Optimization of Heating, Ventilation, and Air-conditioning (HVAC) Chilled Water Plant Systems


Book Description

Heating, Ventilation, and Air-conditioning accounts for about 60% of the total energy consumed in commercial facilities including office buildings, hospitals, retail stores, warehouses, campuses, manufacturing facilities, medical facilities, etc. As the cost of electricity and energy continue to rise, building owners and facility managers continue to witness a rise in the Total Cost of Ownership. Chilled water plant system is the largest consumer of energy in HVAC system consuming 75% of the total energy used in HVAC according to the Department of Energy. Operating chilled water plant systems at the recommended AHRI Standard 550/590 for performance rating of water chilling and heat pumps temperature set-points seldom results in optimized operation and cost savings, since factors such as operation schedules, site-specific conditions such as prevailing ambient conditions, part load operations, keep on changing. The aim of this project was to design an optimized heating, ventilation, and air-conditioning chilled water system for a 100,000 square feet facility complex in Houston, Texas. By selecting a chilled water distribution system; chilled water temperatures, flow rate, and sizes; condenser water distribution system, condenser water temperatures, flow rate, and pipe sizes; cooling tower approach temperatures; and piping system optimization, a saving of 25% on the annual energy costs at peak load operations of the complex facility was obtained. This analysis also showed that as the chilled water supply temperature is set upwards, the pump energy increases but the chiller energy and the cooling tower energy decreases resulting in a positive net system gain.




The Comprehensive Guide to Chilled Water Systems: Design, Operation, and Maintenance


Book Description

Welcome to the world of chilled water systems! In this book, we aim to provide you with a comprehensive understanding of chilled water systems, their components, and their applications. Whether you are a student, a professional in the HVAC industry, or simply curious about this fascinating technology, this book will serve as a valuable resource. Chilled water systems play a crucial role in providing cooling for a wide range of applications, from large commercial buildings to industrial facilities and data centers. They are highly efficient, reliable, and versatile, making them an integral part of modern cooling systems. This book is structured to take you on a journey through the fundamentals of chilled water systems. We will start by explaining the basic principles of cooling and the advantages of using chilled water as a medium for heat transfer. We will explore the various components that make up a chilled water system, such as chillers, cooling towers, pumps, and air handling units, and discuss their functionalities and interconnections. Throughout the book, we will delve into the design considerations for chilled water systems, including system capacity, pipe sizing, insulation, and control strategies. We will also cover topics such as water treatment, maintenance practices, and energy efficiency measures to optimize the performance of chilled water systems. Additionally, we will address common challenges and troubleshooting techniques, allowing you to diagnose and resolve issues that may arise in chilled water systems. We will discuss strategies for system optimization, load management, and integration with other building systems, emphasizing the importance of sustainability and environmental responsibility. As you progress through the chapters, you will find practical examples, case studies, and illustrations to enhance your understanding. The goal is to provide you with a well-rounded knowledge base that empowers you to work with chilled water systems effectively. It is important to note that this book assumes a basic understanding of thermodynamics and HVAC principles. However, we have endeavored to explain complex concepts in a clear and accessible manner, making it suitable for both beginners and experienced professionals. We hope that this book will serve as a valuable reference and inspire you to explore the exciting world of chilled water systems further. So, without further ado, let's dive into the cool world of chilled water systems!




Synergy of Self-optimizing Control and Real-time Optimization With Applications to Building Energy Systems


Book Description

This dissertation research investigates on energy optimal operations of heating, ventilation and air conditioning (HVAC) systems for residential and commercial buildings, with investigations on two classes of approaches, i.e. Self-optimizing Control (SOC) based control structure optimization and Extremum Seeking Control (ESC) based real-time optimization, as well as their synergy. As the preliminary study, three existing ESC methods are compared, i.e. the conventional dither ESC, input-output correlation ESC (IOC-ESC), and proportion-integral ESC (PI-ESC). The primary goal for this study is to evaluate the performance robustness of each ESC to parametric variation. The three ESC strategies are first evaluated with simulation study using a Modelica model of an air source heat pump (ASHP) model. Then, laboratory tests are conducted with IOC-ESC and CON-ESC on a mini-split air conditioning system. Both simulation and experimental results show that PI-ESC archives fastest convergent speed, while IOC-ESC is most robust to parametric variation among three methods. For plant operation with multiple potential inputs for ESC design, an ESC integrated online input selection approach is proposed based on Hessian estimation and SVD analysis. The dimensionality of manipulated inputs can be reduced by pruning and/or combining the available manipulated inputs. Error bound analysis is conducted for the proposed input selection process. Then, the proposed procedure is validated with both numerical example and a Modelica based chilled-water plant model. The SOC based control structure optimization is studied from three perspectives, with the key focus of how to determine the optimal selection of controlled variables (CVs) with online or historical data. First, an online local SOC procedure is proposed by using the ditherdemodulation based gradient and Hessian estimates that have been developed in ESC, and the proposed method is validated with the Modelica ASHP model. Secondly, a data-driven global SOC method is proposed by applying the technique of sparse identification for nonlinear dynamics (SINDy) to historical data. For the static plant model thus derived, tracking the necessary condition of optimality yields the globally optimal solutions of CV selection in an analytical fashion. Such SOC framework is validate with the Modelica-based chilled-water plant operation. Then, this data-driven global SOC approach is extended to plant operation with wide range of disturbance variations which is subject to the changes of active constraint set. With the plant model obtained by the SINDy based procedure, a parametric programming enabled constrained optimization framework is utilized to derive the controlled variables for each region of different active constraint set. Again, simulation based validation is conducted with the Modelica based chilled-water plant model.




