Experimental results of an ammonia-water mixture turbine system (effectiveness with a low temperature heat source)

This paper presents an experimental investigation of the effectiveness of an AWM (Ammonia-Water Mixture) turbine system with low temperature heat sources. The AWM turbine system (AWMTS) features Kalina cycle technology, namely, it employs an ammonia-water mixture as the working fluid and includes a separation / absorption process of NH ₃-H ₂O. Since AWM is a non-azeotropic mixture, its temperature changes during evaporation and condensation. This behavior gives AWMTS the advantage of heat recovery from a sensible heat source such as exhaust gas. It is known that an AWMTS can generate more power than a Rankine cycle system from 250-650 °C sensible heat sources. The authors constructed a 70 KW-experimental facility and investigated the practical applications of AWMTS. It is located at the bottoming stage below a conventional combined cycle composed of a gas turbine and a steam turbine. Its heat source is the exhaust steam from a back pressure steam turbine at the middle stage of the system. The experiment was carried out with changing the back pressure of the steam turbine. The experimental results show that power generation is possible from 138 to 162 °C heat source steam.