Concentrated Solar Power (CSP) plants use solar irradiation as a heat source, in a Rankine-type cycle, to produce electricity. Locations that provide optimal solar conditions for CSP plants are generally also characterized by low water availability. Minimizing water consumption therefore becomes an important consideration when designing CSP plants, especially their cooling systems.
Kelvion Thermal Solutions (Pty) Ltd and ENEXIO Germany GmbH, suppliers of industrial cooling systems, designed a hybrid steam condenser for CSP applications. It comprises a convectional Air Cooled Condenser (ACC) section in parallel with a wet-condenser section. The wet-condenser, or deluge section, is a multiple steam pass heat exchanger containing several rows of nearly horizontal bare tubes that are deluged with water on the air-side. Air flow through the deluge sections (cells) is achieved with fans in a forced draft configuration, similar to the ACC section.
Full-scale deluge cell under construction at Stellenbosch University, Stellenbosch, South Africa (Copyright: Kelvion Thermal Solutions).
Hybrid cooling system with a single deluge cell (Copyright: ENEXIO Germany GmbH).
The hybrid cooling or Deluge ACC system was designed as part of the greater MinWaterCSP project in an attempt to minimize water consumption in CSP plants. The system operates in dry mode (ACC section), with zero cooling water consumption, under favorable ambient conditions. When ambient conditions deteriorate, the wet section is switched on to provide additional cooling capacity. The system consumes 80% less water than a conventional wet system while maintaining plant output over a wide range of adverse ambient conditions (temperature, wind and hot-air recirculation).
The hybrid cooling system for CSP applications will add to the product portfolio of the company, opening up new markets, while providing potential CSP clients with an alternative cooling solution.