Design of solar enhanced natural draft dry cooling tower for solar thermal power plants

For concentrated solar thermal (CST) power plants located in dry and arid areas, dry cooling is the only cost effective alternative. If using existing dry cooling technology, the CST power generation will be reduced significantly at high ambient temperatures. This paper presents design options of a novel cooling tower design concept with the potential to maintain the design-point performance even on very hot days. In this new concept, a natural draft dry cooling tower is modified by adding a solar collector around its base. The function of the solar collector is to make the air inside the cooling tower hotter so the buoyancy force increases. In a natural draft dry cooling tower, increased buoyancy means increased air flow rate through the heat exchangers and, therefore, increased heat transfer capacity. The end result is power plant efficiencies significantly higher than what could be achieved with the unmodified design.