Better Odds On Better Breathing
The Turning Stone Casino Resort in Verona, NY, operated by the Oneida Indian Nation, had a problem with environmental tobacco smoke (ETS). During peak hours as gamblers filled up the gaming floor, a blue haze would cover occupants, and the existing ventilation system didn't do enough to clear the air.
Drastic measures were needed to solve the ETS problem. Interestingly enough, smoking is prohibited in public buildings throughout New York, but visitors to the casino are permitted to smoke, because the facility is located on sovereign land. The Oneida Indian Nation, while wanting to permit smoking, felt strongly about eliminating as much ETS as possible. To achieve that, they were even willing to tear out all the existing mechanical systems in order to improve the air quality within the casino.
And that's just about what happened. A two-phase construction project included demolition of existing mechanical systems and installation of new ones. The first phase of the construction, which was completed in August 2002, consisted of an 80,000-sq-ft expansion of the gaming room. The second phase, which was completed in January 2003, involved a complete renovation of the existing 70,000-sq-ft of gaming floor.
Now 18 months later, a new underfloor air system has helped eliminate the ETS problem, and patrons (and owners) can breathe easy.
Displacing Traditional SystemsPrior to the renovation, the casino used seven air cooled chillers and a traditional overhead air distribution system that employed heat recovery. Even with 100% outside air entering the building, a smoke haze continued to fill the casino. Engineering firm Sacks and Associates, (Syracuse, NY) was brought on board to see what it could do to correct the problem with ETS.
Jerry Cowden, an engineer with Sacks and Associates, said, "We put a lot of thought into the best way to get rid of the smoke, and we came up with the displacement air system, or underfloor air system. We supplied the conditioned outside air down low and exhausted it up high."
Cowden said the firm considered other types of air distribution systems as well, including those used in hospital operating rooms. There, air is often supplied in the middle of the room and exhausted low down on the sides. But the engineers didn't think it would be as effective as pushing the smoke up and exhausting it out the top of the building.
As a result of their research, York's FlexSys™ underfloor air system was installed in the expanded gaming room. The VAV boxes in the underfloor air system modulate to meet the needs of a particular space; subsequently, the speed of the heat recovery unit fans changes in order to meet the static pressure requirement in the floor plenum.
Rick Lopez, owner and sales engineer, Pro Air Plus, Inc., (Syracuse, NY) explained that with an underfloor air system, 100% fresh air is introduced at the floor and all the polluted air is exhausted at the ceiling. "If you go into the gaming area right now and watch people sitting at the slot machines with cigarettes in their hands, you can watch the cigarette smoke move directly towards the ceiling and be carried away by the return air system."
Lopez noted that one of the issues they had to be careful about when installing the new underfloor system was air leakage. The raised floor creates a pressurized supply air plenum, so a good seal is needed where the raised floor is connected to the perimeter walls, interior walls, and columns.
"You have to make sure that partitions and columns go all the way to the subfloor. Taking measures to adequately seal penetrations is very important. Otherwise you see things like the fresh air in the pressurized raised floor going up the column and coming out the thermostat, resulting in poor temperature control," said Lopez.
New Air-Handling System NeededPhase I also included the removal of the casino's air-handling equipment, which contained heat wheels. "The wheels were all getting contaminated from the smoke, so the decision was made to utilize air-to-air plate-type heat exchangers. There's no cross contamination between the two airstreams, so it keeps the heat exchangers clean," said Cowden.
Twenty two brand new, 12,000 cfm, 100% outside air heat recovery units manufactured by Venmar were installed. The units use 95% filters, and a water wash system on the exhaust air cleans all the ETS tar and film from the plate heat exchangers.
The Venmar units are outfitted with cooling coils and hot water coils, along with gas-fired Nortec humidifiers. The humidifiers are necessary, because Syracuse experiences harsh winters, with indoor rh levels down around 20%. With all the fresh air being brought into the casino, humidity must be added back in for occupant comfort.
