On Designing for Enhanced Product Sustainability by Considering the Induced Residual Stresses in Machining Operations

For improving product sustainability, a number of measures can be adopted during the product design stage for manufacturing. The modeling and control of the residual stresses and surface roughness generated by machining are among the major measures which have been shown to demonstrate the strongest influence on the machined component’s performance during its service life. The proper control of the residual stresses would provide increased product lifetime, reduced part distortion, reduced weight and reduced and less frequent maintenance and inspection of the product while maintaining the same safety level, or perhaps even improving it. This paper presents an analysis of the influence of machining parameters on the residual stresses generated in machining operations. This analysis was performed on several work materials, including carbon steels, stainless steels, Inconel alloys and tool steels. This allows developing a number of feasible means to control the residual stresses during manufacturing.

Eco-Design Value Alignment: Keys to Success

This article analyzes the eco-design challenges in the 21st century. In a world of globalization and outsourcing, environmental legislation became a main driver for doing eco-design. Eco-innovation and green money are concepts to create marketing advantages and differentiation from their competitors, transforming a legislative handicap into financial benefits and societal recognition. This paper introduces Life cycle Environmental Value Chain Analysis (LC-EVCA) and Environmental Worth Analysis (EWA) to identify the stake-holders implementing environmental improvement programs and the value relationships among them. Life cycle information and societal concerns are the keys to success for the eco-design value alignment. Philips environmental programs and a brief example illustrate how eco-design can be integrated into product development, and how both customer (society) and producers find themselves in a win-win situation.

Simulation of a Biodiesel Continuous Production Process Using HYSYS®

Elements of Chemical Process Engineering were used in this research to design and simulate two continuous transesterification processes for the production of biodiesel from palm oil, using the chemical simulator, HYSYS®. This design specified the operating conditions of all the equipment required for the continuous production of biodiesel using ethanol and methanol as alcohols. The palm oil was modeled as a mixture of the triglycerides that compose it in greater proportion, estimating the chemical properties of the substances that take part in the transesterification reaction, with group contributions and group interactions theories. Finally, the quality specifications for biodiesel obtained in both simulations were analyzed to verify the fulfillment of the properties required by ASTM (American Society for Testing and Materials) and EN (European Norms) standards.

Experimental and Computational Study of Vaporization of Volatile Organic Compounds

Heated Soil Vapor Extraction (HSVE) is a technology that has been used successfully to clean up subsurface soils at sites containing chlorinated solvents and petroleum hydrocarbons. The costs have been extremely high due to the large amount of energy required to volatilize high molecular weight polycyclic aromatic hydrocarbon (PAH) compounds present in the soil matrix. One remediation contractor states that hydrocarbons are oxidized in situ by achieving temperatures in the >1000 F range near the heaters [1]. A critical question is whether the volatile portion of manufactured gas plant (MGP) hydrocarbons (VOCs) can be stripped out at lower temperatures such that the remaining contaminants will be unavailable for transport or subsequent dissolution into the groundwater. Soil remediation by heated soil vapor extraction system is a relatively new technology developed at the University of Wisconsin-Milwaukee [2]. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. The process developed at UWM, consists of a heater/boiler that pump and circulates hot oil through a pipeline that is enclosed in a larger-diameter pipe. This extraction pipe is vertically installed within the contaminated soil up to a certain depth and is welded at the bottom and capped at the top. The number of heat source pipes and the extraction wells depends on the type of soil, the type of pollutants, moisture content of the soil and the size of the area to be cleaned. The heat source heats the soil, which is transported in the interior part of the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then driven out of the soil by the extraction well. The extraction well consists of the blower which would suck the vaporized gases out of the system. Our previous studies had removed higher boiling compounds such as naphthalene, etc., to non-detectable level. Thus, the current technology is very promising for removing most of the chemicals compounds; and can also remove these high boiling compounds from the saturated zone. Gas chromatography (GC) is utilized in monitoring the relative concentration changes over the extraction period. Gas chromatography-mass spectrometry (GCMS) assists in the identification and separation of extracted components. The experimental research is currently being conducted at the University of Wisconsin-Milwaukee. The objectives of this study are to identify contaminants and time required to remove them through HSVE treatment and provide data for computation fluid dynamics CFD analysis.

