COMPARISON OF CORRECTIVE PHASE CHANGE MATERIAL ALGORITHM WITH ESP-R SIMULATION

Phase change materials (PCMs) can be implemented into building practice to enhance thermal storage performance, reduce indoor temperature fluctuations and improve the thermal comfort of occupants. As building energy simulation is taking an ever larger role in the design and analysis of energy efficient buildings, it is important to understand the capabilities and performance of these tools. A popular and powerful building simulation program is ESP-r, which is capable of incorporating the use of PCM into the thermal simulation. In this paper, the existing numerical methods to simulate phase change materials (PCMs) embedded in passive building structures are reviewed and two forms of the modelling scheme are explained in detail. The first formulation is a non -iterative temperature formulation, which suffers from the requirement of extremely small time steps to produce accurate results. The second formulation is an iterative enthalpy formulation, which by using an iterative correction scheme at every time step, can produce accurate results for comparatively much larger time step values. It was found that there was significant discrepancy in temperature profiles at large time step values when PCMs were introduced. In addition, multilayered PCM demonstrated more realistic thermal behaviour than single layer PCM in some cases.