Mehmet Akif Ezan

Effect of siloxane treatment of jute fabric on the mechanical and thermal properties of jute/HDPE

The mechanical and thermal properties of jute fiber/HDPE composites as a function of alkali and oligomeric siloxane treatment of jute fabric were investigated. The effect of surface treatments on the composites was assessed by means of tensile test, short-beam shear test, three-point bending test, SEM, TGA, and DSC. When jute fabric are first treated with alkali solution and then oligomeric siloxane solution, 34% and 49% increases in tensile and flexural strength were observed, respectively. Moreover, it is interesting to note that after alkali and siloxane treatment of jute fabric, 169% increase in ILSS of jute/HDPE composite was obtained. This demonstrates that the adhesion between jute fiber and HDPE matrix is greatly increased by alkali and oligomeric siloxane treatment of jute fabric. This observation was also confirmed by SEM analysis of fracture surface of composites. Alkali and oligomeric siloxane treatment of jute fabric did not considerably change thermal stability and melting and crystallization temperatures of jute/HDPE.

Solidification and Melting Periods of an Ice-on-Coil Latent Heat Thermal Energy Storage System

This paper presents experimental investigations of charging (solidification) and discharging (internal/external melting) periods of an ice-on-coil type latent heat thermal energy storage system. Experimental investigations are performed for various constant heat loads and inlet temperatures with several flow rates of the heat transfer fluid. In experiments, variations of the solid/liquid interfaces around the tubes are monitored with the aid of 15 interface measurement cards for both solidification and melting periods. Energy variations obtained from the measurement cards are validated by conservation of energy, and the mean difference is obtained as 5%. The parametric results indicated that the inlet temperature and the flow rate of the secondary coolant are significant both on the charging and discharging capability of the system. It is also introduced that, for the current experimental conditions, external melting mode can supply relatively lower outlet temperatures for a longer period in comparison with the internal melting mode.

Numerical study on solidification process inside annulus in presence of natural convection

In this study, solidification process of water around a circular tube is analysed with presence of natural convection and heat gain from surroundings. The present model is validated by comparing the numerical predictions with experimental data. Some considerably high agreements are achieved in terms of time–wise variations of interface positions and temperature values. After validating the numerical method, further analyses are conducted to examine the influence of initial temperature value of water on solidification process. Time–wise temperature, local Nusselt number and local entropy generation variations are presented together with the isotherms, streamlines, and entropy generation patterns. The results indicate that influences of the local entropy generation and natural convection become significant for the initial temperature that is higher than density inversion temperature of water. For the parameters studied, entropy generation as associated with heat transfer becomes a deterministic factor for all cases.

Flow and Heat Transfer Characteristics of an Empty Refrigerated Container

To preserve the quality and the shelf life of perishable foods, it is essential to analyze the airflow distribution inside a refrigerated truck for maintaining homogeneous temperature throughout. This study is an initiation of such analysis, and air distribution patterns of ceiling-slot ventilated enclosure are numerically investigated for three different geometries. Numerical analysis is carried out by using ANSYS-FLUENT software which is based on control volume approach. In the analysis, the container’s cross-sectional area is kept constant. However, by changing the container length as 6 m, 8 m, and 13.3 m, the aspect ratio of the container is varied accordingly. The air velocity at the slot exit is varied in such a way that Reynolds number of the discharge flow covers the range between 20 and 1.23 × 105.

Energy Storage Methods

This chapter specifically dwells on energy storage methods and hence provides the basic aspects of the chemical, electrochemical, electrical, mechanical, and thermal energy storage techniques. Various illustrative examples are presented to highlight the importance of these methods and their deployment in various applications.

Thermal Energy Storage Methods

This chapter is presented to cover the basic aspects and key details of thermal energy storage (TES) methods at low to high temperatures. The chapter specifically covers some important TES techniques, including sensible, latent, and thermochemical methods. There are various examples and case studies presented to illustrate each of these significant methods for applications.

Fundamental Aspects of Thermodynamics and Heat Transfer

The current chapter presents a comprehensive introductory material to provide the readers with the fundamental and basic concepts and details of thermodynamics and heat transfer. The balance equations for energy, mass, entropy, and exergy are developed for various types of closed and open systems. The key modes of conductive, convective and radiative heat transfer mechanisms are also introduced in brief and discussed for various energy storage applications. Furthermore, the chapter includes eight worked examples that are related with the applications of heat storage systems.

Thermal Energy Storage Applications

In this particular chapter, we deal with a wide range of thermal energy storage (TES) applications from residential sector to power generation plants. Some practical applications of sensible heat and latent heat TES systems into heating and cooling systems are presented. The chapter also includes a brief discussion on the phase change materials (PCM) and its applications in thermal management such as buildings, photovoltaics, and thermoelectric generators.

System Characterization and Case Studies

In this chapter, we deal with two important subjects for TES systems and applications, namely system characterization and case studies. In the system characterization, we focus on storage materials and their roles in specific applications while the focus is placed on various selected applications, under case studies, from numerous sectors at various capacities, ranging from micro- to large-scale applications.

System Modeling and Analysis

In this chapter we deal with the analysis and modeling of thermal energy storage systems and applications and present the step-by-step illustrative examples for sensible and latent heat storage systems in particular from both energetic and exergetic points of view. In addition, this chapter covers the fundamentals of heat transfer analysis of latent heat storage tanks and fundamentals of CFD approach.