|Just another project for Mechanical Air Service? Not quite. This high-end home posed some great comfort challenges.|
When it comes to creating and installing an award-winning comfort system in a very high-end home, it takes a great supporting cast of characters. Fortunately, Russ Donnici, founder and president of Mechanical Air Service, Inc., San Jose, CA, has that cast at his second generation, family-owned business.
Donnici is a certified energy manager (CEM), EPA-registered environmental assessor (REA), and certified radiant designer (CRD). So when the call came to create a comfort system for a beautiful new home that includes a movie theater among its many amenities, the technical side of Donnici was thrilled at the challenge.
However, he will be the first to tell you that he wouldn’t be free to create outstanding comfort systems without the support of the staff at his 31-year-old company. Key among those supporters are family: Danielle Larson, vice-president of finance, is his daughter; Matt Donnici, vice president of construction, is his son; and Scott Larson, vice president of service, is his son-in-law. They handle the day-to day operations of the company, which does commercial and high-end residential work in Santa Clara County (Silicon Valley) and San Mateo County.
“It’s such a great blessing to have family members on your team who share the same goals and commitment to our clients,” Donnici says. “Matt and Scott were the real leaders on this project, and set the bar very high for our other employees who worked with them.”
This year, the team at Mechanical Air Service earned a Quality Home Comfort Award for its work at a custom-built, two-story home that checks in at more than 17,000 sq.ft., which includes an 8,000 sq.ft. theater. The home is located in one of the most exclusive residential areas in the San Francisco Bay area. It’s situated on a large lot (two lots combined) with a large swimming pool, guest house, attached garage, and a detached garage/shop.
On this project, Russ Donnici was retained by the architect to provide the engineering and CAD drawings. The main criteria of the homeowner and the architect were a high level of individual comfort for all the rooms in the home, excellent indoor air quality, and energy efficiency.
“This project was originally started by an architectural firm I had done several jobs with in the past,” Donnici explains. “We were chosen for the job because of the high-end work we had done with them, and for our engineering and problem solving abilities. In fact, we had been referred by these architects on a couple of problematic mechanical/radiant projects they had done with other vendors. In the case of each of those referrals, Matt and I were able to solve the problems and help avert a lawsuit by the homeowner to the general contractor.”
Given this history, both the architect and homeowners were very receptive to any and all suggestions Mechanical Air Service made. “There was no selling,” Donnici says. “The homeowners trusted us because of the recommendation of the architect, whom they knew from other projects.”
|The finished project by Mechanical Air Service became a model of Indoor Air Quality, comfort, and energy efficiency.|
Mechanical Air Service served as the engineer of record on the home. Because of the extreme amount of structural steel used in the home’s construction, nine separate HVAC systems were installed, along with a dedicated system for the home’s spectacular basement theater. “The structural steel made for some severe limitations to access from one area to another,” Donnici says. “Had the access been better, we would have used fewer actual systems but the same amount of zones.
“The homeowners do a lot of entertaining, so the HVAC system was sized to handle the additional loads,” Donnici continues. “However, to save energy, high efficiency, 17-SEER, two-stage condensing units were used so that the systems use only the amount of cooling needed for the load at hand. We’re certified energy managers, and the system was designed for the highest efficiency.”
High-efficiency 93% furnaces were installed; however, a radiant floor heating system powered by a high-efficiency condensing boiler operates as the first stage of heat and is the primary source of heat for the home.
To ensure the best Indoor Air Quality (IAQ), all duct ends were sealed at the end of each day during construction to prevent contaminants from entering the system. In addition, all systems have an electronic air cleaner, as well as a high-intensity, dual-bulb UV light system. Three heat recovery ventilators were used to enhance the Indoor Air Quality of the home. Because of the mild Northern California climate, no additional humidity control measures were needed.
|Matt Donnici, left, Russ Donnici, and Scott Larson have earned another QHCA award.|
Just to make sure this wasn’t your average, every day, run-of-the-mill project at a 10,000+ sq.ft. home, the home’s 8,000 sq.ft. theater presented its own set of comfort challenges.
Donnici and his team worked together with the theater designer/engineer to handle the unique needs of this space and to design and install a dedicated system for the theater. “This was a highly-engineered, extremely high-end job,” Donnici notes.
Because of the projector’s sensitivity to heat, a dedicated 1-ton chiller was installed, with a custom-engineered fan coil. The chiller’s operation is integrated into the control system of the basement furnace, to reclaim any heat rejected by the chiller for use in heating the basement.
