Browsing by Author "Dalvi, Akshay S."

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    Integrated System Architecture Development Framework and Complexity Assessment
    (ASME, 2021-11-01) Dalvi, Akshay S.; El-Mounayri, Hazim; Mechanical and Energy Engineering, School of Engineering and Technology
    Systems engineering is the popular top-down systematic approach to understand and develop complex systems. There is a gap between the systems engineering activities and engineering analysis in major system development processes. This paper presents an integrated MBSE development framework with definite and indefinite modeling capabilities to bridge this gap. The framework uses SysML, a system modeling language, to describe its elements from the system architecture’s perspective. A detailed workflow is presented that guides the engineer throughout the modeling process. The workflow establishes traceability throughout the framework. This research uses Functional Mock-up Interface (FMI) standards to integrate system engineering activities and engineering analysis. A district cooling system case study is presented to demonstrate the framework’s capabilities in enabling the system into existence. The system architecture model was developed using SysML language in the Cameo Enterprise Architecture environment. The engineering analysis model used object-oriented Modelica language in the Dymola environment. The analysis results show that the district chiller model developed using Modelica produces chilled water below 6.6 degrees Celsius, satisfying the district chiller’s system requirement. The exponential trend in the system architecture’s complexity pattern is measured and analyzed using complexity assessment techniques. The results show that the structural complexity of the system increases steadily from 2.7080 to 8.1241. However, the behavioral complexity increases drastically from 1.7915 to 59.2686 in the problem domain.
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    Integrated System Model of District Cooling for Energy Consumption Optimization
    (ECOS, 2020-11) Dalvi, Akshay S.; Razban, Ali; El-Mounayri, Hazim; El-Mekkawy, Tarek; Promyoo, Rapeepan; Mechanical and Energy Engineering, School of Engineering and Technology
    The successful modeling of a multi-plant district cooling (DC) system presents several challenges in integrating system level requirements with engineering analysis for verification and optimization. Currently, the ability to predict the behavior and performance parameters such as chilled water temperature difference, annual energy consumption, and central chiller plant coefficient of performance (COP) of the dynamic system is limited. Effective modeling and efficient simulation are required when it comes to complex physical systems. This paper presents an integrated model that combines system architecture with physical modeling to represent and simulate a multi-plant district cooling system (DCS). We refer to this model as model-based systems engineering (MBSE) model of the DC system. A systems modeling language (SysML) model is created to develop a multi-domain architecture of the DC system that will satisfy stakeholder needs and requirements. This model is capable of executing behavior and parametric aspects (or “views”) of the system. A closed-loop of information flow was developed to map SysML constructs with their respective Modelica models to support the integration of simulated experiments with SysML construct. The integrated MBSE model is successfully implemented and the results show that the IPLV.SI value of the chiller model was 6.4157, which is in the acceptable range. Based on the initial conditions provided by the actual plant, the simulation results show that the chilled water temperature predictions by Modelica as 4.8℃ verify the corresponding stakeholders’ requirements captured in the SysML model.