Title: Numerical study of thermal stratification in hot water storage tank

Authors: Robert Smusz

Addresses: Rzeszów University of Technology, Al. Powstańców Warszawy 12, 35-959 Rzeszów, Poland

Abstract: Thermal stratified storage tanks equipped with stratification devices are an effective tool to improve the efficiency of large-scale solar thermal systems. Stratification improves the overall performance of the systems by increasing the efficiency of solar collectors. The modelling of thermal stratification is an important topic for the optimisation of storage tanks in thermal systems. The paper presents the results of numerical and experimental analyses of temperature and velocity fields in a domestic hot water storage tank equipped with three helical heating coils and a cylindrical stratification device during the heating process. The main aim of the paper is to improve the thermal stratification level in a small domestic hot water storage tank by using an appropriately shaped stratification device. CFD numerical simulations were used to analyse the flow characteristics and to determine the working conditions of the stratification device which can reduce recirculation and mixing inside the tank. A 2D-axisimmetric computational fluid flow model was performed. The standard k-ε turbulence model with buoyancy effects and default turbulent constants were used. Numerical simulations were compared with experimental results obtained on the test stand.

Keywords: numerical simulations; thermal stratification; storage tank.

DOI: 10.1504/PCFD.2017.088792

Progress in Computational Fluid Dynamics, An International Journal, 2017 Vol.17 No.6, pp.368 - 375

Received: 03 Nov 2016
Accepted: 13 Mar 2017
Published online: 19 Dec 2017 *

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