Affordable solar-assisted biogas digesters for cold climates: Experiment, model, verification and analysis

Weatherford, Vergil; Zhai, Zhiqiang

doi:10.1016/j.apenergy.2015.01.111

Cited by 34 publications

(24 citation statements)

References 7 publications

(6 reference statements)

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“…Biogas can be produced from a wide range of organic wastes with anaerobic organisms, and its yield is determined by digestion temperature in a closed digester. For the mesophilic anaerobic digestion, temperature is an important environmental factor to control the rate and course of digestion [33]. In general, the increase in temperature of biogas digester leads to the rise in the substrate utilization rate and metabolic rate of digestion microorganisms, thus increasing the biogas yield.…”

Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

“…The inside, wall and outside temperatures of the digester are represented by nodes with thermal potentials. The interior surfaces of digester walls are usually sprayed with insulation materials, such as sheet plastic and rubber, to offer thermal insulation against the cold [33]. Taking a digester with two-layer walls as an example, the internal wall node is linked with the digester inside node via two series resistors with resistances '( /2 and +, , while a peripheral wall node is connected with the outside node by two series resistances '-/2 and ./0 , as shown in Fig.…”

Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

“…where +, , ./0 , '( , and '-are the thermal resistances for internal and external convective heat transfer, conductive heat transfer of the two-layer walls, respectively; 345 is the injected heating energy from RESs; $ , ./0 , '( , and '-are the temperatures of digester inside and outside, the 1 st and 2 nd layer walls, respectively; $ , '( , and '-are thermal capacitances of digester inside, the 1 st and 2 nd layer walls, respectively; k denotes the scheduling time; 8 is the conversion efficiency of electric boiler; :; and <; denote the electricity and thermal energy feedback for digester heating, respectively. The thermal resistance and capacitance parameters of insulation materials adopted here were obtained from [32], [33], [37], and have validated against the historical data (e.g., digestion temperature, outside temperature, thermal energy for digester heating, etc.) for parameter tuning [36].…”

Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

“…In addition to the time complementarity between solar and wind resources [6], biogas plant can offset the diurnal fluctuations of intermittent RESs. Moreover, the available solar and wind generations can be utilized to heat the thermostatic digester in order to improve the efficiency of biogas production from anaerobic digestion [32], [33]. Hence, the biogas-solar-wind energy complementarities can be exploited based on digesting thermodynamic effects to accommodate the fluctuating RESs, and the excess wind and solar energy can be converted to biogas in a gas storage tank.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Scheduling of Biogas–Solar–Wind Renewable Portfolio for Multicarrier Energy Supplies

Zhou

et al. 2018

IEEE Trans. Power Syst.

154

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This paper proposes a multi-source multi-product framework for coupled multi-carrier energy supplies with a biogas-solar-wind hybrid renewable system. In this framework, the biogas-solar-wind complementarities are fully exploited based on digesting thermodynamic effects for the synergetic interactions of electricity, gas and heating energy flows, and a coupling matrix is formulated for the modeling of production, conversion, storage, and consumption of different energy carriers. The multi-energy complementarity of biogas-solar-wind renewable portfolio can be utilized to facilitate the mitigation of renewable intermittency and the efficient utilization of batteries, and a multi-carrier generation scheduling scheme is further presented to dynamically optimize dispatch factors in the coupling matrix for energy-efficient conversion and storage, while different energy demands of end-users are satisfied. The proposed methodology has been fully tested and benchmarked on a stand-alone Microgrid over a 24-hour scheduling horizon. Comparative results demonstrate that the proposed scheme can lower the battery charging/discharging actions as well as the degradation cost, and also confirm its capability to accommodate high penetration of variable renewables. Index Terms-Energy hub, energy storage, renewable energy, Microgrid, multi-energy systems. . His main fields of research include smart grid operation and planning, renewable energy generation, and energy efficiency. Da Xu received the B.Sc. degree in automation . His research interests include power system stability, control, planning and operation, computational intelligence applications, and electric vehicle charging. Yijia Cao (M'98-SM'13) received the B.Sc. degree in electrical engineering from Xi'an Jiaotong University, Xi'an, China, in 1988, and the Ph.D. degree His research interests include power system cascading failure, smart grid information technology, smart grid operation and optimization. Ka Wing Chan (M'98) received the B.Sc. (with First Class Honors) and Ph.D. degrees in electronic and electrical engineering from the University of Bath, Bath, U.K., in 1988 and 1992, respectively. He currently is an Associate Head and Associate Professor in the Department of Electrical Engineering of The Hong Kong Polytechnic University. His general research interests include smart grid and renewable energy, power system stability analysis and control, power system planning and optimization, real-time power system simulation. Qiuwei Wu (M'08-SM'15) received the B.Eng. and M.Eng. degrees from

