HVAC: It's Payback Time
Part 1: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
By Loren Snyder - January 2010 - HVAC
Pundits and politicians alike have declared the recession over. That may be good news, but it doesn't necessarily mean that the belt-tightening is through.
Organizations continue to look for ways to trim costs without incurring significant expenses. For facility managers, that means turning a sharp eye and a red pen to operating costs. Given its impact on the bottom line, the HVAC system is an especially important target. In today's business climate, the winning projects are often low-cost fixes or more costly projects that are worth the expense because of a rapid payback.
One strategy to consider is commissioning. Most facility managers have heard of the term, though more than a few might be hard-pressed to define exactly what commissioning is and what it can do.
Evan Mills, a staff scientist at the Lawrence Berkeley National Laboratory (LBNL), has studied the potential of commissioning extensively and calls it an "enigmatic practice whose visibility severely lags its potential."
Although commissioning is not limited to HVAC systems, those systems — both software and hardware — are the foundation for commissioning.
When applied to existing buildings, Mills notes, commissioning identifies the almost inevitable "drift" from where things should be and puts the building back on course.
Another similar definition comes from BetterBricks: "Commissioning is a process to evaluate performance and identify fixes, but not a fix in itself," according to Janice Peterson, manager of the Northwest Energy Efficiency Alliance's BetterBricks' building operations program.
Mills further says that commissioning is a systematic, forensic approach to quality assurance, rather than a technology — and that's no small distinction for facility managers.
Neither is the potential savings that result from commissioning a small distinction for facility managers. According to a study commissioned by LBNL, the median normalized cost to deliver commissioning was $0.30 per square foot for existing buildings. What do facility managers get for the money? The commissioning projects in the LBNL study revealed more than 10,000 energy-related problems, resulting in 16 percent median whole-building energy savings. HVAC systems, of course, will be a constituent slice of that energy-savings pie.
According to the LBNL report — which examined hundreds of buildings across the U.S. — cash-on-cash returns for existing buildings is upwards of 91 percent, and in the mid-20s for new buildings. Overall payback time in existing buildings was 1.1 years, and 4.2 years in new construction. When segmenting out HVAC concerns only, payback time is still 1.6 years in existing buildings. Nearly 99 million square feet of building space was part of the study, with more than 90 million square feet of that space in existing buildings.
"These findings demonstrate that commissioning is arguably the single-most cost-effective strategy for reducing energy, costs and greenhouse gas emissions in buildings today," Mills says. He also notes that energy savings tend to persist at least over a three- to five-year span, if not longer.
Individual findings can vary greatly. Laurie Gilmer, an associate at Facility Engineering Associates, says she has found that commissioning can net between 5 and 20 percent savings for an organization.
Building System Operations Map
Once the commissioning process restores the HVAC system (and other systems within a facility) to their original design specifications, developing a building system operations map to dig a bit deeper should be the next step.
Specifically, an operations map examines current conditions and building uses. It should identify major energy-using systems and occupancy types by area. It then focuses on optimizing setpoints and scheduling to achieve efficiency improvements, with the end goal of precisely matching energy systems to actual use.
"Developing the map requires reviewing utility bills, as-built drawings, and sequences of operations," says Peterson. "That includes interviewing building operations and maintenance staff and reviewing systems and equipment with a focus on targeting particular HVAC systems for potential energy savings."
Gilmer says that the process of finding the right setpoints and scheduling can yield lots of "little gems" in building operation.
"Things like finding a sequence of control that was supposed to be initiated but never was," she says. "It's a simple matter of adjustment to bring the system on at appropriate times and, when that's done, the savings can really add up."
SimonMayport wrote re: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
on 2/9/2011 3:44:54 AM
I’m all for HVAC systems and I am speaking from an environmentally conscious voice, but it is really up to the schools and training centers to design a god board programs so as to support its accrediting commission organization as it is challenging enough to encourage strong participation.
Bernie Daily wrote re: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
on 9/25/2010 4:31:19 PM
De-optimization of a building, which brings a need to recommission, is most commonly a event based process with definable points on a time line.
Facilities managers have a lot on their plate and there is a certain amount of pain in running a building. A fully optimized building runs with equipment capable of full performance and a defined schedule of occupancy based on the construction design requirements. You really can not plot a curve of decreasing performance over time. It is a step process.
The first time an occupant with political clout works a Saturday and the air conditioning is off an event takes place. If they called the director of facilities the word may come the the maintenance supervisor that "I never want a call like that again." An Event! Now the schedule changes from 6AM-6PM M-F to 6AM-6PM M-S. A small change that removes that piece of pain from the operation. A few more blood curdling "Events" and the whole place is 24/7.
Financially a budget may be cut for water loop chemical treatment. This is an Event. I once saw alternating biocide treatment curtailed because the alternate biocide was "too expensive". These are the decisions that fill coils with silt. It is not the age of the unit. It is the Event of the decision.
Facilities operations are constantly required to react and usually the least painful way wins.
When a third party comes in to recommission they basically put all the operations "pain" back into the building. If they leave the supervisor on his own after their event it will take about three years for a normal process of events to remove the pain. If a managing group is formed as part of the recommissioning the supervisor can have support and reactions can be moderated; sometimes avoided.
Continuous Commissioning with a group buy-in is the way to reduce energy consumption 30 to 40% and a way to get full life cycle performance from your equipment.
HVAC Knoxville wrote re: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
on 9/16/2010 3:08:21 PM
Perfect article. I work for a Knoxville HVAC company and we regularly create commissioning reports for commercial facilities. One thing we try to do with these reports is help our customers understand just how much they can save. I also found another great article here. Keep up the good work!
wross wrote re: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
on 2/26/2010 7:23:51 AM
When we commission equipment at our plant, the process is to make certain the machinery is valid as specified according to our engineering specs, the vendors quote, and our po. If a 10 year old piece of equipment is recommissioned according to spec, then heather above has a good point in limiting the energy performance level based on these requirements.
Doing scheduled PM's and simply upgrading to a programmable t-stat have been found to be effective cost savings.
Gary Gigot, CMO, Optimum Energy wrote re: Commissioning HVAC Systems Can Reveal Ways to Save Energy and Money
on 2/22/2010 1:09:28 PM
Commissioning certainly has benefits, but there are two things to consider with commissioning: 1) commissioning (if done right) can bring an HVAC system back to the performance level of the system as it was originally designed, but that design may very well have not been driven by the goal of optimizing energy performance, limiting the amount of savings that can be achieved; and 2) commissioning is typically performed only once every few years, so in between commissioning, plant operating efficiency is unknown and likely drifts to less-than efficient operations.
We believe the key to true, sustained energy efficiency requires a different approach to commercial HVAC energy efficiency – one that 1) uses technology to optimize HVAC system performance for energy efficiency, continuously and based on real-time load conditions; and 2) provides 24/7 access to measurement and verification, so that plant operators can see, at any point in time, exactly how their HVAC system is performing. That level of real-time insight into actual plant performance means that if the HVAC plant is not performing as efficiently as it should be, problems can be identified and corrections made immediately – eliminating drift and the need for re-commissioning.
Affordable, proven technologies are available today that are reducing HVAC energy consumption by 30-60%, month-after-month, year-after-year, in a wide range of commercial facilities. Instead of periodic commissioning, why not consider a different approach – one that provides ongoing optimal performance and persistent savings?