Pop quiz: Which of the HVAC problems listed on this page have actually been uncovered in high-rise buildings?
Answer: All of them. After talking to energy and HVAC experts, we uncovered some real-world examples of what they’ve seen unfold in both newer and older facilities.
Read on to see what other facilities professionals have had to deal with in their high-rises, and pick up some pointers on preventing these situations in your own building.
High Demand for (Seemingly) No Reason
Sain Engineering Associates’ Senior Energy Engineer Jason Brooks was working on a recent HVAC project involving a 280,000-square-foot high-rise built in the early 1980s. As an all-electric building, it had no natural gas. A new management company had taken over, and the building was fully occupied. When February rolled around, demand suddenly shot through the roof; maintenance personnel were receiving constant hot and cold calls. “When you experience a high number of problems like that, and you have to move from one crisis to the next, it can lead to temporary fixes accidentally becoming permanent repairs,” he emphasizes.
So Brooks analyzed the building automation and energy management control systems to see if he could find the source of the problem. “I spent the majority of my time sitting there just scrolling through data,” he explains. After finding no clues there, Brooks and his team conducted occupied and unoccupied building walkthroughs to see what was taking place during the day and overnight.
The building had an older control system, and everything was being operated manually. “If they had to change the discharge air temperature, they had to go to the seventh floor, walk through an office, go to a mechanical room, and actually change a dial,” says Brooks. It was determined that much of the HVAC equipment wasn’t in auto mode, the economizer on every air handler was set to come on at 45 degrees F. and stay on until 32 degrees F. – and the list of discoveries went on. “That, of course, was driving their heating through the roof with close to 20 air-handling units bringing in freezing outside air in February.”
[pullquote]Most buildings – especially newer high-rises – have pretty robust management systems. But what I don’t feel is always as robust is the building staff.[/pullquote]
Building personnel did the right thing by calling for help when they noticed an increase in demand. Any change like that warrants further investigation. But there are a few things to learn from this situation. First, when you receive a complaint from a tenant or occupant, a quick fix is okay in order to maintain comfort levels temporarily. But temporary repairs can be easy to forget – especially if they’re working. Establish a process to document any temporary repairs made, and make sure you have a plan and timeline in place for fixing the problem permanently.
In many high-rise buildings, lack of staffing may be part of the challenge. “A lot of times, high-rise facilities staff are almost slaves to the complaint box,” Mike Della Barba, director of commissioning services at Environmental Health & Engineering, points out. When staff members are so bogged down with addressing complaints, it’s hard for them to find time to assess system performance. Instead of being proactive (making sure set points are programmed correctly, schedule modes aren’t being overridden, alarms are being addressed instead of being taken offline because they’re a nuisance, etc.), facilities staff may have no choice but to be reactive and address problems as they pop up.
“Most buildings – especially newer high-rises – have pretty robust management systems,” says Della Barba. “But what I don’t feel is always as robust is the building staff. They have their hands full; there are so many things on their plates that monitoring on a regular basis is difficult.” If hiring additional staff isn’t in the cards, Della Barba says there are systems available with add-on software programs that will monitor certain criteria according to ranges and system performance goals, from damper and valve positions to discharge temperature. If something falls out of these pre-determined ranges, the facilities team receives an alert.
“If you can’t walk every air handler or all your systems daily, at least have someone monitoring this trend data,” Della Barba recommends.
Repair vs. Replacement
In a local high-rise condo with four 30-year-old rooftop air conditioners providing anywhere from 10 to 40 tons of cooling each, Tony Mori, commercial HVAC estimator/planner at Crockett Facilities Services, noticed the units were limping along and band-aided together. “One of the things we realized was that these four units controlled the stairwells, main atrium areas, and hallways. It was built sort of like a hotel. If any of these units went down, the building’s main meeting room and all the hallways would be without air-conditioning.” After pointing out the problems with a system designed this way, the condo’s management team decided to replace the rooftop units after learning about the energy-savings potential, as well as the rebates available for making the change.
[pullquote]If they shut off the boilers, they were afraid that the hot water piping was going to start leaking, and they understandably didn’t want to take risks of damaging expensive equipment in the building – so they chose to leave the boilers running year-round.[/pullquote]It may seem out-of-budget to replace aging systems if they’re still running, but it’s important to also keep in mind the potential problems they cause due to age. In this example, a lack of air-conditioning could impact productivity and tenant satisfaction, as well as paint a negative picture of living conditions if potential tenants were visiting when a rooftop unit went down.
When determining whether new HVAC equipment is worth the investment, take into account the energy savings it will provide, as well as any incentives or rebates being offered to offset upfront or operating costs.
Covering Up Major Problems
In a HVAC project involving a high-rise built in the early 1990s, Brooks was working with a team that didn’t want to shut off boilers. “If they shut off the boilers, they were afraid that the hot water piping was going to start leaking, and they understandably didn’t want to take risks of damaging expensive equipment in the building – so they chose to leave the boilers running year-round.”
Two of the building’s maintenance professionals had been on staff for approximately 15 years. During this time, they indicated that one of the boilers had never been shut off. Brooks finally convinced them to shut it down and see what happened, so they could find out what they needed to fix. Although it was nerve-wracking, the boiler was shut off – and the team was able to find and repair the leaks.
It might be scary, but if you’re aware of a potentially large underlying issue with the HVAC system, it’s best in the long run to bite the bullet and address it. Imagine how much this 1990s high-rise could have saved in utility costs by tackling the issue head-on several years ago instead of letting boilers run continuously for decades to avoid making necessary repairs.
