Experimental and analytical heat transfer analyses for a calibrated hot box and fenestration systems
In this dissertation, Calibrated Hot Box measurements on two different types of fenestration systems (one window and one glazing unit) are presented. The research program included: renovation of the University of Massachusetts Hot Box test facility, an analysis of measurement uncertainty, experimental refinements to the test method ruggedness', calibration of the extraneous heat transfer of the Hot Box, and a numerical analysis of the two-dimensional heat transfer in the Hot Box. The finite element method was also used to analyze the heat transfer (thermal transmittance) for each of the fenestration systems tested. These analytical results are then compared with experimental results obtained from Hot Box measurements.
Renovation consistent with existing ASTM standards aimed at improving the precision of test method with the University of Massachusetts Calibrated Hot Box test facility were conducted and documented. The uncertainty of the Hot Box measurement results was estimated from an uncertainty analysis of the thermal transmittance. Ruggedness experiments consistent with ASTM test method E 1169–89 (1999) were performed, and results enabled the researcher to refine the hot box measurement methodology and reduce the variability of the measurements. Finally, hot box calibration experiments were designed and performed in order to account for the various heat transfer losses in the hot box so that the more accurate measurements of the net heat transfer through a fenestration system may be produced.
Using a finite element method, two-dimensional and three-dimensional numerical heat transfer analyses of the calibrated hot box and fenestration systems were conducted. These analyses were compared with the experimental calibration results. These included two- and three-dimensional numerical heat transfer analyses of the metering chamber extraneous heat transfer, and the specimen flanking heat transfer. Analytical heat transfer results with combined conduction, convection and radiation effects were compared with experimental results. The heat transfer through two different fenestration products (a glazing unit and a PVC framed window with three glazing units) was investigated. The results are compared with the experimental results on these products using the ASTM C 1199-97 (2000) standard test method for determining the thermal transmittance (U-factor) and the ISO/DIS 12567 (1999) window thermal testing standard.