Experimental and Numerical Evaluation of a Hybrid CTES Tank with PCM

The growing global demand for cooling technologies, driven by climate change and increasing energy consumption, creates a need for effective solutions to reduce energy use and carbon footprint. One promising approach is the application of Cold Thermal Energy Storage (CTES) systems, which enable the temporal shifting of electricity demand and the optimization of cooling system operation. This paper presents an experimental analysis of a hybrid PCM–water storage tank using the commercially available material RT11HC (Rubitherm®). The measurement results demonstrated that the integration of PCMs increases the duration of thermal comfort provision and enhances system flexibility, while an appropriate PCM fraction significantly affects the dynamics of cold energy storage and release. The introduction of a copper matrix as a heat transfer enhancement element accelerated the phase change process by more than 20% and ensured a more uniform charging and discharging behavior of the storage tank. A numerical simulation performed in ANSYS software confirmed the experimental results with minimal deviations. The proposed hybrid storage tank concept demonstrates high application potential in both building and industrial applications, contributing to reduced energy demand and supporting sustainable operation.