bluuebunny/crossref_metadata_2025 huggingface dataset:
The Analysis and Application of Energy-Internet in the Low-Carbon Community
Authors: Liang Hao , Long Weiding , Song Yingqian , Liu Fang
Published: January 2011

The energy-Internet is a new energy supply method based on urban compact and densely populated community in a low-carbon city. The principle is to connect small energy generation stations and combined heat and power system (CHP) based on distributed energy technology and renewable energy into a network in the urban district. In this way, the cooling, heating and electricity could all back each other up. Each building of the community could collect the energy and then put that energy into the energy-internet to supply the heating and power to buildings. The power in the energy-internet could also be used for charging electric vehicles. So the energy use in the urban community would be basically self-sufficient. The energy generation stations in the energy-internet could be solar power, wind power, biomass cogeneration (including refuse power generation), household fuel cell, low-grade heat in rivers, lakes, urban sewage and soil. In this way, large-scale renewable energy and unused energy could be fully used and applied in a compact and dense community. If the energy-internet is suitable designed, the equipment capacity, energy consumption and CO2 emission of the community could be greatly reduced, energy efficiency could be optimized and improved and the heat island effect could also be alleviated. This article explores three major problems of the construction of energy internet and their solutions: namely, the location and layout of the energy station, the environmental economic dispatch model of the energy internet with power dispatching as an example, the optimal path design of hot water pipe network combined with graph theory and genetic algorithms.
The Feasibility Study of Household Units PV Cells for Carbon Emission Reduction in Developing Countries: A Case Study of N. Cyprus
Authors: Agboola O. Phillips , Egelioglu Faut , Agboola O. Mary
Published: January 2011

In this paper the feasibility of using photovoltaic cells to reduce electricity generation from fossil fuels in North Cyprus (N. Cyprus) was studied. In this work it is proposed to use photovoltaic systems to power heating and cooling systems (i.e., mainly heat pumps) in household units and it was found that this is economically feasible. It was also discovered that despite the extensive use of solar water heaters in N. Cyprus, the awareness of photovoltaic cells is still very low and few house owners take advantage of its economic and environmental friendliness. It was also observed that PV cells are not widely available in the local market; coupled with the fact that formal awareness of energy friendly electricity means is not well promoted in developing countries. The result of this work shows that about 40% of yearly electricity consumption in N. Cyprus, which is mainly generated from plants using fuel oil no. 6, can be reduced if all household units use PV systems to heat or cool the house depending on the weather conditions. According to the electricity forecast carried out in this paper it was observed that the annual net electricity consumption is expected to increase by 30.65% in the year 2015. This means that the utility company will need to augment its current facilities to accommodate the increment; by expanding its facilities or opting for energy conservation policies. The latter has proved to be inefficient in this part of the world; the former will increase the use of fossil fuel thereby increasing the CO2 emission. This work also provides economic analysis for PV systems investment for household owners and policies to help increase availability of PV cells in N. Cyprus market.
Economic Evaluation of Residential Central Air Conditioning Systems
Authors: Wei Bing , Yang Huayi , Luo Wen
Published: January 2011

Nowadays the residential central air conditioning systems are being widely used in China, and there are several different system options in the actual applications. Different residential central air conditioning systems will have different initial costs and operating costs. It is quite important for the decision-makers to choose an economical air conditioning system. In this paper six residential central air conditioning systems are introduced, which are the air-source heat pump system, household gas-fired air conditioning system, air-cooled chiller unit/gas-fired boiler system, water loop heat pump system, ground-source heat pump system and solar heat pump system. By using the method of dynamic total annual cost with an example of residential building in Beijing, the total annual costs of chosen six air conditioning systems are calculated and compared, and the sensitivity of total annual cost are analyzed with the rates of electricity and natural gas being used as the sensitive factors. The results show that the total annual cost of water loop heat pump system is the minimum among the six systems, which is the optimal option under the given conditions. The rates of electricity and natural gas will influence the raking of systems.
Development of Workforce for Wind Energy
Authors: Mehta Kishor C. , Swift Andrew H. P. , Walker Richard P. , Seger Kelsey L.
Published: January 2011

Our vision at Texas Tech University is to develop work force through education and training that can provide a steady stream of personnel for the rapidly growing wind energy industry. Our objectives are to establish interdisciplinary curricula at all levels of higher education which can educate and train people to work in the wind energy industry including design and construction, maintenance, business, finance, supervision, management, policy making, environmental impact, as well as research and development. The nature and breadth of the wind energy industry demands that the degree programs be interdisciplinary with flexibility to provide emphasis in various areas. Two degree programs, bachelor and doctoral degree curricula are presented in the paper.
Evaluation of Ground Source Heat Pump Energy, Demand, and Greenhouse Potential in Colorado Residential Buildings
Authors: Studer Daniel , Krarti Moncef
Published: January 2011

