Comparative assessment of Organic Rankine Cycle integration for low temperature geothermal heat source applications

Depleting fossil fuel resources and the horrible environmental impacts due to burning fossil fuels emphasize the importance of using renewable energy resources such as geothermal and solar energies. This paper compares performance of CO2 transcritical cycle, organic Rankine cycle, and trilateral Rankine cycle using a low-temperature geothermal heat source. Thermodynamic analysis, exergetic analysis, economic analysis, and exergoeconomic analysis are applied for each of the aforementioned cycles. In addition, a sensitivity analysis is performed on the system, and the effects of geothermal heat source temperature, evaporator pinch point temperature, and turbine inlet pressure on the cycle's performance are evaluated. Finally, the systems are optimized in order to minimize product cost ratio and maximize exergetic efficiency by using the genetic algorithm. Results indicate that the maximum thermal efficiency is approximately 13.03% which belongs to organic Rankine cycle with R123 as working fluid. CO2 cycle has the maximum exergetic efficiency, equals to 46.13%. The minimum product cost ratio refers to the organic Rankine cycle with R245fa as working fluid. Moreover, sensitivity analysis shows that increasing geothermal heat source temperature results in higher output power, product cost ratio, and exergy destruction ratio in all cycles.

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Thermodynamic Optimization Of An Organic Rankine Cycle For Power Generation From A Low Temperature Geothermal Heat Source

Proceedings of the 58th Conference on Simulation and Modelling (SIMS 58) Reykjavik, Iceland, September 25th – 27th, 2017 ◽

10.3384/ecp17138251 ◽

2017 ◽

Cited By ~ 1

Author(s):

Inés Encabo Cáceres ◽

Roberto Agromayor ◽

Lars O. Nord

Keyword(s):

Power Generation ◽

Low Temperature ◽

Heat Source ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Thermodynamic Optimization ◽

Geothermal Heat

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Multi-objective optimization of evaporator of organic Rankine cycle (ORC) for low temperature geothermal heat source

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2015.01.034 ◽

2015 ◽

Vol 80 ◽

pp. 1-9 ◽

Cited By ~ 53

Author(s):

Muhammad Imran ◽

Muhammad Usman ◽

Byung-Sik Park ◽

Hyouck-Ju Kim ◽

Dong-Hyun Lee

Keyword(s):

Low Temperature ◽

Heat Source ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Multi Objective Optimization ◽

Geothermal Heat ◽

Multi Objective

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Thermal Comparison of an Organic Rankine Cycle Activated by a Low-Temperature Geothermal Heat Source

Journal of Mechanics Engineering and Automation ◽

10.17265/2159-5275/2018.07.004 ◽

2018 ◽

Vol 8 (7) ◽

Author(s):

Vera-Romero Iván ◽

Corona-Ruíz Silvia L. ◽

Martínez Reyes J. ◽

Moreno Nava I. ◽

Ordaz Murillo O. ◽

...

Keyword(s):

Low Temperature ◽

Heat Source ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Geothermal Heat

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Performance Investigation of Solar Organic Rankine Cycle Systems With and Without Regeneration and With Zeotropic Working Fluid Mixtures for Use in Micro-Cogeneration

ASME 2020 14th International Conference on Energy Sustainability ◽

10.1115/es2020-1616 ◽

2020 ◽

Author(s):

Wahiba Yaïci ◽

Evgueniy Entchev ◽

Pouyan Talebizadeh Sardari

Keyword(s):

Low Temperature ◽

Heat Source ◽

High Efficiency ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Industrial Wastes ◽

Working Fluid ◽

Condensation Temperature ◽

Thermodynamic Performance ◽

Cycle Efficiency

Abstract Globally there are several viable sources of renewable, low-temperature heat (below 130°C) particularly solar energy, geothermal energy, and energy generated from industrial wastes. Increased exploitation of these low-temperature options has the definite potential of reducing fossil fuel consumption with its attendant very harmful greenhouse gas emissions. Researchers have universally identified the organic Rankine cycle (ORC) as a practicable and promising system to generate electrical power from renewable sources based on its beneficial use of volatile organic fluids as working fluids (WFs). In recent times, researchers have also shown a preference for/an inclination towards deployment of zeotropic mixtures as ORC WFs because of their capacity to improve thermodynamic performance of ORC systems, a feat enabled by better matches of the temperature profiles of the WF and the heat source/sink. This paper demonstrates both the technical feasibility and the notable advantages of using zeotropic mixtures as WFs through a simulation study of an ORC system. The study examines the thermodynamic performance of ORC systems using zeotropic WF mixtures to generate electricity driven by low-temperature solar heat source for building applications. A thermodynamic model is developed with an ORC system both with and excluding a regenerator. Five zeotropic mixtures with varying compositions of R245fa/propane, R245fa/hexane, R245fa/heptane, pentane/hexane and isopentane/hexane are evaluated and compared to identify the best combinations of WF mixtures that can yield high efficiency in their system cycles. The study also investigates the effects of the volumetric flow ratio, and evaporation and condensation temperature glides on the ORC’s thermodynamic performance. Following a detailed analysis of each mixture, R245fa/propane is selected for parametric study to examine the effects of operating parameters on the system’s efficiency and sustainability index. For zeotropic mixtures, results showed that there is an optimal composition range within which binary mixtures are inclined to perform more efficiently than the component pure fluids. In addition, a significant increase in cycle efficiency can be achieved with a regenerative ORC, with cycle efficiency ranging between 3.1–9.8% and 8.6–17.4% for ORC both without and with regeneration, respectively. Results also showed that exploiting zeotropic mixtures could enlarge the limitation experienced in selecting WFs for low-temperature solar organic Rankine cycles.

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