Sea trials of an organic triangle system (OTC) for waste heat recovery
Document type:
Konferenzbeitrag
Author(s):
Lance Hays; Atsushi Otsuka; Patrick Boyle
Absract (alternative):
The organic triangle cycle (OTC) incorporates a simple liquid counter-current heat exchanger, eliminating the “pinch point” limitation of the heat input to organic Rankine cycle (ORC) systems. A flashing liquid expander is used to generate power from the heated high pressure liquid. Improvements in power production from heat sources of as much as 20 to 40% have been calculated, subject to the efficiency of the flashing liquid expander and the minimum allowable return temperature of the heat source (DiPippo,2007). Several applications of a flashing liquid expander known as the Variable Phase Turbine (VPT) were successfully addressed; including the replacement of expansion valves in chillers and industrial refrigeration and in a geothermal OTC system. These applications substantiated the efficiency and reliability of the VPT for OTC applications (Welch et al, 2011) Recently the VPT was applied to an OTC system for waste heat recovery from a shipboard engine. The rated engine output was 17,650 kW. The source of waste heat was hot air from the turbocharger compressor. The shipboard propulsion engine was manufactured by Mitsui E&S Machinery Co., Ltd. (MES) to power a bulk carrier ship. The OTC was manufactured by MES, factory tested, and subsequently installed with the engine on the ship. Performance and design of the OTC system for the factory test and sea trials are provided. The system produced power from air at a range of 183 C to 191 C. The hot air was produced from a turbocharger compressor of the propulsion engine. Maximum power produced by the VPT was 234 kW. The OTC system was operated for 4,079 hours during a sea trial. The system was insensitive to pitch and roll of the ship. After shakedown and qualification tests the system was demonstrated for six (6) commercial voyages of the ship. The system was operated for 2079 hours during these voyages. The generated power was fed into the ship grid. The power required from the ship diesel electric generator and hence, greenhouse gas emissions for the ship were reduced. Design of the installation, controls and electrical system to ensure compatibility with the ship systems is provided. Performance, reliability and operational experience for the sea trial are reported. Reduction in carbon emissions from reduction of the power required by the ship diesel electric generator is estimated. The sea trials of the OTC demonstrated its reliability for marine applications. Additional marine waste heat recovery possibilities include power generation from the propulsion engine exhaust and cooling water, as well as supercharger waste heat.