SUMMARYA latent heat thermal energy storage system using a phase change material (PCM) is an efficient way of storing or releasing a large amount of heat during melting or solidification. It has been determined that the shell-and-tube type heat exchanger is the most promising device as a latent heat system that requires high efficiency for a minimum volume. In this type of heat exchanger, the PCM fills the annular shell space around the finned tube while the heat transfer fluid flows within the tube.One of the methods used for increasing the rate of energy storage is to increase the heat transfer surface area by employing finned surfaces. In this study, energy storage by phase change around a radially finned tube is investigated numerically and experimentally. The solution of the system consists of the solving governing equations for the heat transfer fluid (HTF), pipe wall and phase change material. Numerical simulations are performed to investigate the effect of several fin parameters (fin spacing and fin diameter) and flow parameter (Re number and inlet temperature of HTF) and compare with experimental results. The effect of each variable on energy storage and amount of solidification are presented graphically.

In this study, the influences of the changes in fin geometry on heat transfer and pressure drop of a plate fin and tube heat exchanger are investigated, numerically. A computational fluid dynamics (CFD) program called Fluent is used in the analysis. The segment of one tenth of fin is used in the modeling, due to symmetrical condition. The results of heat transfer, static, and total pressure drop values of ten different fins are tabulated and the normalized values of them are, also, given for the comparison of the models. The distance between fins is found to have a considerable effect on pressure drop. It is observed that placing the fin tube at downstream region affects heat transfer positively. Another important result of the study is that increasing ellipticity of the fin tube increases the heat transfer while it, also, results in an important reduction in pressure drop.

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In this study, an external melt ice-on-coil thermal storage was studied and tested over various inlet conditions of secondary fluid}glycol solution}flow rate and temperature in charging process. Experiments were conducted to investigate the effect of inlet conditions of secondary fluid and validate the numerical model predictions on ice-on-coil thermal energy storage system. The total thermal storage energy and the heat transfer rate in the system were investigated in the range of 10 l min À1 4 ' V460 l min À1 : A new numerical model based on temperature transforming method for phase change material (PCM) described by Faghri was developed to solve the problem of the system consisting of governing equations for the heat transfer fluid, pipe wall and PCM. Numerical simulations were performed to investigate the effect of working conditions of secondary fluid and these were compared with the experimental results. The numerical results verified with experimental investigation show that the stored energy rises with increasing flow rate a decreasing tendency. It is also observed that the inlet temperature of the fluid has more influence on energy storage quantity than flow rate. consumption, depending on site-specific design, notably where chillers can be operated at full load during the night.Another advantage of thermal energy storage is the ability to use energy more efficiently. Storing energy at night time when the ambient temperature is less than day time is more efficient for the system because of the low temperature of fluid, which enters the condenser. In summer, the system works at a condensing temperature, which is 208C less than daytime, cause 2-3% more efficient usage relative to a system working throughout the day without energy storage (Dincer and Rosen, 2002).A number of studies have been conducted to analyse the thermal behaviour of latent heat thermal energy storage systems. A detailed review about latent energy storage system has been provided by Eckert et al. . It has been determined that the shelland-tube type heat exchanger is the most promising device as a latent heat storage system that requires high efficiency for a minimum volume. In such an energy storing unit, the phase change material (PCM) fills the gap between the shell and the tubes in which heat transfer fluid (HTF) flows, also serves to convey the stored energy to and from the unit. Recently, a theoretical model of the shell-and-tube type unit for storing energy has been reported by Ismail and Alves (1986). In addition, Faghri (1991b, 1992) also has modelled a similar problem at which both the heat charging and the recovery processes have been performed by the circulating fluid. For both models, the shell wall of the unit was assumed to be adiabatic. Using the enthalpy model, the problem of storing energy in a shell-and-tube type unit was also solved by Bellecci and Conti (1993). Cao and Faghri (1991a) have studied the latent heat energy storage systems for both annular and countercurrent flows and numerically determined that the stor...