Air-cooled power plant condensers at water-cooled performance levels - is it possible?

Dry air-cooled condensers (ACCs) represent a promising minimal water consumption power-plant cooling technology compared with conventional once-through liquid and evaporative approaches. However, due to the poor thermal transport properties of air, current ACCs have high capital costs and yield a 5 - 10% reduction in plant-level efficiency relative to wet cooling. ACCs have therefore been highlighted as critical targets for enhanced heat transfer engineering, but the potential for plant-level gains has not been critically assessed. In this study, a model of a representative air-cooled condenser system is employed to explore the potential to approach wet-cooled plant performance levels through techniques that reduce the air-side thermal resistance, and by raising the air mass flow rate. This ACC unit model is coupled to a representative baseload steam-cycle power plant model. It is found that water-cooled power-plant efficiency levels can be approached by using enhanced ACCs with significantly increased air flow rates (+68%), reduced air-side thermal resistances (-66%), and air-side pressure losses near conventional levels (+24%). Emerging heat-transfer enhancement technologies are evaluated for the potential to meet these performance objectives. Results from this investigation provide guidance for the adoption of ACCs, and identify promising pathways for air-side enhancement.