Economic and Performance Benefits Resulting from the Use of Large Diameter Fans on Air Cooled Heat Exchangers (A Case Study in the Use of Large Fan Air Cooled Condensers at the Neal Hot Springs Geothermal Power Plant, Oregon)
- Key words
- Air cooler; air cooled condenser; ACC; geothermal; power plant; operating costs; maintenance costs; O&M costs; capital cost; construction cost; recirculation; fan; fan efficiency; motor efficiency; direct drive motor; wind direction; Hudson
- Location
- Neal Hot Springs, Oregon
- Conference
- Geothermal Resources Council Transactions
- Year
- 2012
- Session
- Equipment design; Power plant cooling; Condensers; Economics
- Language
- English
Abstract
A significant improvement in air cooler technology was implemented at the Neal Hot Springs geothermal power plant in Vale, Oregon. Large cooling tower fans were used in an induced draft arrangement (fans above the heat exchanger). The total number of fans was reduced from 270 x 12ft / 3.7m fans to 30 x 33ft /10m fans. The present value of the O&M and power savings totals $1.6 million dollars. The decision to use variable frequency drives yielded additional power savings with a present value of an additional $3.1 million dollars. While the capital costs were higher, specific design elements were implemented to offset these additional capital costs. Computational fluid dynamics (CFD) was used to show that the large fan design virtually eliminates hot air recirculation yielding substantial annual generation and net revenue benefits, compared to recirculation rates of small fan arrays that produced 5% to 35% recirculation rates.
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