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This study presents a comparative analysis between Jatropha seed production systems to generate bioelectricity versus production of biodiesel under current and optimised conditions. An LCA (life cycle assessment) has been developed, comprising both upstream and downstream processes, encompassing the farming, collection, fuel processing and usage phases. The following energy and environmental indicators...
To investigate the effect of the molecular structure of nitrogen compounds on the CO and NO emissions from experiments conducted in a bench-scale BFBC (bubbling fluidized-bed combustor), feed materials are prepared by mixing the model compounds (including pyridine, pyrrole, quinolone, aniline, nitrobenzene, 1-naphthylamine, urea, and arginine) with activated carbon to keep the overall nitrogen content...
Effectiveness of SEHRAC (storage-enhanced heat recovery room air-conditioner) for water heating in residential buildings in Hong Kong and elsewhere has been confirmed in previous studies. However, given these studies assumed a theoretical maximum recoverable heat, whether its use is still energy effective in practice, in particular under intermittent operation, is of concern. Intermittent operation...
This paper describes a novel approach for predicting the thermal impact of gas cavitation in hydraulic circuits. The developed model utilizes a thermal-hydraulic modeling concept for calculating the oil temperatures inside the control volumes divided from the circuit, taking into account the gas evolution process in the cavitating pump. The heat generated by cavitation is interpreted as the result...
An experimental campaign has been conducted on a solar parabolic trough collector feeding a micro-CHP system (micro-cogeneration). The originality of the solar field is the DSG (direct steam generation) using a two axis tracker and a small size (46.5 m2) collector. The first step of the characterisation of the CHP (Combined Heat and Power) system is the study of the solar field under direct steam...
Slow air transport in the cathodes limits the performance of the metal-air battery. In this work, the diffusion mechanisms in the lithium-air battery have been investigated. It has been found that Knudsen diffusivity can be influenced dramatically by the different pore sizes while bulk diffusivity is almost a constant at a fixed temperature. Limiting current density and concentration polarization,...
MnO2+δ (Manganese oxide) nanoflakes were synthesized for use as electrode material in electrochemical supercapacitors. The nanoflakes were produced via RF-magnetron sputtering with various excess oxygen contents (δ), and the electrochemical supercapacitive properties of the MnO2+δ nanoflakes were investigated as a function of δ with the use of a Na2SO4 electrolyte. The excess oxygen (δ) induces the...
A model-FUNNEL-GHG-OS (FUNdamental ENgineering PrinciplEs- based ModeL for Estimation of GreenHouse Gases in the Oil Sands) based on fundamental engineering principles was developed to estimate the specific energy consumption and GHGs (greenhouse gas emissions) for upgrading bitumen to produce SCO (synthetic crude oil). The model estimates quantity of SCO produced, the consumption of hydrogen, steam,...
In the present study, a thermoelectric mini cooler coupling with a micro thermosiphon cooling system has been proposed for the purpose of CPU cooling. A mathematical model of heat transfer, depending on one-dimensional treatment of thermal and electric power, is firstly established for the thermoelectric module. Analytical results demonstrate the relationship between the maximal COP (Coefficient of...
DEA (data envelopment analysis) has been widely used for the efficiency analysis of industrial production process. However, the conventional DEA model is difficult to analyze the pros and cons of the multi DMUs (decision-making units). The DEACM (DEA cross-model) can distinguish the pros and cons of the effective DMUs, but it is unable to take the effect of the uncertainty data into account. This...
Tidal-stream energy devices currently require spring tide velocities (SV) in excess of 2.5 m/s and water depths in the range 25–50 m. The tidal-stream energy resource of the Irish Sea, a key strategic region for development, was analysed using a 3D hydrodynamic model assuming existing, and potential future technology. Three computational grid resolutions and two boundary forcing products were used...
For a fuel system with a tangent cam or a constant-velocity cam, the peak injection pressure continues to rise as the injection duration increases, but overly high peak pressures induce mechanical loads and wear, limiting the maximum engine speed and injection quantity. To improve the performance of an EUP (Electronic Unit Pump) fuel system for heavy-duty diesel engines, this work proposes a new pump...
A multi-objective function F(X) by the incorporation of single-objective functions, i.e., net power output Wnet, exergy drop of the exhaust gas from inlet to outlet ΔEg, total exergy destruction rate I and system total cost C2013, has been put forward as the subcritical organic Rankine cycle (ORC) performance indicator and solved with the method of linear weighted evaluation function. The optimization...
The present study is concerned with the exergoeconomic performance analysis of a storage-type electrical water heater, being subjected to two volumes of hot water removals at 5 L/min; the first one immediately after the heating of water in the tank, and the second, after some time has been waited since the completion of the first discharge. This two-stage discharging regime is designed and experimented...
A thorough assessment and diagnosis is critical for understating and enhancing building energy performance while most buildings cannot provide sufficient energy use data for a detailed diagnosis. This paper presents a multi-level energy performance diagnosis method for energy information-poor buildings where very limited energy use data are available. A simplified monthly energy performance calculation...
As a result of the gas pressure drop in natural grid pipelines in the cold seasons, the feedstock of steam power plant is changed from the natural gas into the heavy fuel oil. Sometimes this change happens for the whole winter and causes lots of environmental problems for the cities near the big power plant. Gasification is a technologically advanced and environmentally friendly process of disposing...
This paper presents a modeling and optimization investigation of a solar driven adsorption cooling system working with activated carbon–methanol pair. It deals with the effect of internal fins on the thermal behavior of the adsorber and on the system performance. A two-dimensional model describing the coupled heat and mass transfer in the adsorbent bed and energy balance in the main components of...
A data-driven approach to optimize the total energy consumption of the HVAC (heating, ventilation, and air conditioning) system in a typical office facility is presented. A multi-layer perceptron ensemble is selected to build the total energy model integrating three indoor air quality models, the facility temperature model, the facility relative humidity model, and the facility CO2 concentration model...
The simulation of existing crude oil distillation processes is distinctive and difficult owing to its complex nature and interactions, including variable feedstocks, highly integrated processes, tight cuts specifications, and environmental limitations. This study introduces a systematic simulation-based algorithm for retrofitting an existing crude distillation column. The algorithm accounts for all...
In the renewable energy production solid biomass has became one of the most important source for power and heat generation, in particular woody materials in the form of wood chips, pellet and briquette. Technical standards on solid biofuels require information about origin and source of the biomass, differentiating for example between coniferous and broadleaf. In this work different wood samples were...
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