This paper summarizes the results of a detailed energy analysis carried out for a typical Colorado residence using three different HVAC systems for 10 distinct locations in Colorado. The HVAC systems considered in the analysis include: • 78% efficient furnace with a 13 SEER air conditioner; • Vertical well ground source heat pump with a heating COP of 3.5 and a cooling EER of 17.1; • Slinky ground source heat pump with a heating COP of 3.5 and a cooling EER of 17.1. The results of the analysis indicate that relative to the conventional systems, ground source heat pumps (GSHPs) offer several benefits including lower annual energy costs, electrical peak demand, and carbon emissions. However, GSHPs use more electrical energy use. Specifically, it was found that relative to a 78 AFUE furnace / 13 SEER AC system, in all locations both GSHPs, vertical well and slinky, show on average a 41.2% increase in electricity use, a 10% decrease in energy cost, a 4.5% decrease in CO2 emissions, and a 16.8% average decrease in peak summer electric demand.
Assessment Indexes and Systems of Environmental Quality of Green Buildings in China
Authors: Wei Bing , Luo Wen , Zhang Bin
Published: January 2011

With the rapid development of modern economy in China, the concept of “green building” is paid more attention, and the assessment to green buildings becomes more important than before. In green building assessment systems, the assessment to the environmental quality is one of the most important content. The research to the assessment index systems of environmental quality is of great significance to developing green buildings in China. In this paper, based on the technical requirements and design outlines of green buildings, the assessment rule, object, method and mode that are suitable for the situations in China are discussed by combining the characteristics of indoor and outdoor environment of green buildings, and the assessment index and system of environmental quality are set up. In the process, the evaluation models of AHP (analytic hierarchy process) are established. The weight factor of the indexes of environmental quality are made certain using the method of AHP, which will be the basis of the whole assessment system of green building and the reference for the implement of green building evaluation policy in China. All the work is to promote the development of green buildings.
Integrative Analysis of Non-Renewable and Renewable Energy Sources for Electricity Generation in U.S.: Demand and Supply Factors, Environmental Risks and Policy Evaluation
Authors: Agarwal Ramesh , Wang Ping , Chusak Lee
Published: January 2011

An equilibrium economic model for policy evaluation related to electricity generation has been developed; the model takes into account the non-renewable and renewable energy sources, demand and supply factors and environmental constraints. The non-renewable energy sources include three types of fossil fuels: coal, natural gas and petroleum, and renewable energy sources include nuclear, hydraulic, wind, solar photovoltaic, biomass wood, biomass waste and geothermal. Energy demand sectors include households, industrial manufacturing and commercial enterprises (non-manufacturing businesses such as software firms, banks, restaurants, service organizations, universities, etc.). Energy supply takes into account the electricity delivered to the consumer by the utility companies at a certain price which maybe different for retail and wholesale customers. Environmental risks primarily take into account the CO2 generation from fossil fuels. The model takes into account the employment in various sectors and labor supply and demand. Detailed electricity supply and demand data, electricity cost data, employment data in various sectors and CO2 generation data are collected for a period of seventeen years from 1990 to 2006 in U.S. The model is calibrated for the aggregate data. The calibrated model is then employed for policy analysis experiments if a switch is made in sources of electricity generation, namely from fossil fuels to renewable energy sources. As an example, we consider a switch of 10% of electricity generation from coal to 5% from wind, 3% from solar photovoltaic, 1% from biomass wood and 1% from biomass waste. It should be noted that the cost of electricity generation from different sources is different and is taken into account. The consequences of this switch on supply and demand, employment, wages, and emissions are obtained from the economic model under three scenarios: (1) energy prices are fully regulated, (2) energy prices are fully adjusted with electricity supply fixed, and (3) energy prices and electricity supply both are fully adjusted.
Sustainable Transportation Fuels From Off-Peak Wind Energy, CO2, and Water
Authors: Holte Laura L. , Doty Glenn N. , McCree David L. , Doty Judy M. , Doty F. David
Published: January 2011

