In comparison to other traditional and non-traditional methods used by the city, city leaders found the results were so conclusive that the Los Angeles City Department of Water and Power contracted with Dynamic Water Technologies to install the reactors at the city's downtown headquarters as part of the city's proactive efforts to save water.
NREL established pilot programs at a variety of facilities, including LA City Hall East. The East Hall, named James K. Hahn City Hall East after former mayor James K. Hahn, is home to the HVAC plant that supplies cooled water to East City Hall and the adjacent city hall building. It is 18-stories tall and contains about 530,000 square feet.
Cooling tall buildings uses an enormous amount of water that is circulated throughout the cooling system. The water is used for several cycles, but has to be replenished or completely removed when hazardous contaminants and scale accumulate. Adding water to replace water lost to evaporation and the cooling process is called "make-up" water. The dirty, contaminated water that is removed is called "blowdown" water.
In the LA City Hall study, NREL reported a 19 percent reduction in make-up water and a nearly 66 percent decrease in blowdown. Before the DWT installation, water was recycled between 3-5 times. After the installation, water cycles exceeded 10 cycles.
"By re-using the water for the additional cycles, we are able to save millions of gallons of water," said DWT co-founder, Neil Ginsberg. "Make-up and blowdown are two areas where any large building -- whether it's a government building, hospital, shopping center, office complex, power plant, refinery, industrial processes – they all expend millions to tens of millions of gallons of water. Reducing those gallons also saved on sewer and treatment costs."
In addition, the DWT system reduces mineral build-up in tubing, pipes and throughout the cooling system, extending the life of the equipment, and again reducing costs, he said.
Another government study showed similar results at a federal building in Savannah, Ga. In late 2018, the General Services Administration released a report based on a multi-month study at the 242,000 square-foot Juliette Gordon Low Federal Building. The building has two cooling towers that used traditional chemical water treatment for the cooling water circulating through the two chiller condensers.
That study took place from July to October in 2017. Researchers found that the system effectively treated the water without the expense of added chemicals and reduced water use by 32 percent, resulting in a recommendation of the GSA for a governmentwide adoption of the DWT's electrochemical process water treatment technology.