Performance evaluation of heat recovery generator for ammonia–water mixture in combined cycle power plants

ABSTRACTCombined cycle offers the capability of making effective utilisation of heat for power generation by synergetic operation of two or more power cycles at different temperatures. The present paper deals with the thermodynamic evaluation of utilisation of heat carried by the gases leaving the topping cycle in heat recovery generator (HRG) for enhancing the output from bottoming cycle to augment the power generation. HRG is considered for operating the Kalina cycle with ammonia–water mixture as working fluid instead of pure water with the objective of enhanced heat recovery. Performance evaluation indicates that the increase in ammonia mass fraction offers increase in overall heat transfer coefficient up to 960 W/m2 K.