Doty Energy is developing advanced processes to permit the production of fully carbon-neutral gasoline, jet fuel, diesel, ethanol, and plastics from exhaust CO2 and off-peak clean energy (wind and nuclear) at prices that can compete with fossil-derived products. Converting CO2 into fuels will eliminate the need for CO2 sequestration, reduce global CO2 emissions by 40%, and provide a nearly insatiable market for off-peak wind. It has long been known that it is theoretically possible to convert CO2 and water into standard liquid hydrocarbon fuels at high efficiency. However, the early proposals for doing this conversion had efficiencies of only 25% to 35%. That is, the chemical energy in the liquid fuels produced (gasoline, ethanol, etc.) would be about the 30% of the input energy required. The combination of the eight major technical advances made over the past two years should permit this conversion to be done at up to 60% efficiency. Off-peak grid energy averaged only $16.4/MWhr in the Minnesota hub throughout all of 2009 (the cheapest 6 hours/day averaged only $7.1/MWh). At such prices, the synthesized standard liquid fuels (dubbed “WindFuels”) should compete even when petroleum is only $45/bbl. A more scalable alternative for transportation fuels is needed than biofuels. It is in our economic and security interests to produce transportation fuels domestically at the scale of hundreds of billions of gallons per year. WindFuels can scale to this level, and as they are fully carbon-neutral they will dramatically reduce global CO2 emissions at the same time. Switching 70% of global transportation fuels from petroleum to WindFuels should be possible over the next 30 years. WindFuels will insure extremely strong growth in wind energy for many decades by generating an enormous market for off-peak wind energy. WindFuels is based largely on the commercially proven technologies of wind energy, water electrolysis, and Fischer Tropsch (FT) chemistry. Off-peak low carbon energy is used to split water into hydrogen and oxygen. Some of the hydrogen is used to reduce CO2 into carbon monoxide (CO) and water via the Reverse Water Gas Shift (RWGS) reaction. The CO and the balance of the hydrogen are fed into an FT reactor similar to those used to produce fuels and chemicals from coal or natural gas. The processes have been simulated, and key experiments are being carried out to help optimize process conditions and validate the simulations.
Heat Balancing Characteristics of a Domestic Pressure Cooker
Authors: Ravikumar P. , Sivamurugan P.
Published: January 2011

The study of “Heat Balance” in a domestic pressure cooker is an important investigation for energy conservation. In the present study, experiments were conducted on a domestic pressure cooker to measure Input Heat, Utilized Heat and Heat Lost for different volumes of water filled in a pressure cooker. Experiments were conducted on 0.008m3(8litre) pressure cooker filled with water at 12.5%, 25%, 37.5% and 46.25% of its capacity, respectively 1.0kg, 2.0kg, 3.0kg and 3.7kg of water. Two approaches were adopted to determine an optimum condition of the pressure cooker. In first approach, the pressure cooker was insulated and the other in non-insulated. In both cases, cookers of similar capacity, make and design were used. Outer surface of the cooker was insulated with asbestosrope, clay and cow-dung bindings. Interesting results were arrived during the study that, there was not having much difference in heat input, heat utilization for insulated and non insulated cookers when the water level was only about 12.5% volume. In other cases the insulated cooker consumes more heat input than the non-insulated cooker. The reason was found that thermal mass capacity of the insulated cooker was more and stores heat energy. When the pressure cooker is filled with 46.25% of its volume by water, it utilizes a maximum of 30% of total heat supplied. On reducing the volume of water filled in the cooker, the heat loss increased and consumes more thermal energy.
Optimization of Flatback Airfoils for Wind Turbine Blades
Authors: Chen Xiaomin , Agarwal Ramesh
Published: January 2011

In recent years, the airfoil sections with blunt trailing edge (called flatback airfoils) have been proposed for the inboard regions of large wind-turbine blades because they provide several structural and aerodynamic performance advantages. In this paper, we employ a genetic algorithm (GA) for shape optimization of flatback airfoils for generating maximum lift to drag ratio. The computational efficiency of GA is significantly enhanced with an artificial neural network (ANN). The commercially available software FLUENT is used for calculation of the flow field using the Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with a turbulence model. It is shown that the combined GA/ANN optimization technique is capable of accurately and efficiently finding globally optimal flatback airfoils.
Deployment Prospects for Proposed Sustainable Energy Alternatives in 2020
Authors: Doty Glenn N. , McCree David L. , Doty Judy M. , Doty F. David
Published: January 2011

We present brief comparative economic and environmental appraisals of the alternatives that have received the most attention in recent years: conventional biofuels (agrofuels), cellulosic ethanol (CE), microalgae, electric vehicles (EVs), plug-in hybrids (PEHVs), compressed natural gas (CNG) vehicles, “semi-clean” (SCPC) coal, clean coal, wood co-firing, nuclear, photovoltaic solar (PV), concentrated solar power (CSP), geothermal, hydropower, wind, and a novel alternative energy solution known as “WindFuels”. Critical reviews of the projections of both Levelized Cost of Energy (LCOE) and life-cycle CO2 emissions of these primary alternatives for clean, sustainable energy are presented. We identify and review the major challenges faced by these alternatives — many of which have received incomplete treatment in previous studies. Then from the projected LCOE, carbon neutrality, resource availability, technological challenges, and recent market data; the probable growth rates for the various alternatives are projected, and the environmental benefit and economic burdens associated with these alternatives are assessed.
A Comparative Wind Investigation Using Mesoscale Numerical Predictions and Experimental Data at Aubrey Cliffs, Arizona
Authors: Barton Michael S. , Acker Thomas L. , Duque Earl P. N.
Published: January 2011

