Exploring the Design Challenges Behind Las Vegas’ New Circa Casino
From ASHRAE Journal’s 2022 AHR Today
LAS VEGAS—The city that never sleeps makes energy efficiency an even greater challenge—especially in the city’s hotels and casinos.
“Las Vegas is a particularly challenging location when it comes to energy efficiency. Often the guest experience can come at the expense of energy efficiency. It’s hard to keep a casino 65°F (18.3°C) when it’s 110°F (43.3°C) outside and the owner wants the whole side of the building open to Fremont Street. Managing owner expectations and agreeing on reasonable design conditions is often one of the first steps in the design process,” said Ryan Calahan, P.E., Member ASHRAE, who is the vice president of the ASHRAE Southern Nevada Chapter and was part of the design team that created the first new ground-up casino in downtown Las Vegas in more than 40 years.
The Circa Resort & Casino, located on Fremont Street, opened in October 2020 and is an adults-only property offering more than 1.2 million ft2 that includes 777 guest rooms, two levels of casino gaming floor, meeting rooms, restaurants and the world’s largest sportsbook.
The most substantial energy efficiency challenge Circa faced was the high ventilation requirements for casino gaming floors, said Calahan, adding that exhaust air energy recovery and variable speed demand control ventilation are the most effective ways to mitigate these challenges.
“Circa is the first casino in Las Vegas to use variable volume, under-floor air supply to serve the gaming floor. Under-floor air supply allows for a reduction in tonnage due to higher supply air temperature and lower supply air volume versus a standard overhead mixed-air system,” said Calahan. “The system brings in 100% outside air though plate-type heat exchangers before being conditioned to a supply temperature of 63°F (17.2°C). The room air is allowed to stratify with exhaust air captured at the ceiling and exhausted through the plate heat exchanger.”
Calahan said this design also minimizes mixing of indoor air pollutants, such as cigarette smoke and airborne pathogens.
In all, a four-pipe hydronic system fed from three 800-ton water-cooled chillers and six 600-million-Btuh condensing boilers serve Circa, in addition to custom indoor air handlers that are located throughout the low-rise building in mechanical rooms and mezzanine spaces, said Calahan. Also, water-to-water heat exchangers decouple the low-rise and high-rise hydronic piping systems as well as provide domestic hot water.
Las Vegas’ hot and dry climate also presents challenges for the design of comfort solutions, especially with sizing equipment.
“Air-cooled direct expansion equipment must be de-rated approximately 20% to account for high ambient air dry-bulb conditions. However, the ‘dry’ part of the hot and dry climate in Las Vegas actually provides a reduction in cooling capacity with respect to similar projects on the Gulf Coast or the Mid-West,” he said. “Where in a humid climate we would need to over-cool and then reheat the air, here in Las Vegas dehumidification is less of a concern for typical casino application. The dry climate works well for direct evaporative cooling in outdoor or warehouse areas and also provides for greater efficiency on cooling towers.”
Maintaining the equipment is another challenge. Because of Circa’s downtown location and its rooftop pool deck, roof space was limited, so much of the mechanical equipment is located on service platforms over restrooms, kitchens and other back-of-house areas, said Calahan.
“The coordination of stairs, ladders, catwalks and working platforms required for equipment servicing was particularly challenging,” he said.
Creating thermally comfortable, safe indoor environments is a challenge anywhere. But in Las Vegas, the climate and the high-rolling nature of the city are more than just a lucky roll of the dice.