Performance of Transition Metal Ions Exchanged Zeolite 13X in Greenhouse Gas Reduction

This study investigated the performance of multi-transition metal (Cu, Cr, Ni and Co) ions exchanged zeolite 13X catalysts on methane emission abatement, especially at methane level of the exhaust from natural gas fueled vehicles. Catalytic activity of methane combustion using multi-ions exchanged catalyst was studied under different parameters: mole % of metal loading, inlet velocity and inlet methane concentration at atmospheric pressure and 500 °C. Performance of the catalysts was investigated and explained in terms of the apparent activation energy, number of active sites and BET surface area of the catalyst. This study showed that the multi-ions exchanged catalyst outperformed the single-ions exchanged and the acidified 13X catalysts. Lengthening the residence time could also lead to higher methane conversion %. Catalytic activity of the catalysts was influenced by the mole % of metal loading which played important roles in affecting the apparent activation energy of methane combustion, active sites and also the BET surface area of the catalyst. Increasing mole % of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. In view of these, there existed an optimized mole % of metal loading where the highest catalytic activity was observed.

Emerging Energy Development Demands on Water

Currently, electric power generation is one of the largest water withdrawal and use sectors in the U.S. Additionally, future energy development such as biofuels production, hydrogen fuel or synthetic fuels production, oil shale development, carbon sequestration, or nuclear power development could significantly increase water use and consumption. On the other hand, water resource development — distribution, treatment, and transmission — is one of the largest energy use sectors. As future demands for energy and water continue to increase, competition for water between the energy, domestic, agricultural, and industrial sectors, could significantly impact the availability of water supplies for energy development, thus impacting reliability and security of future energy production and electric power generation. Therefore, it is critical that water and energy resources planning and development be integrated and coordinated across state and regional boundaries. This paper provides a short overview of the emerging energy-water challenges and issues identified in a recent series of national workshops on energy and water related issues as well as summarizing the research and development needs to address these emerging energy and water challenges.

Analysis to Develop Hydrogen Production From Bio-Oils

The United States economy’s dependence on fossil fuels has historical significance but lacks vision for a long-lasting fuel consumption policy. Political complications, economic instabilities, supply shortages, and continued pollution contributions pose significant obstacles to continued reliance on oil. Alternative technologies based on renewable resources offer much more promise for a sustainable approach to meeting global energy needs. Recent research and applications have established hydrogen as a viable clean fuel source. Those applications, including fuel cells, have shown promise for the eventual migration from a fossil-fuel economy to one based on renewable energy sources. Air pollution, specifically contributions to greenhouse gases, is a major environmental hazard due to the use of fossil fuel-related hydrocarbons for fuel and industrial applications. An alternative, hydrogen, offers significant advantages as an ultra-clean fuel of the future when it is burned directly or processed through fuel cells. Currently, the main process for hydrogen production is catalytic steam reforming of natural gas. This process is relatively inefficient and does not allow the use of a wide range of feedstock materials including renewable sources. The objective of impending research is to develop this new, ultra-clean and efficient process, which converts a wide range of hydrocarbons, including renewable bio-oils, into pure hydrogen suitable for fuel cells and which also converts CO2 emission into syngas. The main impact is clearly on air pollution and global warming through the minimization of greenhouse gas emission and the economical production of pure hydrogen to foster the hydrogen economy. This new process will achieve considerable increase in hydrogen productivity and considerable decrease in the energy consumed to produce it. The technology will center on a circulating fluidized bed (CFB) that will separate hydrogen from bio-oils in an efficient process that greatly reduces polluting hydrocarbons compared to traditional fossil fuel processing. Early studies will include the mathematical modeling of computational fluid dynamics to identify process parameters. Eventually, a pilot plant will be used to verify/modify the mathematical model, for a wide range of conditions and renewable feedstocks. Testing the pilot plant will lead to the development of reliable design equations suitable for replication, build, and tight control of this novel process.

