Abstract: The demand for energy is cumulatively increasing with time. Since the availability of conventional energy resources is dying out gradually, significant interest is being laid on searching for alternate energy resources and minimizing the wastage of energy in various fields. In such perspective, low-grade waste heat from several industrial sources can be reused to generate electricity. The present work is to further the adoption of the Organic Rankine Cycle (ORC) technology in Indian industrial sector. The present paper focuses on extending the previously reported idea to the next level through a comparative review with three different working fluids using practical data from an Indian industrial plant. For comprehensive study in the simulation platform of Aspen Hysys®, v8.6, the waste heat data has been collected from a current coke oven gas plant in India. A parametric analysis of non-regenerative ORC and regenerative ORC is executed using the working fluids R-123, R-11 and R-21 for subcritical ORC system. The primary goal is to determine the optimal working fluid considering various system parameters like turbine work output, obtained system efficiency, irreversibility rate and second law efficiency under applied multiple heat source temperature (160 °C- 180 °C). Selection of the turbo-expanders is one of the most crucial tasks for low-temperature applications in ORC system. The present work is an attempt to make suitable recommendation for the appropriate configuration of the turbine. In a nutshell, this study justifies the proficiency of integrating the ORC technology in Indian perspective and also finds the appropriate parameter of all components integrated in ORC system for building up an ORC prototype.
Abstract: ORC (Organic Rankine Cycle) has potential of
reducing consumption of fossil fuels and has many favorable
characteristics to exploit low-temperature heat sources. In this work
thermodynamic performance of ORC with regeneration is
comparatively assessed for various working fluids. Special attention is
paid to the effects of system parameters such as the turbine inlet
pressure on the characteristics of the system such as net work
production, heat input, volumetric flow rate per 1 MW of net work and
quality of the working fluid at turbine exit as well as thermal
efficiency. Results show that for a given source the thermal efficiency
generally increases with increasing of the turbine inlet pressure
however has optimal condition for working fluids of low critical
pressure such as iso-pentane or n-pentane.