The condensing unit in the theater features a two-stage compressor. The theater’s fan coil system and another furnace near the theater were both mounted on spring isolators to prevent any vibrations from being transmitted into the theater.
The theater’s controls system was custom-designed by Donnici to function only when the theater is activated. Two additional thermostats, which are independent of the main control system, serve as redundant backups. A post-operation cooling purge is used to dissipate any possible residual heat that might be in the projector enclosure.
The theater’s duct system was designed for a virtually silent NC-15 sound level. A dedicated exhaust fan and make-up air fan were installed to keep the air fresh in the theater.
“We did encounter an unexpected challenge during startup of the chiller for the projector,” Donnici relates. “The compressor was dead on arrival. The factory had a replacement and was to overnight it to us, because the homeowners had some holiday parties planned and very much wanted the theater functioning.
“When the compressor didn’t arrive the next morning. we had a tracer put on it. It turns out it had been damaged during shipping. The factory didn’t have any more compressors and the lead time was two to three weeks. This wasn’t acceptable to us, so we located a compressor at a vendor locally and installed it that same day. The homeowner was very pleased and impressed by the extra effort we put forth for them.”
|equipment includes UV light and media filter.|
Cutting Edge Controls
The thermostat controls throughout the home are integrated into a cutting-edge home control system. In addition to HVAC control, the control system allows any room to select any desired music or movies to be played on the room’s plasma screen. Selection is through the system’s LCD touch screens.
Most of the thermostats use remote sensors, and the thermostats are clustered in various areas throughout the home.
The home’s server room houses all of the electronics and the AV systems for the home. There’s an extreme amount of storage capacity (estimated at 800+ terabytes) to store digital movies and music. This room received a dedicated 3-ton system that features inverter technology.
When it came to the radiant heating system, the homeowner was in very capable hands with Mechanical Air Service. “We’re a factory trained, Uponor HCT-certified contractor, which allows us to provide extended warranties on Uponor components,” Donnici says.
The 26-zone radiant heating system consists of 13,566 lineal feet of -in. PEX tubing encased in 2-in. of gypcrete. The gypcrete in the kitchen area, which is above the theater, had an acoustical underlayment used to isolate any potential sound transmission to the theater.
Slab sensors were installed throughout the home to limit the maximum floor temperature to protect the hardwood floors.
The high-efficiency condensing boiler also provides the domestic hot water. The boiler is equipped with an outdoor temperature reset control to provide only the amount needed by the home based on the outdoor temperature for additional energy savings.
|the radiant heating panel is a design masterpiece.|
An extensive commissioning process was used to guarantee the systems were providing the rated outputs and energy efficiency. In Mechanical Air Service’s commissioning process:
• All airflows were tested and balanced
• All system static pressures were measured and recorded
• All barometric dampers were balanced for proper system operation and airflow
• All furnaces and the boiler were tested for combustion efficiency and adjusted as needed
• All water flows were tested and verified
• All radiant zones were tested for a 10F temperature differential.
Props to the Team
Russ Donnici is proud to add another Quality Home Comfort Award to his company’s trophy case. However, much like an actor accepting an Oscar, he knows it couldn’t have been done without his behind-the-scenes team.
“Matt and Scott provided project management and job supervision as well as start-up and commissioning services. Because of the complexity of the systems and the installation and integration of the radiant heat system, it was truly a group effort,” Donnici says.
• 6 Westinghouse L1RC high efficiency furnaces
• 4 Bryant variable speed fan coils
• 3 Bryant heat recovery ventilators
• 10 Bryant two-speed condensing units
• 7 Aprilaire 6404 zone systems
• 10 Ultravation UMX high intensity UV light systems
• 10 Honeywell F300 electronic air cleaners
• 2 Vibron 22VRS sound silencers
• 1 Truton AC100 chiller
• Carrier custom-built vertical fan coil
• 4 Greenheck fans SQ-75-D and SQ-95-D
• Lochinvar KBN-210 condensing boiler
• Amtrol 120-gal. indirect water heater
• 5 Grundfos UPS 26-99 FC pumps
• 1 Grundfos UPS 15-58
• 6 Taco ZCMs for pump control
• 13,500 lineal feet of -in. Uponor PEX tubing
• Custom-designed Crestron controls system
• Aprilaire zone controls