Projects Highlight Ways to Optimize Building Energy Efficiency
Five case studies outline how different solutions help building owners reach their efficiency goals
With commercial building codes mandating increasing levels of efficiency and energy prices only continuing to rise, many building owners are looking for ways to boost building performance in both new and existing buildings. The following case studies highlight several ways in which HVACR solutions have been implemented to help building owners meet their energy-efficiency and comfort goals.
BRICKELL CITY CENTRE
Brickell City Centre is a new mixed-use complex in Miami that is built locally but designed with a long-term global outlook. When the development of the Brickell City Centre began, Bosch Thermotechnology Corp.’s FHP water-source heat pumps (WSHP) were an obvious choice for the project’s HVAC needs.
The Brickell City Centre features two residential towers with 390 condos in each tower and one hotel.
Bosch worked with Jascko Corp.’s Alex Valdes and Thermal Concepts Inc., a Davie, Florida-based mechanical contractor, to get the right combination of price, efficiency, and footprint for the project. Managers at Thermal Concepts knew they needed a high-efficiency solution that was compatible with the unique design objectives and high-end aesthetics of the overall development and worked with Valdes and Bosch Thermotechnology to develop a specialized unit that fit in the limited footprint of the condos within the Centre.
The developer of the Brickell City Centre project focused heavily on the project’s long-term global outlook. A custom variation of the Bosch FHP LV Model WSHP was used in the residential condo units of the Brickell City Centre towers; the units are compact yet extremely energy-efficient, making them an excellent choice for new construction or for energy-saving replacements.
The LV is an option-rich single-stage product that is available in ½- to 6-ton sizes and meets or exceeds ASHRAE 90.1 efficiency ratings. The unit comes with a unique sound package designed to keep sound levels to a minimum while providing maximum comfort. Because they are WSHP, they do not require outside condensing air, which allows for easier placement in enclosed spaces while still allowing for separate metering of utility costs. The units in this project were equipped with single-point electric heat and were seamlessly integrated into the structure’s building management system (BMS), thereby providing operating feedback and easier serviceability.
With Bosch FHP WSHP units providing smart comfort, efficient performance, and quiet operation, the future Brickell City Centre residents can indeed be home in the heart of it all.
KENTUCKY HEALTH CARE CENTER
Engineers at a 359-bed health care facility in Kentucky struggled to keep the hospital’s cafeteria cool amid the Bluegrass State’s humid climate. Condensate in the air-handling unit (AHU) serving the food service area was leaving a residue in the coil — a buildup that reduced airflow through the unit from the 14,000-cfm design parameter to around 10,000 cfm — nearly 30 percent less than what was originally specified. That, of course, meant the unit couldn’t provide enough cooling volume.
In an attempt to boost cooling capacity, the hospital’s maintenance staff tried to increase the volume of airflow over the coil by performing up to three mechanical coil cleanings per year at roughly $300 per treatment. The cafeteria AHU was the worst performer among the medical center’s roughly 30 air handlers, and staff was considering replacing it — a task that would cost more than $20,000 and require the unit to be shut down for two to three days.
Charles Haskins, a sales engineer with Thermal Equipment Sales in Louisville, Kentucky, arranged for a UV-C technology primer from UV Resources (UVR). Ultraviolet germicidal irradiation uses short-wavelength UV-C light to kill microorganisms and degrade organic matter in HVACR equipment. The technology has been used since the 1990s to eliminate microbial and organic material buildup on cooling coils, air filters, duct surfaces, and drain pans. A UV-C-equipped system yields clean air, uses minimal energy, and needs very little maintenance. UV-C can also slash 10-25 percent of HVAC system energy use, and the cost is often less than a fraction of a coil replacement.
“UV-C systems remove organic growth on the outer and inner surfaces of the coil, thereby restoring the coil’s heat transfer efficiency to ‘as-built’ specifications,” said Dean Saputa, vice president, UV Resources.
Saputa and Haskins were certain they could restore the cafeteria’s airflow levels and meet the desired temperature set point by installing the UV Resources RLM Xtreme™ system.
The RLM Xtreme is a high-output, fixtureless system that offers the flexibility to be easily configured into most HVAC plenums. The configuration installed in the hospital cafeteria’s AHU consisted of four T5 (5/8-inch diameter), 61-inch-long UV-C lamps; a unique LampHolder that allows the lamp to be affixed in any position inside the air handler; and a power supply with a powder-coated, heavy-gauge galvanized steel and NEMA-2-rated housing. Its EncapsuLamp™ (FEP lamp coating) technology protects the system and airstream from glass and mercury residues, should an accidental lamp break occur.
The UV lamps were installed on the downstream, air-exiting side of the coil, where they are most productive killing mold and bacteria and degrading all other organic materials. For the Kentucky medical center, the UV-C installation represented about 10 percent of the cost of a new replacement coil.
