It didn't happen by chance, either. Comfort and ambiance are the primary goals of Station's management and - the truth be told - they couldn't be happier with the outcome.

"Everything we like to do to optimize system operation is represented in this building, including pressurization," said Station's vice president of project administration, Tom Moore. To put it another way, smoke, among other goals, does not get in your eyes inside this particular casino.

WORKING TOGETHER FOR A COMMON GOAL

As Moore will tell you without hesitation, Station Casinos Inc. knows what it wants, sets standards, and ... well, doesn't waver. To maintain control - thus quality of the aesthetics and ambiance, too - Station direct-purchased $60 million in services and equipment. In this instance, it had its own general contractor license. Everyone who had anything to do with aesthetics reported directly to Moore - and that includes facade, signage, marble, granite, interior and exterior look, and the HVAC. In short, the general contractor built a box and Station gladly filled it out.

Listening to Moore describe Station's objectives might lead one to believe that cost didn't matter in the building of Sunset Station. In truth, there was a very tight budget.

"Station Casinos knew what they wanted from their HVAC system - comfort and a smoke-free environment in a smoking facility," explained Robert Higgins, manager of building automation systems for the Trane Company's Las Vegas commercial sales office. Station depended on Trane's Las Vegas office to supply needed expertise, help, and input.

Station also worked with nearby consulting engineers AE Associates (Las Vegas) to produce the plans and specifications and accepted no value-engineering substitutes, even under tight construction budgets. "We would never do otherwise," explained Moore emphatically. "It's not the cost; it's the control of quality."

To challenge the project team even more, casinos by nature are fast-track projects. Because of gaming taxes and revenues, opening on time is ... well ... paramount. It almost goes without saying that casinos are supposed to open on time.

Moore was happy to report that Sunset Station was constructed in less than 18 months, from site work to opening. Quite a task, considering that in addition to the large casino the main building is 360,000 square feet and includes five full-service restaurants plus a 448-room, 20-story hotel. The facility is extremely complex in several ways, including the Spanish/Mediterranean architecture and HVAC comfort system.

Moore commented that very few companies could have put the amount of equipment into a facility this size in the time frame they had, and make it all work right. "This was the smoothest start-up I have ever had," he said.

In this instance, Trane and mechanical contractor Southland (Las Vegas) worked side-by-side, managing to get the job done on time. "For as big and sophisticated as this system is, we had no problems," said Moore.

About IAQ, he added, "We place a high premium on overall feeling in terms of temperature and smokiness inside the building, and we pay a lot of money to get quality. We could do things a lot cheaper if we wanted to. A little smoky is not OK for repeat customers. Just OK doesn't cut it."

Rob Finnegan, engineer of record and principal of AE Associates, said his company used both passive and active means to achieve good IAQ. For instance, supply air enters from the side walls and is pulled up from higher elevations. This, he said, is designed to eliminate the mixing and diffusion of smoke-laden air. According to Finnegan, this also helps it exit the building or pass through filtration. And, there are no ceiling diffusers, as the ceiling is very important to Sunset Station.

STOPPING SMOKE, SAVING ENERGY

While extraordinary results suggest that new technologies may have been used in Sunset Station, the fact is the success is based on good, sound engineering practices. Finnegan described it as, "... simply taking a common sense approach to achieving good IAQ."

For example, Finnegan said his company used 95 percent filtration, which he discovered "works as well as active smoke removal systems and electronic filtration in many applications. Combined with high levels of outside air, we created the indoor atmosphere we were looking for."

The fact that Finnegan and AE Associates recommended modulating outside air with IAQ sensors turned out to be another big plus. Consider it experience talking, as AE Associates is recognized in many HVACR circles as one of the leading firms in the United States in designing systems that produce good IAQ.

"It's a good system for enhanced indoor air quality," assured Finne-gan, adding, "What we've given them is an active IAQ system in which we control outside air for maximum benefit when the casino is busy and energy savings when it's not fully occupied."

According to Sunset management and all involved, nonsmokers, both patrons and employees, wel- come the resulting indoor atmosphere. And, the truth be told, the owners couldn't be happier.

"The gaming industry is concerned about IAQ for patrons and employees alike," stated Finnegan. "As we travel around the country dealing with IAQ projects, mostly in the gaming industry, we sometimes feel like smoke busters. It's a very hot issue."

NO COMPROMISING IAQ

While budgets for its flagship property were tight, there was never any thought of compromising IAQ. AE Associates did not try to design a prototype, supersophisticated system. They drew on its experience to design a practical system, using proven techniques.

"There was nothing really new," said Tom McGahey, project engineer for AE Associates. "We incorporated all the good practices we could. A good example is the 95 percent filtration system."

In McGahey's estimation, it doesn't cost all that much more to install the filter housing over one for a 65 percent filtration system. AE Associates had set up its own test laboratory and found that 95 percent filtration works well and, in its estimation, is comparable to an electrostatic filtration system. Still, air filtration is only part of the Sunset Station story. According to McGahey, the central station air handlers are fitted with an integral, factory-mounted air monitoring and control system called Traq™, which is designed to modulate the amount of ventilation air entering the building. With the help of the Tracer Summit® building automation system, McGahey said the Traq system, which is also manufactured by Trane, is able to dynamically adjust the outside air to satisfy building ventilation requirements.

According to the manufacturer, an active part of the system uses volatile organic compound (VOC) sensors to detect organic materials. It is designed to sense a broad range of gaseous compounds and then respond by increasing or decreasing the amount of outside air brought into the building. In AE Associates' estimation, outgassing of VOCs is especially prevalent in Sunset Station's case, with all of the special materials used to carry the theme throughout the complex.

