Performance enhancement and dual-phase change heat transfer mechanism for latent heat storage system using phase change nanoemulsion

Phase change nanoemulsions are used as an alternative to water (conventional HTF) to enhance the thermal response rate of LHTES systems. The phase-change characteristics of nanoemulsions and PCM contribute to the formation of a dual-phase change coupled heat transfer mode with a stable high heat transfer temperature difference. In contrast, the conventional heat transfer mode of water and PCM has a consistently lower heat transfer temperature difference and thus a consequent decrease in heat transfer driving force. [Display omitted] •PCM nanoemulsion is used to accelerate the discharge rate for latent heat storage systems.•The discharging time is reduced by 11.4% and average power is increased to 2.66–6.96 kW compared to water.•A dual-phase change coupled heat transfer mode with high-temperature difference is proposed.•At least 6 °C of phase change temperature difference between nanoemulsion and PCM is commended. Latent-heat thermal energy storage (LHTES) based on phase change materials (PCMs) is an effective way to alleviate instantaneous high-power refrigeration loads. However, the low charge/discharge rate of LHTES is a significant challenge that negatively affects its overall performance. Herein, we demonstrate a strategy to enhance the thermal-response rate of LHTES by improving the heat transfer inside the channel fluid through PCM-nanoemulsions. The effects of the nanoemulsion content and flowrate on energy discharge performance were investigated. The heat-transfer mechanism of the nanoemulsions was investigated using simulations. The results show the nanoemulsions can accelerate the discharge rate of LHTES with a reduction of discharge time by 11.4%. The enhanced heat transfer of LHTES was attributed to a new type of dual-phase-change heat-transfer mode. This mode is characterized by a substantial temperature difference that results from the phase-change thermostatic properties of both the nanoemulsions and PCMs, promoting a higher rate of energy release. Briefly, this study provides novel insights into accelerating the heat-transfer rate of LHTES.