As variable refrigerant flow (VRF) systems continue to gain marketplace acceptance in the U.S., the technology is being used in a wider variety of applications. VRF is an attractive alternative to traditional HVAC options due to its ability to simultaneously heat and cool, design flexibility, highly efficient performance, and more. Below are three working examples of how VRF technology helped a historical building never designed for air conditioning reach Leadership in Energy and Environmental (LEED) Gold certification, a high-rise project meet Title 24 standards, and a convent save $80,000 a year on energy costs.
FUTURES WITHOUT VIOLENCE CENTER
Once the living quarters of the U.S. 6th Army band in the Presidio of San Francisco, the Futures Without Violence Center faced the challenge of cooling a building that was never designed for it with minimal impact on the existing structure — and making it energy efficient. The original building was built in the early 1900s with a concrete foundation, primarily wood framing, brick, and some structural steel. It was designed for heating only via hot water radiators on the perimeter with windows that opened for natural ventilation.
Because of the building’s status as a historic structure, the retrofit faced substantial limitations on what could be modified, which meant no new equipment chases, structural changes, or soffits, and only small wall penetrations.
Allied Heating and Air Conditioning Co. Inc. in San Rafael, California, a mechanical contractor and engineering firm that designs about 25 percent of its build projects, looked at rooftop air-handler units, variable refrigerant volume (VRV), chilled beams, standard variable air volume (VAV), and displacement ventilation through VAV for the 35,000-square-foot Futures Without Violence Center. Daikin Industries Ltd. offered quick payback and installation times and required no structural changes for the installation.
Energy consumption was a factor, but ease of installation without modifying the building structure was very important. The architect on the project, San Francisco-based BAR Architects, did not want to add space for low-pressure ductwork, and only minimum penetrations were required to run refrigerant lines. Daikin’s small, lightweight equipment made it easy to place within the structure.
“By eliminating big ductwork, we’re saving the plenum space, satisfying the architect, and providing individual control per zone through the wired controller. And all of this satisfies the owner,” said Theo Garcia, former vice president of Allied. “We apply this technology a little differently in that we use low-profile ducted fan coils per zone with standard air distribution. This keeps airflow rates within the ideal range, and we’re doing it all with less ductwork and very low noise levels.”
The retrofit also included an original conference room design that called for multiple split systems or a larger package rooftop unit with supply and return ducts coming down from the roof and branching out. When the design was changed to VRV, a number of advantages were realized. Daikin’s ability to provide more capacity in a smaller footprint gave Garcia more flexibility in equipment placement, which allowed him to raise ceiling heights by 12 inches.
The VRV system enabled a smooth, on-budget installation with individual zone control, and the project received LEED Gold certification.
When J.H. Snyder, a national full-service real estate and building developer, took on The Vermont project, a twin-tower apartment complex in Los Angeles, the firm knew it had to make the new building energy efficient while still providing tenants with the best possible living experience. The Vermont’s two towers are 30 and 24 stories tall, respectively, and house 464 units in one- and two-bedroom layouts. Located in downtown Los Angeles in historic Korea Town, The Vermont concept offers iconic views as well as a high-end destination for living, shopping, and dining. With a ground floor that houses restaurants, markets, banking, retail sites, and residential spaces that begin on the seventh floor, builders knew the towers would need the right combination of technology and equipment to reach the mixed-use space’s lofty efficiency and comfort needs.
After putting out a call for proposals, the build was awarded to The Limbach Co. due to its choice of VRF technology. By switching out the originally scoped water-source heat pumps with an LG Multi V VRF system, decision makers at The Limbach Co. recognized they’d be able to install the system with higher energy efficiency for about the same cost as the original plan. Additionally, the LG Multi V III system features higher energy efficiency, longer piping capabilities, lower operational costs, minimal-to-no ductwork, tenant comfort with individual zoning, and the ability to maintain the structure’s architectural integrity with zoned comfort, which made the decision to switch to VRF that much easier.
“This is [one of] the first high-rise VRF projects in Southern California, and we’re excited to continue working with high-rise developers,” said Scott Gilchrist, the LG representative on the project. “We’re even set to work with the contractor on submitting the project for LEED certification.”
The VRF system will also add to the overall comfort of the building by providing optimal cooling and heating throughout the two towers. Additionally, the system itself is quieter, adding to The Vermont’s high-end feel, making the Multi V an exceptional choice for the build. LG Electronics was so impressed with the unique strategy to make the installation work that The Vermont was given the Multi V Job of the Year Award in recognition of the most innovative new construction with a Multi V product. The Vermont received its total cost of ownership (TCO) in May of 2014.
