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.

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

2016 ◽  
Author(s):  
Mohammadreza Nazemi ◽  
Jiankai Zhang ◽  
Marta Hatzell
Keyword(s):  
Power Density ◽  
Current Density ◽  
Salinity Gradient ◽  
Electrical Energy ◽  
Hydrogen Energy ◽  
External Resistance ◽  
Membrane Area ◽  
Reverse Electrodialysis ◽  
Gradient Energy

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. If technologies are developed which are capable of converting this energy into a usable form (electricity or fuels), salinity gradient energy may be able to dramatically increase the worlds supply of renewable energy. Here we present 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 volumes of HC and LC solutions (0.001m3), the maximum energy extracted is found to occur with 5 number of membrane pairs. At this operating point, 0.4 kWh/m3 can be extracted as electrical energy and 0.95 kWh/m3 of energy is extracted as hydrogen energy. The electrical energy conversion efficiency approaches 15%, whereas the hydrogen energy efficiency is 35%. Overall, the maximum system conversion of Gibbs free energy to electrical and hydrogen energy approaches 50%. The results show that as the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.2 W/m2 to 3.7 W/m2. Likewise, the power density from electrical energy decreases from 1 W/m2 to 0.3 W/m2. This is because of increase in the total membrane area as increasing the number of membrane pairs. The stack voltage increased from 1.5V to 6V as the number of membrane pairs is increased from 5 to 20. This corresponds to an increase in internal resistance from 600 Ω.cm2 to 2400 Ω.cm2. Long term trade-off between improving the system voltage, while decreasing the system resistance will be crucial for improved long term RED performance. Furthermore, optimum operation of RED, depends on proper selection of external resistance. A small external resistance will increase hydrogen energy and decrease electrical energy, particularly using a small number of membrane pairs. With the fixed small external resistance, as increasing the number of membrane pairs, the difference between internal and external resistance increases. Therefore, the load potential and current density do not increase considerably. For the cases analyzed with 8.29 Ω.cm2 external resistance, the maximum current density increases from 11.1 mA/cm2 to 12.4 mA/cm2 as the number of membrane pairs increases from 5 to 20. Likewise, the load potential rises from 92 mV to 102 mV.

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.

scholarly journals PERANCANGAN PEMANAS AIR OHMIK SEDERHANA BERBAHAN DASAR SENDOK MAKAN LOGAM

2018 ◽  
Vol 8 (1) ◽  
pp. 22-31
Author(s):  
Hazairin Nikmatul Lukma
Keyword(s):  
Energy Efficiency ◽  
Data Analysis ◽  
Electrical Power ◽  
Electrical Energy ◽  
Heating Process ◽  
Water Heater ◽  
Ohm’S Law ◽  
Current Limiting ◽  
Heating Water ◽  
Further Development

Penelitian ini bertujuan untuk mengetahui hasil pemanfaatan sendok makan logam yang digunakan sebagai pemanas air menggunakan prinsip Ohmik, yang didesain sedemikian rupa sehingga sendok makan dapat berfungsi sebagai elektroda. Ketika dua buah sendok makan dengan jarak tertentu yang dapat diatur jaraknya dialiri arus, maka akan dihasilkan kalor yang mampu meningkatkan suhu air dalam suatu wadah yang terbuat dari isolator, sebagaimana prinsip Hukum Ohm. Jarak kedua sendok dapat diatur, dimana semakin dekat jarak antara dua sendok, makin cepat proses pemanasan air. Penelitian dilakukan di Laboratorium Teknik Universitas Islam Balitar pada bulan April hingga Juni tahun 2017. Hasil analisis data menunjukkan bahwa semakin besar antara kedua sendok, makin lama proses pemanasan, namun daya yang diperlukan lebih rendah. Sedangkan ketika jarak antara kedua sendok dibuat lebih dekat, proses pemanasan berjalan lebih cepat, akan tetapi daya listrik yang diperlukan juga semakin besar. Nilai efisiensi energi listrik dari pemanas air ohmik diperoleh sebesar 90%. Nilai efsiensi ini tidak terlalu tinggi dikarenakan selama proses pemanasan, daya listrik yang dibutuhkan terus meningkat. Untuk pengembangan selanjutnya, desain alat pemanas air ini dapat ditambah komponen pembatas arus, sehingga daya listrik yang digunakan dapat terkontrol.This research aims to determine the results of the use of metal tablespoons used as a water heater using Ohmik principle, which is designed in such a way that the tablespoons can function as an electrode. When two tablespoon with a certain distance can be adjusted the distance flow, the heat will be produced that can increase the temperature of water in a container made of insulators, as the principle of Ohm's Law. Spacing of two spoons can be adjusted, where the closer the distance between two spoons, the faster the process of heating water. The research was conducted at the Technical Laboratory of Islamic University of Balitar in April to June 2017. The result of data analysis showed that the bigger between the two spoons, the longer the heating process, but the required power is lower. Meanwhile, when the distance between the two spoons is made closer, the heating process runs faster, but the power required is also greater. The value of the electrical energy efficiency of the ohmic water heater is 90%. The value of this efficiency is not too high because during the heating process, the electrical power required continues to increase. For further development, the design of this water heater can be added current limiting components, so that the electrical power used can be controlled.

scholarly journals Low cost carbon electrodes to produce salinity gradient energy using reverse electrodialysis membranes: Effect of feed flow velocities and addition of Mg2+

