A number of seawater desalination technologies have been developed and widely used during the last several decades. In the current investigation, a new approach of seawater desalination process is presented, which utilizes phase change microcapsules (PCμCs) and thin film evaporation. In this process, the PCμCs are placed into hot seawater. Then the hot seawater and the PCμCs containing the liquid phase change material (PCM) are ejected into a vacuum flash chamber. A thin liquid film of seawater is formed on the surface of the PCμCs, which subsequently vaporizes. This evaporation significantly increases the evaporation heat transfer coefficient and enhances desalination efficiency. Film evaporation on the PCμCs’ surfaces decreases their temperature by releasing sensible heat. If their temperature is lower than the PCM phase change temperature, then the PCμCs change phase from liquid to solid releasing their latent heat, resulting in further evaporation. The PCμCs with solid PCM are pumped back into the hot seawater, and the salt residue left on the PCμCs can be readily dissolved. In this way, the efficiency can be increased and the corrosion reduced. A mathematical model was developed to determine the effects of PCμCs and thin film evaporation on the desalination efficiency. An analytical solution using Lighthill’s approach was obtained. Results show that when PCμCs with a radius of 100 μm and a water film of 50 μm are used, the evaporation rate and evaporative capacity can be significantly increased.
- Heat Transfer Division
Heat Transfer Analysis of Phase Change Microcapsules With Thin Film Evaporation
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Guo, Y, Fu, B, Ji, Y, Su, F, Wilson, C, & Ma, H. "Heat Transfer Analysis of Phase Change Microcapsules With Thin Film Evaporation." Proceedings of the ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 2: Heat Transfer in Multiphase Systems; Gas Turbine Heat Transfer; Manufacturing and Materials Processing; Heat Transfer in Electronic Equipment; Heat and Mass Transfer in Biotechnology; Heat Transfer Under Extreme Conditions; Computational Heat Transfer; Heat Transfer Visualization Gallery; General Papers on Heat Transfer; Multiphase Flow and Heat Transfer; Transport Phenomena in Manufacturing and Materials Processing. Washington, DC, USA. July 10–14, 2016. V002T08A006. ASME. https://doi.org/10.1115/HT2016-7038
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