Institutional HVAC Projects Provide Energy, Cost Savings
Case studies highlight several HVACR solutions
With increasingly strict energy codes and standards as well as ever-increasing energy prices, building owners and facility managers in the health care, hospitality, and school markets are constantly searching for ways to increase performance and lower costs. The following case studies highlight several ways in which HVACR solutions have been implemented to help various buildings in these three markets meet their energy-efficiency and comfort goals.
Cancer is a cruel opportunist that is always taking away. Though, lately, modern health care has won more battles against the disease than it’s lost. And in Missoula, Montana, one facility is a fine example of how patients with the disease receive comfort with treatment. It’s smart, deep-down comfort and energy savings from Mother Nature herself.
The new Community Cancer Care facility at the Community Medical Center benefits from a system that gives new meaning to comfortable, convenient health care.
The 30,000-square-foot, state-of-the-art cancer treatment facility, also referred to as the Oncology Center, rests a mere 40 feet above the Missoula Aquifer. The massive underground aquifer is all that remains of prehistoric glacial Lake Missoula, which once held as much as 600 cubic miles of water. According to the University of Montana, the aquifer flows at 3-4 feet per day, which is a rapid pace compared to most aquifers that move that distance over the span of a year. In Missoula, the water is consistently around 50°F. It’s the ideal resource for groundwater cooling applications.
To make good use of the aquifer, the Oncology Center uses a “pump-and-dump,” groundwater cooling system to tap the aquifer. Water is drawn from the ground, pumped through a large plate-and-frame heat exchanger, and injected back into the aquifer.
“It’s the most holistic approach to geothermal cooling,” said Jared Swartz, office manager for Associated Construction Engineering Inc. (ACE), the company that designed the mechanical, electrical, and fire-suppression systems at the Oncology Center. “The system has no compressor or refrigerant — just a pump and a stainless steel heat exchanger to handle the building’s 1-MBtuh cooling load.”
“The pump-and-dump cooling system isn’t that unusual here in Missoula,” said Cory Hanninen, project manager at 4G Plumbing and Heating Inc. “The system is designed to bring in groundwater at about 53°- 55° and return it to the ground at roughly 65°. The aquifer is so huge that every building in Missoula could use it for cooling and it wouldn’t make a noticeable effect on the
The cooling system that ACE designed stems from redundant, 10-inch bore extraction wells that are each 130 feet deep. Each supply well has a 20-hp submersible pump. Groundwater moves through the 350-gallons per minute (gpm) plate-and-frame heat exchanger and is then returned to the aquifer via an injection well. On the building side of the big heat exchanger, redundant 15-hp, variable frequency drive (VFD)-powered Taco Comfort Solutions FI3011 frame-mounted, end-suction pumps circulate a glycol-based solution to rooftop air-handling units that supply ducted a/c.
While the groundwater system at the Oncology Center is a unique way of cooling a building, the heating side of the system includes its own uncommon elements. There are some interesting and underutilized approaches to providing patient comfort.
Two 1.5-MBtu condensing Aerco Benchmark boilers are setup in lead-lag fashion. A 300-MBtuh brazed-plate heat exchanger from Taco pulls heat from the building’s 180°, 6-inch primary heating loop to supply 120° water to the radiant panels. The 16 small rooms are split into four zones.
The low-temp branch stemming from the small heat exchanger also heats 2,400 square feet of sidewalk outside the main doors. Before the building approach was poured, 4G installed ¾-inch Watts Radiant PEX+. The concrete is kept dry throughout Montana’s lengthy snow season, which further adds to patients’ comfort, safety, and convenience.
To heat common areas and offices and provide supplemental heat to infusion rooms, high-temperature water is pumped to the rooftop air handler and multiple VAV boxes throughout the building. The primary loop uses a 7.5-hp, VFD-powered Taco base-mounted pump.
The fast-flowing aquifer, which is constantly recharged by the Clark Fork River, is a boon to the Missoula community. When coupled with engineering and mechanical aptitude, it indirectly makes health care more affordable for those nearby.
“The hospital received a $43,000 rebate from the local utility for installing the groundwater cooling system,” said Swartz. “But we’ve calculated that the system also provides an energy savings of around 150,000 kWh per year when compared to a traditional chiller system, delivering an additional benefit of $11,000 or so per year.”