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Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

Section: A Digesting Thermodynamic Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Optimal Scheduling of Biogas–Solar–Wind Renewable Portfolio for Multicarrier Energy Supplies

Zhou

et al. 2018

IEEE Trans. Power Syst.

154

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“…where, m h , bg = the biogas stored in the holder, kg; _ m dc;bg = the flowrate of biogas consumed by cooking, kg/s; V h = the volume of the biogas holder, m 3 ; v = the specific volume, m 3 /kg; P h , bg = the pressure of the holder, kPa; and a and b = the Van der Waals constants of the biogas in the holder, respectively, m 6 ·Pa·kg À2 and m 3 ·kg À1 .…”

Section: Dynamical Equationmentioning

confidence: 99%

Simulation of a solar-biogas hybrid energy system for heating, fuel supply, and power generation

Wang

Duan

et al. 2017

Int. J. Energy Res.

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Summary Biogas production from organic wastes has been widely utilized for several decades, but maintaining right temperature for anaerobic bacteria is a challenge. In order to overcome the inhibition of the bacteria growth and biogas production due to the low temperature, a solar‐biogas hybrid energy system for heating, fuel supply, and power generation has been proposed for converting domestic garbage into biogas in a rural area of China. In this system, the solar energy has been included as one of the heating sources during an anaerobic digestion process. A mathematical model has been developed to evaluate the influence of system operating characteristics. Based on the simulation results, the biogas production rate, thermal efficiency, temperature of the digester, energy distributions in the system, optimal operating parameters, economic efficiency, and thermodynamic characteristics of the system were analyzed. The impact of solar irradiation on the efficiency of the system was also studied. According to the results, in cloudy days, the reactor volume and solar collector area greatly influenced the steady energy supply. In winter, the produced biogas is mostly utilized by the aided boiler to maintain the proper organic mixture temperature in the bioreactor. Heat loss from bioreactor dramatically increases the organic mixture volume. Per simulation, the longest return on the investment of this type of the biogas system is about 5.54 years, and the shortest return on the investment is less than 4 years if the battery is removed and the electric grid can be used. Therefore, in this study, the feasibility of a hybrid energy system for converting domestic garbage into energy has been validated. Copyright © 2017 John Wiley & Sons, Ltd.

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Heat transfer analysis of cylindrical anaerobic reactors with different sizes: a heat transfer model

Liu

Zhou

et al. 2017

Environ Sci Pollut Res

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The temperature is the essential factor that influences the efficiency of anaerobic reactors. During the operation of the anaerobic reactor, the fluctuations of ambient temperature can cause a change in the internal temperature of the reactor. Therefore, insulation and heating measures are often used to maintain anaerobic reactor's internal temperature. In this paper, a simplified heat transfer model was developed to study heat transfer between cylindrical anaerobic reactors and their surroundings. Three cylindrical reactors of different sizes were studied, and the internal relations between ambient temperature, thickness of insulation, and temperature fluctuations of the reactors were obtained at different reactor sizes. The model was calibrated by a sensitivity analysis, and the calibrated model was well able to predict reactor temperature. The Nash-Sutcliffe model efficiency coefficient was used to assess the predictive power of heat transfer models. The Nash coefficients of the three reactors were 0.76, 0.60, and 0.45, respectively. The model can provide reference for the thermal insulation design of cylindrical anaerobic reactors.

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Affordable solar-assisted biogas digesters for cold climates: Experiment, model, verification and analysis

Cited by 34 publications

References 7 publications

Optimal Scheduling of Biogas–Solar–Wind Renewable Portfolio for Multicarrier Energy Supplies

Optimal Scheduling of Biogas–Solar–Wind Renewable Portfolio for Multicarrier Energy Supplies

Simulation of a solar-biogas hybrid energy system for heating, fuel supply, and power generation

Heat transfer analysis of cylindrical anaerobic reactors with different sizes: a heat transfer model

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