Mathematical evaluation of a buried phase change concrete cooling system for buildings

A laminated phase change concrete duct system has been numerically analysed for cooling applications in buildings. The analysis shows that number of transfer units (NTUs) have considerable effect on the thermal performance of the system. For instance the highest factor of phase change material (PCM) melting thickness and surface temperature fraction were achieved with the lowest NTU value of 0.1. In terms of cooling effects, the two scenarios achieved maximum cooling capacities of 12.5 kW and 25 kW respectively. However in order to achieve effective thermal response in a mechanically ventilated ductwork system, some form of turbulent flow through surface roughness and configuration would have to be created. Even though the model was developed based on the assumption that the PCM is pure and may melt at a specific temperature the results appear to be a fair representation of what might happen in practise. Experimental validation is however recommended towards commercial and economic evaluation.