Abstract
Organic Rankine Cycle (ORC) power plants have become very popular and have found their applications in systems with renewable sources of energy. So far their overall efficiencies are not very impressive and only for the upper temperature of about 300 °C do they exceed 20%. A drawback of these cycles is the limitation of the cycle upper temperature due to the heat exchanger technology and the materials used. However, it is possible to overcome these difficulties by certain modifications of the thermodynamic cycles, a proper choice of the working medium and the optimization of cycle parameters. In the paper the problems of choosing the working medium and the question of higher temperature at the turbine inlet have been discussed. Different modifications of the schemas of the thermodynamic cycles have also been taken into account. The variants of power plants with regenerators, reheaters and heat exchangers have been considered. The proposed increase in temperature (in some cases up to 600 °C or higher) and innovative modifications of the thermodynamic cycles allow to obtain the power plant efficiency of above 50%. The modified cycles have been described in detail in the paper. The proposed cycles equipped with regenerators and reheaters can have the efficiency even slightly higher than classical steam turbine plants with a reheater and regenerators. Appropriate cycle and turbine calculations have been performed for the micro power plants of turbine output in the range of 10 kW–300 kW (up to several MW in some cases). The best arrangements achieved very high values of the overall cycle efficiency.
Highlights
At present, due to coal-fired plants, the power systems in many countries, are characterized by a relatively low efficiency [1,2]
Higher values of efficiency are obtained by ultra-supercritical steam turbine power plants [9,10], combined gas-steam thermal cycles [11] or modified Organic Rankine Cycle (ORC) cycles [12]
Biofuels have become very popular and have been treated as renewable sources of energy. They can significantly vary in quality, heating value and other parameters which can cause some serious problems when used as fuel for stroke engines and gas turbines
Summary
Due to coal-fired plants, the power systems in many countries, are characterized by a relatively low efficiency [1,2]. Air a working medium forair both the compressor as well as the turbine [19,20] This solution allows us the to burn fuels of varying in the external combustion without anycan harmful. ORC power plants the most property of the applied as working fluids apart from the traditional medium, i.e., steam. It is a very popular opinion that above heat of rather low temperatures (heat emitted from engines, gas turbines and industrial processes or efficiency than power plants waste). [22].AtOur analysis shows that thermodynamic withcorrect organicand fluids canrefer achieve a better cycles efficiency steam plants [22] Our this statement is notcycles entirely may to simple andthan relatively low temperatures analysis shows that this statement not entirely correct and may refermore to simple cyclescycles and relatively which characterize current practicalisapplications.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
