VRF System Delivers Quiet Comfort and Savings for TV Station
The first station to provide western Michigan with color television (1953), WOOD-TV 8 (WOOD), Grand Rapids is an NBC affiliate providing 24-hour news, events, weather, traffic and sports to Grand Rapids, Kalamazoo, Battle Creek and Muskegon, Mich. Surrounded by vintage Victorian homes, WOOD moved into its current building in the historic Heritage Hill neighborhood in 1955.The use of machines and systems has always impacted the station’s operation. Flat panel TV technology introduced many additional electronic devices – all generating significant heat – to support news, weather and sports. Live segments from the newsroom and sports desk meant increased high-powered lighting for these areas resulting in added heat and significant comfort issues.
As new technology was added, the challenge to keep on-air personalities cool and comfortable became more difficult. Meeting the cooling needs in the studio with traditional systems caused noise problems and the air conditioning had to be turned off during the broadcast to maintain quiet. With two-hour news broadcasts, studio temperatures would rise resulting in comfort concerns for studio personnel. As HVAC systems were adjusted to accommodate the on-air broadcasts, comfort for other station personnel became a problem and temperature complaints became an everyday occurrence. Increased cooling requirements resulted in soaring energy bills.
Challenge: Station Requirements: “no more piece-meal”
WOOD’s long-time HVAC contractor was family-owned and operated Seaman’s Air Conditioning & Refrigeration, Inc., Grand Rapids, Mich. Seaman’s will celebrate its 50th anniversary in June 2011. Account Manager Pat Murphy had been working for many years to meet WOOD’s ever-changing needs. By 2008, Murphy decided it was time to stop using piece-meal fixes when major changes were needed. Working closely with WOOD’s engineering staff and operating departments, Murphy identified the concerns and goals to tackle with this retrofit.
With LEED® energy-savings projects as a specialty, Murphy’s mandatory checklist included: improving comfort for personnel throughout the station, especially the on-air personalities; cutting energy costs; noise-free HVAC operations in all broadcasting studios; scalable, flexible HVAC systems to accommodate constantly changing requirements for WOOD’s future operations; control options to monitor system operation at each employee location in the building; minimal equipment footprints as space was a critical issue; and installing replacement equipment must not disrupt station operations.
With support from Scott Hoogewind, Seaman’s design engineer, and local distributor Young Supply Company, Grand Rapids, the team decided the VRF system from Mitsubishi Electric Cooling and Heating Solutions (Mitsubishi Electric), Suwanee, Ga., was the best technology to satisfy the demanding HVAC needs on Murphy’s checklist.
Murphy and Hoogewind had one other key consideration guiding their decision to specify the Mitsubishi Electric VRF system. The 55-year-old building is totally surrounded by the high-end homes of Grand Rapids’ Heritage Hill neighborhood so the new HVAC equipment and technology must have very little impact on its surroundings.
Solutions: VRF Meets HVAC Needs
Murphy explained how the Mitsubishi Electric VRF zoning system met all the challenges of the WOOD installation.
Cutting Energy Costs: Industry research1 clearly demonstrates that VRF systems are consistently 30 to 40 percent more efficient than traditional systems. Fixed-speed compressors in traditional HVAC systems are either “off” or “on” wasting huge amounts of energy when operating under part load conditions. Statistics show that partial load conditions exist 97 percent of the time at most locations. In contrast to traditional compressors, Mitsubishi Electric compressors operate with super-efficient INVERTER technology. This means the compressors ramp up quickly providing the exact energy necessary to achieve the cooling or heating demand of each zone. Then, working in tandem with system controls and sensors, the INVERTER compressor varies its speed to maintain the desired comfort level.
Solving Significant Comfort Issues: WOOD’s studio heat temperatures caused by increased lighting demands were easily controlled and a high degree of comfort was achieved through the zoning capabilities of the Mitsubishi Electric VRF system. Intelligent indoor unit sensors measure room air temperature in each zone and deliver just the right amount of refrigerant (comfort) to precisely meet the load of each zone. Indoor units can be controlled to operate only in those occupied areas that need conditioning and turned off in vacant areas. By conditioning only the occupied areas, energy is not wasted.
