A solution for the problem of losing generation capability by a power plant due to the use of a dry cooling tower is to supplement the dry tower during the hours of peak ambient temperatures by a wet tower. It is, therefore, important to do an accurate representation of all possible methods of making up capacity loss when optimizating power plants with dry cooling towers. The results indicate that the optimization is very sensitive to the method of making up lost capacity. Since the method of making up lost capacity depends on the situation of a utility, considerable effort has been placed on testing the effects of using different methods of replacing lost capacity at high ambient temperatures by purchased energy. For a 1200 MWe nuclear plant, these are 22 and 25%, respectively. As a result of using dry cooling towers in an 800 MWe fossil plant, more » the incremental costs with the use of high back pressure turbine and conventional turbine over all-wet cooling are 11 and 15%, respectively.

In the base case study, the method of replacing lost capacity assumes the use of gas turbines. The program optimizes the design of the heat exchanger and its air and water flow rates. The optimization minimizes the power production cost. A total optimization was performed for power plants with dry cooling tower systems using metal-finned-tube heat exchangers and surface condensers. Also, the savings by using wet/dry instead of all-dry cooling were determined. This study determined the cost of dry cooling compared to the conventional cooling methods. Using the information presented, it will be possible to incorporate wet cooling tower design and simulation into a procedure to evaluate and optimize power plant = , This information is also useful in power plant cycle evaluation. In addition, a method for simulation of cooling tower performance at various operating conditions is presented. The rule-of-thumb design method provides information useful in power plant cycle optimization, including tower dimensions, water consumption rate, exit air temperature, power requirements and construction cost. A rule-of-thumb method for the optimized design of cooling towers is presented. The cooling tower fill constant (Ka) is defined and values derived. The Merkel equation (the fundamental equation of heat transfer in wet cooling towers) is presented and discussed. The theory of heat exchange in wet cooling towers is briefly summarized. A survey of wet cooling tower literature was performed to develop a simplified method of cooling tower design and simulation for use in power plant cycle optimization.

Cooling tower sizing guide