Barocaloric Material with High Thermal Conductivity for Room-Temperature Refrigeration

Barocaloric refrigeration technology, one of the caloric-effect refrigeration technologies, is drawing more and more attention. Neopentyl glycol (NPG) was reported to have a giant barocaloric effect, making it a potential barocaloric material. However, the high solid-solid (S-S) phase transition temperature and low thermal conductivity hinder the application of NPG in barocaloric refrigeration. This work lowers the S-S phase transition temperature and improves the thermal conductivity of the NPG-based barocaloric material. An NPG/TMP (TMP: Trimethylolpropane) binary system with an S- S phase transition temperature of 283.15 K is prepared, in which the mass ratio of TMP is 20%. Graphene is then added to the binary system to enhance thermal conductivity, and the optimal mass ratio of graphene was determined to be 5%. The thermal conductivity of this composite is 0.4 W/(m center dot K), increased by 110% compared to the binary system. To predict the effect of enhanced thermal conductivity on the cold-extraction process of the barocaloric refrigeration cycle, a numerical model is developed. The results show that the cold-extraction time of the barocaloric refrigeration cycle utilizing the composite with 5% graphene as the refrigerant is shortened by 50% compared with that using the binary system.

Automated summary

This study successfully lowered the phase transition temperature and improved the thermal conductivity of the NPG-based barocaloric material by adding graphene. The thermal conductivity of the composite was increased by 110% compared to the binary system. The numerical model results showed that the cold-extraction time of the barocaloric refrigeration cycle using the composite with 5% graphene as the refrigerant was shortened by 50%.