Overall energy performance assessment of a new heat blocking coating

In subtropical Hong Kong, clear glass is normally used as the translucent material for external windows of residential buildings, but it has poor heat insulation performance especially the tremendous solar heat gain in summer. To improve the thermal performance of conventional clear glass, a new heat blocking coating was developed. The coating can effectively absorb the near infrared radiation, so it can reduce the solar heat gain and therefore the energy use from air-conditioning systems. In this paper, the preparation of the heat blocking coating was firstly introduced. Then the optical and thermal properties of different types of window glazing were tested in the laboratory. Based on the experimental data, a combined daylight, thermal environment and building energy numerical model of a public rental housing was established to fully simulate the performance of different types of windows glazing. The results indicated that the heat blocking coating can reduce about 275.4 kWh (14.4%) electricity use per year compared to conventional clear window.