Saving Water in Sin City
Lake Mead is America’s largest reservoir. Formed by the famous Hoover Dam on the Colorado River, it provides water for nearly 20 million people, as well as substantial areas of farmland. However, due to drought and climate change, Lake Mead’s water level has been falling drastically over the past decade: in May, 2022, its capacity was measured at just over 25%.
As a result, the federal government has acted to limit the amount of water that is withdrawn from Lake Mead and the Colorado River, and the states that rely on its supply are taking measures to cut consumption. For the Southern Nevada Water Authority, which includes Las Vegas within its area of operation, a whole tranche of new measures were recently introduced, such as the banning of new water features and fountains on the famous Vegas Strip, a moratorium on new golf course development, and restrictions on the size of new residential swimming pools.
Significantly, the Authority has also banned the installation of evaporative cooling in new commercial developments. Research has shown that evaporative cooling is the second-largest consumer of water in Southern Nevada, after outdoor irrigation, and uses around 10% of the region’s annual allotment of water from the Colorado River. According to Dave Johnson, the Authority’s Deputy General Manager, the main concern is the kind of large cooling towers found at Las Vegas resorts.
When the Forum Shops mall at the celebrated Caesars Palace resort recently decided to revamp its existing air-conditioning, water usage was the major concern in choosing a new system. The luxury mall, which comprises 675,000 sq. ft. of tenant space, first opened in 1992 and houses high-end boutiques from the likes of Balenciaga, Giorgio Armani, Breitling and Tom Ford.
The decision was made to replace the existing evaporative coolers with three Güntner High Density Adiabatic Dry Coolers with hydroBLU™. These compact units combine dry-cooling heat exchangers with Güntner’s pre-cooling system based on humidification pads. As long as the temperature in the cooling system doesn’t exceed a pre-set threshold, no cooling water is used. Once the threshold is passed due to a peak in load or ambient temperature, humidification of the pads is activated and dynamically adjusted by the intelligent control module.
In this case, on-site analysis by Güntner and the local HVAC contractor established that the units could run dry up to a temperature of 77F, meaning the water savings compared to a conventional water cooled system would be considerable and would potentially earn the client a significant cash rebate under Southern Nevada’s Water Efficient Technologies programme.
Schafer believes that the combination of regulation and cash incentives will encourage many other companies in Las Vegas to follow the same route as the Forum Shops mall. “This was a high-profile installation on a building that’s known all over the world, and it shows the way forward,” he says. “Demand for water is starting to outpace supply, so we need to consider alternative modes of heat rejection that allow us to manage the resources that we have. Adiabatic cooling is a very effective way to do that – and not just in Nevada, but in other states in the US and in many countries around the world.”