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Electricity and power produced from waste heat is particularly relevant in shipping because fuel expenses constitute the majority of the cost of operating the ships; however, the cost-benefit aspect limits the widespread implementation of waste heat recovery power units on ships. This paper presents the thermodynamic analysis of a concept that aims at reducing the cost of an organic Rankine cycle unit by using one of the cylinders in a large diesel engine as expansion device. Numerical models were used to optimise the process parameters and thereby determine the power potential for this concept. The evaluation of 104 working fluids points to cyclopropane, R245fa and R1234ze(z) as the most promising. The results suggest that the power produced by the organic Rankine cycle cylinder is at least equivalent to that of the cylinders operating with the diesel process. This enables potential fuel savings and emissions reductions of about 8.3% in the studied scenario. [ABSTRACT FROM AUTHOR]

Overthe last few decades, researchers have developed a number of empiricaland theoretical models for the correlation and prediction of the thermophysicalproperties of pure fluids and mixtures treated as pseudo-pure fluids.In this paper, a survey of all the state-of-the-art formulations ofthermophysical properties is presented. The most-accurate thermodynamic properties areobtained from multiparameter Helmholtz-energy-explicit-type formulations.For the transport properties, a wider range of methods has been employed,including the extended corresponding states method. All of the thermophysicalproperty correlations described here have been implemented into CoolProp,an open-source thermophysical property library. This library is writtenin C++, with wrappers available for the majority of programming languagesand platforms of technical interest. As of publication, 110 pure andpseudo-pure fluids are included in the library, as well as propertiesof 40 incompressible fluids and humid air. The source code for theCoolProp library is included as an electronic annex. [ABSTRACT FROM AUTHOR]

Abstract: Much attention is focused on increasing the energy efficiency to decrease fuel costs and CO2 emissions throughout industrial sectors. The ORC (organic Rankine cycle) is a relatively simple but efficient process that can be used for this purpose by converting low and medium temperature waste heat to power. In this study we propose four linear regression models to predict the maximum obtainable thermal efficiency for simple and recuperated ORCs. A previously derived methodology is able to determine the maximum thermal efficiency among many combinations of fluids and processes, given the boundary conditions of the process. Hundreds of optimised cases with varied design parameters are used as observations in four multiple regression analyses. We analyse the model assumptions, prediction abilities and extrapolations, and compare the results with recent studies in the literature. The models are in agreement with the literature, and they present an opportunity for accurate prediction of the potential of an ORC to convert heat sources with temperatures from 80 to 360 °C, without detailed knowledge or need for simulation of the process. [Copyright &y& Elsevier]