The purpose of this paper is to demonstrate the validity of mesoscale numerical weather prediction modeling near the complex terrain at Aubrey Cliffs, Arizona, and to investigate the influence of the outer domain size employed on the computational results. Mesoscale Modeling v5 (MM5) was implemented to produce numerical wind data that was compared with experimental wind data. The results obtained from the analysis show that MM5 predicts the wind flow near the Aubrey Cliffs accurately. In addition to predicting the wind speed and direction, the wind power density at the site was also computed. A three month MM5 simulation was completed for the proposed site, with a grid resolution of 1-km in the proximity of the cliffs. Two different gridding scenarios were used to investigate the accuracy of the numerical results and the effect outermost modeling domain. It was found that the model predicts the average wind speed at the site within 4% of the actual observed values. It was also determined that the MM5 model does not require an extended radius of influence to correctly determine the wind speed.
Development and Testing of an Automated Building Commissioning Analysis Tool (ABCAT)
Authors: Bynum John D. , Claridge David E. , Curtin Jonathan M.
Published: January 2011

Experience has shown that buildings on average may consume 20% more energy than required for occupant comfort which by one estimate leads to $18 billion wasted annually on energy costs in commercial buildings in the United States. Experience and large scale studies of the benefits of commissioning have shown the effectiveness of these services in improving the energy efficiency of commercial buildings. While commissioning services do help reduce energy consumption and improve performance of buildings, the benefits of the commissioning tend to degrade over time. In order to prolong the benefits of commissioning, a prototype fault detection and diagnostic (FDD) tool intended to aid in reducing excess energy consumption known as an Automated Building Commissioning Analysis Tool (ABCAT) has been developed. ABCAT is a first principles based whole building level top down FDD tool which does not require the level of expertise and money often associated with more detailed component level methods. The model based ABCAT tool uses the ASHRAE Simplified Energy Analysis Procedure (SEAP) which requires a smaller number of inputs than more sophisticated simulation methods such as EnergyPlus or DOE-2. ABCAT utilizes a calibrated mathematical model, white box method, to predict energy consumption for given weather conditions. A detailed description of the methodology is presented along with test application results from more than 20 building years worth of retrospective applications and greater than five building years worth of live test case applications. In this testing, the ABCAT tool was used to successfully identify 24 significant energy consumption deviations in five retrospective applications and five significant energy consumption deviations in four live applications.
Resource Accounting and Waste Impact: Limitations of Exergy as a Sustainability Tool
Authors: Gaudreau Kyrke , Fraser Roydon A. , Murphy Stephen
Published: January 2011

Exergy is a thermodynamic concept that has been widely promoted for assessing and improving sustainability, notably in the characterization of resources and wastes. Despite having notable benefits, exergy is often misused by authors who tend to apply it as an intrinsic characteristic of an object (i.e., as a static thermodynamic property). Using both theoretical and empirical evidence the authors introduce the challenges involved with applying exergy as an intrinsic characteristic matter with particular focus on resource value and waste impact. These challenges lead to an in-depth discussion of current major reference environment formulations and reveals that the properties of exergy reference environments are not reconcilable with the properties of the natural environment. The authors conclude by arguing that exergy practitioners should abandon attempts to formulate standard comprehensive reference environments and return to process dependent reference environments that exergy was originally based upon. In this regard, the authors are proposing that exergy be seen as a context- or environment-dependent decision-making tool and not as an intrinsic characteristic of matter.
Energy Efficiency in Industrial Operations: An Evaluation of Benefits and Cost of the Most Effective Interventions Within the Italian Industrial Sector
Authors: Cagno Enrico , Trianni Andrea
Published: January 2011

The attention towards the topic of reducing the energy expenditures has dramatically grown in recent crisis times that have forced firms to reduce them. This reduction in energy expenditures of a firm can be pursued through a wise energy procurement (we can call it “administrative energy efficiency”), thus with a reduction in the specific cost of energy (both electricity and other energy sources). But, the highest effective saving — for the whole system — would come from a direct reduction of the consumption, thus increasing the so-called “operational energy efficiency”, the unique true energy efficiency, implying the effort of the whole firm, since it requires a lower and wiser use of energy, and new and more efficient technologies. It is quite diffused the perception that governments are now taking measures to reach a common and more efficient environmental and energetic policy, but the effort is still not sufficient. The attention has obviously been paid towards the industrial sector, that covers about 30% of the consumption, second just after transportation: since now several actions have been taken to achieve the energy performance of buildings, but very few in the operations. Furthermore, it should be clear that to be really effective in this field governments should focus their attention on Small & Medium Enterprises (SMEs), usually less efficient than Large Enterprises (LEs), since SMEs represent the vast majority of the total number of industries and cover a consistent share of the energy consumption of a whole domestic industrial sector. This paper aims at providing an overview of the most effective interventions for reducing energy consumption in industrial operations that have been successfully implemented in a large number of case studies investigated in North America and Europe. The paper provides different scenarios according to the implementation of those interventions, characterized all by being Best Available Technologies and Practices, showing the impact on the energy consumption for a set of Italian industrial districts. The final results show that, under certain assumptions, the financial support of the most effective interventions eventually provided by governments’ energy efficiency policies, would lead to a widespread increase of the overall energy efficiency of a district with strong benefits for the whole industrial system.
Modeling Solar Thermochemical Splitting of CO2 Using Metal Oxide and a CR5
Authors: Chen Ken S. , Hogan Roy E.
Published: January 2011

