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  • Article
    Citation - WoS: 89
    Citation - Scopus: 99
    Optimization of Electric Vehicle Recharge Schedule and Routing Problem With Time Windows and Partial Recharge: a Comparative Study for an Urban Logistics Fleet
    (Elsevier, 2021) Bac, Ugur; Baç, Uğur; Erdem, Mehmet; Erdem, Mehmet; Baç, Uğur; Erdem, Mehmet; Industrial Engineering; Industrial Engineering
    The use of electric vehicles (EVs) is becoming more and more widespread and the interest in these vehicles is increasing each day. EVs promise to emit less air pollution and greenhouse gas (GHG) emissions with lower operational costs when compared to fossil fuel-powered vehicles. However, many factors such as the limited mileage of these vehicles, long recharging times, and the sparseness of available recharging stations adversely affect the preferability of EVs in industrial and commercial logistics. Effective planning of EV routes and recharge schedules is vital for the future of the logistics sector. This paper proposes an electric vehicle routing problem with the time windows (EVRPTW) framework, which is an extension of the well-known vehicle routing problem (VRP). In the proposed model, partial recharging is considered for the EVRPTW with the multiple depots and heterogeneous EV fleet and multiple visits to customers. While routing a set of heterogeneous EVs, their limited ranges, interdependent on the battery capacity, should be taken into consideration and all the customers' deliveries should be completed within the predetermined time windows. To deal with this problem, a series of neighbourhood operators are developed for the local search process in the variable neighbourhood search (VNS) and variable neighbourhood descent (VND) heuristics. The proposed solution algorithms are tested in large-scale instances. Results indicate that the proposed heuristics perform well as to this problem in terms of optimizing recharging times, idle waiting times, overtime of operators, compliance with time windows, number of vehicles, depots, and charging stations used.
  • Article
    Citation - WoS: 48
    Citation - Scopus: 52
    A Comprehensive Evaluation of the Most Suitable Hvac System for an Industrial Building by Using a Hybrid Building Energy Simulation and Multi Criteria Decision Making Framework
    (Elsevier, 2021) Bac, Ugur; Alaloosi, Khalid Abdulwahab Mohamed Saed; Turhan, Cihan
    Great demand for energy and growing trend in the use of energy-efficient HVAC systems force researchers to focus on the importance of choosing the most appropriate HVAC system for industrial buildings during design process. Therefore, developing a model to select the most suitable HVAC system is vital for industrial buildings. To this aim, this study provides a comprehensive evaluation of different HVAC systems for an industrial building by using hybrid multi criteria decision making (MCDM) method. An industrial building in Ankara/Turkey is selected as a case building. Eleven HVAC systems are evaluated based on twenty seven criteria, which are determined as a result of extensive literature research, and are grouped under six categories including ergonomic, environmental, reliability, technical, and economical aspects. A hybrid application of building energy simulation (BES) integrated modified Stepwise Weight Assessment Ratio Analysis (SWARA) and Weighted Additive Sum Product Assessment (WASPAS) framework is developed for supporting the decision making process. The novelty of the study is integrating the objective results of a well-calibrated dynamic BES tool with subjective criteria which are collected from expert opinions by applying questionnaires with face-to-face interview method. The results of MCDM framework and sensitivity analysis showed that the water-source heat pump is the best and suitable alternative for the industrial building. The outcome of this study would benefit the HVAC engineers and specialists in order to design the best HVAC systems in industrial buildings while providing an insight into different criteria. Moreover, key contribution to the literature is the usage of hybrid MCDM framework integrated with BES tool in the building sector.