Hakeem Niyas Avatar

Hakeem Niyas

Research Scholar

I am working in the area of Solar Thermal Energy Storage


Assistant System Engineer  
Tata Consultancy Services, February 2008 to April 2011, Chennai India
(Product Lifecycle Management)


Indian Institute of Technology Guwahati  
Doctor of Philosophy, Mechanical Engineering, Jul, 2012 to Present

PSG College of Technology  
Bachelor of Engineering, Mechanical Engineering, Jun, 2003 to May, 2007


Performance investigation of a lab–scale latent heat storage prototype – Numerical results     
Published by (Elsevier - Energy Conversion and Management)
Authors: Hakeem Niyas, Sunku Prasad, P. Muthukumar.  Published March 01, 2017

In the current study, numerical analysis of the charging and discharging characteristics of a lab-scale latent heat storage (LHS) prototype is presented. A mathematical model is developed to analyze the performance characteristics of the LHS prototype of shell and tube heat exchanger configuration. Effective heat capacity (EHC) method is implemented to consider the latent heat of the phase change material (PCM) and Boussinesq approximation is used to incorporate the buoyancy effect of the molten layer of the PCM in the model. For proper modeling of velocities in the PCM, Darcy law’s source term is added. The governing equations involved in the model are solved using a finite element based software product, COMSOL Multiphysics 4.3a. The number of embedded tubes and fins on the embedded tubes are optimized based on the discharging time of the model. Various performance parameters such as charging/discharging time, energy storage/discharge rate and melt fraction are evaluated. Numerically predicted temperature variations of the model during charging and discharging processes were compared with the experimental data extracted from the lab-scale LHS prototype and a good agreement was found between them.

Performance investigation of high-temperature sensible heat thermal energy storage during charging & discharging cycles     
Published by (Springer - Clean Technologies and Environmental Policy)
Authors: Hakeem Niyas, Likhendra Prasad, P. Muthukumar.  Published February 01, 2015

This paper presents the thermal modelling and performance predictions of high-temperature sensible heat storage (SHS) models of 50 MJ capacity designed for solar thermal power plant applications in the temperature range of 523–648 K. The SHS unit is a regenerator-type heat exchanger which stores/releases the heat on passing hot/cold heat transfer fluid (HTF) through the tubes embedded into it. A mathematical model of cylindrical configuration with embedded multi-tube is developed employing concrete and cast steel as the storage media. The number of embedded charging/discharging tubes in the storage model is optimized based on the charging time using the finite element method-based simulation tool, COMSOL Multiphysics. Numerically predicted results match well with the data reported in the literature. Thermal performance parameters of SHS bed such as charging/discharging time, energy stored/recovered, charging/discharging energy efficiency and overall efficiency have been evaluated. Axial variations of HTF temperature during charging/discharging cycle are analysed, and the parametric studies are carried out by varying the flow rate of HTF. For cast steel bed, the increase in HTF velocity resulted in the proportional reduction in charging/discharging time, while these effects in concrete were less because of its low thermal conductivity.