scholarly journals Design, Construction, and Evaluation of the Performance of Dual-Axis Sun Trucker Parabolic Solar Cooker and Comparison of Cooker

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Solomon Tibebu ◽  
Arkbom Hailu
Keyword(s):  
Energy Cost ◽  
Energy Demand ◽  
Energy Input ◽  
Focal Length ◽  
Aluminum Foil ◽  
Cooking Time ◽  
Aperture Diameter ◽  
Short Period ◽  
Time And Energy ◽  
Design Construction

Energy demand is increasing due to population increment and industrialization. To meet this energy demand, technologies that use renewable energy such as solar energy are being developed. A parabolic solar cooker is one of the main solar cookers, which can cook food and boil water at a high temperature within a short period. This study aimed to design, construct, and evaluate the performance of the constructed parabolic solar cookers. Moreover, this study aimed to compare the constructed cooker with firewood, charcoal, kerosene, and electricity in terms of cooking time and energy cost. The cooker was constructed using different materials such as old satellite dishes, tyres, steel, and aluminum foil. The aperture diameter, aperture area, receiver diameter, receiver area, depth of the parabola, focal length, rim angle, circumference of the circle, surface area, length of the circumference, and concentration of the cooker were 1.8 m, 2.54 m2, 0.16 m, 0.02 m2, 0.3 m, 0.67 m, 67.38°, 5.76 m, 2.81 m2, 5.76 m, and 123.46, respectively. The cooker can track the sun from north to south and from east to west. The performance of the cooker was evaluated by calculating the efficiency and power. The output energy, input energy, and average upcoming solar radiation of the constructed parabolic solar cooker were 0.182 kW/m2, 1.691 kW/m2, and 0.665 kW/m2, respectively. The efficiency and power of the cooker were 10.75% and 0.3 kW/hr, respectively. The constructed parabolic solar cooker relatively showed better performance in cooking different foods. A family, which has five members, was considered to compare the constructed cooker with other fuels in terms of energy cost of cooking. Since the parabolic solar cooker does not have any energy cost, it can save the energy cost of cooking foods. Therefore, parabolic solar cookers have a great advantage for developing countries including Ethiopia.

Design, Construction, and Analysis of Pavements Using Accelerated Loading Facility

1997 ◽  
Vol 1590 (1) ◽  
pp. 73-79
Author(s):  
Freddy L. Roberts ◽  
Louay N. Mohammad ◽  
Ludfi Djakfar ◽  
Amar Raghavendra
Keyword(s):  
Fatigue Cracking ◽  
Primary Response ◽  
Performance Data ◽  
Test Facility ◽  
Response Analysis ◽  
Damage Prediction ◽  
Testing Facility ◽  
Short Period ◽  
Transportation Research ◽  
Design Construction

The Louisiana Transportation Research Center has recently completed the construction of a full-scale pavement test facility using the accelerated loading facility (ALF) machine. This facility contains nine pavement test sections, 12-m (38-ft) long and 3.66-m (12-ft) wide that are loaded by the ALF machine with loads ranging from 34.71 to 111.25 kN (7,800 to 25,000 lbf) on a dual-tire assembly. The advantage of this testing facility is its ability to cause a pavement to fail in a short period of time. In addition, the data acquisition methods and instrumentation used in this testing facility allow researchers to obtain reliable and representative performance data. The first test section has been loaded to failure and a preliminary analysis of the data is completed. VESYS 3A-M, a microcomputer version of the VESYS series, has been selected for the analysis due to its ability to predict damage and its flexibility. The analysis consists of the primary response analysis to determine strains, stresses, and deflection of the pavement and damage-prediction modeling that includes rutting, fatigue cracking, and roughness. The analysis was conducted by comparing the data obtained from field with that predicted by VESYS 3A-M. The performance data obtained from the field include fatigue cracking, rutting, and roughness. The analysis showed that VESYS 3A-M outputs are in good agreement with those obtained from the field.