“Before this building was complete, we enjoyed very high satisfaction with our cancer treatment services, but we wanted a facility that could offer even more,” said Devin Huntley, vice president of operations at Missoula Community Medical Center. “With the new facility, we set out to provide the best atmosphere and service possible. Patients and family members now tell us every day how much they love it. From an administrations perspective, I can honestly say this is the first project I’ve worked on in a long time that far exceeded my expectations.”
UNIVERSITY OF PITTSBURGH MEDICAL CENTER
The University of Pittsburgh Medical Center (UPMC) set out to make the new $252 million Monroeville, Pennsylvania, facility the most sustainable of its 30-hospital network, and its design team delivered, constructing a building that’s saving an estimated $350,000-$500,000 annually.
“Our HVAC system design exceeds ASHRAE 90.1-2004 requirements, and when combined with reduced electrical and lighting loads, it’s saving an estimated 18 percent in energy versus the standard minimum construction requirements of an average HVAC system,” said Matthew Stevens, senior project manager, CJL Engineering. Stevens and Matthew Sotosky, managing partner, CJL, were members of a design team consisting of Joseph Badalich, corporate construction project director, UPMC, and architect Timothy Spence, principal, BBH Design.
The green design for the 302,000-square-foot, 155-bed facility is Leadership in Energy and Environmental Design (LEED) Silver certified. The facility’s sustainability measures haven’t gone unnoticed. It was recently awarded “Project of the Year” honors in the Commercial Category for 2013 from the Engineers’ Society of Western Pennsylvania in Pittsburgh.
“This is certainly one of the most, if not the most, sustainable hospital designs in the Mideast region,” said Badalich, who oversaw the project’s construction for UPMC.
While some engineers rely only on major HVAC equipment to rack up LEED credits, CJL sees every green opportunity as critical to building performance, such as specifying doorways with Berner Intl. air curtains for energy conservation. High-efficiency boilers, chillers, and rooftop DX systems were major contributors to overall energy savings; however, if the energy escapes through doorways, it diminishes the sustainability effort, according to Stevens. Therefore, CJL specified 11 air curtains for energy conservation by protecting all entrances from outdoor air infiltration.
Installed by the project’s mechanical contractor, Ruthrauff Sauer LLC, 10 of the air curtains are in-ceiling models that appear as flush ceiling grilles and supplement the facility’s aesthetic design. Furthermore, the air curtains all draw clean air from the lobby through an integral diffuser, which doesn’t require supply duct or claim air from potentially contaminated, unconditioned air spaces above the ceiling.
Besides energy savings, the air curtains all have electric heaters that are critical for lobby indoor air comfort. The heaters are efficiently controlled with a delay that continues spot heating at a lower air velocity until the doorway area’s set point temperatures are reached.
The 11th air curtain is a conventional model mounted above the emergency room (ER) doorway that saves energy and prevents infiltration of any idling ER vehicle fumes, which is a common IAQ issue in hospitals.
All the air curtains use three-speed fans that can be adjusted for proper doorway sealing and minimal operational decibel levels. Berner Intl. trained the building’s engineering staff to calibrate and maintain the units for peak performance and energy efficiency.
While air curtains helped contribute sustainability, most of the seven facilities’ HVAC LEED credits were attributed to a combination chilled water loop and rooftop/variable air volume (VAV) design consisting of three high-efficiency, 750-ton, water-cooled chillers by Trane; three 9,900-MBtuh boilers by Bryan Steam LLC, and one 6,000-MBtuh domestic hot water boiler by Leslie Controls Inc. The boilers operate exceptionally efficiently due to VFDs.
THE BICYCLE CASINO
Since 1984, The Bicycle Casino has been a gaming destination in Los Angeles. With the addition of a new, 118,000-square-foot hotel, The Bicycle Hotel & Casino (Bicycle) is now a high-end boutique resort destination — not just for patrons of the casino, but for anyone looking for a comfortable place to gather professionally or recreationally. The project team wanted a quiet and reliable HVAC system with a contemporary look to contribute to the overall feel. The selected system would also have to meet the varying needs of the hotel’s many guest rooms and amenities. The solution was variable refrigerant flow (VRF) from Mitsubishi Electric US Inc. Cooling & Heating Division.
The Bicycle’s dynamic gaming facility attracts televised poker tournaments and their audiences regularly. For Doug Lee, architect, Lee & Sakahara Architects, Irvine, California, that meant creating a hotel concept and actual construction process that would not interrupt the facility. It was also important to not interrupt patrons’ enjoyment. “To do that, [Bicycle] needed an HVAC system that was compatible with the iconic contemporary design concept, and that offered minimal disturbance during operating hours.”
