Paradise Required a Zoned Solution
May 17, 2010
HONOLULU - At 909 Kapiolani, this 36-story, residential glass tower, completed in September 2007, is located in the Kaka’ako commercial-retail district of Honolulu. It offers stunning views of Diamond Head and the beaches of Waikiki.
The elevator lobby, upscale shops, and private-access entry of 909 Kapiolani are located on the street level. Homeowner parking occupies the first five floors. A recreational deck, swimming pool, and landscaped plaza start the living levels. Floors six through 33 house the living areas called “The Residences,” where each floor has four one-bedroom, one-bath units and four two-bedroom, two-bath units.
“The Penthouses” reside on floors 34 and 35. Each consists of three two-bedroom units with two baths; one two-bedroom unit with two and a half baths; and one three-bedroom unit with two and a half baths.
Finally, the 36th floor hosts two rooftop “Terrace Penthouses,” which consists of one two-bedroom unit with two and a half baths and a wrap-around, 1,700-square-foot lanai; and one three-bedroom unit with two and a half baths and a 1,427-square-foot lanai. Each one of the 227 condominiums has its own lanai, ranging in size from 42 to 1,700 square feet.
Each area of the building also presented zoning challenges.
U.S. APPLICATIONNone of the members of the project’s HVAC team knew of a residential high-rise in the United States that was specified almost entirely with Mr. Slim® split-ductless systems, which is what they wanted to use to meet their various zoning requirements.
Gary Imamura, president of AC Warehouse Inc., Honolulu, said, “It’s pretty common to have split-ductless systems in a hotel; in fact, I know of three Mr. Slim systems installed in hotels around Waikiki - the Waikiki Joy, the Equus (formerly the Hawaiian Polo), and the Wyland Hotel Lofts. But I don’t know of one residential high-rise like 909 Kapiolani.”
Ron Swenson, sales manager for mechanical contractor Critchfield Pacific Inc., Honolulu, got a call from Hawaiian Dredging Construction Co. Inc., Honolulu, in spring 2005 to bid on the HVAC system design.
It was accomplished with the help of Bobby Hahn of the Pacific Systems Group, Torrance, Calif., a manufacturer’s rep for Mitsubishi Electric HVAC’s Advanced Products Division, Suwanee, Ga. Swenson submitted the winning bid for the HVAC contract.
The split-ductless systems “are all about comfort and convenience - ideal attributes for residential living, regardless of the number of floors,” said Swenson. “For 909 Kapiolani, the combination of Mr. Slim on the first 33 floors and the City Multi® Variable Refrigerant Flow Zoning (VRFZ) system for the penthouses on the top three floors worked perfectly.
“These systems were very easy for my crew to install because there are very few parts,” he added. “Before the first families moved in last fall, we fired up all 227 systems, and they started without a hitch - extremely rare in this business.”
SYSTEM BENEFITSSwenson described the key system benefits that determined the contract award for 909 Kapiolani:
• The inverter-driven compressor technology (variable-frequency drive) provides high-speed cooling (28,600 Btuh) and dehumidification.
• The systems keep the “discomfort quotient” (the term is used to describe the high humidity level of Hawaiian heat) in check. The air conditioning systems accomplish this by reducing the humidity in each zone. Each indoor unit has a dry mode setting, accessible by pressing a button on the wireless remote controller.
• The outdoor unit, engineered for 48 dBa at cooling, is rated to be 20 percent quieter than the sound code required by the city of Honolulu.
• Because the outdoor units sit on each lanai, it was extremely important that the next-door neighbors would not be able to hear the outdoor unit’s compressor. This feature was influential in the decision-making process.
• The systems require no ductwork, keeping material and installation costs to a minimum. Each room in the condominium has individual zone control over comfort and temperature.
LUXURY PENTHOUSES“Some people have asked why we didn’t specify Mr. Slim systems for all 36 floors,” Swenson said. “The answer is really quite simple. For the 12 luxury penthouses on the top three floors, we wanted the indoor units to be hidden, out of the homeowner’s view. Similarly, we wanted the outdoor units hidden from view as well.
“This meant putting the outdoor units on the roof, instead of the lanai as we did with the other outdoor units. The simplicity of the two-pipe system and nonpolar, two-wire connection made this task easy.”
According to Swenson, the PUHY-P108TGMU outdoor unit provides a 108,000-Btuh cooling capacity and zone cooling. Its footprint is 39 by 32 inches, and the inverter-driven compressor technology delivers air conditioning to up to 32 zones.
“Finally, by incorporating T-branches and headers, the Y-Series provides the ultimate in piping design flexibility,” he said. “My crews found this system incredibly easy to install.”
The client received a $70,000 energy rebate from Hawaii Electric Co. Inc. And six months after the first family moved in, Young Jun Choi, controller, POSEC Hawaii, Inc., declared that the 227 units of 909 Kapiolani were 80 percent sold out.
Because of the inverter-driven, multizone technology on the first 33 floors, the building owners received a significant, one-time energy rebate award of $70,000 from Hawaii Electric Co.
Publication date: 05/17/2010