Towards zero water consumption in solar tower power plants

Important efforts are dedicated to reduce water use in the power generation sector. In this paper the use of a dry Heller cooling system is proposed to diminish the water consumption of a concentrated solar tower power plant. The Heller system is an indirect cooling system where the exhaust steam from the turbine is condensed in a direct contact heat exchanger. Part of the condensate and cooling water are pumped to the feed water heaters while the rest is pumped to the dry cooling tower. In this particular case a natural draft dry cooling tower is employed. The detailed cycle of the power block and the cooling system have been modeled. The results indicate an increase of the energy production by almost 6% compared to a mechanically draft dry cooling system and a reduction of the annual energy production of less than 3.7% compared to a wet cooling system. Furthermore, it has been found that this cooling system is able to reduce almost 1.4.10 6 in 3 of water per year, which makes it an attractive choice especially in arid regions. A cost model has been presented to determine the equivalent water price that makes profitable the use a Heller system (Water price =1.96$/m(3)).