Department of Mechanical engineering

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    A designer workbench with real-time capture and reuse of information on product evolution and rationale
    (ICED, 2005) Kota, Srinivas
    Product Life Cycle Management promises management of all intellectual assets generated for all life cycle phases of a product [1]. This includes supporting capture and structure of information generated about an evolving product during the PD process [1]. Many structures for product information [3, 4, 5, 6] and rationale information [7, 8] have been suggested, and some turned into a tool, e.g. [7, 8]. However, a practical tool for automated capture and structure of product information including rationale information without interrupting the working of the designer, especially as a product evolves through the PD process, is yet to be developed. The framework reported here has been developed by analysing the proceedings from design experiments and literature to capture, segregate and store the information generated in product design without interrupting designer. The main features of the framework are implemented into the preliminary version of a software tool and evaluated for the ease of use and reuse for designers and re-designers (re-users of rationale). The main functions currently supported are: creation and modification of a three-dimensional assembly, exploring the details of a version tree and product structure, and, exploring the events via video/audio clips attached to the version tree.
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    Use of dfe methodologies and tools - Major barriers and challenges
    (ICED, 2007) Kota, Srinivas
    Products make substantial impact on environment. Product to waste mass generated through out the product lifecycle can be as high as 1:20. Design for Environment (DfE) is an approach to design where all the environmental impacts of a product are considered over the entire life cycle of a product. Early stages of product development are the key for this because if we know the environmental impacts of potential designs while designing, we can make changes to these designs then and there so as to reduce their environmental impacts [1, 2]. However, unlike cost and performance, use of environmental criteria and DfE is far from part of mainstream designing [3]. Most DfE tools are conceptual in nature, and there is very little adoption of these in industry. Methods like [4] are useful for specific phases of the lifecycle of a product. However, during product development there is a need to consider the whole lifecycle rather than a single phase of the product
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    Product development platform for real-time capture and reuse of evolving product information
    (Inder Science, 2007-12) Kota, Srinivas
    Product life cycle management promises management of all intellectual assets generated for all life cycle stages of a product. In engineering, over 75% of design activity comprises case-based design ? reuse of previous design knowledge to address a new design problem. This means that rationale capture and reuse are critical in design and redesign projects. The goal of this paper is to report empirical study of designing carried out to understand the needs and constraints for design rationale capture, and to detail the concept, implementation and preliminary evaluation of an unobtrusive, real-time design rationale capture framework.
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    Development of a platform for supporting design for environment
    (ICED, 2007) Kota, Srinivas
    Individual guidelines often exist for DfE but these are not integrated with design tools. There is no comprehensive method that can be useful for the whole life cycle of a product in various stages of its design. Few tools exist that could aid iterative changes to a design required in product development and there is a need for an integrated methodology and computational support for designers. Life Cycle Assessment (LCA) [1] is arguably the most promising and scientifically defendable method for estimating environmental impacts of a product during its lifecycle [2]. Like DfE guidelines, LCA tools are not well integrated with design process and tools. Consequently, there is a need for an LCA tool integrated into the natural design process that can be applied to early as well as detailed design stages
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    Development of a method for estimating uncertainty in evaluation of environmental impacts during design
    (ICED, 2007-08) Kota, Srinivas
    Life Cycle Assessment (LCA) is currently the most promising and scientifically defendable technique for estimating environmental impacts of a product during its lifecycle. Currently, detailed LCA is critically dependent on high volumes of product specific data, time consuming, often unaffordable and used in the detailed stages of design. Current approximate LCA methods are either incomplete, inaccurate or require prior knowledge of what data is important. There is substantial uncertainty involved in the environmental impact calculations in LCA. Literature suggests that impact estimation results must be accompanied by an estimation of its uncertainty or imprecision, without which the decisions taken could be misleading. During development of a product, there is often a lack of accurate information about its structure, lifecycle stages, and related environmental impact information. As information about the product lifecycle continues to evolve during development, the assessment method should be such that it incorporates the different levels of abstraction about product information. A key result to be presented in this paper is a preliminary method developed using interval algebra and probabilistic theory taking product structure and lifecycle uncertainties into account. This method helps in estimating impact values of a product proposal in the earlier stages of design by providing an uncertainty value in terms of confidence on the result calculated, with the intention of supporting design decision making
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    A method for evaluation of product lifecycle alternatives under uncertainty
    (ICED, 2009) Kota, Srinivas
    In each stage of product development, we need to take decisions, by evaluating multiple product alternatives based on multiple criteria. Classical evaluation methods like weighted objectives method assumes certainty about information available during product development. However, designers often must evaluate under uncertainty. Often the likely performance, cost or environmental impacts of a product proposal could be estimated only with certain confidence, which may vary from one proposal to another. In such situations, the classical approaches to evaluation can give misleading results. There is a need for a method that can aid in decision making by supporting quantitative comparison of alternatives to identify the most promising alternative, under uncertain information about the alternatives. A method called confidence weighted objectives method is developed to compare the whole life cycle of product proposals using multiple evaluation criteria under various levels of uncertainty with non crisp values. It estimates the overall worth of proposal and confidence on the estimate, enabling deferment of decision making when decisions cannot be made using current information available.