Low-Noise Operation: These units are ideal for applications where quiet is an absolute necessity, like a sound studio or a library. The indoor evaporator units range from 22 dB(A) (the sound of a whisper) at low speed to 47 dB(A) at high speed. Compare these to standard indoor sound levels which are generally between 45 and 55 dB(A). The same is true for the outdoor units. This industry-leading advantage was of the utmost importance for ensuring little impact on the neighborhood.
System Simplicity and Flexibility: Mitsubishi Electric uses the only two-pipe heat recovery system in the industry making the installation simple, easy to install and easy to maintain. Besides the simple piping, only non-polar, two-wire control connectors are required between the outdoor condenser and indoor air handling units. The system uses a modular design where multiple outdoor units can be connected together to create larger sizes. These outdoor systems can be connected to a variety of indoor unit styles to fit the needs of the building. System flexibility allows one to easily add, change or remove zones in the system, making the system perfect for the ever changing comfort requirements at WOOD.
Systems Control: Each Mitsubishi Electric VRF system can be configured for up to 16 zones within a building. Multiple VRF systems can be integrated into the Mitsubishi Electric controls network to air-condition and manage up to 2,000 zones from a single networked computer using Mitsubishi Electric furnished software.
Michigan Winters: Putting the Outdoor Units Inside
Because Michigan winters are often severe, Design Engineer Scott Hoogewind decided to place the 20-ton R2-Series (PURY-240) outdoor unit in a basement mechanical room of the WOOD building. A unit that is capable of simultaneous cooling and heating, the PURY generates a capacity of 240,000 Btu/h for cooling and/or heating.
Hoogewind explained that the Michigan environment has an ambient design condition of zero degrees Fahrenheit, so using heat pumps in Michigan takes special design considerations. “These units sit indoors to eliminate excessive winter ambient conditions when they are operating in heating mode and the condenser fan motors modulate to move just enough air to meet capacity needs,” he said. Additional waste heat in the mechanical room from the other building systems help to supplement the unit.
“While the Mitsubishi Electric system actually works very well at extremely low temperatures and does not have to be placed indoors, here in Michigan, about 30 percent of the heat pump installations have the outdoor unit placed indoors. In dealing with air-source equipment (PURY models), by placing the outdoor units indoors (mechanical room, etc.), we can better control the heating capacity adjustment due to the cold ambient temperature, unlike if they were placed outdoors.
“The Mitsubishi Electric system allows, through the use of dip-switch settings, ductwork to be added to the unit up to an external static pressure of 0.24 inches of water column,” Hoogewind explained.
“Happy Campers: a Huge Accomplishment”
All of Murphy’s goals were met with the Mitsubishi Electric VRF system. The on-air personalities report great relief, and because of the system’s virtually silent operation, there is now plenty of comfort during broadcasts: a huge accomplishment according to WOOD’s Chief Engineer Mike Laemers.
The many features of the VRF system helped WOOD achieve its energy savings goal – in the range of 30 to 35 percent, Laemers estimates. Shifting heat from areas with excess heat from all the electronics and lighting to areas that needed the heat saved significantly on the energy bottom line. The ability to cool some areas while heating others at the same time has been a real plus. Complaints about temperature and comfort have virtually disappeared and the facilities manager has the ability to set and monitor comfort settings for each room and ensure predetermined settings are being maintained.
“The VRF systems’ modular design has also solved the problem of the HVAC system’s flexibility and adaptability,” Laemers said. “As areas need to be remodeled, it is a simple matter of relocating the units and the line sets without having to change any duct work, because there is no duct work required.”
And finally, Laemers was especially pleased that there was zero impact on the station’s operation during the installation. The old system was left in place and operating throughout the installation. Once the Mitsubishi Electric VRF system was up and running and put through its paces, the demolition and removal of the old system began.
1Consulting-Specifying Engineer, March 2008
