The Pinnacle of HVAC Engineering
Inspired by the architecture of the Andalusia region of southern Spain, the InterContinental Montelucia Resort & Spa is a $325 million luxury resort located at the base of Camelback Mountain, Paradise Valley, Ariz. It is fashioned on the 30-acre site of the former La Posada Resort and features a lodge, spa, 253 guest rooms in 17 buildings and 34 detached single-family villas. Crown Realty & Development Corp. (Crown), Paradise Valley, Ariz., opened the doors to the refurbished resort in November 2008.Green HVAC Systems Requested
Sunstate Mechanical Services (Sunstate), Scottsdale, Ariz., was awarded a contract to install HVAC systems for the seven guest room buildings renovated from the original La Posada complex. Crown requested green, sustainable HVAC systems that would provide zoned comfort, effective energy usage, ultra-quiet operation and outdoor units with a small footprint.
Sunstate’s 22-year HVAC veteran Kevin Flores said, “The real issue for us was space. There was minimal space in the old ceilings for ducting and no area on the grounds or on rooftops for multiple condensing units. To meet the green concerns for HVAC design, we turned to Crown’s local architectural firm, Allen + Philp, Scottsdale, Ariz., whose project manager referred us to Glumac Engineers, Irvine, Calif., a firm with well-known LEED® credentials and experience. We discovered that Glumac had 60 LEED accredited professionals on staff to make sustainability happen.”
Overcoming Design Limitations
Glumac Associate and LEED Mechanical Engineer Dave Summers was assigned the task. “Montelucia was quite challenging because there were a lot of limitations for the HVAC design,” Summers said. “A central plant proposal was turned down by the owner due to cost. Rooftop HVAC equipment was not allowed by the city because of aesthetic concerns. If we had used traditional split DX (direct expansion) units, we would have had a virtual ‘farm’ of outdoor condenser units on the ground next to the seven buildings.” To meet Crown’s specific demands, Glumac specified Variable Refrigerant Flow (VRF) zoning systems from Mitsubishi Electric Cooling and Heating Solutions, Suwanee, Ga. “There are few other systems in the world with the technology and flexibility to overcome these tough parameters,” Summers said. “With the Mitsubishi Electric VRF system, we only needed a single outdoor unit per building to serve multiple guest rooms, while allowing individual temperature control for each zone.”
Compact Design
Summers said the dimensions of the Mitsubishi Electric VRF units made the installation possible. “They are relatively compact with minimal clearance requirements. The R2-Series outdoor units have the smallest footprint available. These made screening within the landscape design much easier. The dimensions of the indoor units are also conveniently small and slim. Each unit fits in the ceiling space above the guest room entrance or in the bathroom. This accommodation was particularly important at Montelucia because the guest rooms were renovations of existing buildings.”
INVERTER Technology Delivers Energy Savings and High Efficiency
Mitsubishi Electric R2-Series outdoor units are two-pipe heat-recovery systems with INVERTER-driven technology, systems that Summers views as highly efficient. “Energy savings is a big plus for these systems,” he said. “Additional energy savings are possible when some guest rooms call for heating and others call for cooling. Since the Mitsubishi systems provide simultaneous cooling and heating, wasted energy is minimized and optimum energy usage is reached by the heat recovery operation.”
Ultra-Quiet Performance
Flores said the indoor and outdoor units are perfectly suited for hotel and resort environments because of their ultra-quiet performance—as low as 28 dB(A) for the indoor units and 31 dB(A) for the outdoor units. “This was the perfect system to meet each one of Crown’s HVAC requirements, including fitting refrigerant piping and ducting into tiny attic spaces.”
Split-ductless Systems: “Pinnacle of HVAC Engineering”
All 17 buildings at Montelucia have two rooms (electrical and data) that require cooling-only equipment. For this specific need, Glumac selected Mitsubishi Electric split-ductless systems. The high-performance, cooling-only outdoor units also employ Mitsubishi Electric’s INVERTER-driven compressor technology (on MUY models) (Variable Frequency Drive) and environmentally friendly R410A refrigerant.
Because the innovative engineering optimizes the capabilities of the INVERTER technology, only 14 outdoor units were needed to service the seven original buildings. Because split-ductless systems don’t require ductwork, include similar energy efficient features and are designed for smaller spaces, they were ideal for renovating these older buildings. Flores said, “The system’s ductless design and long allowable refrigerant piping lengths made it possible for us to overcome serious space limitations for duct and unit locations.”
“From my 22 years in this business, Mitsubishi Electric VRF zoning and split-ductless systems are the pinnacle of HVAC engineering,” Flores said. “They accomplish all that standard HVAC systems do with approximately half the power consumption.”
