Analytical determination of the water thermal accumulator capacity in a consumption mode with a constant debit and a fixed temperature

Abstract

The water thermal accumulators for heat and cold storage are an important part of various engineering installations. This article examines a tank with volume of 1000 [l] in a consumption mode with a constant debit and a fixed temperature. The output volumes of hot water in two regimes – weak stratification and strong stratification are calculated analytically and are compared with the results from an analogical simulation in ANSYS. The ANSYS simulations are unconditionally more accurate, but require specialized knowledge and software. The solutions without simulation procedures are suggested. The output volume of hot water with fixed temperature - as a function of initial and final temperatures in accumulator, flow debit, tank construction and external conditions - can be calculated fast and accurate enough for the engineering practice. Relative differences between analytic and simulations results for all regimes are below 10.5%.