Managers Analyze the Performance of Existing Equipment
*Tom Broene, Assistant Chief Engineer, San Diego Marriott Hotel & Marina
*George E. Kevins, Facilities Project Manager, Central Kitsap School District 401, Silverdale, Wash.
*Tom Laabs, Director of Facilities Services, Mercy Medical Center, Oshkosh, Wis.
As building systems age and facility operations expand, maintenance and engineering managers do their best to ensure equipment performs as close to design specifications as possible. As these three managers have discovered, retrocommissioning is a strategy that assesses the extent to which system performance has changed and provides a roadmap for returning equipment to peak operating condition.
Question: What are the key considerations in deciding on the systems and components to retrocommission?
KEVINS: What we do here at the district is look at our energy use and compare it on a local or national building energy index. A building energy index is in units of Btus per square foot per year and is an attempt at normalizing energy usage so facilities can be compared against other similar facilities. Then we look at the number of customer complaints. That also is a good indicator, particularly for HVAC issues. The majority of retrocommissioning has to do with mechanical equipment, HVAC, and energy-management systems, sometimes called direct-digital control (DDC) systems. When you deal with schools, as you do with other facilities, like office spaces, occupants have a tendency of changing the usage over time of the space, compared to design. The result is indoor air quality issues or ventilation issues, leading facility managers to look at retrocommissioning to evaluate and correct the occupant's issues.
BROENE: First of all, (we look at) the needs of the building. Through a lot of different techniques, we find the pulse of the property and find out what it's telling us and (what it) needs. In the case of the chilled-water plant, we found that we were way under capacity. We kind of knew that from operating because we had to shuffle load around during busy times. Also, the age of the current equipment, the potential of efficiency gain, and minimizing impact to our guests to try and provide the best experience we can. The return on investment (ROI) is a huge consideration as well.
LAABS: We've been involved with an energy team, and the energy team consists of our local service provider, WPS (Wisconsin Public Service), Focus on Energy (a Wisconsin company that funds and coordinates energy-efficiency projects), plus myself. Depending on the project, we've brought marketing in, we've brought IT (information technology) in, and Focus on Energy and WPS will bring in their experts, as well as our representatives from our company. We'll meet and look at what incentives and what projects should be considered. We have a running Excel spreadsheet of open items and items to be looked at from an energy perspective.
Question: What were the cost considerations involved with the projects? Was it a tough sell justifying those costs?
KEVINS: (For an elementary school project) the upfront costs were in the neighborhood of about $10,000 a few years ago. Today's prices have increased. Comparing the building energy index for similar schools will indicate how difficult it will be to justify. Management looks at payback, and a project with a poor building energy index (result) will pay back quickly. Cost savings graphed based on improving the building energy index is a good presentation for showing dollar savings and justifying retrocommissioning.
LAABS: What we've looked at from an energy-team perspective is, we try to identify things that we can have an 18-month payback or less. If we have an 18-month or less payback, we normally will do that project anyway. I'll use the boiler heat-recovery system as an example. The payback (for that project) was closer to 24-28 months, so what Focus on Energy can do for us with a grant is they can grant us enough money to bring the payback down to an 18-month payback. Our senior leadership probably wouldn't have OK'd that project without Focus on Energy's grant help.
BROENE: When it involves money, it's always a tough sell. First of all, we had to consider the ROI. Whenever we can get an ROI of less than 1.5 years, it's usually very simple to get that project passed. In the case of the chilled-water plant, I don't believe it was less than 1.5 years. However, we were able to prove that the old chillers we had without VFDs (variable-frequency drives) were running relatively inefficiently. Whereas, by putting in another chiller of approximately the same size as those — we had two 600-ton (units) and we put in a 550-ton chiller with a VFD — and integrating that into our new BAS (building-automation system), we were able to use that as a base-load chiller, where it ran at its most efficient at part load, which is a good portion of the time that our chillers run. We were able to sell it that way.
Question: In what ways does retrocommissioning go beyond or complement preventive maintenance (PM) programs?
LAABS: It's been 10 years since we opened up the hospital. Over the course of those 10 years, we know that we've had space utilization that has changed, and we're really not sure if the (mechanical and electrical) systems changed with those space-utilization changes. Even though our building might be set up and working the way it was designed to originally, (the question is), "Is it still working that way now, and does it meet our needs?" We're going into this in-depth study of all these systems and what they're actually being used for now, comparing all the data between what they were designed for and what they're being used for. My goal is to not only identify projects that can be done and have a quick fix right now, but I'm hoping for a three- to five-year roadmap of identified energy savings so that I know where the best place to put my investment is.