A detailed study of ray tracing performance: render time and energy cost

2018 ◽  
Vol 34 (6-8) ◽  
pp. 875-885 ◽  
Author(s):  
Elena Vasiou ◽  
Konstantin Shkurko ◽  
Ian Mallett ◽  
Erik Brunvand ◽  
Cem Yuksel
Keyword(s):  
Ray Tracing ◽  
Energy Cost ◽  
Time And Energy

scholarly journals Energy balance of irrigated maize silage

2018 ◽  
Vol 48 (5) ◽  
Author(s):  
Tomás de Aquino Ferreira ◽  
Sílvia Costa Ferreira ◽  
Jackson Antônio Barbosa ◽  
Carlos Eduardo Silva Volpato ◽  
Rute Costa Ferreira ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Energy Balance ◽  
Total Energy ◽  
Energy Demand ◽  
Energy Input ◽  
Irrigation System ◽  
Diesel Oil ◽  
Maize Crop ◽  
Energy Inputs ◽  
Direct Energy

ABSTRACT: The aim of the present study is to evaluate the energy balance and energy efficiency of the silage maize crop in the Center for Research, Development and Technology Transfer of the Universidade Federal de Lavras (CDTT-UFLA). The crop was irrigated by center pivot and the stages of maize cultivation and energy inputs were monitored for the 1st and 2nd crops of the 2014/2015 harvest. Results from the energy analysis showed the crop had a total energy input of 45,643.85 MJ ha-1 and 47,303.60 MJ ha-1 for the 1st and 2nd crops and a significant predominance of direct energy type (about 92% of the matrix). Regarding direct energy inputs, the diesel oil was the most representative, contributing with approximately 38% of the total energy demand. Conversely, the irrigation system contribute with 3.92% e 5.97% in the 1st and 2nd crops, representing the largest indirect energy input. Nevertheless, irrigation and crop management allowed the system achieving high levels of productivity, resulting in an energy efficiency of 25.1 and 28.1 for the first and second crops respectively.

A Member Saved Is a Member Earned? The Recruitment-Retention Trade-Off and Organizational Strategies for Membership Growth

2017 ◽  
Vol 82 (2) ◽  
pp. 407-434 ◽  
Author(s):  
Yongren Shi ◽  
Fedor A. Dokshin ◽  
Michael Genkin ◽  
Matthew E. Brashears
Keyword(s):  
Energy Demand ◽  
Two Dimensions ◽  
Curvilinear Relationship ◽  
Organizational Strategies ◽  
Opportunity Structures ◽  
Open Networks ◽  
Long Line ◽  
Organizational Ties ◽  
Time And Energy

A long line of research documents the essential role of social networks in mediating the recruitment and retention of members in organizations. But organizations also comprise a primary context where people form social ties. We investigate how the network structure an organization creates among its members influences its ability to grow and reproduce. In particular, we propose that two dimensions of organizational strategy influence affiliation dynamics: (1) the extent to which an organization induces social interaction among its members (social encapsulation), and (2) the time and energy that an organization demands of its members (time and energy demand). We examine membership dynamics in an ecology where competitor organizations deploying varied strategies vie for the same pool of members. Results show a curvilinear relationship between membership growth and the rate of social encapsulation. Furthermore, we find that time and energy demand mediates the effect of social encapsulation by shaping its members’ opportunities for maintaining external affiliations. Different opportunity structures result in different levels of network turnover, thus either reinforcing or dissolving intra-organizational ties. For most types of organizations, attaining sustained growth requires a balance between open networks (for recruitment) and network closure (for retention).

Design of Fresnel Lens With Constant Height Spherical Facets

2020 ◽  
Author(s):  
Kuldeep Awasthi ◽  
Desireddy Shashidhar Reddy ◽  
Mohd. Kaleem Khan
Keyword(s):  
Ray Tracing ◽  
Concentration Ratio ◽  
Focal Length ◽  
Constant Width ◽  
Fresnel Lens ◽  
Aperture Diameter ◽  
Constant Height ◽  
Proposed Model ◽  
Fresnel Lenses ◽  
Ray Tracing Model

Abstract In the present work, a ray tracing model based on Snell’s law of refraction is developed using MATLAB for the design of Fresnel lens with spherical facets of equal height. In practice, the facet curvature is approximated by straight line, which causes an increase in spherical aberrations and reduction in concentration ratio. The proposed model takes facet curvature into consideration, which will result in effective utilization of incident solar radiations. Fresnel lenses are available with facets having constant width and facets with constant height. A comparison of spherical aberrations in the two cases has also been presented using different f - numbers (ratio of focal length to aperture diameter). Effect of different parameters like number of facets and refractive index of lens material on concentration ratio is also presented in present study. The proposed ray tracing model is validated with the model developed in SolTrace, an open access software. The predictions from the proposed model are in good agreement with the results of SolTrace model with an average deviations of 6.8% for concentration ratio and 2.2% for focal length.

