Thermodynamic Assessment of Heat Source Arrangements in Kalina Power Station

Kalina power plants have an efficient system of heat recovery compared with a single-fluid system because of a better temperature match between hot and cold fluids. The high-temperature regenerator (HTRGN), economizer, and evaporators are serially connected in a regular low-temperature Kalina power system. A higher amount of vapor from the generator followed by a separator gives high power output by a turbine. But with this condition, low heat recovery in HTRGN results in low thermal efficiency with the serial connected heat exchangers. It can be solved by sharing the heat load between HTRGN and a boiler (economizer plus partial evaporator) based on available heat with parallel arrangement in place of serial. It also facilitates the flexible operation of heaters with the heat source conditions. The current work has been focused on the comparison of these two heat recovery configurations with energy and exergy criteria to select a best layout. The influence of vapor fraction, separator temperature, turbine concentration, and solar beam radiation on performance of the plant has been studied. The key parameters are optimized to get a high performance with minimized collector's cost. The results show that at high vapor fraction, the parallel arrangement results in higher improvement. The total variations in plant energy efficiency, cycle energy efficiency, and cycle exergy efficiency are 0-2%, 0-5%, and 0-12%, respectively, with the parallel arrangement of heaters at variable operational conditions. (C) 2013 American Society of Civil Engineers.