The shape of the working fluid’s temperature-entropy saturation boundary has a strong influence, not only on the process parameters and efficiency of the Organic Rankine Cycle, but also on the design (the layout) of the equipment. In this paper, working fluids are modelled by the Redlich-Kwong equation of state. It is demonstrated that a limiting isochoric heat capacity might exist between dry ...

This paper describes a 1 to 3.5 kWe hermetic scroll expander-generator modified from a standard hermetic compressor, an organic Rankine cycle test facility built to test expanders up to 1 0 kWe and a set of experimental results using HCF 134a in the dry vapor domain. Peak overall isentropic efficiencies in the range of 63 to 65% for speeds of rotation varying between 2400 and 3600 rpm are repor...

The paper proposes two alternative approaches for the design of a dynamic model for an Organic Rankine Cycle (ORC) to be used for the design of control and diagnostics systems. The model has been developed in Modelica language and simulated with Dymola. The two modeling approaches, based on moving boundary and discretization techniques, are compared in terms of accuracy, complexity and simulati...

In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. ...

A multi-variable optimization program has been developed to investigate the performance of Wet Organic Rankine Cycles for low temperature heat recovery applications. This cycle model contains a detailed thermodynamic model of the twin-screw expander, and the methods used to match the operation of the expander to the requirements of the cycle are described. The capability of the cycle model has ...