“Our customer was focused on a cost-effective building addressing both construction and sustainability needs, but also wanted to achieve LEED Gold,” said Armando Estrada, contract manager and project executive for The Limbach Co. “We proposed an LG VRF system for their high-rise configuration. After running preliminary calculations and confirming building requirements, we found it was a viable system due to its equipment sizing and overall cost-savings in the buildings’ mechanical, electrical, structural, and plumbing trades.”
VRF systems have a much greater piping capability than traditional direct expansion-style systems. Therefore, the longer line lengths of the Multi V III allowed the piping to run up more than 30 stories, ideal for the two towers that make up The Vermont. The Multi V III’s flexible design helped result in a layout that effectively met Title 24 — California’s building energy-efficiency standards — and ASHRAE requirements for refrigerant volume as well as the contractor’s goals for the building.
MARYMOUNT CONGRESSIONAL HOME
The Marymount Congregational Home, located in Garfield Heights, Ohio, dates back to 1925. The 78,000-square-foot building originally served as a residence for the Sisters of St. Joseph, Third Order of St. Francis, and a high school for young women. Today, it houses the Sisters, provides administrative offices, and hosts a child care center. The Sisters have long been committed to promoting a legacy of sustainability and care.
About five years ago, Marymount underwent a massive renovation. Eighty-four dormitory-style bedrooms were turned into 28 individual apartments as part of an effort to gradually move the building into its role as a public senior residence. The renovation also included a total overhaul of the HVAC system.
Before the renovation, Marymount was disappointed in the quality of heating and cooling. The facility had average energy costs of more than $9,000 per month. “There were two giant boilers in the basement about the size of a Volkswagen Beetle,” said Sister Joyce Hallkamp, business and facilities coordinator at Marymount. “When we turned them on, the gas company had a party. Part of the building would be cold and part would be hot. About one-third of the building had window units, and none of the bedrooms were air conditioned.”
The Sisters of Marymount considered a geothermal system, but were concerned with tearing up the lawn. They turned to Solon, Ohio-based KW Lang Mechanical, which suggested variable refrigerant flow (VRF) zoning for the project. A VRF zoning system from Mitsubishi Electric US Cooling & Heating Division was selected. Now, with years of energy data in hand, the results are what Hallkamp calls “amazing.”
Choosing VRF zoning over geothermal was the right move, according to Mike Stephenson, mechanical design coordinator for KW Lang. “Like many of the jobs we’ve gotten that started way over budget, we value-engineered the job and showed them how we could get the efficiency they wanted while being under budget,” he said.
Once the team settled on a VRF zoning system, selecting Mitsubishi Electric products came down to comparing brands. “We knew from reading reviews that the Mitsubishi [Electric] system was a very good system,” Stephenson said. “We weren’t worried about its performance, so it was a matter of dollars.”
Mitsubishi Electric offers a two-pipe system, which appealed to Stephenson, because the two-pipe system kept the copper cost down.
The VRF zoning system helped Marymount save significantly on both energy consumption and cost. The full remodel on the facility meant installers had easy access to the areas requiring work. The team was also able to work around a tricky situation by finding a creative solution.
“There was no place on the grounds for outdoor units,” Stephenson said, “so a rep from Mitsubishi [Electric] came up with a protocol for an indoor setup. There was a basement-level room we took over and set up for outdoor units with exhaust and so on.”
Energy data has shown the VRF system has saved Marymount roughly $80,000 a year. The savings have been so significant that KW Lang’s original prediction for a payback period of seven to eight years was met early.
“There’s also more of a savings with the control system because I can time everything,” Hallkamp said. “I have offices and the child care center on a timer. I don’t have to keep it at 72 degrees all night long. I can turn it down to 69 or 70, and, then, an hour before everyone arrives in the morning, I can turn it back up.”
The benefits of the system also extend beyond energy savings and into comfort.
“You can walk around the building now, and it’s comfortable,” Hallkamp said. “Before, the chapel would be beastly hot, but not anymore. Someone said, ‘Sister Joyce, when are you going to turn the heat on?’ I said, ‘You can go upstairs right now and turn the heat on in your own room.’
“With individual controls, she can have the heat on while I have air conditioning. Each room can do its own thing. Some people even leave it on automatic. Everyone can be happy. It’s a cost-saver, but it’s also saving natural resources,” she continued. “It’s an energy-efficient system. We wanted to go Earth-friendly. [VRF zoning] was even friendlier than geothermal.”
Publication date: 11/23/2015