Energy audits, measurement and verification (M&V) efforts, and strategic energy management (SEM) programs typically collect significant data from systems like compressed air, refrigeration, hot water, etc. The availability of this data is increasingly prevalent and allows energy efficiency engineers to track performance, determine load profiles, and quantify energy savings. Unfortunately, this data is not commonly utilized by design engineers or equipment vendors when sizing equipment replacements or system expansions. Instead, these teams typically rely on theoretical load calculations, rules of thumb, or simply specifying sizes to match existing equipment.

This paper demonstrates the power of energy data in design by presenting case studies where common design practices result in inaccurately sized systems, reduced efficiency, and increased equipment costs. In each study, energy data was collected through a different effort such as an energy audit, M&V effort, or SEM project and then analyzed to validate the equipment sizing proposed by design teams. This process improved the proposed designs and the selected equipment. It was also sometimes faster, less expensive, more accurate and even preferred by the design team, in hindsight, over their own approach. The goal of this paper is to display through case studies how energy data can be a tool for not just quantifying energy efficiency improvements, but also for optimizing expensive system design decisions.