Thermal Recuperation Modeling of a Solar Thermochemical Reactor

2011 ◽  
Author(s):  
Luke J. Mayer ◽  
Darryl L. James
Keyword(s):  
Energy Demand ◽  
Energy Input ◽  
Three Dimensional ◽  
The United States ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Reactive Material ◽  
Reactor Geometry ◽  
Carbon Neutral ◽  
Solar Thermochemical

The United States spends over 700 billion dollars on foreign oil every year. A promising method to reduce this dependence, and be carbon-neutral as well, is concentrated solar thermochemical technology. Concentrated solar thermochemical technology has the potential to directly convert sunlight into a useable, carbon-neutral fuel that can be easily stored and integrated into our existing forms of energy demand such as transportation and heating fuels. Research is being performed by several groups at Sandia National Laboratories to fundamentally understand the complex physics and chemistry occurring within a solar thermochemical reactor prototype named the CR5 [counter-rotating-ring receiver/reactor/recuperator]. The objective of the work presented in this paper is to understand recuperative heat transfer within the CR5 as a function of reactor geometry and operational conditions. The CR5 vessel utilizes counter-rotating disks to provide for thermal energy recuperation, which is a necessity for an efficient reactor. Initially a simplified steady-state two-dimensional recuperation analysis was made to evaluate the relationship between the reactive material fin height and recuperation. The results from the simplified two-dimensional model indicate that recuperation is a strong function of fin height. Next, a more detailed, but still simplified, transient, three-dimensional model was developed. The initial three-dimensional simulations presented in this paper were performed to determine recuperator effectiveness and mesh density requirements for a generic case that had 2.5 kW energy input, fin height to gap ratio of 0.9, and finned reactor disks rotating at 1 rpm. A recuperator effectiveness of 88% and 85% was calculated from the finer and coarser meshes, suggesting that the coarser mesh (lumped in the fin thickness direction) is adequate for future parametric analysis simulations. This analysis will lead to a better understanding of recuperation as a function of reactor geometry, energy input, rotational speed, and thermophysical properties.

Low energy treatment system for brewery wastewater reuse

2003 ◽  
Vol 3 (3) ◽  
pp. 141-148 ◽  
Author(s):  
K. Parameshwaran ◽  
A.G. Fane ◽  
B.D. Cho ◽  
R. Moosbrugger ◽  
K.J. Kim
Keyword(s):  
Energy Cost ◽  
Energy Demand ◽  
Low Energy ◽  
Transmembrane Pressure ◽  
Time Interval ◽  
Net Energy ◽  
Brewery Wastewater ◽  
Membrane Unit ◽  
Membrane Area ◽  
Treated Effluent

A pilot plant consisting of UASB, SBR and microfiltration in series was operated for 15 months to study a low energy treatment option for brewery effluent. The UASB was loaded up to 18 kg/kL.d. However for trouble free operation the loading had to be limited to 14 kg/kL.d. More than 80% of the feed COD was removed in the anaerobic process and a further 60% COD removal was observed in the aerobic process. An air backwashable microfiltration unit was used to remove suspended solids so that the treated water could be reused. The membrane unit was optimised by operating under dead-end, controlled flux conditions (permeate pumping) and air backwashing at set transmembrane pressure (TMP) (in practice the membranes are backwashed at set time interval). Operating energy cost calculations for the membrane system showed that the unit needs to be operated at low flux (say 20 to 30 L/m2.h) to have a low energy demand. However this necessitates a large membrane area. Optimisation for capital and energy cost indicates that the unit needs to be operated at more than 60 L/m2.h depending on the maximum TMP specified. The system energy balance was also calculated. The energy needed for the operation of all units less the energy gained from methane gas generated indicates that the system could yield a net energy of 2.5 kWh/kL water treated. The treated effluent had a turbidity of less than 1.2 NTU and the BOD5 less than 20 mg/L.