Since those operating hours never end, the casino and hotel are open 24/7. The selected HVAC system would have to work continuously and quietly. Lee said, “We recommended VRF from the very beginning. The hotel is right next to I-710, which is already loud, so we needed a quiet system. And we were already using Mitsubishi on a hotel by Disneyland, so we knew how quiet it could be.”
John Ramirez, vice president of construction, R.D. Olson Construction Inc. in Irvine, explained another challenge of the project: “It’s a really large facility. The hotel is seven stories tall and has 100 rooms. The rooms are all large and luxurious. The hotel also includes a full spa, restaurant, bar, brewhouse, multi-purpose room, coffee shop, gift shop, meeting rooms, gaming areas, and offices, which include control rooms and management spaces.”
Lee said that with such varying uses and spaces, “The challenge was to make sure every space was comfortable, and VRF did just that.”
Corey Hampton, commercial estimator, Thermal-Cool Inc., Riverside, California, preferred Mitsubishi Electric because of product quality and project support. “This is our fourth time using Mitsubishi, and, so far, it’s been great. We’ve yet to have one service call – and service calls can be a real nightmare for contractors. With the hotel project, we had support the entire time. We really called on Mitsubishi, and we got answers right away. They were even on-site for start-up. It’s the best customer service I’ve dealt with.”
The installation included 15 PURY R2-Series outdoor units, 84 PLFY 4-Way Ceiling-recessed cassette indoor units, 99 PMFY 1-way ceiling-recessed cassette indoor units, five PVFY concealed vertical ducted indoor units, seven AG-150 centralized controllers, and 188 PAR Deluxe MA remote controllers.
“Mitsubishi Electric’s management system allows an engineering staff to ensure the system is functioning as it’s supposed to,” Ramirez said. “You can put the management system in a central location, so everything can be overseen from one spot. A lot of ground is lost without a system like that.”
Lee addressed the importance of a quick installation. “Initially, the management wanted the project completed in 10-12 months, so it was an aggressive timeline. We wanted a system that would help facilitate and speed up that construction.” VRF’s small footprint and flexibility offered just that. “We had the system installed in 50 days.”
The project team has been impressed by how the technology ensures a positive experience for hotel guests.
“We’ve done so many big hotels,” Hampton said. “What I’ve learned is that, in hotels, you can really hear the air conditioning. With PTACs [packaged terminal air conditioners] – you just can’t sleep. But Mitsubishi units are super quiet. You can’t hear it. For a hotel, that’s a real advantage.”
Lee added, “I’ve been at this for 35 years now, and I’ve never had such an interesting project. When you have management who says, ‘We want the very best, so give us what you’ve got,’ it’s like having an open canvas to work with. They were receptive to new ideas like VRF, and they gave us a lot of latitude to design. The results have been great. The comments from visitors and word-of-mouth have all been positive.”
When Winwood Hospitality Group and its president, Amit Patel, made the decision to build a full-service Embassy Suites by Hilton at Brier Creek in Raleigh-Durham, North Carolina, they knew from years of experience in the hospitality industry that delivering a higher level of comfort for their guests would complement the increased level of service the hotel wished to provide.
Teeter Engineering Group, working closely with the engineering and HVAC experts at Hoffman & Hoffman Inc., was tasked with engineering a solution with minimal impact on available space and room design, quiet operation, and refrigerant piping installation. A Daikin VRV heat recovery system was chosen because of its ability to maximize energy efficiency by providing simultaneous heating or cooling from the same system as well as varying the refrigerant volume to provide only the necessary heating or cooling capacity required to meet the needs of each individual room.
When compared to the more common design alternatives, the Daikin VRV option offered several benefits, including minimal to no ductwork, which allowed for higher ceilings or reduced overall building height; no large mechanical room, which meant potential revenue generating space or less square feet and building cost; individual, simultaneous heating and cooling room-by-room control; higher efficiencies; lower sound levels; improved exterior aesthetics; and less hot and cold spots.
Daikin’s vertical air handlers were chosen for installation in all 175 guest rooms. The units were concealed in small mechanical closets in each room and a minimal amount of ductwork supplied conditioned air in a uniform manner throughout the space. Quiet fans that are housed in a sound-absorbing thermal insulated cabinet kept ambient sound at satisfactory levels. The vertical installations made it easier to conceal the units, which improves both available room space and aesthetics.
