First International Seminar on ORC Power Systems

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11:50
20 mins

OPTIMUM CONDITIONS OF A CARBON DIOXIDE TRANSCRITICAL POWER CYCLE FROM LOW TEMPERATURE HEAT SOURCE FOR POWER GENERATION
Fredy Velez, José J. Segovia, M. Carmen Martín, Gregorio Antolin, Cecilia Sanz, Farid Chejne

Session: Parallel Session: System Design, Optimization and Applications Ime
Session starts: Thursday 22 September, 11:10
Presentation starts: 11:50
Room: Senaatszaal

Fredy Velez (CARTIF Centro Tecnológico, División Químico-Alimentaria. Parque Tecnológico de Boecillo, Parcela 205. 47151 Valladolid. (España). 983143804.)
José J. Segovia (Departamento de Ingeniería Energética y Fluidomecánica, Universidad de Valladolid, Valladolid)
M. Carmen Martín (Departamento de Ingeniería Energética y Fluidomecánica, Universidad de Valladolid, Valladolid)
Gregorio Antolin (CARTIF Centro Tecnológico, División Químico-Alimentaria. Parque Tecnológico de Boecillo, Parcela 205. 47151 Valladolid. (España). 983143804.)
Cecilia Sanz (CARTIF Centro Tecnológico, División Químico-Alimentaria. Parque Tecnológico de Boecillo, Parcela 205. 47151 Valladolid. (España). 983143804.)
Farid Chejne (Grupo de Termodinámica Aplicada y Energías Alternativas TAYEA, Universidad Nacional de Colombia; Carr. 80 No. 65–223, Facultad de Minas, Medellín. (Colombia). )

Abstract:
Since that conventional steam power cycles cannot give a better performance to recover low-grade waste heat, and due to with this same purpose, other possible processes such as the Organic Rankine Cycles show the known pinching problem, the use of carbon dioxide in supercritical conditions solves both problems. The present paper aims to report the results obtained after analyzing energetic and exergetically the effect of the inlet turbine pressure on transcritical Rankine cycles using refrigerant carbon dioxide (CO2) as the working fluid, which achieves a variable temperature when heat is added to the working fluid, giving therefore a better fit with the heat source. The procedure for analyzing the behaviour of the proposed cycle has consisted in modifying the turbine input pressure, from 66 bar until the point in which the net work reaches approximately zero, while the inlet turbine temperature is maintained in a constant value of 150 ºC. As a result, the maximum value of the energy efficiency is 8.1% whereas the exergy efficiency has no maximum. On the other hand, while the operation pressure of the process rises, the exergy efficiency also increases.