Measurement of Fenestration Net Energy Performance: Considerations Leading to Development of the Mobile Window Thermal Test (MoWiTT) Facility

摘要

A detailed consideration of the energy flows entering the energy balance on a building space and the effect of random measurement errors on the determination of fenestration performance is presented. Estimates of the error magnitudes are made for a passive test cell and it is shown that a more accurate test facility is necessary for reliable measurements on fenestration systems with thermal resistance in the range 2 to 10 times that of single glazing or shading coefficient less than 0.7. A test facility of this type, the MoWiTT, which has been built at Lawrence Berkeley Laboratory, is described. The effect of random errors in the MoWiTT is discussed and computer calculations of its performance are presented. The discussion shows that, for any measurement facility, random errors are most serious for nighttime measurements, while systematic errors are most important for daytime measurements. It is concluded that, for the MoWiTT, errors from both sources are expected to be small. (ERA citation 10:000801)