BROENE: Putting some of my guys with (the consultant) definitely helps our preventive maintenance programs because they learn this equipment better than they ever knew it. Through the equipment upgrades and the tracking of data, I would say that it helps to integrate new upgrades with our current equipment. It improves the performance of the other equipment. For example, when we did the chilled-water system and we put booster pumps in with VFDs on them, it increased the performance of the pumps that got the VFDs and definitely increased the performance of the boiler.
KEVINS: There are many examples of how retrocommissioning can improve system performance, and they all complement the preventive or planned maintenance program. Economizer control and control of the HVAC outside- and return-air dampers for free cooling from outside air during the mild weather is an area often overlooked during the PM process. The retrocommissioning process goes beyond the operation of the equipment and checks the seating and sequencing of the dampers, which allows the economizer control to function at peak performance. Any overlapping of the heating and cooling sequences are also caught during retrocommissioning but commonly missed during preventive or planned maintenance. With cost cutting and staff reductions, maintenance staffs are constrained by time and, as a result, are moving from problem to problem. Economizer and heating and cooling overlap issues are energy and operating cost issues, not necessarily problem areas.
Question: What type of experience and expertise should managers consider when putting together a team for a retrocommissioning project?
KEVINS: You need an in-house person, someone who understands and knows the systems that you're dealing with and also knows the space usage. That's on the in-house side. On the side that is brought in, the ability to re-calculate air flows to meet the current needs that's been a key issue in schools. The ability to operate and review the software for the DDC system is important for a consultant or commissioning agent coming into the facility. One (outside) person who's knowledgeable in the mechanical-engineering menu, as well as the DDC side, and an in-house person that's knowledgeable on the systems and can assist that individual that's brought in is important to make up the retrocommissioning team.
LAABS: Focus on Energy, if you want to have their program, they require a third-party engineering firm that manages the project. In the initial contract, there are some things you are agreeing to, one being that you're going to supply the maintenance individuals in-house to supply these engineers with the information that they need. They have a list of recommendations of people they've worked with in the past, but by no means do you have to use one of those people.
BROENE: It all starts with a really passionate outside consultant. Our consultant was the most passionate guy about saving energy that I've ever met and a very, very smart man. Since he became so popular with Marriott, we (have been) looking to find a new consultant. We've gone through quite a few. Some of things we've looked at in considering them are their previous retrocommissioning experience, definitely their passion to properly operate equipment, and passionate about energy savings. (Consultants should be) very passionate about professionalism and very flexible in their ability to sell the projects on the financial aspects. Also, (consultants should be) passionate about follow-up and documentation.
Question: What are some of the most important lessons you learned from the project?
BROENE: It got our focus on the systems, rather than just the individual piece of equipment. As a team, we learned — through all the different projects that we've done — that there are a lot of incentives out there to pay for this, which makes it an easier sell. (Our utility has) really great incentive programs. That's one of the things we really learned to take advantage of. Through that, we learned that with everything going on every day, we don't think much about refrigeration gaskets or the fact that we have inefficient lighting in our parking lots. It kind of opens up your eyes.
KEVINS: The biggest thing was we spent about half of the time working on the DDC system. Once we started going through the mechanical equipment, we collected a lot of data that could be used and actually inputted into the PM program — things like belt sizes, pulley sizes, and horsepower. Once we started getting into the controls, that's where the biggest issues were found, and they were issues that weren't as obvious because they were buried into the software. For the elementary school project, one of the big issues was re-calculating the CFMs (cubic feet per minute) necessary for the spaces. We ended up redesigning the HVAC distribution system because things had changed so much. What we were doing before was over-cooling some areas to cool others, and same thing on the heating side. Redistributing the airflow and calculating what the needs were made a big difference. Those, to me, are the areas that you really have to spend time on.
LAABS: You really need to spend some time with the staff and make sure that they understand why you're doing this and why it's important for them to share as much information as possible (with the third-party engineer) and make it a real positive thing, rather than having it spun into getting defensive that they might be doing something wrong. Before they even get a hint of a third party coming in, you need to spend that time upfront with your staff.
Question: Once the retrocommissioning process is complete, what type of documentation should managers and technicians receive to implement suggested changes and maintain the systems throughout their life cycle?
KEVINS: I actually create a set of forms that gives me the specifications for each piece of equipment — horsepower, belt size, CFMs. I set it up in three columns. (The first column says) this is what the design was. (The second says) this is what I actually measured when I started. (The third says) this is where I'm going to be when I leave. That's one part of the documentation — the information on the equipment. That is helpful for the PM program, and it gives the mechanic a starting point. Then I actually write out the sequence of operations for the piece of equipment and show the verification of the sequence with actual temperatures under given conditions.
BROENE: (We have) very thorough documentation on what happened and why we did what we did. (Our consultant) went as far as making a book with pictures of valves and locations. (It says), "If you have issues with balancing, make sure you check that this valve is open or this valve is closed."