According to the consulting engineering firm, another active part of the system polls each of the more than 450 variable air volume (VAV) terminal units, looking for the most open VAV damper. The data is collected at the Tracer system, which is designed to adjust the duct static pressure set point for each air-handling unit. The supply fan is designed to generate only enough pressure to get the required flow through this critical VAV terminal. According to Trane, this is designed to ensure that no zones are starved for air, yet allows the central station air handlers to operate at the lowest possible energy level.

To control building pressurization, the Tracer Summit control system is designed to continually poll each central station air handler for the total outside air being brought into the building through the Traq dampers. According to the manufacturer, it is designed to total all the outside air and then stage building exhaust fans as required to maintain proper building pressure. Per Trane, the system is then designed to maintain a slightly positive pressure to prevent air infiltration.

According to AE Associates, as part of the ongoing commissioning process, the contractor is trending all of the air-handling units. The trend logs are to show actual readings, compared to set points, and how dampers are responding. From this information, Sunset can decide whether to bring in more or less outside air.

FINDING THE SWEET SPOT(S)

When the building staged through the commissioning process, engineers at AE associates and the controls contractor searched for sweet spots. "Every building has its own pulse," said Finnegan, "and it takes time to find it."

They continue to monitor kW usage of each air handler in the chiller mode and in the economizer mode to find what strategies and set points work best and ultimately where to operate the building. Moore emphasized the critical importance of operating costs and commissioning in this manner, noting that it takes time to go through every single piece of the system and make sure it's working to spec.

"Leaning it down, leaning it down until everything is just right: This gets you the efficiency," explained Moore.

By following this commissioning process, he said, equipment lasts longer, there are fewer breakdowns, and it saves "tons of money."

"Design is a best guess," said Moore. "Commissioning is making it work; making the boxes work as a system, not as components. We're trending IAQ, supply air temperature, and other things."

For example, instead of running two 1,400-ton machines, the team can run just one and reset water temperature to supply the water the building needs, instead of running everything wide open, and still satisfy comfort and air quality. But one cannot do it by hand, Moore explained.

"You have to have sophisticated controls and do it by computer," he said. "This is an electronic system."

Sunset Station's building operators are currently relying heavily on Trane to help learn the idiosyncrasies of system optimization. Because of the extreme importance of maintaining temperatures in the casino, operators are very conservative for fear of losing part of the building. Because of this situation, Trane system engineers are there, ready to help define how far they can go.

ALL IS WELL

The bottom line is this: Sunset Station presented to AE Associates' engineers many challenges, which included a tight budget, strict deadline, and the requirement for aesthetics inside and out. Finnegan put it this way: "We had to step back and put on our practical hats and be very innovative. We took the practical approach to solving problems and ended up with something a little different. It's a big system. Lots of constraints."

That doesn't mean the task was insurmountable. Everyone on the team is proud of what they've accomplished on the Sunset Station Casino project.

"Everything we like to do to optimize system operation is represented in this building, including pressurization. We've put together a system that works very well. AE, Southland, and Trane worked together to complete the project on Station's aggressive construction schedule. It took a good team effort."

The owner cannot argue with the end product. "I'm a happy camper," he admitted.

Sidebar: Factoring Into the Equation

LAS VEGAS - Don't get management wrong. All attention given to Sunset Station Casino here was not given strictly to the air side. Several practices were used to optimize the refrigeration-side system performance.

AE Associates said it optimized everything in sight, getting help from Robert Higgins, manager of building automation systems for the Trane Company's Las Vegas commercial sales office, and the rest of the controls team.

For instance, the chiller plant consists of three 1,400-ton CenTraVac® centrifugal chillers, which are manufactured by Trane. According to AE Associates, they are piped into a parallel configuration, with a bank of three commonly headered primary chilled water pumps. Building water is provided through three commonly headered secondary chilled water pumps, each on variable-speed drives designed to be capable of pumping from 40-100 percent of pump capacity, said the consulting engineering company.

According to the project team, pump control is accomplished by maintaining a constant differential pressure between building supply and return.

Per AE Associates, the control strategy in the chiller plant is to operate one chiller as long as possible before bringing on a second chiller. There may be times when the system (secondary) water flow exceeds the chiller (primary) water flow, but the chiller is still not fully loaded. At these times, the consulting engineering firm said reducing the primary temperature allows the chiller to increase the load it can satisfy. System water temperature is maintained, it said, by mixing the reduced temperature primary water with system water. The effect of this control is to delay starting an additional chiller, it explained.

Overall, this strategy is designed to keep chillers from being staged on before the existing enabled chillers have fully loaded. When a chiller has been taken to its lowest chilled water supply set point and building, leaving water continues to rise, another chiller is staged on, it explained. Other optimization strategies were used to take advantage of cooler air during the winter months. AE Associates' Tom McGahey described them as "a double-barreled approach." It involves an air side economizer and a plate-and-frame heat exchanger.

During the cooler months, they can use either or both, explained McGahey. Because outside air was such a big component of the design, AE Associates designed the air intake for 100 percent outside air. And, according to McGahey, the plate-and-frame heat exchanger can be used in areas that can't use 100 percent outside air, such as in fan coils, equipment rooms, and even hotel rooms. The 100 percent outside air and heat exchanger are perfectly complimentary, he explained.

Publication date: 10/23/2006