POWER PLANT HEAT REJECTION SYSTEM MODELING AND COMPARISON

As noted in a Summer 2007 EPRI Journal article entitled Running Dry At The Power Plant, "Securing sufficient supplies of fresh water for societal, industrial, and agricultural uses while protecting the natural environment is becoming increasingly difficult in many parts of the United States. Climate variability and change may exacerbate the situation through hotter weather and disrupted precipitation patterns that promote regional drought." [1] Currently, in the United States, thermoelectric power production accounts for approximately 41% of freshwater withdrawals [2] and 3% of overall fresh water consumption. [3] The Electric Power Research Institute, EPRI, as part of its Technology Innovation (TI) program, is collaborating with Johnson Controls to conduct a feasibility study comparing the performance of a water saving Thermosyphon Cooling Hybrid System (TCHS) with other heat rejection systems for power plant applications. The TCHS employs a sensible heat rejection device, a thermosyphon cooler (TSC) in conjunction with an evaporative heat rejection device, an open cooling tower, to satisfy the annual cooling requirements of a given power plant. By reducing the evaporative heat load, the TCHS can significantly reduce the annual water consumed for cooling while still maintaining peak power plant output on the hottest summer days. Details of the interactive simulation program developed to compare various power plant heat rejection systems on an annual 8,760 hourly basis are discussed. Examples of the types of results and comparisons that can be made from the data obtained from the simulation program are presented.