Dynamic Modeling, Simulation, and Control of Transportation HVAC Systems PDF Download

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Languages : en
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Author: Almahdi T M. Abdo-Allah
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Languages : en
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Energy and cost-efficient management of a building's thermal properties requires heating, ventilation and air conditioning (HVAC) systems controllers to be working at optimal settings. However, many HVAC systems employ nonlinear time variances to deal with issues that affect the system's optimal operation. The present work considers an HVAC system at Memorial University's S. J. Carew Building which has been mathematically modeled using a state space multi-input and multi-output system (MIMO) approach for analyses and control system design. An IDA-ICE (Indoor Climate and Energy) simulation program has been applied for modeling the building, note that the four-story Carew Building includes an air-handling unit (AHU) on every floor. Compared with real data for one year's (2016) power consumption, the simulated annual power consumption for the building shows good agreement. Based on that data, two scenarios are applied for building the system models. Scenario 1 considers the HVAC system as a single unit with energy consumption (kWh) as inputs and zonal temperature and CO2 concentrations as outputs. By employing the MATLAB system identification toolbox, a MIMO-based system forms the basis for a state space model. In the model for Scenario 1, there are eight main AHU inputs (hot water power usage and power usage) and eight main outputs (return airflow temperature and CO2 levels). The state feedback controller obtains good results for both responses rise time and stability. In Scenario 2, there are four AHUs in total. Each of this scenario's AHUs features three main inputs (hot water, internal-to-internal air flow, and external-to-internal air flow) and three main outputs (static air pressure, CO2 levels, and temperature). In the first AHU (AHU1), we apply state-of-the-art fuzzy logic controllers (FLCs) to control fan speeds, CO2 concentrations, and temperature in the building in accordance with the flow rates for air and hot water. This strategy represents a novel approach for adapting FLCs by modifying fuzzy rule using the Simulink. The modified system shows improved levels of thermal comfort. The final part of the work presents the design for a supervisor fuzzy logic controller (SFLC) that can be applied to the entire S. J. Carew Building HVAC control. This SFLC features 24 inputs and 12 outputs and employs a state-space model that considers each AHU as an individual system. The SFLC detailed design and system simulation results are presented in this thesis.

Author: Liujia Dong
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Category : Air source heat pump systems
Languages : en
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Building heating ventilation and air conditioning (HVAC) systems have significant impact on the energy consumption of residential and commercial buildings. The Variable Refrigerant Flow (VRF) systems, by distributing refrigerant instead of air flow, have emerged as an appealing class of HVAC system that features quieter operation, higher flexibility, and lower cost of installation and maintenance. However, such systems also present higher challenges for controls that can realize its achievable performance. This dissertation research proposes to investigate the dynamic simulation modeling and modelfree control strategies for energy efficient operation of VRF systems with single or multiple outdoor units (ODUs) under fluctuating and uncertain load and ambient conditions. Modelica based dynamic simulation models are developed for VRF systems of different configurations, which involve modeling of indoor units (IDUs), ODUs, and various control valves for thermal regulation. Motivated by a preliminary study on applying multi-variable extremum seeking control (ESC) for an air-source heat pump (ASHP) system, a model-free self-optimizing control strategy is investigated for efficient operation of a multi-functional VRF system under both heat pump modes and heat recovery modes. With the feedback of the total power only, the multi-variable ESC takes different combinations of manipulated inputs, including IDU superheat setpoints, compressor pressure setpoints, ODU fan speed, and ODU superheat setpoint. Input selection is carried out based on their respective impact on the total power. To realize automatic and smooth switching between different operation modes of multi-functional VRF system, the mode switching strategy is proposed. Whether to turn on or off an IDU is determined by the zone temperature and a preset hysteresis band about the temperature setpoint. Based on the thermodynamic analysis, a decision variable for determining the mode of ODU heat exchanger (HX) is proposed as the ODU-HX air-side temperature differential normalized by the dimensionless outdoor unit fan speed. For the smooth switching between two compressor pressure controllers, two bumpless transfer methods are applied. The simulation results validate the effectiveness of the proposed strategy and performance of bumpless transfer strategies. For the multi-ODU VRF systems, an integrated efficiency operation strategy is proposed to optimize the energy efficiency, which consists of three respects: i) for a given operating condition, a multi-variable ESC strategy is used to optimize the settings of manipulated inputs of operating ODUs, by use of a load-sharing valve array and feedback of the normalized total power; ii) a model-free ODU compressor staging strategy with ESC integrated control logic; and iii) a modelfree ODU heat exchanger mode switching strategy with ESC integrated control logic. For staging on additional ODU compressor, the saturated operation of compressor speed (i.e. saturated to the higher limit) is used as the indicating variable. With ESC-alike real-time optimization strategy in operation, the least efficient compressor would be driven, which will then be staged off. As for automatic mode switch of ODU heat exchangers during heat recovery operation, the saturation of IDU EEV opening is utilized as the indicating variable, and the ODU heat exchanger (or fan-coil unit) with least efficiency under ESC operation will switch its operational mode. Similar to many other HVAC systems, the ESC operation of VRF systems is subject to state and/or input constraints. In this dissertation research, the general problem of constrained ESC is studied. The penalty-functions based framework of constrained ESC is studied. The dither-demodulation design is modified for penalty-function based ESC with assumption of Wiener-Hammerstein system composition. An online penalty-weight adaptation scheme is proposed with online Hessian estimation, and its convergence analysis is conducted in the context of numerical optimization ESC (NOESC).