A two-dimensional, multi-physics computational model based on the finite-element method is developed for simulating the process of solar thermochemical splitting of carbon dioxide (CO2) using ferrites (Fe3O4/FeO) and a counter-rotating-ring receiver/recuperator or CR5, in which carbon monoxide (CO) is produced from gaseous CO2. The model takes into account heat transfer, gas-phase flow and multiple-species diffusion in open channels and through pores of the porous reactant layer, and redox chemical reactions at the gas/solid interfaces. Results (temperature distribution, velocity field, and species concentration contours) computed using the model in a case study are presented to illustrate model utility. The model is then employed to examine the effects of injection rates of CO2 and argon neutral gas, respectively, on CO production rate and the extent of the product-species crossover.
Pre-Feasibility Analysis of a Wind-Solar-Diesel Electricity Generation System for a Remote Island Community in the Gulf of Guayaquil in Ecuador
Authors: Salazar Pablo Tagle , Duque-Rivera Jorge
Published: January 2011

Reliable energy provision to poor island communities is a challenging problem, particularly in developing countries. This paper presents a pre-feasibility analysis of a wind-solar-diesel electricity generation system to satisfy residential demand in a small, poor island community located in the Gulf of Guayaquil in Ecuador, using HOMER as an analysis tool. The community currently has unreliable diesel generated electricity that energizes homes and street lights, but wishes to replace it with renewable sources as they see that these sources are more aligned with their intention to move into sustainable tourism as a source of income. Relevant meteorological data is lacking and there is only anecdotal evidence that wind is strong in summer time nights at the site. Data for solar irradiance and wind speed were taken from a meteorological station located in Guayaquil, a city relatively close to the island. Wind speed was estimated during a field visit. The community is composed of 85 households for a total of 650 people. Domestic demand data was available and categorized into two types of households. HOMER was used to model four generation system types combining wind turbines, PV panels and Diesel generators to satisfy five different demand models with varying proportions of total households of each type. Selection of the best system is based in both energy and cost optimization, with low use of diesel and low excess of electricity. A sensitivity analysis of the wind and solar resources is included to account for the unavailability of reliable data for wind speed and solar irradiance. The expansion of the system due to population and ensuing demand growth is considered in the analysis using a 25 years project lifetime. The results show that there is potential to install a wind-solar-diesel system under medium-high weather conditions (more than 4 kWh/m2d for solar irradiance and 3.5m/s for wind speed). As a sample, at a 4.5kWh/m2d solar irradiance and 4.6m/s wind speed, a wind-solar-diesel system presents a total NPV of $1,616,615 and a LCOE of $0.23 per kWh, with a diesel reduction use of 81.8% and a excess energy percentage of 3.44%.
Thermal Analysis of a Building’s Roof With Cone Frustum Holes Containing PCM
Authors: Alawadhi Esam M. , Alqallaf Hashem J.
Published: January 2011

The thermal effectiveness of a building’s roof with Phase Change Material (PCM) is presented in this paper. The considered model consists of a concrete slab with vertical cone frustum holes filled with PCM. The objective of incorporating the PCM into the roof structure is to utilize its high latent heat of fusion to reduce the heat gain during the energy demand peak hours by absorbing the through the melting process in the roof before it reaches the indoor space. The problem is numerically solved in a three-dimensional space using the finite element method. The thermal effectiveness of the proposed roof-PCM system is determined by comparing the heat flux at the indoor surface to a roof without the PCM during typical working hours. A parametric study is conducted to assess the effect of the cone frustum geometry, as well as, the PCM’s type. The results indicate that the heat flux at the indoor surface of the roof can be reduced up to 39% when the PCM is incorporated and a conical geometry for the PCM shows the best thermal performance.
Ecological Sustainability of Fiber Optic Solar Lighting in the Future of the State of Qatar
Authors: AhsanShaikh Mohammad , Mahfoud Musbah S.
Published: January 2011

