A New Approach to Energy and Exergy Analyses of Latent Heat Storage Unit

Abstract

In this article, a new approach for energy and exergy efficiencies and effectiveness of latent heat storage systems is developed and applied to a shell-and-tube type latent heat storage system for its charging process. First, a numerical model is introduced to study the heat transfer and thermodynamic parameters and aspects (shell radius and pipe length, Reynolds number, inlet temperature of heat transfer fluid [HTF], etc.), and solved through the governing equations for HTF, pipe wall, and phase change material. Second, some extensive parametric studies are conducted to investigate how the solidification fronts, stored heat, heat transfer rates, entropy generation number, and both energy and exergy efficiencies change with time, particularly in the dimensionless form as the Fourier number. Third, both energetic and exergetic effectiveness concepts are newly developed and applied to a latent heat storage system. The results show that energy and exergy efficiency and effectiveness concepts appear to be significant tools for assessment and optimization of the thermal energy storage systems.

Acknowledgments

The authors acknowledge the support provided by Dokuz Eylul University in Turkey, as well as by the University of Ontario Institute of Technology and the Natural Sciences and Engineering Research Council in Canada.

Aytunc Erek is an assistant professor in the Department of Mechanical Engineering at Dokuz Eylul University in Izmir, Turkey. He received his Ph.D. in the area of thermodynamics from Dokuz Eylul University in 1999. His main research interests include CFD analysis of heat exchangers and thermal energy storage systems. He is a member of the Turkish Association of HVAC Engineers and the Chamber of Mechanical Engineers. He has published several refereed journal and conference papers in the area of thermal energy storage systems.

Ibrahim Dincer is a full professor in the Faculty of Engineering and Applied Science at University of Ontario Institute of Technology in Canada. He has authored and co-authored several books and book chapters, nearly 400 refereed journal and conference papers, and numerous technical reports. He has chaired many national and international conferences, symposia, workshops, and technical meetings. He has delivered more than 80 keynote and invited lectures. He is an active member of various international scientific organizations and societies, and serves as editor-in-chief, associate editor, regional editor, and editorial board member on various prestigious international journals. He is a recipient of several research, teaching and service awards, including the Premier's research excellence award in 2004. He has made innovative contributions to the understanding and development of sustainable energy technologies and their implementation.