Part 1: Smart Metering, Energy Audits and Your Desktop
Smart Metering, Energy Audits and Your Desktop
By Laurie A. Gilmer, P.E. March 2013 - Facility Maintenance Decisions Columnists
The idea behind the audit is to identify energy use in a building and look for ways to maximize energy efficiency without compromising operations. In other words, the audit helps maintenance and engineering managers understand the building's efficiency and potential for improvement, and it identifies steps for realizing this potential.
In 2004, the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) developed a guideline, Procedures for Commercial Energy Audits, which identified a three-level approach to conducting an audit:
Level 1. In this walk-through survey, an auditor reviews the building's energy history, typically through the energy bills, analyzing energy-use patterns and comparing building performance to similar buildings in a benchmarking analysis. During the visit, the auditor identifies building uses, energy-consuming equipment, schedules, and processes. Out of this effort, managers receive low-cost and no-cost efficiency measures, as well as any capital-intensive measures, that merit further consideration. The resulting report captures the benchmarking analysis and building performance, and it looks at the energy and financial performance impact of the identified low-cost and no-cost measures.
Level 2. This energy survey and analysis includes a systematic breakdown of energy use in a building, a peak-demand analysis, analysis of capital-intensive measures, and review of maintenance and operations practices. Its goal is to identify measures that meet the owner's constraints and economic criteria.
Level 3. While previous audits can be done independently, this audit — a detailed analysis of capital-Intensive modifications — typically builds on a prior audit, focusing on specific, potential capital-intensive projects previously identified. The analysis of each measure requires additional data gathering, increased economic rigor, and life-cycle-cost analysis. The goal is to provide detailed project costs and savings calculations that will result in a high level of confidence sufficient for major capital investment decisions.
These approaches are typical, whether implemented as a best practice, required for building certification, or mandated by law. The challenge, particularly for managers with large portfolios, is assessing many buildings efficiently and effectively. Now an emerging approach — the desktop building energy audit — seeks to address that challenge.