Hybrid Cooling for Power Generation and Water Scarcity in the South African Context

Traditionally, water is used in thermal power plant for heat rejection processes such as in the steam condenser for use in a Rankine cycle. Typically, research has shown that approximately 2 litres of water are required to generate 1 kWh of electricity on a wet-cooling system; which on a bigger scale could translated to more than 11000000 m³ per year of make-up water for a 600 MWe coal-fired plant. The ever-increasing cost of water resources as well as the water resource scarcity have paved a path to dry-cooling systems which alternatively provide a significant cooling potential. However, dry-cooling systems performance are generally driven by the atmospheric conditions which at time do not meet the desired cooling temperatures resulting in significant drop in their performance. Recent developments in cooling technology suggest that hybrid systems (dry-wet) be used to insure good and manageable performances while maintaining the cost of operation at admissible range. In light of the recent draught experienced in South Africa, attention was drawn to evaluation of deluged systems performance as well as water consumption to increase the public awareness in the field. In this study, a deluged bundle was used to experimentally determine the cooling performance characteristic as well as water consumption for performance management. The above is then considered on a bigger scale to in order to open floor for further discussion on future strategies in term of the South African policy on water usage.