LBNL Report Number
Infrared thermal imagers are used at Lawrence Berkeley National Laboratory to study heat transfer through components of building thermal envelopes. Two thermal chambers maintain steady-state heat flow through test specimens under environmental conditions for winter heating design. Infrared thermography is used to map surface temperatures on the specimens warm side. Features of the quantitative thermography process include use of external reference emitters, complex background corrections, and spatial location markers. Typical uncertainties in the data are +/- 0.5 deg. C and 3 mm. Temperature controlled and directly measured external reference emitters are used to correct data from each thermal image. Complex background corrections use arrays of values for background thermal radiation in calculating temperatures of self-viewing surfaces. Temperature results are used to validate computer programs that predict heat flow including Finite-Element Analysis (FEA) conduction simulations and conjugate Computational Fluid Dynamics (CFD) simulations. Results are also used to study natural convection surface heat transfer. Example data show the distribution of temperatures down the center line of an insulated window.