Developing a facility for glass façade performance testing

This research aims to investigate whether real spaces can support legitimate measurements on glazing energy and thermal comfort analysis. This paper presents the development of a research facility for doing this. It will test simple to complex glazing and shading systems in a real (occupied) interior office environment. The purpose of this research project is to compare measured results with those being simulated with existing software and to discover discrepancies between simulation and real measured results. What parameters characterize a glazing system, whether simple or complex? Can these parameters be used to predict the energy transfer and comfort in the space? One must begin with simple glazing systems and verify measured with readily known simulated results. It is, at present, very difficult to use geometric based software with thermal based software to predict the performance of complex glazing systems. However, if we can characterize glazing systems with a set of reliable measurements, we can provide the data necessary for predicting performance in a live space. Specifically, the Solar Heat Gain Coefficient (SHGC) is a variable parameter based upon solar incident angle to a glazing system and is intended to be measured in its integral components: solar transmittance and inward-flowing fraction (radiative/convective) heat gain. A new instrumental approach through variable surface coated heat flux meters is being investigated to provide the measurement of interior glazing surface radiative and convective heat gain. The results suggest that this instrumentation may support be a viable method of testing inward-flowing heat gains from the interior glass surface. The test set-up also considers the application of a well-known B&K 1221 Comfort Meter for determining thermal comfort responses in the ‘perimeter zone’ on the interior side of a façade. This work requires further investigation, but is intended to be used in conjunction with solar pyranometers measuring transmittance as well as the heat flux meter and surface temperature instrumentation.