2018 ◽  
Vol 197 ◽  
pp. 09006
Author(s):  
Tsalis Wahyu Najmiyah ◽  
Lina Aziyah ◽  
Yusuf Hendrawan ◽  
Dewi Maya Maharani ◽  
La Choviya Hawa ◽  
...  
Keyword(s):  
River Water ◽  
Power Density ◽  
Sea Water ◽  
Salt Water ◽  
Water Solution ◽  
Salinity Gradient ◽  
Low Cost ◽  
Electrical Energy ◽  
Feed Solution ◽  
Flow Velocities

In this research , we investigate the effect of feed flow velocity in both monovalent (Na+) and divalent (Mg2+) salt water solutions to harvest the electrical energy from the reverse electro dialysis (RED) membranes module. The synthetic sea water solution uses 0.5 M concentration of salt and the synthetic river water salt concentration of 0.017 M were used. The carbon electrode was used, due to its low cost, higher melting point, and insoluble in water. Variation of feed flow velocities (sea water and synthetic river water) of 8 cm2/s, 14 cm2/s, 19 cm2/s were used, in addition to compare electrical energy produced from the used of monovalent and divalent ions. The best result was obtained by using the velocity of feed solution 19 cm2/s with the electricty value of 8.033 mV, 0.002 Ω/cm2 and power density of 1,141 mW/m2, while the influence of the addition of Mg2 + ion in the feed solution resulted the electricty value of 4.47 mV, 0.003 Ω/cm2 and power density of 0.15 mW/m2. Albeit the results, some more configuration is needed and worth to be investigated in the future.

Optimization of a Pyroelectric Energy Converter for Harvesting Waste Heat

2010 ◽  
Author(s):  
Ashcon Navid ◽  
Damien Vanderpool ◽  
Abubakarr Bah ◽  
Laurent Pilon
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
Silicone Oil ◽  
Waste Heat ◽  
Electrical Power ◽  
Optimum Operating ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Energy Converter ◽  
Novel Approach

Pyroelectric energy conversion offers a novel approach for directly converting waste heat into electricity. This paper reports numerical simulations of a prototypical pyroelectric energy converter. The two-dimensional mass, momentum, and energy equations were solved to predict the local and time-dependent pressure, velocity, and temperature. Then, the heat input, pump power, and electrical power generated were estimated, along with the thermodynamic energy efficiency of the device. It was established that reducing the length of the device and the viscosity of the working fluid improved the energy efficiency and power density by increasing the optimum operating frequency of the device. Results show that a maximum efficiency of 5.2% at 0.5 Hz corresponding to 55.4% of the Carnot efficiency between 145 and 185°C can be achieved when using commercial 1.5 cst silicone oil. The maximum power density was found to be 38.4 W/l of pyroelectric material.

scholarly journals Potential of brackish water and brine for energy generation by salinity gradient power-reverse electrodialysis (SGP-RE)

RSC Advances ◽  
2014 ◽  
Vol 4 (80) ◽  
pp. 42617-42623 ◽  
Author(s):  
Ramato Ashu Tufa ◽  
Efrem Curcio ◽  
Willem van Baak ◽  
Joost Veerman ◽  
Simon Grasman ◽  
...  
Keyword(s):  
Power Density ◽  
Brackish Water ◽  
Salinity Gradient ◽  
Energy Generation ◽  
Maximum Power ◽  
Maximum Power Density ◽  
Cell Pair ◽  
Reverse Electrodialysis ◽  
Solar Pond ◽  
Salinity Gradient Power

Salinity Gradient Power-Reverse Electrodialysis (SGP-RE), tested on brackish water/solar pond brine, resulted in maximum power density of 1.13 W m−2 cell pair, 63% less than that of pure NaCl solutions with comparable salinity.

scholarly journals Pengujian Sludge Battery Dengan Teknologi Microbial Fuel Cell Sebagai Sumber Energi Listrik Terbarukan

2018 ◽  
Vol 8 (2) ◽  
pp. 35-42
Author(s):  
Ika Novia Anggraini ◽  
Afriyastuti Herawati
Keyword(s):  
Fuel Cells ◽  
Electric Power ◽  
Power Density ◽  
Microbial Fuel Cells ◽  
Electrical Power ◽  
Electrical Energy ◽  
Series System ◽  
Single Vessel ◽  
Sea Mud ◽  
Marine Mud

ABSTRACTMicrobial Fuel Cells are devices which convert chemical energy into electrical energy through catalytic reactions by microorganisms. In this study, the potential of electricity in MFC will be analyzed by using samples of sea mud, lake mud, land mud, and river mud. While the method used in this study is one series connected vessel, two vessels connected series with mud-water, two mud-mud series vessels, and the stack series method. The highest electrical conductivity produced by river mud reaches 3.63 mS/cm, while the lowest is lake mud with a conductivity value of 0.35 mS/cm. The highest electric power density produced by river mud by the two mud-mud vessel method is 46.766 mW/m2, while the lowest electrical power density in lake mud is 18.040 mW/m2. The highest electrical power is produced by river mud through a single vessel series system with a maximum power of 7.26 mW, while the lowest power is found in marine mud with a system of two mud-water vessels which is equal to 0.30 mW. The pattern of increase in voltage or current produced by the battery sludge is on average until the 7th day, then a decrease occurs until the last day of testing. The greatest potential for electrical energy is obtained by river mud using a single vessel series system with a maximum voltage of 5.38 V and lasting up to 14 days.Keyword : electric power density, microbial fuel cells, sludge battery

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.

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