One high-rise’s lighting and HVAC systems were controlled by a building automation system (BAS) – a good step toward efficiency and savings. Despite this, three vacant floors had lights on during the day, and the spaces were kept at nearly 70 degrees F.
After looking through the BAS, Brooks discovered that the air handlers could be turned off on those three floors. In an attempt to keep the systems off, however, someone had mistakenly set a time schedule telling the HVAC and lighting systems to come on at 24:00 and shut off at 23:59. Instead of keeping the systems off 24/7, this schedule kept them on all the time. “It’s a common error, and would be easy to do,” Brooks emphasizes. The schedule was set, but no one ever checked to see if the controls were performing the intended tasks.
Brooks has also seen occupancy change within a high-rise without building systems being adjusted accordingly. “If a tenant originally had people coming in on the weekends, but then switched to weekdays only, it’s possible that the HVAC system’s occupancy schedules were never changed to match.”
Communication and routine preventive maintenance checks could have prevented these situations.
“You have to know your load in the space,” says Della Barba, “including your occupied demand, unoccupied demand, critical demand, and non-critical demand. And is the system scheduled accordingly? In other words, if you’ve got a one-shift operation from 7am to 7pm, does your building have an unoccupied mode it switches to after 7pm to allow equipment, infrastructure, and main energy-using equipment to throttle back?” Della Barba has encountered several buildings with staff members who indicate that they do have an unoccupied setback mode, but further investigation shows that it’s not working or isn’t being used.
The Maintenance Factor
[pullquote]I’ve never seen less than 10-percent savings on any HVAC optimization project.[/pullquote]
In an effort to save costs, Mori knows one company with approximately 50 locations in Washington DC, Virginia, and Maryland that chose to cut HVAC maintenance back from quarterly to semi-annually. Their reasoning? “They weren’t making a lot of service calls, and weren’t having problems with their HVAC system,” Mori explains. “But that’s because we were coming out every quarter and keeping up on things.”
Once maintenance was cut back to semi-annual, Mori was inundated with service calls. After realizing the problems associated with cutting corners on maintenance, the company decided to go back to a quarterly maintenance plan.
Maintenance and optimization are crucial – and can prevent HVAC problems by catching small issues early on and addressing them. Even simple things, such as filter changes and belt adjustments, can keep systems running smoothly and prevent downtime.
The typical savings associated with optimizing high-rise building systems can be between 10 and 20 percent. “I’ve never seen less than 10-percent savings on any HVAC optimization project,” says Della Barba. “When we do HVAC work, the simple payback for a large building with total utility costs of $750,000 per year or more is typically 12 months. If the local utility provides rebates for savings, the payback period will be substantially less.”
More Expert HVAC Advice
The experts we talked to also had a few more recommendations to share with building owners and facilities managers who are responsible for HVAC systems in high-rise buildings:
Learn About Your System
[pullquote]Our energy savings this year were equal to the cost of putting 10 students through college for a semester.[/pullquote]If a major retrofit project involves HVAC systems, make sure you receive full training, discuss the preventive maintenance required, and obtain a full and accurate O&M (operations and maintenance) manual, which will include directions for filter changes, controls checks, etc. “Get all the documentation you’re owed on day one. Get a solid benchmark from the construction and commissioning team that goes beyond the obvious, ‘You’ve got a 500-ton Trane chiller or McQuay air handler.’ Are the dampers set correctly, are the actuators set correctly, are all the control points pointed correctly? Is the monitoring station set up correctly, with all the graphics that are supposed to be there? Really grill the construction and commissioning team, and make sure you understand the preventive maintenance requirements, know who to call from a manufacturer standpoint, and schedule a checkup while the warranties are still in place to make sure everything runs like it did on day one,” says Della Barba.
No- and Low-Cost Recommendations
- Hang a sign-in sheet right next to the BAS, Brooks says. Anyone who makes changes should write them down and call the appropriate person to let them know what changes were made.
- Maintain a common parts inventory to reduce temporary quick fixes. For example, if an outside air dampener actuator goes bad, it’s just as easy to grab one off the shelf and replace it instead of disconnecting the linkage, opening it, and then deciding to go order one, says Brooks.
- Buy programmable thermostats, recommends Mori. “They cost between $100 and $150, and will save you run hours and wear and tear on the equipment. Aside from changing air filters, this is one of the cheapest improvements you can make.”
Involve Tenants and Occupants
Whether it’s through incentives or competitions, encourage tenants and occupants to reduce HVAC energy waste in the building. Brooks also recommends keeping them looped in about energy achievements. “On an intranet homepage, some companies include energy dashboards that display today’s consumption vs. yesterday vs. this time last year. Instead of displaying kilowatts per hour saved, turn those numbers into something more tangible: ‘Our energy savings this year were equal to the cost of putting 10 students through college for a semester.’ ”
Take Advantage of Downtime in Between Tenants
When tenant improvement projects occur, it’s not uncommon to overlook HVAC systems. Before a new tenant moves in, building management often brings in a contractor to tear down walls, install new doors and lights, and repaint. “Most of the time, they leave the old HVAC equipment there without checking it,” Mori says, “and it’s old, running on bubble gum and duct tape.”
When you’re in between tenants, and already planning to make space improvements, don’t forget to examine at any HVAC equipment impacting that space. It’s a good time to look for existing problems or red flags, or replace aging equipment.