scholarly journals Cost Efficient Real Time Electricity Management Services for Green Community Using Fog

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3164
Author(s):  
Rasool Bukhsh ◽  
Muhammad Umar Javed ◽  
Aisha Fatima ◽  
Nadeem Javaid ◽  
Muhammad Shafiq ◽  
...  
Keyword(s):  
Real Time ◽  
Energy Management ◽  
Data Center ◽  
Energy Cost ◽  
Energy Demand ◽  
Data Centers ◽  
Management Service ◽  
Cooling Systems ◽  
Electricity Cost ◽  
Cost Efficient

The computing devices in data centers of cloud and fog remain in continues running cycle to provide services. The long execution state of large number of computing devices consumes a significant amount of power, which emits an equivalent amount of heat in the environment. The performance of the devices is compromised in heating environment. The high powered cooling systems are installed to cool the data centers. Accordingly, data centers demand high electricity for computing devices and cooling systems. Moreover, in Smart Grid (SG) managing energy consumption to reduce the electricity cost for consumers and minimum rely on fossil fuel based power supply (utility) is an interesting domain for researchers. The SG applications are time-sensitive. In this paper, fog based model is proposed for a community to ensure real-time energy management service provision. Three scenarios are implemented to analyze cost efficient energy management for power-users. In first scenario, community’s and fog’s power demand is fulfilled from the utility. In second scenario, community’s Renewable Energy Resources (RES) based Microgrid (MG) is integrated with the utility to meet the demand. In third scenario, the demand is fulfilled by integrating fog’s MG, community’s MG and the utility. In the scenarios, the energy demand of fog is evaluated with proposed mechanism. The required amount of energy to run computing devices against number of requests and amount of power require cooling down the devices are calculated to find energy demand by fog’s data center. The simulations of case studies show that the energy cost to meet the demand of the community and fog’s data center in third scenario is 15.09% and 1.2% more efficient as compared to first and second scenarios, respectively. In this paper, an energy contract is also proposed that ensures the participation of all power generating stakeholders. The results advocate the cost efficiency of proposed contract as compared to third scenario. The integration of RES reduce the energy cost and reduce emission of CO 2 . The simulations for energy management and plots of results are performed in Matlab. The simulation for fog’s resource management, measuring processing, and response time are performed in CloudAnalyst.

scholarly journals Exercise-Induced Muscle Damage and Running Economy in Humans

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Cláudio de Oliveira Assumpção ◽  
Leonardo Coelho Rabello Lima ◽  
Felipe Bruno Dias Oliveira ◽  
Camila Coelho Greco ◽  
Benedito Sérgio Denadai
Keyword(s):  
Muscle Damage ◽  
High Intensity ◽  
Energy Demand ◽  
Negative Impact ◽  
High Intensity Exercise ◽  
Running Economy ◽  
Running Performance ◽  
Downhill Running ◽  
Short Period ◽  
Exercise Induced

Running economy (RE), defined as the energy demand for a given velocity of submaximal running, has been identified as a critical factor of overall distance running performance. Plyometric and resistance trainings, performed during a relatively short period of time (~15–30 days), have been successfully used to improve RE in trained athletes. However, these exercise types, particularly when they are unaccustomed activities for the individuals, may cause delayed onset muscle soreness, swelling, and reduced muscle strength. Some studies have demonstrated that exercise-induced muscle damage has a negative impact on endurance running performance. Specifically, the muscular damage induced by an acute bout of downhill running has been shown to reduce RE during subsequent moderate and high-intensity exercise (>65% VO2max). However, strength exercise (i.e., jumps, isoinertial and isokinetic eccentric exercises) seems to impair RE only for subsequent high-intensity exercise (~90% VO2max). Finally, a single session of resistance exercise or downhill running (i.e., repeated bout effect) attenuates changes in indirect markers of muscle damage and blunts changes in RE.

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