Since 1990, Fern Engineering has been contractor to the Electric Power Research Institute (EPRI) in the study and development of methods for gas turbine power augmentation. As part of that overall program, Fern first became involved with the development of direct spray coolers in 1993 and we concluded early on that cooling of gas turbine inlet air via direct water spray was one of the most cost-effective ways of augmenting power. As a result of this conclusion, EPRI funded Fern's development and application of the first engineered direct spray evaporative cooling system in 1996.

In 1999, Fern and American Moistening Company (AMCO) formed a strategic alliance known as AMCO-FERN and we are now offering our Direct Inlet Spray Cooler (DISC) for evaporative cooling of gas turbine inlet air. AMCO, a longtime supplier of industrial humidification systems, and Fern, with its prominent position in direct spray cooler development and research, form a unique partnership designed to provide state-of-the-art evaporative cooling systems for our clients. Our initial units were delivered in May 1999 for installation on two GE LM6000s and customers now include Westinghouse, GE, Enron, and Jacksonville Electric. For more information, please contact Paul Simas.

Our spray coolers have several innovative features offering improved performance over conventional media type evaporative coolers and other direct spray coolers, maximizing power by achieving 100% saturation and providing additional power through overspray. The design employs state-of-the-art of water spray nozzles and judicious placement within the inlet to maximize droplet evaporation and control the size of unevaporated droplets. While most of the water is evaporated, fine droplets, termed overspray, continue downstream, are carried into the compressor, and evaporate within a short residence time to cause an interstage cooling effect. By permitting only small droplets to enter the compressor, the potential for blade erosion is mitigated and evaporative efficiency within the compressor is enhanced.

Shown below is some actual test data from a GE Frame 7EA operating with a Fern-designed DISC. Tamb is ambient (dry bulb) temperature. Tcit is the compressor inlet temperature. The DISC delivered 25 degrees of cooling, producing about a 12% increase in power.

As part of the first Fern/EPRI system produced in 1996, Fern Engineering developed software, operating in a Microsoft Windows environment, to operate, monitor, and control the spray cooler through a dedicated personal computer and data acquisition system.

Fern and EPRI are continuing efforts to improve spray cooler technology by assisting EPRI members in evaluating the potential use of these systems at EPRI-member plants. In 1998, Fern and EPRI participated in a second inlet cooling development project where spray coolers were designed and installed on a total of eight units at two sites.

Our experience has put Fern at the forefront of technology development in this area, as confirmed by the fact that several other spray cooler manufacturers are using the technology developed through the Fern/EPRI demonstration programs. Fern will remain at the forefront of this technology for the foreseeable future through its association with EPRI and through other research programs like our contract with the U.S. Navy to conduct research on boosting ship-board gas turbine power.

The schematic drawings below show the water delivery system and header arrangement for our spray coolers.

Power benefits to the owner can be estimated on a site-specific basis. Contact Fern Engineering for a free analysis of your application.

Contact:

Paul Simas