Glazing made simple: A decision support system tool using ms excel VBA

Abstract

Larsen & Toubro (L&T) -being the largest construction company in India - realizes the importance of being able to offer the best glazing systems to its huge national and international customers. The architects at L&T select glazing systems based on three components: glass type, frame type, and shading. The glass type is chosen based on four sub-criteria: the color, solar heat gain coefficient, visible light transmittance, and U-value. As part of a NSF International Research Experiences for Students (IRES) project a team of graduate and undergraduate students at a major U.S. university worked with L&T's design engineers at the Center for Excellence and Futuristic Design (CEFD) in conducting all the necessary calculations to determine the annual cooling loads for each of the glass-frame-shading combinations. The goal was to tabulate all the necessary values and calculations into an Excel spread sheet and then develop a simple interface -using Visual Basic for Applications (VBA) - for L&T's architects. The program accesses a hidden database that allows the architects to simply select their desired values for the glass type sub-criteria, frame type, and shading type, and then make a decision about which combination is ideal for their particular building design. The decision is based not just on aesthetics, but energy performance as well as some financial metrics such as additional investment and payback period. This results in a simplified decisionmaking tool with instantaneous consequence comparisons. © 2012 American Society for Engineering Education.