Installing the new heat recovery equipment was a challenge, because it turned out the units were heavier than anticipated. A helicopter was hired to place the equipment on the roof. However, the units were too heavy, and each unit had to be disassembled into sections, hoisted to the roof by helicopter, then reassembled.
Energy Efficient ChangesThe six and 10-year-old air cooled chillers didn't have adequate capacity to cool the new space, so a new 1,000-ton water-cooled York chiller was installed for the addition. The original goal was for the air cooled and water cooled chillers to run together to meet the expanded needs of the casino. However, in a short period of time, the casino grew from a 3,000-ton connected load to a 6,000-ton connected load.
More capacity will also be needed in the near future, because the casino is in the process of building a 20-story hotel, 300-room lodge, an indoor garden area with waterfalls and plants, and a new showroom. With these new additions scheduled to open by fall 2005, it was decided to abandon the air cooled chillers in favor of a central station chilled water plant.
Pockets of natural gas were also found on the reservation, and a cogeneration plant was subsequently built. The original water cooled York chiller was moved over to the power plant, and two 1,500-ton Trane two-stage absorption chillers were also installed, along with two Trane 1,000-ton centrifugal chillers.
The casino will use the waste steam off the electricity-producing gas turbine for the absorption chillers to produce approximately 3,000 tons of free cooling during the summer months. In the winter, a plate-and-frame heat exchanger will be used for the base load.
Bill Hollenbeck, senior facilities supervisor, Turning Stone Casino, said that even though it cost a lot to purchase all the new chillers, they're already seeing a big difference in their operating costs. "We get more for our money with the power plant. The air cooled chillers were only 1.3 kW/ton, but the York chiller is 0.3 kW/ton. That's because it's got a 10% turndown on variable speed, so we can run it way down low."
The Venmar units also have VSDs on the supply and exhaust fans, so Hollenbeck can lower the power consumption on all 22 of the units. "We can run a low static pressure on the duct, run the fans down, and get the amperage down. If you look at the whole picture, you can see how much energy we're saving. Say a motor that used to run 70 amps, we can run it under 20 now. The power savings is phenomenal."
Fourteen new high-efficiency, 2,000,000-Btu gas-fired modulating boilers were also installed, along with variable-speed pumping systems for energy conservation. The casino was already using an Alerton BAS, so it was expanded into the addition. The existing BAS was also upgraded for the new chilled water plant, heating plant, and additional renovations.
Renovation a ChallengeOnce the addition was finished, it was time to turn everyone's attention to the existing gaming space. The entire building was gutted, which made it a little easier to install the new mechanical systems. But there were still challenges.
As Cowden noted, the biggest hurdle during the renovation was to fit all the equipment into an existing space and still be able to get rid of the ETS as effectively as the systems did in the addition. "In the addition we could do whatever we wanted. For example, we could support our equipment on the roof, because it was a brand new building, and we could design the structure to support everything. In the existing building, we had to reinforce the roof and build platforms and that was a big challenge."
It was also challenging to install the underfloor air system in the existing area, because trenches had to be dug in the existing floor slabs to accommodate this system. Hollenbeck said that it also took time to lag in all the floor supports, construct the raised floor, then put in the units. "We had to install access panels carefully, because we only have 32 or 34 in. to do our work in. It was time consuming, but in the long run, it's paying for itself."
Decorative fake columns were installed to distribute the air at floor level. Heavier gauge floor platforms and panels had to be used to allow casino personnel to drive forklifts on the gaming floor to service lighting fixtures and other equipment.
Although the primary purpose of the underfloor plenum was for air distribution, once the space was created, everyone wanted to take advantage of it, said Cowden. As a result, the plenum was also utilized for power, data, and control wiring.
Now that all the work is finished, everyone agrees that the air is much clearer with the underfloor air system in place. "We have floor space sensors that modulate the dampers, and everything's running fine," said Hollenbeck. "I don't know how long the underfloor system has been available, but it's something that's really helped us out considerably." ES