Studies on Thermally-Balanced Type Storage Tank : Part 1-Experimental Study

Abstract

The characteristics and design principles of water storage tanks have been established by various experimental and theoretical studies. However, the performance of the storage thank deteriorates drastically when the temperature difference between the inlet side and outlet side of the tank is reduces. The thermally-balanced storage tank is proposed and designed as a countermeasure against this. This tank has two additional sub header pipes connected to the main tank by several connecting pipes. Thermally stratified heat storage is achieved by selective input corresponding to the temperature profile in the main tank and the input water temperature. This paper first introduces the principle and objective of the thermally-balanced storage tank. Experiments were conducted under various conditions to estimate the performance and characteristics of the tank, and they were proved by visual tests. The results of these experiments indicate that the thermally-balanced storage tank is effective in maintaining stratification for variable water temperature systems, and that three connecting pipes between the header and main tank seems neccesary and sufficient. Thermosyphon system for solar collection, however, does not require balanced storage because of its self regulating effect. Visual tests clearly proved the principle and selective operation of the water input due to pressure difference.