Dynamic performance analysis of sensible and latent cold thermal energy storage systems for building cooling networks

Abstract

In the context of increasing energy demands and the need for efficient cooling strategies in buildings, Cold Thermal Energy Storage (TES) systems offer a promising solution for enhancing the energy flexibility of district cooling networks. However, there remains a need to better understand and quantify the dynamic performance of different TES technologies particularly under realistic operating conditions. This study aims to develop and compare the dynamic thermal performance of sensible and latent cold TES systems integrated into building cooling networks. A lumped dynamic thermal model is proposed for a shell-and-tube TES configuration, enabling fast and accurate simulation of system behavior. The model is validated using experimental data from the literature and applied to analyze chilled water (sensible storage) and phase change materials (PCMs) including RT4 and RT5HC (latent storage). Key performance indicators such as constant cold power delivery duration, tank state of discharge, and average cooling effectiveness are evaluated. Results demonstrate that increasing the cooling load from 50 kW to 70 kW reduces the cold power delivery duration by approximately 45 %. Conversely, increasing the PCM tank volume from 2 m³ to 4 m³ extends this duration by up to 80 %. The PCM RT5HC enables a discharging period 4.5 times longer than chilled water, with a cooling effectiveness reaching 60 % for a 6 m³ tank compared to only 25 % for a 2 m³ tank. These outcomes underscore the potential of latent TES especially when using high-latent-heat PCMs like RT5HC for achieving enhanced thermal stability, extended discharge capacity, and improved energy efficiency in practical district cooling applications. The proposed modeling approach provides a valuable tool for system design, control, and future optimization.