Ground source heat pump systems (GSHP) are one of the sustainable energy resources that provide heating and cooling to buildings. A stable ground temperature has a key role in the performance of the GSHP, in which the overuse (extract/release) of the underground energy can destabilize the ground temperature, leading to the system's failure. A GSHP's performance can be improved by stabilizing the ground temperature, which can be achieved by adding thermal energy storage (TES) to the system. This study aims to present a potential solution to improve the thermal performance of the GSHPs by coupling them to a latent heat TES system. PCMs are widely used for latent heat TES application; however, their poor thermophysical properties are a drawback, so adding nanoparticles has been considered as one of the solutions to address this drawback and improve PCM's properties. This study investigated the thermal performance of a nano-enhanced phase change material (NE-PCM) as an underground TES by developing a finite element numerical model and validation of the experimental apparatus. To this end, PDA@hBN/MXene as a thermal enhancer has been used to develop the NE-PCM. Then, the NE-PCM was utilized in a storage tank with a diameter of 30 cm and a height of 60 cm. The experimental apparatus consists of 8 NE-PCM pipes and four borehole heat exchangers. The experimental temperature of the NE-PCM pipes was used to validate the numerical model for heating and cooling the system within 0.3 °C and 0.2 °C, respectively. Then, the numerical model was used to study the potential of the proposed TES in three scenarios, including no PCM, base PCM, and NE-PCM, with both parallel- and serial-connected heat exchangers. The total heat transfer with NE-PCM was increased by 38.4 % compared to no PCM case and 24.6 % compared to the base PCM. Lastly, the results of three different flow rates showed up to 11.5 % enhancement of the thermal storage efficiency by increasing the flow rates. The results show the potential of using the new NE-PCM in GSHP applications, adding the NE-PCM as the thermal storage medium can improve the performance of the hybrid TES-GSHP system.
Performance evaluation of a novel nano-enhanced phase change material for thermal energy storage applications / Daneshazarian, R.; Eslami, R.; Azizi, N.; Zarrin, H.; Berardi, U.. - In: JOURNAL OF ENERGY STORAGE. - ISSN 2352-152X. - 74:(2023). [10.1016/j.est.2023.109376]
Performance evaluation of a novel nano-enhanced phase change material for thermal energy storage applications
Berardi U.
2023
Abstract
Ground source heat pump systems (GSHP) are one of the sustainable energy resources that provide heating and cooling to buildings. A stable ground temperature has a key role in the performance of the GSHP, in which the overuse (extract/release) of the underground energy can destabilize the ground temperature, leading to the system's failure. A GSHP's performance can be improved by stabilizing the ground temperature, which can be achieved by adding thermal energy storage (TES) to the system. This study aims to present a potential solution to improve the thermal performance of the GSHPs by coupling them to a latent heat TES system. PCMs are widely used for latent heat TES application; however, their poor thermophysical properties are a drawback, so adding nanoparticles has been considered as one of the solutions to address this drawback and improve PCM's properties. This study investigated the thermal performance of a nano-enhanced phase change material (NE-PCM) as an underground TES by developing a finite element numerical model and validation of the experimental apparatus. To this end, PDA@hBN/MXene as a thermal enhancer has been used to develop the NE-PCM. Then, the NE-PCM was utilized in a storage tank with a diameter of 30 cm and a height of 60 cm. The experimental apparatus consists of 8 NE-PCM pipes and four borehole heat exchangers. The experimental temperature of the NE-PCM pipes was used to validate the numerical model for heating and cooling the system within 0.3 °C and 0.2 °C, respectively. Then, the numerical model was used to study the potential of the proposed TES in three scenarios, including no PCM, base PCM, and NE-PCM, with both parallel- and serial-connected heat exchangers. The total heat transfer with NE-PCM was increased by 38.4 % compared to no PCM case and 24.6 % compared to the base PCM. Lastly, the results of three different flow rates showed up to 11.5 % enhancement of the thermal storage efficiency by increasing the flow rates. The results show the potential of using the new NE-PCM in GSHP applications, adding the NE-PCM as the thermal storage medium can improve the performance of the hybrid TES-GSHP system.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
