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Optimal Design of ORC Systems with a Low-Temperature Heat Source
Faculté de Génie, Université de Sherbrooke, Sherbrooke QC, J1K 2R1, Canada
* Author to whom correspondence should be addressed.
Received: 5 December 2011; in revised form: 30 January 2012 / Accepted: 8 February 2012 / Published: 21 February 2012
Abstract: A numerical model of subcritical and trans-critical power cycles using a fixed-flowrate low-temperature heat source has been validated and used to calculate the combinations of the maximum cycle pressure (Pev) and the difference between the source temperature and the maximum working fluid temperature (DT) which maximize the thermal efficiency (ηth) or minimize the non-dimensional exergy losses (β), the total thermal conductance of the heat exchangers (UAt) and the turbine size (SP). Optimum combinations of Pev and DT were calculated for each one of these four objective functions for two working fluids (R134a, R141b), three source temperatures and three values of the non-dimensional power output. The ratio of UAt over the net power output (which is a first approximation of the initial cost per kW) shows that R141b is the better working fluid for the conditions under study.
Keywords: waste heat; renewable energy; subcritical cycle; trans-critical cycle; R134a; R141b
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Khennich, M.; Galanis, N. Optimal Design of ORC Systems with a Low-Temperature Heat Source. Entropy 2012, 14, 370-389.
Khennich M, Galanis N. Optimal Design of ORC Systems with a Low-Temperature Heat Source. Entropy. 2012; 14(2):370-389.
Khennich, Mohammed; Galanis, Nicolas. 2012. "Optimal Design of ORC Systems with a Low-Temperature Heat Source." Entropy 14, no. 2: 370-389.