-This paper reviews some leading novel energy conversion approaches which are aimed at improving power generation efficiency and/or reducing harmful emissions. Some of the concepts used for cycle improvement are higher top temperatures, improved combustion systems, evasion of the Carnot limit by integration with fuel cells and direct nuclear energy conversion to power (the nuclear generator), r...

In this paper, a new solar-heated generation system with capacity of 10kW is designed. The system is based on solar-heated Rankine cycle. The CPC solar energy collector array is used as the main heat source, and the gas boiler as the assistant heat source. The heat storage facility provides heat for put-off 24 hours generating without sun’s radiation. The paper is focused on the analysis of fou...

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...

In this paper combined Brayton–Rankine cycle was mathematically simulated. In the Matlab program package an adequate numerical procedure has been developed to determine the maximum thermal efficiency of the combined cycle limited by the temperature of exhaust gases at the entrance of the gas turbine and the temperature of the condensation of water vapour in the steam condenser. Furthermore, add...

Organic Rankine Cycles (ORCs) are particularly suitable for recovering energy from low-grade heat sources. This paper describes the behavior of a small-scale ORC used to recover energy from a variable flow rate and temperature waste heat source. A traditional static model is unable to predict transient behavior in a cycle with a varying thermal source, whereas this capability is essential for s...

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...

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