Manipulating the effects of dynamic flow properties on thermoclines using assemblies with porous and diffuser configurations

Abstract

Thermal accumulators are used as energy-storing components in heat pumps and solar collectors and determine the extent to which solar collectors are viable.This paper introduces mechanical design solutions to managing flow dynamics and heat transport and analysing the formation of thermal stratifications in terms of the proposed configurations. Two versions of double perforated discs combined with a diffuser have already examined, and the small-spacing format proved superior to the wide-spacing configuration. This paper compares assemblies of small-spacing versions of double perforated discs, a single porous plate, a radial flow diffuser, and tubular upright flow in different arrangements and investigates the quality of the resulting thermal stratifications. The solutions are treated numerically under severe flow rate conditions, with an applied flow of 22 l/min to examine the capability of the modes of assembly. The effect of an insulated inlet tube has already been examined, and an insulated inlet tube is implemented in the model for all scenarios. The radial flow diffuser is mounted on an inlet pipe with an upward flow direction. The comparisons and fidelity of the designs are evaluated using three-dimensional modelling and simulations of the proposed layouts.Comparisons of the structural designs are made in terms of a stratification benchmark, energy storage potential of the cases, and density of the heat transfer mechanisms. The qualification of the generated tracks of stratification is investigated to assess the nominated layouts. Cinematic visualization is provided to allow evaluation of the trends of the heat development and the tracks of the flow motion.The numerical result including cinematic visualization showed that the application of an innovative assembly including a porous disk at the top of the thermal accumulator and a radial flow diffuser contributes to higher energy savings and improves the stratified thermal layers when an insulated upward hot flow is introduced in the tank.The radial temperatures develop evenly and the downward temperature decreases. Higher energy is conserved in the top of the tank, which is desirable from the energy conservation perspective.