Design and Performance of a Fuel Cell Plant Heat Recovery System

A 1 MW Direct Fuel Cell® (DFC) power plant began operation at California State University, Northridge (CSUN) in January, 2007. This plant is currently the largest fuel cell plant in the world operating on a university campus. The plant consists of four 250 kW DFC300MA™ fuel cell units purchased from FuelCell Energy, Inc., and a waste heat recovery system which produces dual heating hot water loops for campus building ventilation heating, and domestic water and swimming pool heating water for the University Student Union (USU). The waste heat recovery system was designed by CSUN’s Physical Plant Management and engineering student staff personnel to accommodate the operating conditions required by the four individual fuel cell units as well as the thermal energy needs of the campus. A Barometric Thermal Trap (BaTT) was designed to mix the four fuel cell exhaust streams prior to flowing through a two stage heat exchanger unit. The BaTT is required to maintain an appropriate exhaust back pressure at the individual fuel cell units under a variety of operating conditions and without reliance on mechanical systems for control. The two stage heat exchanger uses separate coils for recovering sensible and latent heat in the exhaust stream. The sensible heat is used for heating water for the campus’ hot water system. The latent heat represents a significant amount of energy because of the high steam content in the fuel cell exhaust, although it is available at a lower temperature. CSUN’s design is able to make effective use of the latent heat because of the need for swimming pool heating and hot water for showers in an adjacent recreational facility at the USU. Design calculations indicate that a Combined Heat and Power efficiency of 74% is possible. This paper discusses the integration of the fuel cell plant into the campus’ energy systems, and presents preliminary operational data for the performance of the heat recovery system.

Preliminary Mechanical Analysis for Novel Woven/Wound Composite Axial-Compressor

This paper introduces an impeller design for a turbo compressor based on a novel composite material winding technology. The main objective is to develop a high performance impeller, which can be economically produced for refrigeration plants using water as a refrigerant (R718) even below 300 kW (100 ton) capacity. Water as a refrigerant can provide a very high coefficient of performance, while it is environmentally inert and hence preferred. The impeller is required to be able to handle large volume flows and also withstand high stresses due to high speed rotation for high compression ratios. Here, an impeller suitable for a counter rotating axial or mixed flow impeller is presented. Carbon Fiber Reinforced Polymer (CFRP) is chosen as the material as it has light weight and also high strength. Finite element modeling is performed in order to check the impeller designs for failure. It is found that the impeller is able to sustain high rotational stresses using CFRP material. The manufacturing process of the impeller consists of winding endless fibers of CRFP on a commercially available winder suitable for CAD/CAM integration. With this design, also the motor and the bearings can be integrated with the impeller. Further, the interweaving of electrical components enables shaftless designs. This in turn allows for implementing conveniently multiple counter rotating impellers in axial and mixed flow configurations. Consequently this promises to considerably reduce overall costs of production of such high-performance impellers that even have an outer shroud as inherent element of the design.

Frost Growth CFD Model of an Integrated Active Desiccant Rooftop Unit

A frost growth model is incorporated into a Computational Fluid Dynamics (CFD) simulation of a heat pump by means of a user-defined function in a commercial CFD code. The transient model is applied to the outdoor section of an Integrated Active Desiccant Rooftop (IADR) unit in heating mode. IADR is a hybrid vapor compression and active desiccant unit capable of handling 100% outdoor air (dedicated outdoor air system) or as a total conditioning system, handling both outdoor air and space cooling or heating loads. The predicted increase in flow resistance and loss in heat transfer capacity due to frost build-up are compared to experimental pressure drop readings and thermal imaging. The purpose of this work is to develop a CFD model that is capable of predicting frost growth, a potentially valuable tool in evaluating the effectiveness of defrost-on-demand cycles.