Finally a qualitative comparison with other heat engines based on exergetic efficiency is provided. This comparison highlights that the SGP technologies could be very promising future converters of low-grade heat (temperature range of 50 to 100°C; e.g. solar and geothermal energy or waste heat) into electric energy, thus justifying large room for future research and development aimed at moving each theoretical case beyond conceptualization. Acknowledgement This work has been performed within the RED-Heat-to-Power project (Conversion of Low Grade Heat to Power through closed loop Reverse Electro-Dialysis) - Horizon 2020 programme, Project Number: 640667: . Francesco Giacalone is acknowledged for his help in data processing. Notation active area of one cell pair [m2] A Jones and equation parameters AΛ, BΛ, CΛ Dole’ Staples correlation parameters Aγ, Bγ, Cγ, Dγ, Eγ separation ratio [-] a molar concentration [mol/l] C Salt permeability coefficient [m2/sec] Dsalt Cell pair voltage [V] Estack volumetric flow rate [m3/sec] F constant (96490) [C/mol] F Faraday’s salt flux [mol/m2 sec] Jsalt electrical current density [A/m2] j molality [mol/kg] m cell pairs number [-] N open circuit voltage [V] OCV electric power [W] P power density [W/m2] Pd volumetric flow rate [m3/sec] Q thermal power [W] universal gas constant [l atm/(mol K)] R blank resistance Rblank [Ω m2] cell pairs resistance Rcells [Ω m2] AEM resistance RAEM [Ω m2] CEM resistance RCEM [Ω m2] resistance of concentrate solution RHIGH [Ω m2] resistance of dilute solution RLOW [Ω m2] external load resistance Rext [Ω m2]
Finally a qualitative comparison with other heat engines based on exergetic efficiency is provided. This comparison highlights that the SGP technologies could be very promising future converters of low-grade heat (temperature range of 50 to 100°C; e.g. solar and geothermal energy or waste heat) into electric energy, thus justifying large room for future research and development aimed at moving each theoretical case beyond conceptualization. Acknowledgement This work has been performed within the RED-Heat-to-Power project (Conversion of Low Grade Heat to Power through closed loop Reverse Electro-Dialysis) - Horizon 2020 programme, Project Number: 640667: . Francesco Giacalone is acknowledged for his help in data processing. Notation A active area of one cell pair [m2] AΛ, BΛ, CΛ Jones and Dole’ equation parameters Aγ, Bγ, Cγ, Dγ, Eγ Staples correlation parameters a separation ratio [-] C molar concentration [mol/l] Dsalt Salt permeability coefficient [m2/sec] Estack Cell pair voltage [V] F volumetric flow rate [m3/sec] F Faraday’s constant (96490) [C/mol] Jsalt salt flux [mol/m2 sec] j electrical current density [A/m2] m molality [mol/kg] N cell pairs number [-] OCV open circuit voltage [V] P electric power [W] Pd power density [W/m2] Q volumetric flow rate [m3/sec] thermal power [W] R universal gas constant [l atm/(mol K)] Rblank blank resistance [Ω m2] Rcells cell pairs resistance [Ω m2] RAEM AEM resistance [Ω m2] RCEM CEM resistance [Ω m2] RHIGH resistance of concentrate solution [Ω m2] RLOW resistance of dilute solution [Ω m2] Rext external load resistance [Ω m2]
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