HELLER OR DIRECT AIR COOLED AN ANALYTICAL COMPUTER AIDED SELECTION METHOD.

This paper reflects the result of the latest studies for determining the appropriate cooling system for the power plants to be located in different areas of Iran, according to the costs and economic consideration and their results will be presented for Arak power plant project [1]. First, Theortical studies on Direct air cooled (DAC) and Helier systems were done and the correlations for Thermo - Hydralic calculation were found. In the meantime, selection of design temperature and provision of temperature Duration curve were studied and finally the proposed calculation procedures were tested and with due regard to acceptable error range, The studies continued. Afterwards, with the provided computer program. the calculations were generalized. In the second step, the economic evaluation of the selected systems was proceeded. In Helier system economy, considering the local manufacturing of some ports, the costs were divided in local and foriegn currencies with, the provided computer program, it is possible to analyse and compare the cost items of DAC and Helier system. To be able to determine the most appropriate system, from operation point of view, the recorded data of their performance , are required.