VRF Zoning Technology: An Ideal HVAC Solution for Healthcare Facilities
Friday, December 07, 2012
A proven HVAC technology worldwide, Variable Refrigerant Flow (VRF) zoning systems are poised for dramatic growth in all areas of commercial construction because they provide precise zoned control that can contribute toward the achievement of LEED® certifications. This paper describes the major features and benefits of VRF zoning systems and how they are flexible, energy-efficient HVAC solutions ideally suited for hospitals, urgent care centers, hospice and other healthcare facilities. Finally, this paper outlines how VRF zoning systems can help healthcare facilities garner a substantial number of LEED points.
VRF ZONING SYSTEM FEATURES
VRF zoning is a method of providing precise comfort control to buildings with multiple floors and areas by moving refrigerant through piping to the zone to be cooled or heated. Regardless of time of day, sun or shade, season of the year or special requirements, VRF zoning systems provide personalized comfort to each room or space. The systems, which can simultaneously cool some zones while heating others, have many features.
Precise comfort control. The system's INVERTER heat pump offers year-round comfort with a single system, even on the coldest days in northern regions, while its hot-start technology provides warmth from the start, reducing drafts. As important, the technology provides the flexibility to control a variety of zones - operating rooms, laboratories, patient rooms, large waiting areas, lobbies and dining areas - simultaneously heating some areas while cooling others.
Quiet operation. Technologies built into each system contribute to its quiet operation. The INVERTER-driven compressor modulates to ramp up and down to meet the needs of the space. The compressor is housed in its own compartment, surrounded by sound-dampening insulation, and is mounted on vibration-absorbing feet. Special fan designs add to the quietness of outdoor and indoor units. Unlike traditional systems that can start up and shut down with a bang, VRF zoning systems operate at a whisper-sound level, which is important for healthcare environments.
Energy efficiency. Because its INVERTER-driven compressor in the outdoor unit varies the motor rotation speed and capacity, the system precisely meets each zone's load requirement. Power consumption is reduced because the system operates only at the levels needed to maintain a constant, comfortable indoor environment. Some indoor units have sensors that compare air and floor temperatures and adjust the output as needed to optimize comfort.
Design and installation flexibility. The compact outdoor air-source and water-source units, indoor units and other components can be installed in tighter spaces because they require less piping and duct space. Plus, the system's two refrigerant pipes with nonpolar, two-wire control connections provide faster installations with fewer installers.
Lighter weight. VRF zoning systems are 31 percent lighter than chilled-water systems, so they are easier to handle and cost less to transport. Moreover, the load can be distributed across an existing structure or avoided by mounting the units on the ground.
Discreet indoor units. A wide variety of indoor unit styles offer greater design flexibility. Styles include wall-mounted, floor-standing (concealed and exposed) and vertical concealed. Ceiling options include suspended, recessed and ceiling ducted.
Lower life-cycle costs. The total installed cost of a VRF zoning system is less than or equal to the total installed cost of most conventional systems. Also, maintenance is greatly reduced and requires no special training to perform the simple functions of changing/cleaning filters and cleaning outdoor condensing units.
BENEFITS FOR HEALTHCARE FACILITIES
Architects, engineers and healthcare administrators say that VRF zoning systems are ideal HVAC solutions for healthcare facilities. Here's why:
"I especially admire the advanced controls network. I have control of each indoor unit from my office computer. From there, I can bump the temperature up or down in each patient suite keeping everyone happy." - Linda Swart, executive director, Life Touch Hospice House, El Dorado, Ark.
"I liked the fact that this was easy to install in an historic home and provided simultaneous cooling and heating from one bedroom to the next." - Dave Hamilton, field service, EMCOR Service/Tucker Mechanical, Meriden, Conn., about the Ronald McDonald House installation
"They are extremely quiet - as low as 24 dB(A) - a factor that is especially important in healthcare facilities." - George Skinner, sales manager, GSC Limited, HVAC contractor and distributor, Hamilton, Bermuda, about the Lamb Foggo Urgent Care Center installation
Indoor Air Quality
"The coil units are small and limit the amount of possible cross contamination of air flow between individual zones." - George Skinner, sales manager, GSC Limited
"In 2008, I installed my first VRF system...and I was able to realize a savings of $36,000 a year. That was very gratifying." - Fred Rogers, Rush Health Systems, vice president, chief resource officer and facility manager
"The VRF system saves money for the clients because the outdoor compressor units have the smallest footprint in the industry - and with the two-pipe system there is simply no wasted space." - Stan Williamson, McLain Plumbing & Electrical Services, Inc., Philadelphia, Miss.
Indoor Unit Variety
"These options helped me build a truly unique whole-building solution that fits the function and comfort needs of each station in the hospital."
- Fred Rogers, Rush Health Systems
For LEED certification, VRF zoning systems can contribute a great number of points in the Energy & Atmosphere (EA) and Indoor Environmental Quality (IEQ) categories for the following LEED ratings: New Construction and Major Renovations; Core and Shell Development; Existing Buildings; Schools (new and renovation); Retail (new and renovation); and Healthcare (new and renovation).
ENERGY & ATMOSPHERE (EA)
Prerequisite: Fundamental Commissioning of the Building Energy Systems
A VRF zoning system meets this prerequisite because it has an integrated control system providing for testing, control and reporting.
