Combined Rankine Cycle and dew point cooler for energy efficient power generation of the power plants - A review and perspective study

Abstract

The Rankine Cycle is a thermodynamic process widely applied to power plants such as coal-fired power plants or nuclear reactors. The thermal efficiency of a power plant is largely dependent upon the temperature difference between a heat source and a cold source; an increased temperature difference leads to the significant increase in the thermal efficiency and power generation rate of the power plant. Integrating the dew point cooler, i.e., Maistosenko Cycle system, into the traditional Rankine Cycle is an effective approach to reduce the temperature of the cold source (i.e. condenser), and thus, increase the thermal efficiency and power generation rate of the power plant. The paper presents a close overview of the combined Rankine/Maisotsenko Cycle, concerning with: (1) current development of Rankine Cycle power systems and Maisotsenko Cycle evaporative cooling technologies; (2) existing pre-cooling technologies for the cooling tower; and (3) thermal efficiency of the combined Rankine/Maisotsenko Cycle and its relevant impact factors. It is concluded that the combined Rankine/Maisotsenko Cycle can overcome the limit of the existing similar technologies, has great energy-saving potential and is economically viable. The further research should focus on a number of critical issues which require effective solutions to enable the energy efficient power generation. These include: (1) Optimisation of the combined Rankine/Maistsenko cycle using advanced multi-objective evolutionary optimisation algorithms; (2) Prediction of the future operational performance of the combined Rankine/Maistsenko cycle based power plant using future weather forecast scenarios and associated machine learning algorithms; (3) Analysis of thermal economics performance of the combined cycle using entropy and exergy analytic approach; and (4) Analysis of energy costs of the combined cycle using the exergo-economic and emergoeconomic analytical methods. This benefit also thanks to the recent development of the dew point cooling technology with highly enhanced COP, especially in hot and dry climates.