Dr. Amal (Master)

Thesis Title

EXPERIMENTAL STUDY ON THE TRANSIENT BEHAVIOR OF THERMAL LIQUID
STORAGE TANKS

Awarding University and Year

Faculty of Engineering- Cairo University-1993

Abstract

This research studies the thermal behavior of the cylindrical Liquid storage tanks. The study started with a comprehensive critical review of the existing literature in the area of thermal energy storage in general and the sensible heat storage in liquids in particular. The review revealed the importance of the energy storage systems especially for the systems depending on solar radiation as a prime source. It has been also. Concludedthrough the review. That further work is needed.And that there is need for more experimental work to meet the extensive mathematical models available in the literature. A separate chapter has been devoted to the mathematical modeling and simulation of storage tanks.

A special experimental set-up was designed and used for this investigation. It consists of a cylindrical storage tank. Well insulated to minimize the heat loss to the surroundings. The solar collector was simulated with an electric heater in a separate tank. The temporal and spatial temperature distribution were measured by means by means of thermocouples located at 30points inside the tank.

The variables considered are the mass flow rate, the hot inlet temperature and initial cold temperature.

The experiments are repeated for the discharging as well as charging mode. The results are presented and discussed to illustrate the effects of different design and operational parameters. A special program was developed to enable the drawing of the isothermal lines inside the tank at various test conditions. The results are discussed in details in view of the previous work and the available theoretical analysis. In case of the well insulated tanks, the one-dimensional model was found to be satisfactory for estimating the thermal behavior inside the tank with very reasonable accuracy sincethe radial variation of temperature was very small in most of the cases. It has been recommended to further extend this work to include the utilization of phase-change material as heat storage medium in addition to other important recommendations.