Modelling of thermal processes in a glazing structure with temperature dependent optical properties - An example of PCM-window

Abstract

Abstract The presented study proves the possibility of modelling variable optical properties actuated by a temperature inside the layer of phase change material (PCM) placed in a glass container. The new approach was implemented in ESP-r simulation tool by refining solar.F subroutine. The paper presents the results of numerical analysis of complex, triple glazed PCM-window. The optical properties substitution due to the change of phase is executed by refined control algorithm for windows. The idea of the control/actuator algorithm and its implementation in ESP-r software was described. The new approach was computationally tested for office room equipped with triple glazed window. The outer cavity was filed with paraffin. Five different paraffin waxes were analysed as a PCM filling and compared with traditional triple glazed window. The optical properties of the whole glazing used in the simulations were determined experimentally for liquid and solid state of PCM. The results were analysed in terms of energy for cooling, energy for lighting, visual discomfort, glare effect and thermal discomfort. It was concluded that there is none optimal type of PCM, and the best solution is to divide the glazing into sections filled with PCM with different melting temperatures.