RP-577 -- Attic Radiant Barrier Systems PDF

This report documents the results of ASHRAE research project 577-RP. The primary purpose of this project was to collect experimental data under controlled conditions to evaluate the effect of attic radiant barriers on heat gain through residential ceilings. The bulk of this report then consists of the experimental data collected. The impact of radiant barriers on attic heat flow is complex and including their impact in design heat gain calculations is not always simple. For example, it is not likely that the effect of a radiant barrier can be represented simply by an adjustment in R-value for the attic particularly when attic ventilation is employed. One of the primary uses expected for the data collected in this project is the evaluation of various calculation techniques and simulation models which predict the effect of attic radiant barriers. For this reason, the data collected are reported in great detail. These data are voluminous, to say the least, and are presented as a separate appendix in order to keep the main report to a manageable size. The data are also available on floppy disks from the contractor upon request. The remainder of the report is divided into three parts: Summary, Results, and Utilization. The Summary section consists of a technical paper that has been submitted to ASHRAE for publication. This paper is expected to be the primary means of communicating the results of the study to the ASHRAE membership. It documents the tests conducted and presents the results of each test in summary form. It also summarizes the important findings and describes conclusions that can be drawn. The Results section of the report expands upon the information presented in the Summary section. Additional discussion and results are presented that were omitted from the Summary because of the space limitations of an ASHRAE technical paper. The utilization section of the report describes how the data may be used to evaluate calculation techniques and simulation models. Two examples are presented. The first example is a simple hand calculation technique that incorporates a radiant barrier and attic ventilation. The second example compares the results of a sophisticated attic simulation model to the experimental data.