Expansion of organic Rankine cycle working fluid in a cylinder of a low-speed two-stroke ship engine

Abstract

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Improving the Overall Efficiency of Marine Power Systems through Co-Optimization of Top-Bottom Combined Cycle by Means of Exhaust-Gas Bypass: A Semi Empirical Function Analysis Method

“…At a turbocharging efficiency of 68.8%, the exhaust-bypass ratio was adjusted from 0% to 9.0%, and the turbine-inlet temperature increased by 50 • C. The turbocharger exhaust temperature increased more than 40 • C, resulting in an increase of 414 kW in the total power generation, while the overall efficiency increased from 50.34% to 54.84%. Moreover, the results of increasing efficiency were the same as those given in the MAN report [42,43]. Because of the assumption that the minimum intake-pressure ratio of a diesel eng remains unchanged under the same load, the maximum excess-air ratio can be obtain by combining it with the compressor characteristic curve, and the maximum exhaust pass ratio of the diesel engine can be obtained, based on Figure 9.…”

“…The such solution could reduce the combustion efficiency and improve the exhaust-gas temperature, thereby achieving a higher WHR efficiency, as shown in Figure 1 [41]. In practice, the tuning strategy of bypassing the exhaust gas was first proposed by Larsen et al [42,43], whose combinations included PT, RC, and PT-RC systems. They indicated that employing PT would provide a 3-5% recovery ratio, while adopting RC would provide a 5-8% recovery ratio, and utilizing PT-RC would provide an 8-11% recovery ratio.…”

“…al. [42,43], whose combinations included PT, RC, and PT-RC systems. They indicated that employing PT would provide a 3-5% recovery ratio, while adopting RC would provide a 5-8% recovery ratio, and utilizing PT-RC would provide an 8-11% recovery ratio.…”

Heat exchanger network design of an organic Rankine cycle integrated waste heat recovery system of a marine vessel using pinch point analysis

“…An economic analysis showed that the proposed ORC systems have payback periods varying between 4 and 9 years according to the average fuel price. Larsen et al 9 introduced the concept of two-stroke engine, which utilizes one of the cylinders as the expander of the ORC fluid. While the remaining eleven cylinders produce power by the injected fuel, the expander cylinder produces power and delivers the torque through the crankshaft of the engine simultaneously with the others.…”

Thermodynamic analysis of waste heat recovery using Organic Rankine Cycle (ORC) for a two-stroke low speed marine Diesel engine in IMO Tier II and Tier III operation

“…Larsen et al [35] also proposed a new concept of an ORC system, aiming at reducing the cost of the bottoming cycle installation using one of the cylinders of the engine for the expansion process. Numerical models have been used in order to assess the maximum power output of the proposed architecture, while 104 different fluids have been evaluated, obtaining best results for R245fa and R1234ze(z).…”