The important indications for assessing CCHP(combined cooling,heating and power)systems are their supply-demand matching characteristics between the user demand side and the energy supply *** characteristics are prima...
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The important indications for assessing CCHP(combined cooling,heating and power)systems are their supply-demand matching characteristics between the user demand side and the energy supply *** characteristics are primarily influenced by different building types and operating *** view of the energy redundancy of the following electric load(FEL)and following thermal load(FTL)operation strategies and the energy deficiency of the following hybrid electric-heating load(FHL)operation strategy,this paper proposes an improved following balanced heat-electrical load(IFBL)operation strategy based on the following balanced heat-electrical load(FBL)operation *** on the energy utilization rate as the objective function,this paper optimizes the installed capacity of CCHP systems in different buildings and proposes an energy factor for evaluating the supply-demand matching characteristics of the *** results show that the energy utilization rate and energy factor of the system under IFBL are optimal relative to the other operation ***,the hotel building has the highest energy utilization rate and the lowest energy factor;on the contrary,the office building has the lowest energy utilization rate and the highest energy ***,the analysis of supply-demand matching for different building types under multiple operating strategies shows that the hospital and hotel systems exhibit optimal supply-demand matching performance under the IFBL strategy,with values of 0.945 and 0.938,respectively;on the contrary,the office system has an optimal supply-demand matching of 0.935 under the FEL *** the FTL strategy,the systems of all three buildings exhibit poor matching performance.
Advanced high performance light weight composite materials have been highly demanded due to rapidly progressing technical activities in aerospace, transportation and automobile over the past three decades. This study ...
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Hastelloy is a nickel-chromium-molybdenum-iron-based alloy and a member of the ‘superalloy’ family. Hastelloy has exceptional properties like high strength, wear resistance and hightemperature stress-corrosion resis...
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Based on the system dynamic model, a full system dynamics estimation method is proposed for a chain shell magazine driven by a permanent magnet synchronous motor(PMSM). An adaptive extended state observer(AESO) is pro...
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Based on the system dynamic model, a full system dynamics estimation method is proposed for a chain shell magazine driven by a permanent magnet synchronous motor(PMSM). An adaptive extended state observer(AESO) is proposed to estimate the unmeasured states and disturbance, in which the model parameters are adjusted in real time. Theoretical analysis shows that the estimation errors of the disturbances and unmeasured states converge exponentially to zero, and the parameter estimation error can be obtained from the extended state. Then, based on the extended state of the AESO, a novel parameter estimation law is designed. Due to the convergence of AESO, the novel parameter estimation law is insensitive to controllers and excitation signal. Under persistent excitation(PE) condition, the estimated parameters will converge to a compact set around the actual parameter value. Without PE signal, the estimated parameters will converge to zero for the extended state. Simulation and experimental results show that the proposed method can accurately estimate the unmeasured states and disturbance of the chain shell magazine, and the estimated parameters will converge to the actual value without strictly continuous PE signals.
In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubr...
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In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.
The present work aims to study the formability of AA7079 alloy to fabricate circular frustum cones using the SPIF technique. Experiments were conducted as per L9 orthogonal arrays, and the Taguchi technique was used t...
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Heat storage properties of phase change materials(PCMs) are essential characteristics that perform a key role in thermal heat energy storage *** thermal properties of PCMs can be improved by developing metal foam/PCM ...
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Heat storage properties of phase change materials(PCMs) are essential characteristics that perform a key role in thermal heat energy storage *** thermal properties of PCMs can be improved by developing metal foam/PCM *** addition of metal foam in PCMs has a significant effect on the thermal characteristics of *** this paper,the heat storage properties of two different metal foam/PCM composites were experimentally *** behavior of paraffin in metal foam(copper and iron-nickel)/paraffin composites concerning pure paraffin at a constant heat flux of 1000 W/m^(2) in three directions simultaneously(x,y,and z) was *** was infiltrated into copper and iron-nickel foams to develop composite materials which resulted in enhancing the thermal conductivity of the paraffin.A comparative analysis is made on the heat storage properties of paraffin in copper and iron-nickel foams/paraffin *** temperature distribution during the phase transition process is experimentally *** comparison indicates that temperature uniformity in copper foam/paraffin composite is better than in iron-nickel foam/paraffin composite and pure paraffin at the same heat *** results show that at heat flux of 1000 W/m^(2),the heat storage time for copper foam/paraffin composite is 20.63% of that of iron-nickel foam/paraffin composite.
Electric vehicles (EVs) are the most interesting and innovative technology in the 21st century because of theirenormous advantages, both technically and economically. Their emissions rate compared to fuel-based vehicl...
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Electric vehicles (EVs) are the most interesting and innovative technology in the 21st century because of theirenormous advantages, both technically and economically. Their emissions rate compared to fuel-based vehicles isnegligible as they do not consume fuel and hence do not emit any harmful gases. However, their bulk production,adoption and lack of charging stations increase the stress of power stations due to modern-day lifestyles. If Electricvehicles demand increases drastically then conventional power stations will not bear their demand and if theygenerate electricity by conventional means it will be very costly and may further add greenhouse gases. Therefore,this research provides the techno-economic assessment of a stand-alone renewable-dependent electric vehiclecharging station, excluding any burden on electrical utility. The proposed study is carried out in Bahria Town,Karachi, a city in Pakistan. In this study, HOMER Pro software was utilized for techno-economic assessment. Ahybrid system comprising solar Photovoltaic/Wind Turbine/Fuel cells and battery storage is included in the *** and wind resources were taken from NASA’s website, where charging stations will be integrated. The overallresults show promising in terms of total Net Present Cost and the Cost of Energy which are 2.72M $ and 0.237 $,respectively. The total system generation is 3,598 Megawatt hours per year, and the total energy consumption is 885Megawatt hours per year.
This study focuses on the impact of graphite (Gr) and titanium diboride (TiB2) hybrid reinforcement on the thermal conductivity of hybrid composite Al7075. Using liquid metallurgy, hybrid composites with two distinct ...
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The objective of this study is to analyze a three-way ball valve using computational fluid dynamic simulations in ANSYS Fluent to achieve better flow control and improve the efficiency of the system. The need to impro...
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