Development of Graphical Indices for Building Energy Data

Abstract

Graphs are an effective and efficient way of displaying quantitative and statistical information. Unfortunately, only a few studies have systematically looked at presenting data in forms which are both informative and easy to comprehend. With the advancements in computing, the development of sophisticated graphing packages, and easy access to micro and mini computers, the concept of graphical indices is more timely than ever before. There are, however, a few drawbacks. Graphs can easily be made to look impressive, but they can become so complicated so quickly that they hide or obscure important information, or worse, they may mislead the analyst. In the Texas LoanSTAR program, a $98 million revolving loan program for funding energy conservation retrofits in state agencies, hourly building energy consumption data are collected each week from about 200 sites located around the state. Collecting, inspecting, and archiving this amount of data present a daunting task. In this thesis, graphical indices are developed to analyze several years of hourly data (20,000 to 30,000 data points) collected from each site. These indices are meant to be efficient displays that show data in specific graphic forms developed to highlight certain features. Many aspects of a building's energy consumption behavior can be discovered visually using these graphical indices. Moreover, these indices have also been designed so that buildings can be compared with each other. The graphical indices in this thesis were developed to be an aid for the staff in the LoanSTAR program, further testing of these indices with building operators and administrators is desirable in order to gauge their effectiveness in conveying specific aspects about a building's energy use characterstics. In this thesis, two buildings are analyzed in detail using the indices to illustrate their usefulness. One of these buildings, an engineering center, is discussed in detail in the body of the thesis. The other building, an office/classroom, is discussed in limited detail, with supporting information included in the appendix. Such graphical indices will become increasingly useful as utilities and building professionals study customers' hourly data in order to better understand building energy use.