Here is a new twist on the Rankine cycle that may change things to the better: http://www.dself.dsl.pipex.com/MUSEUM/POWER/ammonia/ammonia.htm look up 'Kalina cycle'. Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist