The case study reveals the contribution that VRF systems have made in a Los Angeles hotel seeking LEED Silver Certification.
by Mitsubishi Electric
Located in the Miracle Mile area between Beverly Hills and Hollywood, the Wilshire is a luxurious 74-room boutique hotel created from a '50s doctor's office building.
Less than 12 months after its opening, in September 2011, the hotel was awarded 4 diamonds by the AAA; was included in Fox News' list of the 10 best new hotels; received awards from Redbook and Harper's Bazaar, and made california Home + Design magazine's "50 Best Designed Hotels" list.
An elegant boutique hotel
Michael Orwitz and Spence Mitchum, partners in the Los Angeles real estate business, have developed, in partnership with OSM Investment Company, residential apartments, commercial retail projects and boutique hotels throughout the city. These developers have the talent to find hidden gems and opportunities ignored by others in up-and-coming neighborhoods.
In 2008, the couple located a rickety six-story medical building, located between Beverly Hills and Miracle Mile. Where others only saw an outdated structure, Orwitz and Mitchum recognized the opportunity to make a good investment in a magnificent location. The densely populated Miracle Mile area is the ideal market for a boutique hotel. In order to make this vision a reality, they brought together a group of experienced professionals from the hotel industry:
Killefer Flammang Architects, for the passion that this firm has demonstrated for the adaptive reuse and sustainable design of its historic buildings in Los Angeles, which have been deserving of different recognitions.
KNA Design, for its expertise in designing unique elements for luxury resorts and boutique hotels. RD Olson Construction, located near Irvine, due to its track record in the hotel industry.
The city of Los Angeles considered the Wilshire Hotel to be a new construction, so seeking LEED® certification was one of the developer's top priorities. The design team set a viable goal of obtaining LEED Silver certification. Guest comfort and indoor air quality were achievements that also perfectly matched the requirements of LEED Silver certification. Mitchum was tasked with finding the optimal and most advanced HVAC technology on the market.
The arrival of VRFs
At the Kappa Kappa Gamma house on the Campus of the University of Southern California (USC), Mitchum learned about a new HVAC technology called Variable Creeping Flow (VRF) zoning from the Mitsubishi Electric US Cooling & Heating division (Suwanee, Georgia). He was impressed with the success of this installation and contacted Randy Scholnick, sales manager of Sirius Mechanical (Moreno Valley, California), who had installed the system at the fraternity.
After another successful retrofit, for OSM's boutique hotel in Los Angeles, Mitchum turned to Sirius Mechanical to advise the design team on the feasibility of installing Mitsubishi Electric's VRF zoning systems at the Wilshire Hotel. Advised by the design team, Mitchum hired Creative Engineering Group (Canoga Park, California) to design the HVAC system and extraction system. Olson Construction began by reducing the medical office building to its original concrete frame: tearing down walls, reinforcing the structure of the building, adding a terrace with pool and turning the frame into 55 rooms, 19 suites (including a penthouse suite) and common areas.
LEED Silver Certification
Allison Massett, of Killefer Flammang, was the architect appointed for the project. "By getting rid of all the old walls, we had the freedom to create a renewed image for the façade overlooking Wilshire Boulevard," he said.
He added that "we wanted to create a series of contemporary and geometric rectangular frames with floor-to-ceiling windows. We designed luxurious bathrooms with frosted glass walls that separate the bathtub from the room. We installed an attractive rooftop pool for guest entertainment, as well as a private, elegant penthouse with a 500-square-foot terrace overlooking Wilshire Boulevard. We wanted this new eco-friendly hotel to be a reflection of the relaxed, contemporary vibe of L.A., a luxurious new boutique hotel for business and leisure travelers that echoes the rhythms of the city."
Christine Cho, a member of the AIA (American Institute of Architecture), and a LEED AP BD+C accredited professional (in LEED, building design and construction), is the chief architect, at Killefer Flammang Architects, in charge of LEED certification and sustainable design.
"Because we had a goal of obtaining LEED Silver certification for the Wilshire Hotel, we wanted to have as many LEED EAc1 points as possible [Energy Performance Optimization Credits]. Mitchum researched a large number of systems and options. We felt that selecting Mitsubishi Electric's VRF zoning system was a good way to achieve energy savings and earn significant LEED credits, especially in the Energy and Atmosphere section."
Cho said that, based on an energy modeling carried out, the building is projected to consume 17% less energy and achieve energy savings of 19%, compared to a hotel that meets the minimum requirements of section 24, defined by the American Council on Sustainable Construction (USGBC, for its acronym in English). "We have already submitted our application for LEED Silver certification to the USGBC and look forward to hearing from them soon," Cho said.
Thermal comfort control
Walter Jukes is the project manager for Creative Engineering Group (Canoga Park, California). "When Killefer Flammang asked us to join the design team at the Wilshire Hotel, the offer to work with this Mitsubishi Electric VRF zoning system piqued my interest, in part, because it was still a novel technology here in California," he said.
"What we discovered was overwhelming," Jukes continued. "Several aspects jumped out at you. Because we had very little roof area, Mitsubishi [Electric] outdoor units were ideal, for their compact size. Additionally, Mitsubishi [Electric] engineering allowed us to combine capacitors, saving even more space. With a traditional split system, we would have required a huge area on the roof, which would have left us with no space for the pool."
Jukes also noted that Mitsubishi Electric's VRF zoning represented other important advantages. It is the only two-pipe system in the industry that simultaneously allows cooling and heating: This means that less material penetrates the roof membrane.
"This is also significant," Jukes said, "because thermal comfort control is a fundamental requirement for LEED certification and the Outdoor Units and Mitsubishi [Electric] Control System provide individual comfort controls for each room. And finally, the noise levels, produced both by the ceiling condensers and by the individual fan radiators in the rooms are so low that no one knows that they are in operation."
Outdoor compressors
Scholnick stated that "Walter Jukes is right when he points out why this VRF system is so convenient for hotel facilities, especially outdoor units. There are, in effect, seven heat pump systems located on the roof in a very small space of the Wilshire Hotel."
Scholnick explained that because the thirteen capacitors (seven systems in total) found throughout the hotel operate mostly at part load, the efficiency is unmatched, compared to other technologies. In addition, the thirteen capacitors located on the roof of the hotel, next to the restaurant and the pool, produce a maximum of 63 decibels when operating at their maximum capacity, so that they practically do not produce noise either. "
The experience
The hotel's general manager, Debra Matsumoto, describes its HVAC system as "perfectly efficient and quiet." He said: "As we all know, one of the most frequent complaints in hotels is the noise and discomfort generated by the HVAC system, which is continuously turned off and on in the rooms. On the contrary, the indoor units of the Wilshire hotel are so quiet and the room is so comfortable that the restful experience our guests have in our hotel is unique."
Orwitz stated that "OSM [Investment Company] now has two boutique hotels in Los Angeles, whose success is due, in part, to the comfort systems provided by Mitsubishi Electric's VRF zoning systems. Our guests always come back because they feel that our rooms and the services we provide them with comfort. Spence [Mitchum] and I couldn't be more pleased with this technology for hotels. It's a perfect fusion... and I haven't even mentioned the energy savings we've made thanks to this technology."
