scholarly journals Comparison of Energy Efficiency and Power Density in Pressure Retarded Osmosis and Reverse Electrodialysis

2014 ◽  
Vol 48 (18) ◽  
pp. 11002-11012 ◽  
Author(s):  
Ngai Yin Yip ◽  
Menachem Elimelech
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
Reverse Electrodialysis ◽  
Pressure Retarded Osmosis

Harvesting Natural Salinity Gradient Energy for Hydrogen Production Through Reverse Electrodialysis Power Generation

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Mohammadreza Nazemi ◽  
Jiankai Zhang ◽  
Marta C. Hatzell
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
External Load ◽  
Salinity Gradient ◽  
Electrical Power ◽  
Ionic Current ◽  
Electrical Energy ◽  
Hydrogen Energy ◽  
Mixing Processes ◽  
Reverse Electrodialysis

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. Here, we model a novel approach to convert this source of energy directly into hydrogen and electricity using reverse electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox-based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volume of high and low concentration solutions (1 L), the maximum energy extracted per volume of solution mixed occurred when the number of membranes is reduced, with the lowest number tested here being five membrane pairs. At this operating point, 0.32 kWh/m3 is extracted as electrical energy and 0.95 kWh/m3 as hydrogen energy. This corresponded to an electrical energy conversion efficiency of 15%, a hydrogen energy efficiency of 35%, and therefore, a total mixing energy efficiency of nearly 50%. As the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.6 W/m2 to 2.4 W/m2 at optimum external load. In contrast, the electrical power density increases from 0.84 W/m2 to 2.2 W/m2. Optimum operation of RED depends significantly on the external load (external device). A small load will increase hydrogen energy while decreasing electrical energy. This trade-off is critical in order to optimally operate an RED cell for both hydrogen and electricity generation.

scholarly journals Performance of Microbial Reverse-Electrodialysis Cells for Power Generation at Different External Resistance

2020 ◽  
Vol 13 ◽  
pp. 117862212096008
Author(s):  
Agus Jatnika Effendi ◽  
Syarif Hidayat ◽  
Syafrudin ◽  
Bimastyaji Surya Ramadan ◽  
Candra Purnawan ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
Energy Recovery ◽  
Coulombic Efficiency ◽  
High Energy ◽  
Internal Resistance ◽  
External Resistance ◽  
Reverse Electrodialysis ◽  
Substrate Removal ◽  
Electrodialysis Cell

In this study, the effect of external resistance on the microbial reverse-electrodialysis cell (MRC) performance using organic-rich wastewater as an electron donor was examined. The optimum of external resistance was determined to be 300 Ω. In such condition, the power density of 1.53 ± 0.198 W/m2, substrate removal of 52 ± 2.3%, Coulombic efficiency of 70 ± 2.6%, energy recovery of 3.0 ± 0.4%, and energy efficiency of 53 ± 7.1% were obtained in the MRC. The differences in power density at different external resistances were mainly due to the changes in internal resistance and ion flux efficiency in the MRC. The external resistance affected substrate removal and Coulombic efficiency through the length of batch cycle time, and current density exchanged as well as the Tafel slope. Furthermore, the proper external resistance applied to the reactor created high power production; thus, high energy efficiency and energy recovery were achieved. These results demonstrated that selecting proper external resistance was an essential key for a successful MRC operational.

Pressure retarded osmosis: Operating in a compromise between power density and energy efficiency

Energy ◽  
2019 ◽  
Vol 172 ◽  
pp. 592-598 ◽  
Author(s):  
Rui Long ◽  
Xiaotian Lai ◽  
Zhichun Liu ◽  
Wei Liu
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
Pressure Retarded Osmosis

Evaluation of fouling potential and power density in pressure retarded osmosis (PRO) by fouling index

Desalination ◽  
2016 ◽  
Vol 389 ◽  
pp. 215-223 ◽  
Author(s):  
Youngkwon Choi ◽  
Saravanamuthu Vigneswaran ◽  
Sangho Lee
Keyword(s):  
Power Density ◽  
Pressure Retarded Osmosis

High energy efficiency and high power density aluminum‐air flow battery

2020 ◽  
Vol 44 (9) ◽  
pp. 7568-7579 ◽  
Author(s):  
Hejing Wen ◽  
Zhongsheng Liu ◽  
Jia Qiao ◽  
Ronghua Chen ◽  
Ruijie Zhao ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
High Power ◽  
Air Flow ◽  
High Energy ◽  
High Power Density ◽  
Flow Battery ◽  
High Energy Efficiency

scholarly journals Theoretical power density from salinity gradients using reverse electrodialysis

2012 ◽  
Vol 20 ◽  
pp. 170-184 ◽  
Author(s):  
David A. Vermaas ◽  
Enver Guler ◽  
Michel Saakes ◽  
Kitty Nijmeijer
Keyword(s):  
Power Density ◽  
Reverse Electrodialysis ◽  
Salinity Gradients

scholarly journals Energy Harvesting from Brines by Reverse Electrodialysis Using Nafion Membranes

Membranes ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 168 ◽  
Author(s):  
Ahmet H. Avci ◽  
Diego A. Messana ◽  
Sergio Santoro ◽  
Ramato Ashu Tufa ◽  
Efrem Curcio ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Electrochemical Properties ◽  
Cation Exchange ◽  
Power Density ◽  
Electrochemical Impedance ◽  
Salinity Gradient ◽  
Superior Performance ◽  
Reverse Electrodialysis ◽  
Nafion Membranes ◽  
The Impact

Ion exchange membranes (IEMs) have consolidated applications in energy conversion and storage systems, like fuel cells and battery separators. Moreover, in the perspective to address the global need for non-carbon-based and renewable energies, salinity-gradient power (SGP) harvesting by reverse electrodialysis (RED) is attracting significant interest in recent years. In particular, brine solutions produced in desalination plants can be used as concentrated streams in a SGP-RED stack, providing a smart solution to the problem of brine disposal. Although Nafion is probably the most prominent commercial cation exchange membrane for electrochemical applications, no study has investigated yet its potential in RED. In this work, Nafion 117 and Nafion 115 membranes were tested for NaCl and NaCl + MgCl2 solutions, in order to measure the gross power density extracted under high salinity gradient and to evaluate the effect of Mg2+ (the most abundant divalent cation in natural feeds) on the efficiency in energy conversion. Moreover, performance of commercial CMX (Neosepta) and Fuji-CEM 80050 (Fujifilm) cation exchange membranes, already widely applied for RED applications, were used as a benchmark for Nafion membranes. In addition, complementary characterization (i.e., electrochemical impedance and membrane potential test) was carried out on the membranes with the aim to evaluate the predominance of electrochemical properties in different aqueous solutions. In all tests, Nafion 117 exhibited superior performance when 0.5/4.0 M NaCl fed through 500 µm-thick compartments at a linear velocity 1.5 cm·s−1. However, the gross power density of 1.38 W·m−2 detected in the case of pure NaCl solutions decreased to 1.08 W·m−2 in the presence of magnesium chloride. In particular, the presence of magnesium resulted in a drastic effect on the electrochemical properties of Fuji-CEM-80050, while the impact on other membranes investigated was less severe.

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