AT-90-07-4 -- Window (Glazing and Frame) Heat Transfer Modeling PDF

Seven windows were simulated using a glazing system analysis program and a finite difference program. Three research groups modelled the windows. The result were in agreement and agreed with laboratory test results for the windows. The sensitivity of the simulations to the decisions made by the modeller was studied. A number of the model parameters were varied over a wide range. The results of this sensitivity analysis are presented and indicate that the model parameters need to be accurate in areas of high heat flux. A sensitivity analysis of the parameters in this region is a necessary part of the modelling procedure. The proposed introduction of energy-labelling programmes for windows will require manufacturers to determine the thermal performance of their products. In order to minimise the costs involved in testing the numerous window products and all their variations for such a window-labelling programme, the good agreement of the modelling results and agreement with the test results indicate that testing a few products in a base configuration and obtaining the thermal performance for the other variations of construction by detailed modelling could be a feasible approach.

KEYWORDS: windows, glazing, window frames, thermal resistance, heat flow, calculating, laboratory testing, comparing, computer programs, double glazing.