Improving Cooling Tower Water Efficiency with the Helios TCS
Cooling towers use lots of water. By design their purpose is to transfer heat from recirculating water used to cool buildings or industrial processes, so that fact is no surprise. Add to that the increasing global awareness of water scarcity (approximately 4 billion people, more than half the world’s population experience severe water scarcity during at least one month of the year) and cooling tower water consumption is garnering more scrutiny every day.
In the United States, consistent drought across much of the west and southwestern states is becoming the dangerous new normal. Reduced snowpack is already affecting water resources, and these trends are expected to continue with long-duration drought increasingly possible.
Cooling Tower Water Use
Cooling towers are a key component of many cooling systems providing air conditioning or process cooling. Cooling towers are most efficient when their heat transfer surfaces are clean. However, these are dynamic systems, and fluctuations in the quality of the local water source and the nearby open air environment will impact cooling tower performance and water consumption.
Helios Reduces Cooling Tower Water Use by Increasing Cycles of Concentration
As cooling towers evaporate off water to provide cooling, dissolved solids and minerals are left behind and build up in the recirculating water. To prevent fouling and corrosion of heat transfer surfaces as minerals accumulate, cooling tower operators must dump some water to the drain and add fresh clean water to the cooling tower basin.
The limit of how much dissolved minerals are allowed to accumulate without affecting system cooling performance is known as the Cycles of Concentration (COC).
M = B + E where: M = makeup water flow rate (gpm)
B = blowdown water flow rate (gpm)
E = evaporation flow rate (gpm)
COC = M/B
When a facility manager installs Helios Tube Cleaning Systems on their condensers, the continuous mechanical tube cleaning action provides another tool for optimizing cooling system performance and operation. Because condenser tubes are the warmest portion of the cooling system, they typically foul first. After installing Helios systems, condenser tube fouling is eliminated and facility managers may realize they can save water by increasing their cooling tower’s cycles of concentration. A small 2,000-ton cooling tower system that operates 3,500 hrs/year and increases COC from 3 to 5 will save over 2.5 million gallons of water annually. In fact, one Innovas customer has saved many thousands of gallons of water by increasing cooling tower cycles of concentration after installing Helios systems in their central cooling plant.
Helios Tube Cleaning System Makes Alternative Water Sources Effective & Reliable Options
Because of the focus on cooling tower water consumption, many facility owners are turning to alternative sources of makeup water to reduce water use. Whether the alternative water source comes from a graywater system, stormwater reclaim system, or industrial wastewater reclamation strategy, variable makeup water quality makes cooling water treatment difficult. These systems may have large swings in biological loading or mineral content in the makeup water, and rapid condenser tube fouling is often the result. Chillers plagued with high condenser approach temperatures and frequent shutdowns for manual tube cleaning are a common side-affect of these system designs. Regardless of the chosen strategy for utilizing reclaimed water for cooling tower makeup, the Helios Tube Cleaning System makes them effective. The Helios, with its continuous mechanical tube cleaning, eliminates condenser tube fouling, chillers resume energy-efficient operation, and facility operators are relieved from the burden of perpetual manual tube brushing. Cooling system designs utilizing water recovery strategies that were previously plagued with high condenser approach temperatures have been returned to reliable and efficient operation by the Helios Tube Cleaning System and its elimination of condenser tube fouling.
Summary
In addition to optimizing chiller energy efficiency and reducing maintenance requirements, Helios Tube Cleaning Systems® can provide facility owners with tremendous water-savings opportunities. Whether increasing cooling tower water efficiency by enabling higher cycles of concentration, or improving the reliability and effectiveness of graywater systems, the Helios TCSTM helps facility owners reduce water costs and achieve sustainability goals.
