摘要 |
<p>A method, and associated apparatus, for generating power from medium temperature heat sources in the range of 200 ° to 700 °C with improved efficiency compared to systems operating on a Rankine cycle in which the working fluid is condensed at the same temperature. Water is heated in a boiler (11) with heat from the heat source A, (22) which may be a stream of exhaust gases (22), in order to generate wet steam having a dryness fraction in the range of 0.10 to 0.90 (10 % to 90 % dry). The wet steam is expanded to generate power in a positive displacement steam expander (21) such as a twin screw expander. The expanded steam is condensed at a temperature in the range of 70 °C to 120 °C, and the condensed steam is returned to the boiler. The expanded steam may be condensed in the boiler of an Organic Rankine Cycle (22) to provide additional power, or by heat exchange with a heater of a heating system to provide a Combined Heat and cycle, thereby further improving the cycle efficiency.</p> |