Once the UV-C fixtures were installed, the team planned to evaluate progress following a three-month trial. To document progress, the cafeteria AHU was connected to a Super Scientifics manometer to measure pressure drop across the coil and an Ebtron air-monitoring station to record airflow levels. Both devices were equipped with data loggers.
After 90 days, airflow was back to design specs, and staff was able to maintain the desired temperature set points in the kitchen and cafeteria. The AHU motor was drawing fewer amps and saving the hospital energy. In the end, an independent project audit documented a 35 percent increase in airflow, or an additional 3,700 cfm, as well as the ability to achieve the hospital’s cooling set points in the cafeteria.
Facility staff at the health care center already has plans to retrofit the air handlers serving the operating rooms, patient rooms, and radiology department — a total of four additional units — with UV-C lamps, and other area hospitals began showing interest in the technology.
“Officials at other medical centers in the area learned about the turnaround performance and are now exploring similar upgrades,” Saputa said. “Good news travels fast.”
ONE WORLD TRADE CENTER
At 1,776 feet tall, One World Trade Center — the tallest building in the Western Hemisphere — rises above the Manhattan skyline. Opened in November 2014 and owned/developed by WTC Tower 1 LLC, the skyscraper has raised new standards of design, construction, and prestige and is among the most recognized and desirable office buildings in the world.
The design of all mechanical and life-safety systems at One World Trade Center had to meet the Port Authority of New York and New Jersey’s (PANYNJ’s) strict building-code requirements. As a result, HVAC equipment was highly customized to meet efficiency, IAQ, and sound-performance requirements, among other factors, as systems are located on occupied office floors. Self-contained units were specified to feature high-water-pressure shell-and-tube condensers, a variable frequency drive (VFD), a building automation system (BAS) control system, customized energy-efficient scroll compressors, and waterside economizers.
PANYNJ became familiar with Daikin’s equipment and project work through Prem Air New York, a Daikin representative. Based on the ability to meet IAQ, low-noise, and other technical and operational specifications established by design engineer Jaros, Baum & Bolles Consulting Engineers, Daikin was selected as the manufacturer that could meet the specification requirements.
Daikin provided 166 packaged, self-contained cooling systems to accommodate more than 50 floors of the 104-story building. Design of the HVAC system was highly collaborative among many construction and mechanical firms involved on the project with Daikin providing project management.
“This is a project of a lifetime and was a first for Daikin in that we had never made equipment to match the customer’s unique needs with this level of customization before,” said Robert Lisse, Northeast regional project manager, Daikin.
The prototype self-contained system was subject to strict sound requirements. After the prototype was granted initial approval by the developers, a mock-up of an office floor was created.
“We invited piping and ductwork mechanical firms into the mock-up, and as a result of the collaboration, several changes were made to the HVAC equipment design,” Lisse said.
The effort included 3-D design to simulate maintenance access. The result was the moving of plumbing and fire-rated walls to allow for optimal maintenance and service of the HVAC self-contained system.
Visitors and office workers are enjoying the comfort, reliability, and quiet operation of the Daikin systems that serve more than one half of the floors at One World Trade Center, and the operational costs of the self-contained units greatly exceed ASHRAE Standard 90.1 guidelines. Additionally, the equipment does not require specialized staff to maintain.
“This is a historic project, and we are very proud to have contributed,” Lisse said.
OTTER VALLEY UNION HIGH SCHOOL
Otter Valley Union High School in Brandon, Vermont, is receiving major building improvements paid for with energy cost savings through a partnership with Johnson Controls Inc. The two are implementing a $3.6 million energy performance contract that will help the school make much-needed upgrades to the building and dramatically reduce its carbon emissions while paying for the improvements over the next 18 years through substantial energy cost savings.
Over the past few years, the school budgeted nearly $300,000 a year to meet its energy needs. With the fully implemented energy performance contract, the school expects to spend closer to $100,000 a year in heating fuels and electricity while making an annual payment of about $160,000 to pay for the project, which also includes the installation of a wood pellet boiler to supply most of the school’s heating needs as well as the replacement of 42 classroom unit ventilators and all the windows that are original to the 1961 portion of the building.
“We’re excited to be working with Johnson Controls to make these improvements to our educational environment while becoming much less dependent on fossil fuels and electricity from the grid,” said Jim Avery, principal of Otter Valley Union High School. “These improvements will benefit more than 550 students in grades 7-12 as well as faculty, staff, parents, and visitors for many years to come.”
Prior to working with Otter Valley, Johnson Controls partnered with Rutland City Schools in 2014 to make $5.2 million in improvements to its six schools, and Proctor School District implemented $1.6 million worth of upgrades during the summer of 2015.
“Energy performance contracting is both a financing and project-delivery mechanism that school districts can use to make needed improvements to their facilities that are paid for through annual energy and operational cost savings,” said Johnson Controls’ Ned Raynolds, who oversees energy performance contracts with local governments and K-12 schools in northern New England. “It’s a tremendous way for schools to improve their teaching and learning environments through better use of their energy budgets.”
