Optimized study of continuous latent and sensible heat storage with multi-energy composition based on energy and power characteristics

Abstract

Simultaneously improving energy density and power density of latent heat storage represents a gap in this field. To address this, a multi-energy composition form latent-sensible heat storage device is proposed. In the device, phase change materials (PCMs) with a notable temperature difference in phase change are arranged in a cascaded configuration. During energy utilization, energy composition of the storage device exhibits changes in three stages, enabling a more complete release of sensible heat within a wide temperature range between two PCMs. For the trade-off between energy/power capabilities, coupling effects of PCM layouts and operating conditions on energy/power characteristics are analyzed through Ragone plots. Results indicate that enhancing the energy density of multi-energy composition storage device typically results in a decrease in power density, adjusting porosity can improve both metrics simultaneously, contrasts with conclusions drawn from research focused exclusively on latent heat storage. The energy density can reach 388.35 kWh/m³ under optimal operating conditions, representing a 76 % increase compared to only latent heat storage. Furthermore, optimized storage device demonstrates an increase in energy density of 16 kWh/m³ and a power density increase of 0.27 kW/m³, thereby enhancing energy/ power capabilities simultaneously.