Prerequisite: Minimum Energy Performance
VRF zoning technology provides the means to exceed ASHRAE Standard 90.1-1999, thus achieving the prerequisite for minimum energy performance.
Credit: Optimize Energy Performance
The VRF zoning system's inherent energy efficiency provides the ability to achieve high levels of energy savings above ASHRAE Standard 90.1. INVERTER technology, heat recovery and zone controls provide the best opportunities for energy savings.
Credit: Measurement and Verification
VRF integrated controls and maintenance software provide the ability to monitor and report building-energy usage on an ongoing basis in order to meet this credit.
INDOOR ENVIRONMENTAL QUALITY (IAQ)
Prerequisite: Minimum IAQ Performance
VRF zoning systems can meet this prerequisite (Sections 4 through 7 of ASHRAE Standard 62.1-2004) through indoor units with ventilation connections or integrated dedicated outside air systems.
Credit: Outdoor Air Delivery Monitoring
Integrated controls for CO2 monitoring can be incorporated into a VRF system. Likewise, certain indoor units utilize MERV 8 filtration to meet the credit's intent.
Credit: Controllability of Systems - Thermal Comfort
VRF's zoning capability allows occupant control with wall-mounted remote controllers.
Credit: Thermal Comfort - Design
VRF zoning systems and the building envelope must be designed to meet requirements of ASHRAE Standard 55-2004, Thermal Comfort Conditions for Human Occupancy.
Credit: Thermal Comfort - Verification
When properly designed into a building, VRF zoning systems provide temperature and humidity control in accordance with ASHRAE 55-2004 guidelines.
Credit: Acoustic Environment
Many VRF indoor units have tested noise levels that fall at or below the given ranges in the 2010 FGI Guidelines' Table 1.2-2 Minimum-Maximum Design Criteria for Noise.
Credit: Community Contaminant Prevention-Airborne Releases
VRF systems do not include any gas-fired equipment, so there are no products of combustion to contain.
For more information about how VRF zoning systems can contribute to LEED certifications, visit the U.S. Green Building Council's website at www.usgbc.org.
CASE STUDY: RUSH HEALTH SYSTEMS
Rush Health Systems in Meridian, Miss. serves residents in eastern Mississippi and western Alabama with a variety of inpatient, outpatient and community services. As it expanded its Rush Foundation Hospital over the years, the organization continued to add onto its central four-pipe chilled water and boiler system. But for its new 14,500-square-foot labor and delivery center, Rush sought a more effective HVAC solution.
To best answer a growing chorus of patient complaints, Rush needed a system that provided individual zones so that a patient who wanted her room very warm could be next door to one who wanted her room very cold. Rush selected a VRF zoning system because it automatically adjusts the motor compressor speed to deliver the exact amount of refrigerant needed to maintain the zone temperature. Plus, Rush concluded VRF zoning would save considerable energy costs.
McLain Plumbing & Electrical Service, Inc., Philadelphia, Miss., installed the system in the new center. "The Rush installation was a snap," said Phillip McLain. "My foreman had excellent training in Atlanta. He came back very excited and told us about the great training program. He and one of our technicians installed all the equipment, piping and wiring in less than two weeks…and it has been running flawlessly."
Fred Rogers, Rush vice president, chief resource officer and facility manager, was equally impressed with the multiple styles of indoor units available. For the 18 labor and delivery rooms, Rogers selected ceiling-recessed cassettes with square grills and four-way deflectors, and for the staff break room, he chose ceiling-recessed cassettes with one-way airflow. Where additional ceiling space was available, such as in the corridors, changing areas and nurse stations, he employed ceiling-concealed ducted units.
"These options helped me build a truly unique whole-building solution that fits the function and comfort needs of each station in the center," Rogers said. Best of all, the system is "taking a load off my old chillers, which are huge energy hogs. I call this the great energy swap-out."
CASE STUDY: LAMB FOGGO URGENT CARE CENTER
After a hurricane caused serious damage to Bermuda, the Bermuda Hospitals Board (BHB), the island's sole healthcare provider, decided to build two urgent care centers, one on each side of the island. The first building, a two-story, 7,500-square-foot facility, opened in April 2009 as the Lamb Foggo Urgent Care Center.
After extensive consultation between the board and design team, a VRF zoning system was selected for Lamb Foggo because it provides an excellent comfort solution for healthcare facilities. The center would require different temperatures in different areas at different times simultaneously - and a VRF zoning system was one of the few HVAC products that provide this benefit.
VRF zoning offered the urgent care center other benefits as well. "The system's fan coil units are small and limit the amount of possible cross contamination of airflow between individual zones," said George Skinner, GSC Limited, the project HVAC contractor, Hamilton, Bermuda. Plus, Skinner said the indoor and outdoor units are extremely quiet.
Besides enhanced patient comfort, Skinner said the VRF zoning system would afford Lamb Foggo considerable energy savings over conventional DX or chilled water systems, simplify the HVAC installation compared with conventional chilled water systems and lower maintenance costs.
"I firmly believe the Lamb Foggo design and VRF equipment provide an ideal prototype for the next urgent care center on the west side of the Island," Skinner concluded.
View this and other case studies at www.mehvaccasestudies.com.
Download a pdf file of this white paper here.