Author: Pengfei Li
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Category : Air conditioning
Languages : en
Pages : 618

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Author: Wen Zhen Huang
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Languages : en
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Author: Wenzhen Huang
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Category : Air conditioning
Languages : en
Pages : 0

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Energy Management Control Systems (EMCS) in buildings can help reduce the energy consumption while maintaining satisfactory occupant environment. The energy management control strategies have to be developed taking into consideration the thermal behavior of buildings and the thermal, operational characteristics of mechanical systems in buildings. In this thesis, improved EMC algorithms are developed and implemented in a variable air volume HVAC (VAV-HVAC) system. Firstly, HVAC system component dynamic models are developed. Then, several individual improved EMC functions (outdoor air economical cycle, programmed start time, programmed stop time, reset supply air temperature setpoint, occupied time control strategies) are developed and evaluated. Finally, real-time simulations are carried out, in which the results of implementing above improved EMC functions are compared with those of conventional EMC functions. This comparison reveals that the HVAC system with each independent improved function can save 7% to 12% energy. Simulation results also show that a VAV-HVAC system employing all EMC algorithms can save between 14% to 15% energy during summer and winter operation. An optimization methodology to compute optimal setpoints is proposed. These optimal setpoints were used as tracking signals to PI and adaptive control strategies developed in this thesis. The use of optimal setpoints resulted in 17% energy savings. A real-time supervisory EMC platform is developed in which the developed EMC algorithms are embedded. Simulation results showing the typical operation of a VAV-HVAC system under supervisory EMC system are presented.

Author: Abd-Alhameed Raed
Publisher: European Alliance for Innovation
ISBN: 1631903403
Category : Social Science
Languages : en
Pages : 1790

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This book contains the proceedings of the Second International Conference on Integrated Sciences and Technologies (IMDC-IST-2021). Where held on 7th–9th Sep 2021 in Sakarya, Turkey. This conference was organized by University of Bradford, UK and Southern Technical University, Iraq. The papers in this conference were collected in a proceedings book entitled: Proceedings of the second edition of the International Multi-Disciplinary Conference Theme: “Integrated Sciences and Technologies” (IMDC-IST-2021). The presentation of such a multi-discipline conference provides a lot of exciting insights and new understanding on recent issues in terms of Green Energy, Digital Health, Blended Learning, Big Data, Meta-material, Artificial-Intelligence powered applications, Cognitive Communications, Image Processing, Health Technologies, 5G Communications. Referring to the argument, this conference would serve as a valuable reference for future relevant research activities. The committee acknowledges that the success of this conference are closely intertwined by the contributions from various stakeholders. As being such, we would like to express our heartfelt appreciation to the keynote speakers, invited speakers, paper presenters, and participants for their enthusiastic support in joining the second edition of the International Multi-Disciplinary Conference Theme: “Integrated Sciences and Technologies” (IMDC-IST-2021). We are convinced that the contents of the study from various papers are not only encouraged productive discussion among presenters and participants but also motivate further research in the relevant subject. We appreciate for your enthusiasm to attend our conference and share your knowledge and experience. Your input was important in ensuring the success of our conference. Finally, we hope that this conference serves as a forum for learning in building togetherness and academic networks. Therefore, we expect to see you all at the next IMDC-IST.

Author: Dietmar P.F. Möller
Publisher: Springer
ISBN: 1447156374
Category : Computers
Languages : en
Pages : 356

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This comprehensive textbook/reference provides an in-depth overview of the key aspects of transportation analysis, with an emphasis on modeling real transportation systems and executing the models. Topics and features: presents comprehensive review questions at the end of each chapter, together with detailed case studies, useful links, references and suggestions for further reading; supplies a variety of teaching support materials at the book’s webpage on Springer.com, including a complete set of lecture slides; examines the classification of models used for multimodal transportation systems, and reviews the models and evaluation methods used in transportation planning; explains traffic assignment to road networks, and describes computer simulation integration platforms and their use in the transportation systems sector; provides an overview of transportation simulation tools, and discusses the critical issues in the design, development and use of the simulation models.

Author: Dean Karnopp
Publisher: CRC Press
ISBN: 146656086X
Category : Technology & Engineering
Languages : en
Pages : 321

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Anyone who has experience with a car, bicycle, motorcycle, or train knows that the dynamic behavior of different types of vehicles and even different vehicles of the same class varies significantly. For example, stability (or instability) is one of the most intriguing and mysterious aspects of vehicle dynamics. Why do some motorcycles sometimes exh

Author: United States. Congress. Senate. Committee on Commerce, Science, and Transportation. Subcommittee on Science, Technology, and Space
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Category :
Languages : en
Pages : 112

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