HEAT TRANSFER ENHANCEMENT IN A LATENT HEAT STORAGE SYSTEM1
Section snippets
INTRODUCTION
Efficient and reliable thermal storage systems are an important requirement for solar applications due to the anti cyclic nature of heat demand and availability of solar radiation and also due to the diurnal variation of solar radiation caused by weather variations. Among the thermal energy storage concepts, both sensible heat and latent heat (i.e., phase change) stores are under investigation. The major advantages of phase change stores are their large heat storage capacity and their
Enhancement with fin configurations
There are several methods to enhance the heat transfer in a LHTS system. The use of finned tubes with different configurations has been proposed by various researchers as an efficient means to improve the charge/discharge capacity of a LHTS system. Experimental studies have been performed by Sparrow et al. (1981)for outward solidification on a longitudinal finned vertical tube, viz. for conduction-controlled or natural-convection-controlled heat transfer. Conduction is the controlling mode when
EXPERIMENTAL INVESTIGATION
In the present work three different heat transfer enhancement methods are investigated (see Fig. 1). The first enhancement technique uses internal longitudinal fins inside a cylindrical vertical storage tube containing paraffin. In the second method, the tube is filled with lessing rings of 1 cm diameter which are commonly used in the chemical reactors to enhance the surface contact, and the molten paraffin is poured into the tube. These lessing rings are made of steel and have a thin-walled
RESULTS AND DISCUSSION
Fig. 5 shows the experimental and predicted temperature variation within the paraffin for the fin configuration at the locations of the thermocouples shown in Fig. 1(b). The predicted temperature variation at the above locations is obtained from the numerical model. The theoretical and the experimental curves are in rather close agreement with each other, except that in the theoretical curves, the rate of temperature drop is slower during phase change and faster after phase change is completed
CONCLUSION
A detailed investigation of the different heat transfer enhancement methods for the latent heat thermal storage system has been carried out. The heat transfer enhancement with fin configuration for storage tubes and by using lessing rings in storage tanks is appreciable, and these two methods are highly suitable for solidification enhancement. The storage configuration employing bubble agitation may be suitable for applications where heat transfer enhancement for melting is required. Though the
References (16)
Low temperature latent heat thermal energy storage: Heat storage materials
Solar Energy
(1983)- et al.
Thermal conductivity enhancement for phase change storage media
Int. Comm. Heat Mass Transfer
(1996) - et al.
Performance and modeling of Latent heat stores
Solar Energy
(1992) Study of the heat transfer behavior of a latent heat thermal energy unit with a finned tube
Int. J. Heat Mass Transfer
(1993)Solidification of low conductivity material containing dispersed high conductivity particles
Int. J. Heat Mass Transfer
(1977)- et al.
Freezing on a finned tube for either conduction-controlled or natural-convection-controlled heat transfer
Int. J. Heat Mass Transfer
(1981) - et al.
Experimental analysis and numerical modeling of inward solidification on a finned vertical tube for a latent heat storage unit
Solar Energy
(1997) - et al.
Heat transfer enhancement in a paraffin wax thermal storage system
J. Solar Energy Eng.
(1984)
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Paper presented at the ISES Solar World Congress, Taejon, South Korea, 24–29 August 1997.
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ISES member.