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In this work, the performance of Polymer Electrolyte Membrane Fuel Cells (PEMFCs) with interdigitated gas distributor under clamping pressure is numerically studied. A three-dimensional model of PEMFC has been developed and used to study the effect of displacement and deformation caused by clamping pressure on the transport phenomena and device performance. The influence of different parameters such...
With continuous petroleum exploitation, more and more oil wells have been abandoned, which contain abundant geothermal energy. For utilizing the geothermal energy, this paper presents a new geothermal heating system using abandoned oil wells (AOW), and a comprehensive model combing wellbore heat transfer, formation and building energy transport is built, parameters including geothermal production,...
This paper analyzes the energy consumption of buildings considering the uncertainty of structural and environmental parameters. To this end, two-point estimate method (2PEM) is used to model the uncertainties. EnergyPlus software is used in this paper to evaluate the energy consumption, the thermal comfort, and the energy cost of a building. We examine the proposed method in a retail building to show...
Electrostatic field can change the pressure of dielectric system, and this effect is related to the exerted direction of the electric field. With this characteristic, enhancing mass and heat transfer can be achieved by applying external electric field. In this paper, based on the laws of thermodynamics, the fundamental equation of the dielectric system with the influences of electrostatic field was...
In this study, a laboratory scale continuous-band microwave dryer was fabricated and used for drying the paddy. The experiments were carried out at 3 microwave powers (90, 270, and 450 W), conveyor speed 0.24 m/min, and 3 paddy layer thicknesses (6, 12, and 18 mm). The penetration depth of the waves into the examined paddy was obtained equal to 12.7 mm at 25.46% moisture content (w.b %). The maximum...
Effective use of selective absorbing coating in surface based receivers and nanofluids in volumetric based receivers for better thermal performance have been confirmed in previous studies. However, in practical application, these receivers suffered from the problem of performance degradation after long-term high-temperature operation, and they were high-cost. This study proposed a novel kind of parabolic...
In this research, we evaluated the effect of diesetrol fuel blends (comprised of diesel, biodiesel, and ethanol) on diesel engine exhaust emissions. Biodiesel is a clean fuel of vegetable origin produced from the transesterification of waste cooking oil collected from restaurants. So as to ameliorate the properties of the biodiesel combustion such as cetane number, viscosity and cloud point, ethanol...
The in situ (one-step) acid-catalyzed transesterification step for conversion to biodiesel of biomass from oleaginous yeast Yarrowia lipolytica grown on waste cooking oil (WCO) is studied. The process yield of biodiesel was optimized by investigating effects of various parameters, namely, biomass, methanol, chloroform, catalyst, temperature, time and sonication. A Plackett-Burman statistical design...
A small-scale exhaust energy recovery system has been designed and tested using MEMS (Micro-Electro Mechanical System) fabrication techniques in combination with Additive Manufacturing. The system extracts thermal energy from low temperature exhaust flows with a porous copper heat exchanger and passes that energy to a unified superheater/boiler.MEMS fabrication techniques were utilized for the boiler...
Shirazi and Sachs comment on our publication in Energy “Measurement of Power Loss During Electric Vehicle Charging and Discharging” [1]. Their comment discusses aspects of our methodology and findings on round-trip efficiency during charging and discharging of electric vehicles (EVs) [2]. This reply discuss the transformer used in our experimental process, resulting in a round-trip efficiency of 70%...
Owing to a lack of power density of conventional batteries, the onboard energy storage systems of an electric vehicle has to be oversized to compensate worst-case load condition, which is sub-optimal as it induces a heavy penalty on overall system weight and cost. One solution to overcome this limitation is to hybridize it with supercapacitors in order to boost its power performance via a power converter...
A biogas fuelled constant speed spark ignition engine was studied experimentally for its performance, emissions and combustion, under the influence of an increased oxygen concentration in the intake air and results were compared. A single cylinder diesel engine was modified for the purpose and was operated at 1500 rpm, maintaining the throttle opening at 25% and 100% for various equivalence ratios...
In this study, a downdraft gasifier model is coupled with a single-particle model to analyze the effects of particle geometries such as slab, cylindrical, and spherical on different parameters. Simulations were performed using particles in a thermally thick regime with larger particle sizes of 0.003–0.05 m, which are generally used in commercial gasifiers. This combination of the downdraft gasifier...
The performance of Building integrated photovoltaic (BIPV) depends on the incident solar radiation, photovoltaic (PV) cell temperature, location and orientations of the building. In this work, the building integrated photovoltaic–phase change material (BIPV–PCM) module has been developed to enhance the performance of the BIPV system by regulating its PV cell temperature using PCM. The BIPV and BIPV-PCM...
Energy efficiency has been proposed as one of the most effective instruments for mitigating greenhouse gas emissions. However, the methodologies to estimate the impact of energy savings on these emissions are generally aggregated and simplified. This study presents an approach for evaluating the emissions avoided by energy-efficiency programs; decomposing the energy savings in the national electrical...
This paper reports an investigation of the engine performance and emissions of an engine burning hydrogen-enriched diesel fuel. Hydrogen was chosen as the secondary fuel for its renewability in the long term and overall sustainability as a fuel. A four-cylinder, four-stroke, 1.461-L diesel engine with a common rail injection system was used for our tests. The cylinder pressures, rate of heat releases...
Battery equivalent circuit models (ECMs) are widely employed in online battery management applications. The model parameters are known to vary according to the operating conditions, such as the battery state of charge (SOC). Therefore, online recursive ECM parameter estimation is one means that may help to improve the modelling accuracy. Because a battery system consists of both fast and slow dynamics,...
This paper aims at improving power generation efficiency of marine diesel engine waste heat recovery systems. It presents a novel technique of integrating the heat rejected in the scavenge air cooling process and the exhaust gas in operating a single and dual pressure steam power generation cycles. Moreover, a thermodynamic analysis of proposed systems was performed to identify the optimum operating...
Among the renewable energies available, biomass constitutes an auspicious option, due to its environmental-friendly character allied to its significant energy supply. As a path to maximize biomass energy efficiency, gasification has been reported as an adequate technology. Numerical models that can predict and optimize the experimental conditions as well as the equipment design for biomass gasification...
The completion of Shuibuya, the last hydropower station to be constructed in the Qingjiang cascade, signifies China's successful development of the world's largest mixed cascade hydropower generation system. Joint operation of such cascaded hydropower stations is considered necessary to improve hydropower output in China. In this study, two modeling methods – routine and optimal operations – were...
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