Enhancing thermal mixing efficiency in electric water heaters through inverted cup designs: a comprehensive CFD analysis with experimental validation

Abstract

This study presents a comprehensive computational fluid dynamics (CFD) investigation into thermal mixing enhancement in electric water heaters (EWHs) using innovative inverted cup designs. The research integrates parametric design analysis with rigorous numerical validation to establish reliable simulation methodologies for thermal-fluid systems. A three-dimensional (3D) model of a standard EWH tank was developed and validated against experimental data, followed by systematic evaluation of four inverted cup configurations (Designs 1–4) with varying geometric parameters. Results demonstrate that Design 4 (20–80-60) achieves the target outlet temperature of 313
.
15 K in only 647
.
29 s, representing a 3
.
6% improvement over the conventional nozzle de-sign. Temperature contours and velocity vector analyses reveal enhanced turbulent mixing and reduced thermal stratification with optimized cup geometries. Furthermore, the numerical methodology was rigorously validated through reproduction of an experimental HVAC test case, showing excellent agreement with measured data (discrepancies within 0
.
5 K) and confirming mesh independence beyond 680,000 cells. This research provides valuable insights into passive mixing enhancement techniques for EWHs and establishes a validated computa-tional framework for thermal system optimization, contributing to energy efficiency improvements in residential water heating applications.