Thermal evaluation of a room coated by thin urethane nanocomposite layer coating for energy-saving efficiency in building applications

Abstract

Today, it is common to use thin-layer nanocomposite coatings as insulation to reduce heat loss through building walls. One of the important advantages of these coatings is preventing energy loss as a thermal barrier in low thicknesses and with high efficiency. Investigations on the energy loss and saving of coated buildings are often practiced using numerical and experimental approaches. In this study, numerical simulation and experimental evaluation consisting of modification of nanoparticles and preparation powder coating nanocomposite, are used to study the effects of coated polyurethane nanocomposite containing nano Al2O3 and nano ZrO2 on both sides of the walls of a sample room on temperature distribution and heat transfer. For this purpose, a three-dimensional enclosure was assumed as a room having a radiant cooling panel, which is modeled under various features of the walls’ interior and exterior coating. To determine the flow and temperature fields, the governing equations that include the continuity, momentum, turbulence, and energy equations, which are coupled through the buoyancy term, have been solved using the Fluent software. The SIMPLE algorithm to accommodate the pressure-velocity coupling, the k-ε model for turbulence modeling, the Boussinesq approximation for buoyancy term modeling, and the DO model for radiation simulation, are employed. The results of the thermography of the samples showed that the temperature reduction in the samples containing zirconium oxide compared to aluminum oxide had a better performance in the thermal insulation of the coating and the lowest temperature was observed in the nanocomposite containing 3% zirconium oxide. Numerical studies showed that this thin layer nanocomposite coating reduces energy consumption by 4% and 13%, respectively, compared to pure polyurethane coatings and acrylic paints.