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    Improving IAQ and energy efficiency for buildings using vav air conditioning system based on fuzzy logic
    (AIVC, 2007) Parameshwaran, R.
    In recent years, in the quest focused about energy conservative building design, as a high efficiencyair conditioning scheme, the variable air volume (VAV) systems owe their growing popularity in heating,ventilation and air conditioning (HVAC) applications. This paper reports the simulation study toinvestigate the inherent operational characteristics of direct expansion (DX) VAV air conditioning (A/C)unit when the supply air fan and compressor speeds are varied based on the thermal load persisting inthe conditioned space. Based on the Matlab-Simulink environment, a new fuzzy based simulationmodel of the DX VAV system has been developed and the energy utilization of the air conditioningsystem is investigated by incorporating the concept of combined economizer cycle (EC) and demandcontrolled ventilation (DCV) techniques into the simulated model. Indoor air quality (IAQ) is addressedunder DCV and combined DCV-EC modes of ventilation. Simulation results obtained for the DX VAVA/C system are compared with the conventional constant air volume (CAV) system. The results inferthat the fuzzy control methodology and algorithm developed are feasible with a proper control of IAQbeing achieved. Variation of refrigerant mass flow rate corresponding to the variation of supply air flowrate is also investigated.
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    Experimental Analysis of Energy Efficient Building Air Conditioning System Using Fuzzy Logic Controller
    (AIT, 2009-06) Parameshwaran, R.
    The present work is focused on investigating the thermal comfort and indoor air quality (IAQ) in buildings through the use of energy efficient air conditioning (A/C) system. In this context, a combined variable air volume (VAV) and variable refrigerant volume (VRV) system is developed and tested with different ventilation strategies for summer and winter design conditions. The proposed system is controlled by the intelligent fuzzy logic controller that enhanced the overall system performance. The proposed system is tested under fixed ventilation, demand controlled ventilation (DCV) and combined DCV and economizer cycle (EC) ventilation that ensured better indoor thermal comfort and IAQ without compromising on the energy efficiency. The test results infer that the proposed air conditioning system controlled by fuzzy logic methodology yield a maximum of 34% and 52% of per day energy savings in summer and winter design conditions respectively. The test results for each technique in terms of thermal comfort, IAQ and energy savings potential are presented.
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    Efficient Variable Air Volume Air Conditioning System Based on Fuzzy Logic Control for Buildings
    (STA, 2009-03) Parameshwaran, R.
    A variable air volume (VAV) system is highly preferred to be an energy efficient airconditioning scheme in modern heating, ventilation and air conditioning (HVAC)applications. Based on the energy consumption characteristics, VAV systems are fastreplacing constant air volume (CAV) systems and are capable of maintaining the thermalcomfort for varying load conditions. Fuzzy logic controllers (FLC) are highly preferred ratherthan conventional controllers since FLC exhibits reduced peak overshoot that is observedunder transient conditions of the system. FLC has the capability of controlling the systemprecisely with the set points defined. This paper describes the thermal comfort and energyconservation potential of the VAV system utilizing a fuzzy logic controller (FLC) thatenhances the system performance substantially. A simple VAV building model wasdeveloped and the energy utilization of the VAV system has been experimentallyinvestigated. Input data for fuzzy logic are zone temperature and duct static pressure and theoutput is supply air fan speed. Experimental results show that the energy saving potential ofthe VAV system was 27% at part load conditions, compared with the CAV system.Experimental results express that the required thermal comfort was achieved using FLC.
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    Optimization of energy conservation potential for VAV air conditioning system using fuzzy based genetic algorithm
    (World Academy of Science, Engineering and Technology, 2008) Parameshwaran, R.
    The objective of this study is to present the test results of variable air volume (VAV) air conditioning system optimized by two objective genetic algorithm (GA). The objective functions are energy savings and thermal comfort. The optimal set points for fuzzy logic controller (FLC) are the supply air temperature (T s ), the supply duct static pressure (P s ), the chilled water temperature (T w ), and zone temperature (T z ) that is taken as the problem variables. Supply airflow rate and chilled water flow rate are considered to be the constraints. The optimal set point values are obtained from GA process and assigned into fuzzy logic controller (FLC) in order to conserve energy and maintain thermal comfort in real time VAV air conditioning system. A VAV air conditioning system with FLC installed in a software laboratory has been taken for the purpose of energy analysis. The total energy saving obtained in VAV GA optimization system with FLC compared with constant air volume (CAV) system is expected to achieve 31.5%. The optimal duct static pressure obtained through Genetic fuzzy methodology attributes to better air distribution by delivering the optimal quantity of supply air to the conditioned space. This combination enhanced the advantages of uniform air distribution, thermal comfort and improved energy savings potential