The operational efficiency of the Daikin VRV heat recovery systems has also provided a significant savings benefit for the owners. The Embassy Suites at Brier Creek enjoys a higher-than-average occupancy rate so all of the guest room units are operating nearly year-round.
ROBERT D. CAMPBELL JUNIOR HIGH SCHOOL
Clark County Public Schools has improved upon its chilled beam energy-saving model used in its high school design with the recent HVAC retrofit of a 43-year-old school building.
Robert D. Campbell Junior High School was retrofitted in 2015, replacing unit ventilators that were installed in the 1970s with chilled beams and dedicated outdoor air systems (DOAS), but with a new twist. Chilled beams and DOAS aren’t new, but Campbell is the first known building to use smart, plug-and-play controllable chilled beam pump modules (CCBPM). The CCBPMs helped save hundreds of thousands of dollars in capital equipment and labor/installation costs. They also combine chilled beam pinpoint indoor air comfort temperatures and humidity control with energy efficiency.
Using CCBPMs in Campbell’s two-phase HVAC retrofit saved the school district $147,000 in labor installation costs versus the alternative VRF technology. The chilled beam/DOAS combination also saves $33,000 annually compared to the school’s former unit ventilator system. The energy savings will lower capital dollars spent on the project by $500,000, which is guaranteed by a performance contract with the Lexington, Kentucky, branch of Indianapolis-based, Performance Services Inc. (PSI), an integrated design and delivery engineering contractor that led the project.
PSI’s CCBPM specification enabled the reuse of 100 percent of the existing two-pipe loop’s piping, the pumps, and the relatively new replacement chiller and boiler installed in the 1990s and 2003, respectively. Another advantage is that CCBPMs eliminate the need for heat exchangers.
A CCBPM, which includes a powered, integrated direct digital controller (DDC); chilled and hot water connections; valves; variable-speed electronically commutated motor (ECM) pumps; and smart sensors, is superior in temperature and humidity control to the original unit ventilator design especially during season changes. The plug-and-play CCBPMs eliminate the guesswork associated with chilled beam system specification, installation, balancing, and commissioning. As with most two-pipe designs, the many wildly fluctuating temperatures of spring and fall days previously resulted with uncomfortable indoor temperatures because of the extensively long periods required to switch from heating to cooling modes.
Conversely, Campbell’s design provides pinpoint tempered conditions within a 1°F tolerance, regardless of the season, because its control is based on outdoor dew point, not temperature, according to Semco LLC, which manufactured the project’s 46 NEUTON CCBPMs, 212 IQHC active chilled beams and the Pinnacle 5,000-cfm DOAS units. If the OA dew point is less than or equal to 45°F, the space latent load is satisfied by DOAS ventilation air, which is distributed through each chilled beam and controlled via its respective CCBPM. When the dew point surpasses 45°F, the chiller is needed to maintain space conditions.
The facility uses a building management system (BMS) by Delta Controls Inc. with front-end software by Tridium, which monitors the CCBPM via Ethernet with the BACnet protocol and sends outdoor temperature/humidity information.
Cooling season condensation is prevented with the DOAS ducts that supply 6-inch-round intakes on each chilled beam with conditioned, dehumidified air above dew point and satisfies outdoor air codes. The small 6-inch-diameter air supply ducts easily fit into the restricted ceiling space, which was another impetus for using chilled beams versus other technologies requiring larger outdoor air ductwork.
The project also reused the building’s two 125-ton air-cooled RTAA-Series chillers manufactured by Trane, and three 3 MMBtuh modulating boilers by Thermal Solutions LLC.
Clark County School District Superintendent Paul Christy, who was the catalyst for getting chilled beams specified with geothermal and DOAS in the district’s sustainable award-winning new George Rogers Clark high school, also likes the decibel (dB) reduction of chilled beam induction versus the disruptive operational noise of unit ventilator fans for classroom environments. “The two-pipe conventional unit ventilators that preceded the retrofit were noticeably loud and distracting, whereas now I walk into classrooms with the chilled beams and I can’t hear any sound from the HVAC system.”
The new high school’s attendance numbers climbed versus the school it replaced, which Christy partially attributes to the comfortable learning environment created by the HVAC system. Likewise, the seventh- and eighth-grade students that came from two other schools are showing an attendance increase during Campbell’s first year, which Christy attributes partially to improved IAQ. Rising attendance generally transcends into more productive learning, which will help maintain Clark County Schools’ standing as one of the top districts in Kentucky.
Publication date: 10/31/2016