Development of continuous latent and sensible heat storage device with multi-energy composition for enhancing energy density

• A multi-energy composition continuous latent-sensible heat storage device capable of significantly improving energy density is proposed. • PCM with a lower transition temperature is serially connected for thermal management. • The energy density of the designed TES device can be increased to 386 kWh/m 3 . • Thermal Ragone plot is used to characterize the relationship between effective capacity and power density. Enhancing the capacity of thermal energy storage (TES) within constrained space presents a challenge. With the objective of improving energy density, a multi-energy composition continuous latent-sensible heat storage device is proposed. In this device, phase change materials (PCMs) with significant phase change temperature difference are arranged in a cascaded form. In continuous latent-sensible heat utilization, the energy composition of the storage device changes in three stages, enabling a more complete release of stored sensible heat. Four types of TES units are primarily designed and numerically analyzed. Power/energy density comprehensive response at various operating conditions are established based on the Ragone plot. Results reveal that the designed TES device increases the released sensible heat available for downstream industrial applications by 25.4 %, surpassing the performance of a single PCM in continuous latent-sensible heat utilization. The inclusion of the low-temperature PCM improves the adaptability of the TES device, which is reflected in the significant increase in the energy density of the TES device when the flow rate ranges from 10-20 L/min. The energy density of the designed TES device can be increased to 386 kWh/m 3 , representing a 75 % improvement compared to only latent heat storage, highlighting the potential of thermal storage within market.