability of three commercially available PCMs, based on the overall heat load reduction and their characteristic charging/discharging. The study aims at finding an optimum melting and solidification temperature of the PCM such that it may be discharged during the night by releasing the heat gained during the day and mark its suitability. The results of mathematical modeling indicate that as per the design conditions, the melting/solidification temperature of 34 °C is suitable for New Delhi to absorb the peak intensity of solar irradiation during summer. Based on the thermophysical properties in literature (Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® HS29, PLUSS-TDS-DOC-304 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® OM32, PLUSS-TDS-DOC-394 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2012, “Technical Data Sheet - savEVR HS34, Doc:305,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India), mathematical modeling showed HS34 to be suitable for New Delhi among the three PCMs. To ratify this, characteristic charging and discharging of HS34 is tested experimentally, using differential scanning calorimeter (DSC). The results showed that HS34 is a heterogeneous mixture of hydrated salts having super-cooling of 6 °C, reducing its peak solidification temperature to 30.52 °C during the cooling cycle also making it unsuitable for peak summers in New Delhi.

Heat Transfer Enhancements Using Vibration During Solidification of Paraffin

2010 ◽  
Author(s):  
Johnathan Vadasz ◽  
Josua Meyer ◽  
Saneshan Govender
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Wall Temperature ◽  
Vibration Frequency ◽  
Initial Temperature ◽  
Solidification Process ◽  
Solid Material ◽  
Solidification Temperature ◽  
Change Material

In the current study the effects of vibration on the solidification process of phase change material (PCM) paraffin in a sphere shell are investigated. The amount of PCM used was kept constant during each experiment by using a digital scale to check the weight and a thermocouple to check the consistency of the temperature. A small amount of air was present in the sphere so that the sphere was not filled completely. Commercially available paraffin wax, RT35, was used in the experiments. Experimentations were done on a sphere of 40 mm diameter, wall temperature of 20°C below mean solidification temperature, and consistent initial temperature. A constant vibration frequency of 100 Hz was applied to the setup and results compared with that of no vibration. Samples were taken at different times during the solidification process and compared with respect to solid material present. It was found that the solidification time had been reduced significantly under the vibration. This led to the conclusion that there had been an improvement in heat transfer due to the vibration.

Numerical and Experimental Study of Solidification in a Spherical Shell

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
E. Assis ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Spherical Shell ◽  
Phase Change ◽  
Numerical Simulations ◽  
Phase Change Material ◽  
Void Formation ◽  
Initial State ◽  
Solidification Temperature ◽  
Irregular Boundary ◽  
The Mean ◽  
Change Material

The present study explores numerically and experimentally the process of a phase-change material (PCM) solidification in a spherical shell. At the initial state, the PCM liquid occupies 98.5% of the shell. The upper segment of 1.5% contains air, which flows in as the solidification progresses. In the experiments, a commercially available paraffin wax is used. Its properties are engaged in the numerical simulations. The investigation is performed for solidification in spherical shells of 20 mm, 40 mm, 60 mm, and 80 mm in diameter at the wall uniform temperature, which varied from 10°C to 40°C below the mean solidification temperature of the phase-change material. Transient numerical simulations are performed using the FLUENT 6.2 software and incorporate such phenomena as flow in the liquid phase, volumetric shrinkage due to solidification, and irregular boundary between the PCM and air. The numerical model is validated versus the experimental results. Shrinkage patterns and void formation are demonstrated. Dimensional analysis of the results is performed and presented as the PCM melt fractions versus the product of the Fourier and Stefan numbers. This analysis leads to a generalization that encompasses the cases considered herein.

Sign in / Sign up

Export Citation Format

Share Document