Glazing System U-Value Measurement Using a Guarded Heater Plate Apparatus
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Date
1988
Authors
Wright, John L.
Sullivan, Harry F.
Journal Title
Journal ISSN
Volume Title
Publisher
American Society of Heating, Refrigerating and Air-Conditioning Engineers
Abstract
Precise heat transfer measurements have been carried out during the last 20 years using a guarded heater plate apparatus. This apparatus has been adapted and used over the last several years to perform U-value measurements on a variety of prototypical glazing systems. Results from two sets of measurements are presented. One set of results quantifies heat transfer across stagnant air layers containing an intermediate fluorinated ethylene-propylene (FEP) glazing and bounded by plates of various emissivities. The second set consists of values (i.e., glass-to-glass U-values) for a set of glazing systems that incorporate up to four glazings, one of two solar-control metal coatings and up to two intermediate glazings made of FEP film. In each case the measured results are compared to simulation. In the first study the discrepancy between measured and calculated heat transfer rates was less than 2% in all cases. In the second study the discrepancy was never greater than 8% and was less than 3% in the majority of cases. These results indicate that the test method used is well suited to the reliable measurement of glazing system U-value. It is a useful tool as a developmental test procedure for glazing system design because it can be carried out quickly and at low cost. The apparatus and procedure are described in detail.
Description
© 1988. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions, Vol. 94, Part 2. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAE’s prior written permission.
Keywords
Fenestration, Heat transfer, Measurement