Wayne Robertson: Energy Efficiency
Part 1: Different Levels of Energy Audit
Part 2: Retrocommissioning vs. Energy Audit
Part 3: Definitions of Net Zero Energy
Retrocommissioning vs. Energy Audit
July 2011 - Energy Efficiency
What is the difference between an energy audit and retrocommissioning? What are the benefits of each?
Retrocommissioning can be thought of as an energy audit with an implementation phase, or with follow-up to an energy audit. The energy audit identifies opportunities for efficiency improvements in an existing building and one of these opportunities is frequently the need for a building “tune-up,” or retrocommissioning. Retrocommissioning in this instance would follow the energy audit but sometimes the facility manager realizes the need for both right away and procures the retrocommissioning to include energy audit or energy analysis.
Retrocommissioning is a building tune-up. Just as you wouldn't drive your car for five years without replacing belts, filters, fluids or spark plugs, nether should you operate a complex building for years without a tune-up. A building is, after all, a machine with moving parts intended to work together as a system and after a time, systems deteriorate if left alone. Retrocommissioning is a team sport involving the commissioning agent (CxA) as your quarterback and your maintenance personnel, controls contractor and tab firm as MVP’s. The CxA, probably the one who completed your energy audit, will lead the team to implement the low cost/no cost O&M measures that will move your building back to its original operating condition and design intent.
How do you know it is time for retrocommissioning? There are several clues: 1) have energy bills (measured in units of energy , not dollars) risen inexplicably? 2) Have there been major remodels of spaces within your building that consisted of moving walls around without corresponding changes to HVAC or controls? 3) Were there previous maintenance personnel who were less trained than yours who may have overridden controls they didn’t understand? 4) Does your maintenance staff respond to comfort complaints with Band-Aids instead of with bone fide troubleshooting? 5) Has technology marched on and left your building behind? 6) Has it been five years since your last tune-up? If you can answer yes to one or more of these, perform a Level One energy audit and see where it takes you.
By the way, there is a subtle but minor difference between retrocommissioning and recommissioning, so some in the industry are saying “existing building commissioning” to cover both at once and others are using “r-commissioning,” probably because “existing building commissioning” is such a mouthful! I tend to use retrocommissioning for everything, for simplicity. The difference between retro- and re-commissioning is that recommissioning applies to a building that has been commissioned at some time in the past and now we are commissioning it again while retro refers to commissioning an existing building for the first time. This distinction to me is minor and introduces jargon into the discussion so I prefer the more generic terms.