“Finding the Funds for Good O&M: Success Stories,” a seminar from the Annual Meeting of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), presented documentation showing how those savings can be predicted, as well as financial measuring sticks that are likely to make sense to the owner’s bean counters.
When Bob Baker told people what he was going to speak about before the seminar, he said the response he got was, “Don’t you know building owners only have a few interests? Keep tenants off their backs, and keep the property looking good enough to flip in three to five years.”
DEATH AND THE AHU“I’ve gone through several phases in my understanding of equipment condition,” said Baker, of BBJ Environmental Solutions, Tampa, Fla., when he presented “Air Handler Restoration Repays Cost Many Times Over.” “In 1987, I learned that a system called ‘well maintained’ may not be, and that contamination can kill.” He learned that lesson when four bone marrow patients died from aspergillosis.
In addition, “I’ve come to the opinion there are several different data points to determine whether air-handling units [AHUs] are performing well and efficiently.”
The aspergillis niger was traced to a built-up air handler. “We thought there was good maintenance, but the cold deck was really fouled. There was loss of latent capacity and a high level of condensation on supply grilles.
“It was a life-changing event for me,” Baker said. He started concentrating on infection-control strategies. “AHUs are not as well maintained as they need to be.”
GATHERING DATAThe data-gathering phase on the AHU took place 2002 through 2004. Investigators measured airflow and delta T. The medical building, built in 1979, has 34 floors; two air handlers are on the 19th floor, two are on the 34th. There also are two absorption chillers and conventional pneumatic controls.
With owners’ concerns focused on energy costs, Baker suggested making a maintenance change and documenting costs before and after. Then that change can be applied to systems in other facilities.
The air handler reportedly had been cleaned, but it seemed to have been restricted to the coils, Baker said. There were no known comfort or IAQ problems. Filtration was provided by 4-inch MERV 6 pleats and MERV 11 bag final filters. In general, it was rated in good condition.
“When we started looking at the coils, we questioned whether they had really been cleaned five months prior,” Baker said. “There was a lot of particulate buildup on the coils and in the fans. That much buildup can detriment the fan curve significantly,” reducing its ability 30-35 percent.
During the four-month study period (preceded by a week of pre-cleaning measurements), “We developed 54 separate data sets, monitored chilled-water flow every 15 minutes, logged voltage and amperage on supply and return fans, logged airflow every 15 minutes, measured outside and return air temperature and rh, entering and leaving chilled-water temperature, and condensate temperature.”
After taking preliminary data for a week, they shut the system down and restored it. “It was much more than cleaning,” Baker said.
AHU RESULTSAfter the results were tabulated, “We got a 14 percent pressure drop across the coil,” Baker said. There was a one-degree drop in condensate temperature, so the unit was wringing more moisture out and providing better energy transfer to latent loads.
“We calculated $16,000 savings over 12 months,” he said. The cost of the project was less than $10,000 for a one-year return on investment. From an IAQ standpoint, microbial growth was halted in the coils. “You can never clean a coil completely if it’s a deep coil,” Baker said, “but we got an additional 14 percent improvement in airflow.”
“With a limited number of critical data points - outside air, return air, mixed air, supply air, airflow, and delta T or superheat - you can get a very complete picture on how an air handler is performing.”
ECONOMIC BENEFITSDavid Burggren of Carrier Corp., Beaverton, Ore., presented another data-driven approach to justify preventive maintenance in “Economic Benefits of Preventive Maintenance on HVAC Equipment.” “We’re taking a piece of equipment and over its lifespan, maintaining it to as-new operating condition.”
Considerations for building owners include:
• Service parts. “Things that we know will wear out or plug up. We need to plan on replacing those, not waiting until they cause a problem with the system.”
• Internal rate of return (IRR). “It’s a measure of return on investment. If the IRR is higher than the funds you need to use, it’s a good decision.”
• Net present value (NPV). That’s the present value of all future cash flows minus the initial investment. If the NPV is greater than 0, “do the project,” Burggren said, “but use the smallest possible NPV.”
• Discount rate for the cost of funds. “What are the costs of funds and cost of capital? What do owners expect on a rate of return?”
OTHER VALIDATIONSIn some cases, owners may need to realize what the cost will be if they don’t do the maintenance. When the case for maintenance is qualitative, “I know it feels good, I know it’s right, but I can’t quantify how much it’s going to save,” Burggren said.
For example, if people working in leased spaces become dissatisfied with comfort and reliability, they may move. Occupant turnover, or churn rate, affects the owner’s bottom line. Regular maintenance reduces system downtime and can help prevent tenant dissatisfaction.
“Think of it like your car breaking down on the side of the road during a family vacation,” Burggren said. Before you leave for the trip, you check tire pressure and condition, oil levels, etc. “Those are the kinds of things we’re talking about in a qualitative basis.
“A lot of folks are weighing in on preventive maintenance,” he added, such as local governments, utilities, and advocacy groups. “Performing operational maintenance on a building’s operating system has a direct effect on the energy strategy.”
