Master's Theses

Date of Award

2012

Document Type

Thesis

Department

Mechanical Engineering

Keywords

PCM, Latent, Bees wax

Abstract

Experimentation and implementation of Phase Change Materials (PCM) as suitable Thermal Energy Storage (TES) mediums has garnered greater attention in recent decades. PCMs have the ability to not only store Sensible Heat (SH) within a given temperature range, but also store large amounts of Latent Heat (LH) as they undergo a phase change, whether it is from solid to liquid or liquid to gas. This investigation examines the preparation of a beeswax microemulsion, the analysis of its thermophysical properties, and the experimental method to calculate its heat transfer coefficient under laminar flow conditions. First, the beeswax microemulsion was formulated to possess both a low viscosity to enhance pumpability, as well as a high beeswax percentage by mass for greater Latent Heat Storage (LHS) capacity. A Beeswax/Water-Emulsion was developed wherein beeswax droplets were dispersed in water with the aid of surfactants; another term for this is a Phase Change Slurry (PCS). A sufficient quantity was created and implemented in the experimental setup which simulated uniform heat flux across the test section using an Ohmic Heating System (OHS) to determine the heat transfer coefficient. These results were then compared to water in order to verify the setup accuracy as well as the degree of success of the PCM in heat storage ability. In the case of the PCM, the temperature of the beeswax microemulsion increased as heat was applied around the test section which is expected during the Sensible Heat stage of the process. The temperature then remained constant as the beeswax particles began to melt, storing greater amounts of Latent Heat in the process. This investigation shows that a beeswax microemulsion PCM has greater heat storing abilities than water and can prove to be a much more efficient method for charging and discharging thermal energy during varying environmental conditions.

 
 

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