The use of electric lighting in our homes and our workplaces stands for a significant portion of the society’s electric energy consumption. Furthermore, generating such electricity leads to the production of greenhouse gases. At the same time as the electricity is coming through our lamps inside our houses, an overflow of light is flowing down from the sky and hits the exterior of the same houses. At almost any day of the year, the daylight is superior in both the illumination level and quality compared to the artificial light we are using for our everyday tasks. A technology capable of collecting this abundant sunlight and distributing it, via optical fibers, into the interior of a building will be of great benefit. Sunlight is an abundant and infinite source of energy that is being underutilized in Qatar. The state’s climate is sunny most of the year, with temperatures ranging from 12°C to 48°C, and thus the solar source of energy is abundant. Therefore, it is of an economical benefit for the state to harvest and utilize this energy source in every way possible. In Qatar, a large part of electricity is used for indoor lighting during daytime, accounting for 10% of the total electric energy required for buildings. In many facilities, this percentage is even higher. For example, illumination in an office space of 400 m2 accounts for approximately 40% of the total energy consumption of the space. In fact, Qatar is recognized amongst the world’s largest consumers of energy per capita. According to the United Nations Statistic Division, relative to the size of Qatar’s economy, the country on a whole uses twice the amount of energy as the nations of Germany or Japan. As a partial remedy to reduce the consumption of electrical energy, Qatar can take advantage of its sunny climate, and thus it is possible to collect and focus sunlight on optic-fiber cables that transfer the light to indoor rooms, buildings and stores. In the present work, we wanted to cast some light on fiber optic daylighting and its potential use in a very sunny and relatively hot environment, such as that in Qatar. The main goal of this project was to explore the use of a lighting system based on fiber optics as the main light source.
Experimental Assessment and Thermal Performance of an Ammonia-Water Absorption Heat Pump
Authors: Ibrahim Talaat A.
Published: January 2011

In this paper, an experimental assessment and thermal performance of a prototype ammonia-water absorption heat pump are carried out. The experimentations are conducted for different operating conditions such as: filling up concentration (40 and 47%), inlet brine temperature (-5, +5 and +15 °C) and inlet cooling water temperature (20 [25], 30 and 40 °C). The effects of performance parameters like refrigerant vapor concentration leaving rectifier, mass fraction spread and specific solution circulation ratio are also investigated. The results are divided into two categories. The first one is an external analysis of the absorption system considering thermal loads and system performance. However, the second one represents the internal analysis of the heat pump taking into account the temperature glide and degree of subcooling. Little effect is found for the filling up concentration on the thermal loads for different heat pump components as well as the heating capacity and the coefficient of performance. The refrigerant vapor concentration of the refrigerant vapor should not be less than 0.999 to avoid the effect of temperature glides on the system performance. Temperatures of the cooling water, brine and generator all have large effects on the system performance as any sorption system. Inaccurate expansion valve control leads to lower heating COP. Controlling the mass fraction spread or the specific circulation ratio affects considerably thermal loads of different absorption system components. The control of these two parameters can be accomplished by controlling the solution pump and flow rates in the solution loops.
Impact of Different Charging Strategies of Electric Vehicles on the German Grid
Authors: Hartmann Niklas , O¨zdemir E. Doruk
Published: January 2011

In this paper the impact of different utilization scenarios of electric vehicles on the German grid is analyzed. Two different charging strategies are tested. Firstly the impact of unmanaged charging of electric vehicles on the national grid is simulated. Secondly charging and usage of the mobile storage in off-peak times is simulated. An important part of the simulation is to analyse the availability of electric vehicles. This part determines the percentage of vehicles, which can be plugged into the grid on hourly basis for all days of a typical week. The analysis of the availability of vehicles shows an overall high availability of plug-in electric passenger cars in Germany. A significant difference in the characteristics between weekdays, Saturdays and Sundays is evident. A high potential to use electric passenger cars for balancing the fluctuating renewable energy can be presumed, on the one hand due to the high availability of electric vehicles and on the other hand due to the large number of vehicles being plugged into the grid in the evening hours for which charging could be delayed into the night. In conclusion the simulation shows that with an unmanaged charging strategy the fluctuations of the demand increase above average assuming a rising number of electric vehicles introduced in Germany. If the whole vehicle fleet is substituted by electric vehicles, the national electricity consumption would increase only by about 18%. Concurrently the fluctuations of the national demand in Germany would almost double. However with an optimized charging strategy, a positive impact of the usage of the mobile storage on the national grid (reduction of fluctuations) can be recognized. Thereby the electric vehicles can be charged completely during the night, when the electricity consumption is low.
Optimized Preparation of Moringa Oleifera Methyl Esters Using Sulfated Tin Oxide as Heterogenous Catalyst
Authors: Kafuku Gerald , Mbarawa Makme , Lam Man Kee , Lee Keat Teong
Published: January 2011

