By Marc Karell, P.E., CEM, EBCPClimate Change & Environmental Services, LLC
There is a methodology to reliably and inexpensively reduce energy costs. What is this? Retrocommissioning, the process of reviewing the operations of the existing energy systems of your buildings and optimizing them to ensure they meet your needs. Retrocommissioning of existing building energy systems has been around for some time, as have many benefits – cost and otherwise – for the building owner.
What Exactly Is Retrocommissioning?
Retrocommissioning (or RCx) requires making your existing equipment and operations more efficient and operate as they were originally designed to operate when first installed; in other words, RCx lets you get the performance that you paid for. It requires a thorough review of operations and measurement and verification (M&V) to demonstrate cost benefits. It involves training of staff who operate the systems on a daily basis for optimal operation.
RCx is different from energy auditing. RCx focuses on operations and maintenance issues, while energy audits tend to identify whole energy systems that need replacement or upgrading (useful future capital projects).
RCx often involves corrective actions during the investigation and emphasizes adjustments to improve efficiency and preventative maintenance (pay a little now or pay more later) of existing equipment. Many suggested RCx changes are no or low cost with a simple payback of under one year. It is a simple fact that heating and air conditioning and other energy-consuming systems are not high priorities for maintenance over time and that staff is rarely adequately trained to detect and correct problems. However, as these systems’ performances become less effective in time there is an energy penalty and cost involved for the building. You do not have to “shrug your shoulders” and accept this as inevitable. RCx can get your systems back to near new and optimal conditions, saving energy use and money.
Ongoing RCx is analogous to predictive maintenance as it uses proactive monitoring to discover ways to improve operations or prevent systems from operating sub-optimally.
RCx Is Smart Asset Management
For most buildings and companies, RCx is easier to fund because many efficiency improvements are low cost, compared to the recommended capital equipment upgrades of an energy audit. Therefore, most funding for RCx projects derives from easier-to-tap operating budgets versus that for equipment upgrade projects coming from capital budgets (harder-to-justify and get approval).
And remember, RCx is now mandatory for certain buildings in New York City (Local Law 87). Other cities, such as Boston and San Francisco, have recently promulgated energy efficiency laws. RCx is of growing interest in other US cities and for utilities looking to reduce the growth of energy usage in order to reduce the demand for electricity and the need to build new infrastructure and power plants.
– Money savings. As discussed below, the average energy savings cited in two RCx studies encompassing hundreds of US buildings was 15-20%. And that is the initial year. These savings grow as the unit cost of electricity or fuel rises.
– Reduced productivity losses. In addition, RCx results in lower inconvenience of tenants due to fewer equipment failures. Fewer emergencies to address also means reduced repair and maintenance costs and improved allocation and attention of your maintenance and custodial personnel to other tasks.
– Water conservation
– Reduced productivity declines. RCx results in more comfortable surroundings and thus fewer complaints filed. This also results in lower employee turnover and greater tenant retention rates, which usually mean HR cost savings and larger rents that can be collected.
– Lower environmental impact. An RCx program resulting in lower electricity and fuel usage means a reduced carbon footprint, lower emission rates of other pollutants, and a better chance of compliance with your permits and applicable air regulations.
– Reduced risks. Better performing equipment means enhanced safety (fewer personnel interacting with equipment and thus fewer accidents), improved indoor air quality, fewer costly equipment failures, lower asset degradation, and reduction in litigation and documentation defense. Again, this all results in reduced risks, costs, and more satisfied workers and tenants.
Is This Really True?
Two major studies were published showing the benefits of RCx. A Texas A&M study of over 100 US buildings over a ten-year period showed that retrocommissioning resulted in an average cost savings of 20%, despite little to no capital investment for most items. For most RCx measures incorporated, the simple payback was under 2 years.
Another major study was performed by the Lawrence Berkley National Laboratory covering 106 existing buildings, 22.2 million sq. ft. in 15 states:
- Median existing building size 151,000 sf, median age: 25 years old
- Median number of deficiencies in existing systems found: 11 per project
- Median cost of RCx per project $34,000: $0.27/sf
- Median savings per project $45,000/year or 15% of total building energy cost
- Simple payback on energy alone: 1.0 year; including non-energy benefits: 0.7 years.
Preparing For Retrocommissioning
The most important way to prepare for RCx – to ensure it proceeds smoothly and gives you optimal results – is to have your facility manager and maintenance people present to meet with the RCx professional. Depending on the complexity of the building, the professional may need several days on-site to inspect and operate equipment to make sure it is clean, operates properly, and is coordinated with calibrated controls (sensors, thermostats, etc.). Often RCx studies are conducted over several months or seasons. To save time for one commercial client recently I evaluated a boiler operating on a hot (90°F) day. We operated the boiler during lunch, when most workers were out of the building. Also, make sure that you have handy all of the manuals, specifications, and other documentation about your equipment, to minimize guesswork.
CCES has professionals who are accredited professionals for performing both energy audits and retrocommissioning studies under the Association of Energy Engineers, qualified to work for compliance under New York City’s Local Law 87. We can perform both energy audits and RCx to maximize both the financial and non-financial benefits of energy efficiency and proper system operation for diverse building types and systems. Contact us at 914-584-6720 or at karell@CCESworld.com.
Marc Karell, P.E., CEM, Principal, Climate Change & Environmental Services, LLC
Reprinted with permission by CCES
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