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Cogeneration system has become a valuable alternative approach for cascade waste heat recovery (WHR). In this paper, a novel electricity-cooling cogeneration system (ECCS) based on organic Rankine cycle-absorption refrigeration cycle (ORC-ARC) combined system is proposed to recover the waste heat of marine engine. ORC was adopted in the higher temperature cycle, in which alternatives D4, MDM and MM were selected as the working fluids. An ARC was adopted in the lower temperature cycle to recover the heat of the working fluid at the regenerator outlet in ORC. It aims to satisfy refrigeration requirement aboard ship, in which a binary solution of ammonia-water is used as the working pairs. Electricity output, cooling capacity, total exergy output, primary energy ratio (PER) and exergy efficiency are chosen as the objective functions.

A novel combined power and cooling cycle based on the Organic Rankine Cycle (ORC) and the Compression Refrigeration Cycle (CRC) is proposed. The cycle can be driven by the exhaust heat from a diesel engine. In this combined cycle, ORC will translate the exhaust heat into power, and drive the compressor of CRC. The prime advantage of the combined cycle is that both the ORC and CRC are trans-critical cycles, and using CO₂ as working fluid. Natural, cheap, environmentally friendly, nontoxic and good heat transfer properties are some advantages of CO₂ as working fluid. In this paper, besides the basic combined cycle (ORC-CRC), another three novel cycles: ORC-CRC with an expander (ORC-CRCE), ORC with an internal heat exchanger as heat accumulator combined with CRC (ORCI-CRC), ORCI-CRCE, are analyzed and compared.

This paper presents a model system TEG-DORC that employs thermoelectric generator (TEG) as a topping cycle integrated with a dual-loop organic Rankine bottoming cycle (DORC) to recover exhaust heat of internal combustion engine (ICE). The thermodynamic performance of TEG-DORC system is analyzed based on the first and second law of thermodynamics when system net output power Wnet, thermal efficiency ηth, exergy efficiency ηe and volumetric expansion ratio are chosen as objective functions. The model has many parameters that affect combined system performance such as TEG scale, evaporation pressure of high temperature ORC loop (HT loop) Pevp,HT, condensation temperature of HT loop Tcond,HT. It is suggested that HT loop has a vital influence on system performance.

Because of the great resources potential and the feature of low pollution of gaseous fuel, gaseous fuel internal combustion engines (gas engines) have been paid more and more attention. However, their average thermal efficiency is just about 30-40% wasting a huge amount of energy by exhaust, cooling water and so on, so waste heat recovery is very meaningful. Both the RC (steam Rankine Cycle) and the ORC (Organic Rankine Cycle) are regarded as the suitable way of WHR (waste heat recovery) for internal combustion engines. Therein, RC is usually used in large engines. The WHR system is always designed at rated work condition, while the gas engine may often work at different conditions. This makes the property of the waste heat source change, which affects the performance of WHR system, so it is very important to research its performance at variable working conditions.

A bottoming waste-heat-recovery (WHR) model based on the Organic Rankine Cycle (ORC) is proposed to recover waste heat from exhaust gas and jacket water of a typical diesel engine (DE). The ORC model is detailed built based upon real structural and functional parameters of each component, and is able to precisely reflect the working process of the experimental ORC system constructed in lab. The DE is firstly tested to reveal its energy balance and the features of waste heat. The bottoming ORC is then simulated based on experimental data from the DE bench test using R245fa and R601a as working fluid. Thermodynamic evaluations are done on key parameters like waste heat recovered, expansion power, pump power loss and system efficiency. Results indicate that maximum expansion power and efficiency of the ORC are up to 18.8kW and 9.6%. Influences of engine condition, fluid mass flow and evaporating pressure on system performance are analyzed and meaningful regularities are revealed.

Currently, the thermal efficiency of vessel diesels only reaches 48∼51%, and the rest energy is rejected to the environment in forms of exhaust, cooling water, engine oil and so on. Meanwhile, energy is required when generating electricity and fresh water that are necessary for vessels. A system that combines the ORC thermal electric generation system with the single-effect evaporating desalination system simultaneously driven by waste heat of charge air is proposed. The research object was 12S90ME-C9.2 diesel engine produced by MAN corp., and a calculation model of the system is built by MATLAB. The variation of the output power, the thermal efficiency and the freshwater production with some operational parameters of the combined system are calculated and analyzed.