Presentation of an integrated cooling system for enhancement of cooling capability in Heller cooling tower with thermodynamic analyses and optimization

Abstract

Heller dry cooling towers are being handled in combined-cycle power plants to diminish the temperature of the water returned from condenser. Normally, during the hottest or the most intensive wind blowing times, the performance of the Heller cooling towers is attenuated and subsequently the performance of steam turbine Generator unit of the combined-cycle Power Plant decreases. To solve this problem, an integrated system including the additional heat exchanger and a compression refrigeration cycle driven by an Organic Rankine cycle is linked to the Heller cooling tower to enhance the cooling capability of the cooling tower and subsequently the performance of steam unit. Thus, firstly, the additional heat exchanger and the linked compression refrigeration cycle have been designed via the validated ASPEN HTFS and EES code respectively. The proposed system can cool the water from 313K to 303K and returns it to the condenser of the steam unit in the hottest or wind blowing times to create the stability of steam unit. Afterwards, energetic, exergetic, and exergo-economic analyses as well as the multi-objective optimization of the attached system are conducted. According to the results, the proposed system energized by the waste heat of the exhausted gasses, can help the cooling tower during the above-mentioned times. Also, the optimization increases the exergy efficiency from 33.68% up to 37.59% and decreases the total cost rate from 3945 $/h to 3363 $/h.