The thermal properties of refrigerants can be modified by adding porous nanoparticles into them. Here, molecular simulations, including molecular dynamics and grand canonical Monte Carlo, were employed to study the thermal energy storage properties of an R161/MOF-5 nanofluid. The results show that the thermodynamic energy change of MOF-5 nanoparticles is linear to the temperature. The adsorption heat calculated by grand canonical Monte Carlo is close to that calculated by the Clausius–Clapeyron equation. Additionally, a negative enhancement of the thermal energy storage capacity of the R161/MOF-5 nanofluid is found near the phase transition area.

The efficiency of thermodynamic cycles can be improved by using the optimized working fluid. In the present paper, classic molecular dynamics simulations and grand canonical Monte Carlo were employed to examine the thermal energy storage characteristicsof R125/UIO-66 and R125/MOF-5 nanofluids. The results indicate that the adsorption of R125 in MOF-5 is larger than that in UIO-66. Also, the thermal energy storage capacity of R125 was strengthened by mixing with UIO-66 or MOF-5 nanoparticles. In addition, the R125/UIO-66 mixtures can store less energy than that of R125/MOF-5 mixtures except the temperature difference is 30 K to 50 K.