FUNDING CHALLENGEWhen decisionmakers start talking about a maintenance budget, this is what Burggren said he might need to confront:
• “I can defer maintenance for a little while with little negative effect for some things” (for instance, two maintenance cycles on oil filters and air filters) “with no visible effect.” Those delays need to be qualified for the long term. There may be no obvious problems, but what is happening to the equipment internally?
• The preventive maintenance decision is almost entirely discretionary. “When it comes to your car, gasoline is not discretionary but an oil change can be,” Burggren said. Does that make the oil change less important? Without gas, a car will stop running in the near future. Without an oil change, it will take longer to stop running - and the work required to get it running again will be much more expensive.
WET LEATHERBurggren recalled the replacement of three water-source heat pumps in a three-story retail building with atrium ceilings. He quoted a preventive maintenance contract at about $12,000/year. The owners declined, pointing out that the system was under warranty.
Within the warranty period, the air filters plugged up with lint from all the clothing in the stores. “It created a huge ball of ice and the pan overflowed,” he said. “No switch on the pan could have prevented that.”
The mall had a high-end leather retailer whose merchandise was damaged as a result. “The PM contract would have cost $12,000, vs. $50,000 in ruined merchandise,” Burggren said. “That was a net cost of $35,000 on a $12,000 proposal.”
Another national retailer had a lot of packaged rooftop units. “Previous maintenance contracts had a minor scope,” Burggren said. “It was chosen on a low bid.” It resulted in a reduced total expenditure per store, reduced repair expenditure per store … and reduced customer comfort and sales profits.
Owners and other decisionmakers need to understand: “We’re driving total costs down by driving PM costs up.” Look at long-term expenditures and net value. “Take a chiller crash on a nine-year-old chiller that had minor maintenance but $70,000 repair costs. Plug that into a financial calculator.” Weigh the cost of maintenance against “avoided repairs, energy savings, and the cost of replacing a machine before its time.”
Maintenance “saves energy and prevents unexpected repairs. If the chiller makes it to the end of its useful life, maybe I can even get a few more years out of it.”
Burggren concluded, “The data overwhelmingly says PM on HVAC equipment is a good economic decision. The key is to extrapolate based on known events.”
Sidebar: Getting People on BoardAccording to Mike Moran Jr., Pacific Northwest National Laboratory (PNNL), Richland, Wash., top-to-bottom communication helped get energy-saving points across for a multibuilding campus in the Pacific Northwest. The goal was not only to save energy but to also have as little environmental impact as possible.
“We needed some support from the top,” Moran said during his ASHRAE presentation, “Managing an Energy Program That Affects the Bottom Line.” So, they presented information to the chief operating and executive officers, but “we showed them pictures of what we wanted to accomplish. We wanted them to grease the skids for us to go to facility management.” The method worked.
The consultants also recognized that “those 4,000 people who work in the office have an effect on our bottom line. The employees don’t see the utility bills. If it was in their homes, they would care.”
In order to communicate their energy-saving goals, “We went to staff meetings and got our word out on what we wanted to accomplish. We told them about the effects on the bottom line of just turning off lights and equipment at the end of the day. Little things like that made a difference.”
MAINTENANCE AND LOAD
Retrocommissioning is a critical component in lowering energy consumption of an existing building, Moran said: “taking another look at systems that already exist in your facilities and getting them back to their original design intent.”
Savings also might be found in unexpected places. One of the buildings on this campus, for instance, had a white roof installed to reflect heat. “They didn’t have the maintenance staff to hose off the roof.” Hosing off the 2,000-square-foot roof made a huge difference in the cooling load. “I encourage you, if you have white or solar reflective roof to include cleaning in your maintenance plan.
“Where we really measured the effectiveness of the program was in the Btu/square foot,” he said. Utility rates increased during the time of the project; a drought in the Pacific Northwest placed a strain on the area’s hydro-powered utilities. “We did a lot of good things that affected utility costs, that brought [utility costs] right back where we were before. We fended off the wolves.”
To keep priming employees’ interest in continuing the savings, “We decided to have a contest,” Moran said. In some of the smaller campus buildings, the team recruited “the 4,000 belly buttons walking around our campus” to do simple things, like using blinds for natural light.
The rewards were free coffee and doughnuts for occupants of the campus buildings that achieved the greatest energy savings. However, “When some people knew they couldn’t win, their numbers dropped off the chart.” In general, however, the incentives were successful and the results were good. “It only took us time, coffee, and doughnuts.”
Motivation and education need to be repeated, Moran advised, especially in facilities where people relocate a lot. “Because of the churn rate, a lot of those people aren’t there anymore. But it is on the books to do again.”
It’s also important to learn how a company and/or its employees can benefit from new mechanical technologies, and still more important to let people know when a new technology has been installed, and its purpose. When wireless temperature sensors were installed at PNNL, for example, “Our people didn’t know what they were,” Moran said. “They thought they were recording devices.” It made staff uneasy, to say the least.
- B. Checket-Hanks