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Thermal stress is one of major causes of cracking in high-temperature components of gas turbines. This paper presents a thermo-structural analysis of cracks on the vane of a gas turbine for power generation. The vane components include three airfoils with hub and shroud sections. The airfoils have serpentine-type internal passages and film cooling holes on the pressure-side surfaces for cooling. The...
Because hydrogen can be extracted naturally and stored for a long time, different types of fuel cells have been developed to generate clean power, particularly for use in vehicles. However, the power demand of a running vehicle leads to unstable and irregular loading of fuel cells. This not only reduces fuel cell lifespan and efficiency but also affects driving safety when the slow output response...
Finland has the greatest forest cover of European countries and thus considerable raw material potential for wood pellet market development. Wood pellet production and consumption volumes in the country have increased steadily during the last decades. The aim of this paper is to present an overview of the current status of the Finnish wood pellet business and discuss the main opportunities and challenges...
Biowaste utilization in co-gasification with bituminous coal and lignite gives the benefits of stable supplies of a primary energy source – coal and utilization of a zero-emission, waste material (i.e. agriculture waste, sewage sludge, etc.) with higher process efficiency and lower negative environmental impact than biomass or coal gasification, respectively. The main focus of the study presented...
Water splitting photochemical reaction induced by solar energy in the presence of methanol as a hole-scavenger using different structures of ferrites was demonstrated in this study. A few studies in literature have been reported such types of semiconductors, as photocatalytic reagents, for H2 evolution from water-methanol mixture and a minor quantity of H2 productivity yield was demonstrated. In the...
In the present work, the performance of proton exchange membrane fuel cells is studied for three cases; A fuel cell with two parallel flow channels (model A), locally baffle restricted flow channels (model B), and metal foam as a flow distributor (model C). The fully coupled thermal-electrochemical equations are numerically solved in three dimensions, based on the macroscopic, single-domain, and finite-volume...
In a refining complex, an absorption-stabilization process used in the production of end-use petro-products (i.e. stable gasoline and liquefied petroleum gas) is energy-intensive and costly. A new absorption-stabilization process with a two-stage condensation section is introduced in this work to further improve energy-use performance. In the new process, a condenser, a condensed oil tank, and a side-reboiler...
This paper presents an optimization model for charging station placement in order to minimize the overall cost by satisfying the charging reliability and quality of service expected by electric vehicle owners/drivers. To better understand and illustrate the problem's complexity, set modeling is used to represent the road network and the electric vehicle driving trajectories. By involving the Euclidean...
The feasibility of using more efficient Rankine power blocks in solar power towers (SPTs) with molten salt as the heat transfer fluid has been studied as a method for increasing the global efficiency of these power plants. The temperature and pressure of the main steam and the reheating pressure affect the temperature of the molten salt in the receiver; for temperature increase decreasing the receiver...
Developing the description and gaining an understanding of wind characteristics are important research tasks in wind engineering. Intermittency is one of the most important characteristics of wind. However, little literature is available on its quantitative measurement. In this study, wind speed intermittency is defined from the perspective of the physical nature of wind. According to this definition,...
This paper presents and demonstrates a methodology to explore the flexibility of a heat pump pool. Three points are in the focus of this work: First the procedure to model a pool of residential heat pump systems. Second the study of the response of a large number of heat pumps when the Smart-Grid-Ready interface is used for direct load control. Third a general assessment of flexibility of a pool of...
Microalgae have recently attracted tremendous attention as a possible feedstock for biofuel production. In this study, the pyrolysis characteristics and kinetics of Aurantiochytrium sp. KRS101, a kind of heterotrophic oleaginous microalgae, were investigated by means of thermogravimetric analysis and pyrolysis in a micro-tubing reactor. Most biochemical components of the microalgae (carbohydrates,...
This study contributes to the understanding of cycle-to-cycle emissions variability (CEV) in premixed spark-ignition combustion engines. A number of experimental investigations of cycle-to-cycle combustion variability (CCV) exist in published literature; however only a handful of studies deal with CEV. This study experimentally investigates the impact of CCV on CEV of NO and CO, utilizing experimental...
Thermoelectric energy recovery from waste heat in glass melting process is investigated without any detrimental design or process changes. Melting glass pellets require a furnace with temperature over 1500 °C for downstream glass shaping processes and hence a large amount of exergy is available but currently destroyed. Due to high temperature gradients, parasitic losses are investigated in conjunction...
In a water-ammonia absorption refrigeration system, the rectification heat is dissipated to the surroundings without recovering in traditional single-effect cycle. An improved cycle is proposed for the utilization of rectification heat when the chiller is operated under a large temperature lift or low heat source temperature when GAX (Generator-Absorber heat eXchange) effect is not available. This...
Tetrahydrofuran (THF) as a water-soluble sII clathrate former, cyclopentane (CP) as a water-insoluble sII clathrate former, and tetra n-butyl ammonium chloride (TBAC) as a water-soluble semiclathrate former were used to investigate their thermodynamic promotion effects on clathrate-based CO2 capture from simulated flue gas. The phase equilibria of CO2 (20%) + N2 (80%) + promoter clathrates at different...
Novel multi-step sorption-reaction cycles for air conditioning (cooling, heating) and temperature upgrading are studied. The multi-step sorption-reaction cycle utilizes heat from several processes, such as absorption, dilution, crystallization reaction and thermo-chemical reaction. In the multi-step sorption-reaction single stage solar cooling cycle, the cold storage density can reach the high value...
Despite improvements, the residential sector is one of most energy-intensive sectors in the world and is the third largest consumer of energy across Canada, and in Alberta in particular. This study investigates opportunities to improve energy efficiency and reduce greenhouse gas emissions (GHG) in the residential sector. A case study for Alberta is conducted. Energy modeling and scenario analyses...
Highly concentrated photovoltaic (HCPV) module exhaust heat recycle system incorporated with adsorption air-conditioning (AAC) module and PCM, along with providing domestic hot water was designed and discussed. In light of the different grade of thermal energy, several operating modes were analyzed in this system. Besides, an appropriate composite phase change material (CPCM) was obtained to store...
An exergy analysis was conducted for CO2 removal process from syngas using methyldiethanolamine activated by piperazine (a-MDEA). The process was simulated with Aspen HYSYS and the validation of the results was performed using the field data of Fanavaran Petrochemical Company. The process was divided into five separate sections. In order to determine the exergy loss, exergy balance equation was established...
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