Cooling Water Control Technology Saves Water across Multiple Sectors
Organization: Nalco, an Ecolab Company
SUMMARY: A variety of cooling systems are used across a multitude of sectors, from energy generation to manufacturing. Regardless of the size or design of the cooling system, there are operational challenges that can impact water usage and the bottom line of an organization. Cooling water optimization software can help to mitigate some of these operational challenges by monitoring the system stresses and automatically responding. These case studies highlight operations across multiple sectors that utilize cooling water technology with real-time monitoring, activities-based control, and information management capabilities to realize significant water savings and economic savings.
Las Vegas Hotel and Casino
- Lake Mead supplies Las Vegas with more than 90% of its water, but severe drought in the Colorado River Basin has caused the lake to drop 130 feet since the high-water mark last reached in 2000.
- The hotel and casino sits atop an underground aquifer, and has been encouraged to use a specific amount of groundwater (233.87 acre feet per year) to reduce stress on surface water stores.
- While per-capita water use has decreased significantly in Las Vegas since 1990, despite an increase in population, water conservation to accomodate for future challenges is still imperative.
- The hotel and casino developed a strategy to utilize aquifer water as makeup water for the air conditioning system cooling towers. This was deemed the most beneficial use of aquifer water, as it would reuse the water for multiple cycles, as opposed to only once on landscape irrigation.
- The hotel and casino engineering staff and Nalco determined that utilizing aquifer water for 5-8 cycles of cooling would yield the maxiumum water savings without risking corrosion stress in the system.
- 3D TRASAR™ technology was implemented to monitor and control cycles in the cooling tower in real time, while also optimizing water chemisry conditions and continuously protecting the system from corrosion, scale formation, and microbial infection.
- The implementation of real-time cooling system monitoring and cycle control resulted in more than 57.4 million gallons of water saved in the cooling towers since 2008.
California Power Plant
- A power plant located in the Central Valley of California faced increased demand for water and reduced water supply due to drought and groundwater overdraft.
- The power plant relies on reclaimed wastewater for cooling tower make-up water. Until 2012, the power plant was permitted to dispose of 3.2 million gallons per day of cooling tower blowdown water.
- Continuing with the historic discharge rate of 3.2 million gallons per day with the new terms of the permit issued in 2012 would significantly increase operation costs.
- Reducing water usage came at the risk of compromising the operational integrity of the cooling system by increasing the mineral concentration in cooling water.
- To reduce makeup water use, blowdown discharge and to mitigate the risk of mineral deposition, the power plant implemented 3D TRASAR™ technology to monitor and control key parameters related to the stresses placed on a cooling system in real-time.
- The capability to continuously monitor changing stresses on the cooling system and react in real time allowed the plant to safely reduce water usage without risking damage to the cooling system.
- By implementing real-time cooling tower monitoring and control, the power plant saved 40 million gallons of water (an 11% reduction) per year.
- The power plant was able to reduce sewer discharge by 47 million gallons per year.
- Reduced water usage and sewer discharge amounted to a reduction in water costs of $17,000 per year, and reduced sewer charges of $12.8 million in year 1, and $394,000 in subsequent years.
- A global aircraft manufacturer developed a sustainability initiative to reduce water and chemical consumption by 25% over five years.
- The manufacturer was able to document a decrease in water consumption of 9%, but was challenged to find additional opportunities for savings. Complicating matters further, production demand was at an unprecedented level, leading to increased water usage.
- The cooling tower systems were consuming the most water during the production process. The systems were analyzed and it was determined that the current level of treatment and automation had reached the limit of water consumption possible.
- The plant was concerned that additional water reduction could only be achieved through increasing the cycling of the tower. At higher cycles of concentration the system integrity or performance may be compromised.
- At higher cycling rates, cooling tower systems can experience scale formation, corrosion, and microbial activity.
- The manufacturing plant implemented 3D TRASAR™ Water Saver technology along with an additive that acts as a scale removal dimension to the existing scale prevention platform of the system.
- Under the automated system, as the tower cycles gradually increase, water loss is minimized from the reduction in blowdown. Simultaneously, the 3D TRASAR™ system monitors and controls all critical system operating parameters in real-time to ensure system reliability.
- During the first four months of operation, the cooling tower was gradually cycled up until zero discharge was achieved.
- This means that the plant was able to operate the tower with zero blowdown, maximizing the water reduction capability of the system.
- The automated system with the scale removal dimension was able to reduce blowdown by 100%, allowing the plant to achieve zero liquid discharge from the cooling tower system. This translates into a water savings of 1.16 million gallons of water per year.
- After one year of operation, one of the towers was taken off-line and inspected. There was no evidence of scale or microbial deposition found on the tubes.
Submitted by Nalco, an Ecolab Company - Case studies referenced include:
- "Las Vegas Hotel and Casino Taking Proactive Step to Conserve Water"
- "California power plant uses Nalco technology to save 40 million gallons of water, $12.8 million in discharge fees and reduce annual operations costs by $411,000 per year."
- "Global aircraft manufacturere achieves water reduction and system performance goals."