According to Raynolds, the Otter Valley upgrades are well under way and will be completed by the end of summer or early fall 2016. In addition to the window and unit ventilator replacements and addition of the wood-pellet boiler, other major improvements at the 101,000-square-foot high school include: unifying the building’s three separate heat circulation loops, a legacy of the school’s 1983 and 1991 additions, and upgrading its heating and ventilation controls system to provide better comfort and efficiency; installing energy recovery ventilation (ERV) systems in the gymnasium and auditorium and demand-controlled ventilation (DCV) in the cafeteria; improving the interior lighting system, including installing efficient and dimmable LED lamps and controls; and upgrading parking lot lighting to LED lighting technology.
“Folks in this region are very environmentally conscious, and all of the improvements in the project will make their high school more energy efficient and sustainable,” Raynolds said. “By using wood pellets, Otter Valley will also help support the forest products industry, an important part of the local and regional economy. Because wood pellets are considered carbon neutral, they, along with a solar array, will reduce the school’s carbon footprint by more than 75 percent.”
US STEEL TOWER
In 1970, the U.S. Steel Corp. built a unique headquarters that still stands 64 stories above the Pittsburgh skyline. Built to last 100 years, the skyscraper, now known as the U.S. Steel Tower, fell behind with mechanical equipment that was installed when kilowatts cost pennies and oil was $3 per barrel. That’s why Winthrop Management, the building’s property manager, began a series of retrofits using Danfoss VLT® variable-frequency drives to cut energy costs, resulting in more than $1 million in energy savings and a greener reputation that’s attracting tenants.
“We’ve been applying Danfoss VLT drives in various retrofit projects for nearly 15 years,” said Gary Sechler, engineering manager for Winthrop Management. “After every retrofit project phase, we’ve found the energy savings on pump motors and fans have been outstanding. So, we would embark on another phase. As it stands now, we’ve installed more than 150 VLT drives with more to come.”
The first drive retrofit project was completed in the year 2000 when VLT drives were applied to the four 100-hp pump motors responsible for the building’s domestic water supply.
“Each one can serve the entire building, if needed,” Sechler said. “There are also two boilers on the 64th floor and two centrifugal chillers on the 63rd floor to provide redundant heating and cooling. So, a lot of pumping is needed for domestic water circulation and for the chilled water loops, all of which consume a lot of energy.”
“The old drives were two-step drives like they used in steel mills back in the day. They weren’t true variable frequency drives,” said Jim Rice, owner of Pittsburgh-based Danfoss sales representative M&R Affiliates, which has been working with Sechler since he has been in charge. “We replaced them with four Danfoss VLT model FC102 drives that delivered 100 hp at 460 V and provided a true soft start.”
According to Sechler, the soft start eliminated a lot of wear and tear on the motors and saved energy. “We’re talking big motors to pump water to a 300-gallon cushioning tank on the 64th floor. … I don’t have a record of energy savings from that time, but I do know with the soft start on VLT drives, pump motor rebuilds have been zero.”
In 2010, Winthrop Management applied Danfoss drives to 40 of the building’s large 200- to 250-hp fan motors. “We were absolutely delighted with the energy savings because the drives cut electricity costs by $535,000 annually,” Sechler said. “And, along with those savings, we got rebates that produced a one-year payback. So, naturally, we kept looking for more places to apply drives.”
In 2011, Sechler embarked on phase two of the retrofit project. Once again, the VLT drives were applied to pump motors, this time for the chilled-water and pre-heat water loops.
“These pump motors are considerably smaller than those used for the domestic water pumps,” Sechler said. “But there are more of them.” For this project, VLT drives were applied to 40 pump motors ranging 50-200 hp. And, once again, the savings were astounding: Annual electric costs were reduced another $138,000.
In 2012, a phase three project added 16 drives for 250-hp motors. Phase four of the project in 2013 applied about 40 VLT drives to smaller 7.5- to 60-hp pump and fan motors. After each phase, the electric savings amounted to $317,000 and $152,000 a year, respectively.
“In 2009, our electric consumption averaged 65 million kilowatts hours,” Sechler said. “Now, it’s down to 53 million kilowatts. Our peak demand was 16-17 megawatts and now it’s 12 megawatts. This is a huge savings that goes right to the bottom line. Altogether, nearly 150 Danfoss VLT drives are producing $1.14 million in documented annual energy savings. Plus, improved energy efficiency makes the property more attractive to tenants. We’ve been up to 98 percent occupancy, which is really great in today’s commercial real estate market.”
Editor's Note: This story was modified on July 25, 2016, to reflect a correction to the Brickell City Centre project. We originally reported the project included three residential towers with 820 condos and two hotels; in fact, the development features two residential towers with 390 condos in each tower and one hotel.
Publication date: 7/25/2016