Fatty acid methyl esters (biodiesel), prepared from transesterification of vegetable oils or animal fats, have gained great importance in substituting petroleum based diesel for combating environmental problems and higher diesel prices. Moringa oleifera fatty acids are among the newly investigated potentials for biodiesel production in recent years. In getting rid of soap formation and thus large waste washing water from biodiesel produced from homogenous catalysts, the use of heterogeneous catalysts is currently preferred due to easily separation and purification of the final products. In this study, biodiesel was produced from moringa oleifera oil using sulfated tin oxide enhanced with SiO2 (SO42−/SnO2−SiO2) as super acid solid catalyst. The experimental design was done using design of experiment (DoE), specifically, response surface methodology based on three-variable central composite design (CCD) with alpha (α) = 2. The reaction parameters in the optimization process were reaction temperature (60°C to 180°C), reaction period (1 to 3 hrs) and methanol to oil ratio (1:6 to 1:24 mol/mol). It was observed that the yield up to 84wt% of moringa oleifera methyl esters can be obtained with reaction conditions of 150°C temperature, 150 minutes reaction time and 1:19.5 methanol to oil ratio, while catalyst concentration and agitation speed are kept at 3wt% and 350 rpm respectively.
Experimental Investigation on Variation of FFA in Used Cooking Oil and Optimization of Conversion to Biodiesel
Authors: Chandrasekaran Sriraam Ramanathan , Avasarala Sumant , Jalal Fathima , Miranda Lima Rose , Paneerselvam Selva Ilavarasi
Published: January 2011

The world is currently dependant on fossil fuels as a fuel source for transportation and fuelling the industrial sector. The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of bio-diesel has made it more attractive in recent times. Many researches are being made to commercialize the production. However the cost of bio-diesel is the major obstacle to its commercialization in comparison to conventional diesel fuels. The objective of this paper is to produce biodiesel from Used cooking oil using a two stage process of acid and base catalyzed Transesterification reaction and optimizing the process variable such as Methanol to oil ratio, Catalyst to oil ratio, Reaction temperature and Reaction time as these process variable has adverse effect on the Transesterification reaction. The optimized parameters gave an yield of about 96%. Also an attempt had been made to examine the effect of temperature, moisture and storage time on the accumulation of free fatty acids in Used cooking oil. The results showed that the triacylglycerides was hydrolysed and the free fatty acid content was raised.
Energy Conservation Building Code in India: Status, Issues and Opportunities
Authors: Mathur Jyotirmay , Garg Vishal , Jangra Vijeta
Published: January 2011

The Energy Conservation Act 2001 was the first major initiative in India to channelize and catalyze energy efficiency improvement in various sectors of economy. The Bureau of Energy Efficiency was set up per the provision of this act, which in 2007 brought out Energy Conservation Building Code (ECBC) with an overall purpose of providing minimum requirements for the energy efficient design and construction of buildings. ECBC covers building envelope, heating, ventilation and air-conditioning system, interior and exterior lighting system, service hot water, electrical power and motors. Since the launch of this code in May 2007, efforts are being made to promote and facilitate the adoption of this code through several training and capacity building programs. A program committee has been set to take care of the comments from stakeholders and inconsistencies, due to which revision of the code was brought out in May 2008. Currently the code is voluntary in the initial phase, but it is designed to be mandatory in future. One major feature of the code is that implementation is left under the scope of State and local governments. During the capacity building effort, a need was felt to provide additional guidance to design and construction professionals on the rationale behind the ECBC specifications and provide explanations to the key terms and concepts. The ECBC User Guide was therefore developed and released in July 2009 for this purpose. This paper describes the current status, experiences during capacity building and market transformation required for successful implementation of this code. It also covers commentary on how various stakeholders are contributing towards one common goal in different ways. With successful implementation, the code is expected to reduce the energy consumption of the upcoming new buildings by 20–40% from their average performance level at the time of launch of ECBC. Having this huge potential of energy saving, there is an urgent need to address the problems and issues for early adoption of the energy conservation building code in the country.
EnergyPlus Simulation Speedup Using Data Parallelization Concept
Authors: Garg Vishal , Chandrasen Kshitij , Tetali Surekha , Mathur Jyotirmay
Published: January 2011

EnergyPlus is an energy simulation tool which models heating, cooling, lighting, ventilation, and other energy flows in buildings. It is based on the popular features of BLAST and DOE-2. Though EnergyPlus is more advanced than DOE-2, it comes with a drawback of larger simulation runtime. A decrease in the simulation runtime of EnergyPlus would increase the usability of the software. In this paper, a concept has been proposed which uses data parallelization to speed up EnergyPlus simulation. Data parallelization is a form of parallelization for computing across multiple processors or multiple computers in a cluster, run under a suitable environment. Data parallelism focuses on distributing the data across different parallel computing nodes by breaking it into smaller chunks, each of which is processed on by the same function, running in parallel on different cores/machines. In the proposed concept, this is achieved by breaking a simulation with annual RunPeriod into several simulations of smaller RunPeriod, each handled by a separate computer. Each computer instead of running an annual simulation, handles a chunk of smaller RunPeriod, say one month, thus taking lesser time. This paper discusses the concept and presents the results of the preliminary investigations. It has been observed that a speed gain of approximately 6.8 times can be achieved by this method.
Experimental Studies on a DI Diesel Engine Using Tire Pyrolysis Oil Diethyl Ether Blends
Authors: Murugan S. , Nagarajan G.
Published: January 2011

