The Federal Energy Management Program (FEMP) identified advanced cooling tower controls as a water-saving technology that is relevant to the federal sector, is commercially available, and offers significant water-savings potential.
This overview provides agencies with key information to deploy innovative products and systems that may otherwise be overlooked. It also helps agencies identify water-efficient technologies for consideration when entering into energy savings performance contracts or utility energy service contracts.
FEMP used the following considerations when selecting this technology.
- Underutilized in the federal sector
- Broad applicability across the federal sector
- Water and cost savings potential
- Market availability
- Produced by multiple manufacturers
- Ease of installation/suitable as a retrofit
Advanced cooling tower controllers provide real-time monitoring in cooling tower systems to manage chemical feed and cycles of concentration. Also known as "cycles of concentration ratio," a cycle of concentration is the ratio of the dissolved minerals in the recirculating water compared to the dissolved minerals in the fresh water make-up of a cooling tower.
Advanced cooling tower controllers ensure that cooling towers operate at specified cycles of concentration by continuously monitoring and controlling the conductivity of the recirculating water. The controllers react dynamically to changing operational conditions that affect cooling towers and heat exchangers, optimizing system performance continuously, so cooling towers and chillers operate at maximum efficiency. The results are:
- Energy savings because of cleaner heat-exchange surfaces
- Water savings by running optimal cycles of concentration
- Chemical savings by eliminating needless overfeeding of treatment products.
Multiple manufacturers produce variations of advanced controllers for cooling towers that are widely available. These controllers can be installed on new cooling towers or retrofitted onto existing operating systems. Installation and programming should be coordinated with a water-treatment specialist to ensure that proper set-points are programmed into the controller based on water quality, treatment program, and cooling tower operating conditions.
Proven Savings Potential
An independent 2011 study for the state of California determined that implementing cooling tower controls and maximizing cycles of concentration state-wide on evaporative cooling towers 150 tons and larger could save 32.3 million gallons of water in the first year. (Source: California Statewide Utilities Codes and Standards Team, Cooling Tower Water Savings. accessed June 23, 2015.)
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