Evaluating Fenestration Products for Zero-Energy Buildings: Issues for Discussion

Publication Type

Conference Paper

Date Published

08/2006

LBNL Report Number

LBNL-61249

Abstract

Computer modeling to determine fenestration product energy properties (U-factor, SHGC, VT) has emerged as the most cost-effective and accurate means to quantify them. Fenestration product simulation tools have been effective in increasing the use of low-e coatings and gas fills in insulating glass and in the widespread use of insulating frame designs and materials. However, for more efficient fenestration products (low heat loss products, dynamic products, products with non-specular optical characteristics, light redirecting products) to achieve widespread use, fenestration modeling software needs to be improved.

This paper addresses the following questions:

1) Are the current properties (U, SHGC, VT) calculated sufficient to compare and distinguish between windows suitable for Zero Energy Buildings and conventional window products? If not, what data on the thermal and optical performance, on comfort, and on peak demand of windows is needed.

2) Are the algorithms in the tools sufficient to model the thermal and optical processes? Are specific heat transfer and optical effects not accounted for? Is the existing level of accuracy enough to distinguish between products designed for Zero Energy Buildings? Is the current input data adequate?

Conference Name

SimBuild 2006: Building Sustainability and Performance Through Simulation

Year of Publication

2006

Conference Location

Cambridge, MA

Call Number

LBNL-61249