Many alternative fuels have been introduced in the fuel market in the recent years. But, still there is a lot of research work going on around the world in the conversion of waste substances into useful energy. Some of the researchers show a remarkable interest in using pyrolysis oil as an alternative fuel for diesel engines. Tire pyrolysis oil (TPO) from waste automobile tires has been found to be an energy source. It could be blended with diesel fuel and used as an alternative fuel for diesel engines. But, it cannot be used as the sole fuel in diesel engines due to its poor ignition quality. Diethyl ether (DEE) is a good ignition improver having a cetane number of more than 125. In the present investigation, two different blends of Tire pyrolysis oil and DEE (with addition of DEE at 0.5 and 1%) were used in a single cylinder four stroke water cooled direct injection diesel engine developing a rated power of 3.7 kW at 1500 rpm. The engine was able to run with 100% Tire pyrolysis oil with a maximum DEE addition of 1%. Results indicated that nitric oxide emission reduced by about 4% with an 8% increase in smoke emission at full load when the engine was fueled with TPO and 1% of DEE compared to that of diesel fuel operation. The brake thermal efficiency of the engine fueled with TPO-DEE blends was found to be lesser than that of diesel operation at full load. Brake specific energy consumption was also found to be higher with TPO DEE blends compared to that of diesel fuel operation. The results of the performance and emissions of the DI diesel engine are presented in this paper.
Finite-Time Consensus in Undirected/Directed Network Topologies
Authors: Doostmohammadian Mohammad Reza , Sayyaadi Hassan
Published: January 2011

The main contribution of this paper is to introduce a novel non-Lipschitz protocol that guarantees consensus in finite-time domain. Its convergence in networks with both unidirectional and bidirectional links is investigated via Lyapunov Theorem approach. It is also proved that final agreement value is equal to average of agents’ states for the bidirectional communication case. In addition effects of communication time-delay on stability are assessed and two other continuous Lipschitz protocols are also analyzed.
Deployment of Multi-Agent Robotic Systems in Presence of Obstacles
Authors: Soltani Ali , Sayyaadi Hassan
Published: January 2011

The deployment of multi-agent systems in presence of obstacle deals with autonomous motion of agents toward a specified target by sensing each other and boundaries of obstacles. In this paper, asynchronous, scalable, distributed algorithm is used to deploy agents. Boundaries of obstacles are modeled by virtual agents. Algorithm was implemented by solving continuous n-median problem called generalized Fermat-Weber problem. It is shown that deployment is performed when position of real agents are the geometric median of their Voronoi cells. Simulation results show the validity of the proposed algorithm very well.
Design Optimization of Gimbal Robotic Joints Based on Task Space Manipulability
Authors: Mohammadi Foad , Hemmatian Iman , Osgouie Kambiz Ghaemi
Published: January 2011

Featuring a nonlinear novel design, Gimbal transmission, is a replacement for traditional robotic joints like gearboxes and revolute joints. This mechanism is one of the most recent types of nonlinear direct transmission (DT) methods in robots. As an alternative for traditional drive methodologies — herein called direct drive transmission (DD) methods, DT provides dynamic coupling and joint interaction attenuation while its capability to be adjusted for a desired task space point, smooth input-output characteristic, and varying reduction ratio lead to a desired force and motion behavior for the whole manipulator. In this paper, design optimization of a gimbal mechanism used as a replacement of simple robotic revolute joints is investigated. Kinetostatic model of the robotic arm is made and based on Manipulability Ellipsoid analysis the amount of force at the tip of the manipulator is maximized and compared with the same quantity for a simple manipulator. The best design variables are found using Genetic Algorithm and it is shown that this replacement leads to greater forces at the tip of the manipulator in that desired direction.
Effect of Geometrical and Loading Parameters on Fatigue Crack Growth of Stainless Steel 316L
Authors: Benachour Mustapha , Hadjoui Abdelhamid , Benachour Nadjia
Published: January 2011

For their high mechanical characteristic (capacity resistance, hardness and impact resistance), the stainless steels remain not easily replaceable materials. This material can be used in significant fields such as the nuclear power, the storage of the chemical products. This work presents fatigue crack growth of austenitic stainless steel 316L at constant amplitude loading. The double through crack at hole specimen is used where the influence of dimension of hole, maximum amplitude loading and stress ratio are studied. The Nasgro model was used to prevent the fatigue crack growth. The effect of the stress ratio is highlighted, where one notices a shift of the curves of crack growth. The increasing of dimension of hole and the maximum amplitude loading decrease the fatigue life. Different situations permit to select the optimized hole.