Abstract
A thermally-blanced tank has more than one additional sub-header pipe connected to the main tank with 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. In this paper, a simulation program to predict the characteristics of the thermally-balanced type storage tank has been developed. This contains the concept of R-value model which was developed for mathematical estimation of a temperature-stratified type storage tank. The R-value model assumes that temperature distribution in the tank can be calculated in two regions, namely the perfect mixing region and one-dimensional diffusion region, and the R-value which is a ratio of depth of the perfect mixing region to the tank depth can be estimated by Ar-number (Ar_<in>) at the tank inlet. This paper first describes a mathematical model and studies acuracy of the model by compairing the calculated results with experimental ones which was shown in Part 1. The effect of the dimension of the sub-header pipes and the proportion of the tank on the performance is then examined by the simulation program. The characteristics of balanced type storage tank under stepwise input condition has also been examined using a new Ar-number (Ar_h), the representative length of which was the height of the tank (H) as the following Ar_h=Hg(Δρ/ρ_0)/u^2 Finally effectiveness of balanced type storage tank is described by comparing with the temperature-stratified type under several conditions.