HVAC Psychrometrics: Understanding and Optimizing Air Conditioning Systems


Book Description

Air conditioning systems play a crucial role in providing comfortable indoor environments, whether it's in residential, commercial, or industrial settings. Understanding the principles of psychrometrics is essential for designing, operating, and optimizing these HVAC (Heating, Ventilation, and Air Conditioning) systems effectively. Psychrometrics is the study of the thermodynamic properties of air and its moisture content. It involves the measurement and analysis of parameters such as temperature, humidity, pressure, and enthalpy to determine the state of air and its ability to hold moisture. These parameters are crucial for designing air conditioning systems that can maintain optimal indoor conditions for human comfort, equipment operation, and various industrial processes. This book aims to provide a comprehensive understanding of psychrometrics and its practical applications in HVAC systems. It explores the fundamental concepts and equations related to air properties, psychrometric charts, and the psychrometric processes involved in air conditioning. Moreover, it delves into the various components and systems that make up an air conditioning system, such as air handlers, cooling coils, refrigeration cycles, and ventilation systems. Optimizing air conditioning systems is a key focus of this book. By leveraging the principles of psychrometrics, engineers and technicians can enhance the efficiency and performance of HVAC systems, resulting in energy savings, improved indoor air quality, and increased occupant comfort. The book covers topics such as load calculations, equipment selection, airflow distribution, humidity control strategies, and system optimization techniques. Throughout the book, real-world examples, case studies, and practical tips are provided to illustrate the application of psychrometrics in different scenarios. Whether you are a HVAC professional, engineer, technician, or someone interested in understanding the inner workings of air conditioning systems, this book serves as a valuable resource to enhance your knowledge and skills. It is worth noting that while this book provides a comprehensive overview of psychrometrics and air conditioning systems, it does not delve into the intricacies of HVAC design and installation. For detailed design guidelines and standards, it is recommended to refer to relevant industry codes, manuals, and regulations. With a solid understanding of psychrometrics and its role in air conditioning systems, readers will be equipped with the knowledge necessary to design, optimize, and maintain efficient HVAC systems, creating comfortable and healthy indoor environments for all. Let us embark on this journey into the fascinating world of HVAC psychrometrics and unlock the secrets of optimizing air conditioning systems.




HVAC - Chilled Water vs DX System


Book Description

Purpose of the Book The heating, ventilation, and air conditioning (HVAC) industry plays a crucial role in ensuring the comfort, productivity, and well-being of building occupants. Among the myriad of HVAC systems available, chilled water and direct expansion (DX) systems stand out as the two primary choices for large-scale cooling needs. This book aims to provide a comprehensive comparison of these two systems, exploring their components, operational principles, advantages, and disadvantages. By doing so, it seeks to equip engineers, architects, facility managers, and decision-makers with the knowledge necessary to select the most appropriate cooling solution for their specific needs. Scope and Structure This book is structured to offer a detailed examination of chilled water and DX systems, starting from fundamental concepts to in-depth analysis and case studies. The content is organized into ten chapters, each focusing on a specific aspect of these HVAC systems: Fundamentals of HVAC Systems: An introduction to HVAC systems, their importance, and an overview of different types. Chilled Water Systems: Detailed exploration of chilled water systems, including components, design, advantages, and disadvantages. Direct Expansion (DX) Systems: Comprehensive coverage of DX systems, their components, design, advantages, and disadvantages. Energy Efficiency and Performance: Comparison of energy consumption, performance metrics, and efficiency between the two systems. Cost Analysis: Evaluation of initial, operational, and lifecycle costs of chilled water and DX systems. Environmental Impact: Discussion on refrigerants, emissions, sustainability, and future trends in HVAC technology. Application Scenarios: Analysis of how each system performs in different types of buildings and special applications. Design and Implementation: Best practices for system selection, design, installation, commissioning, and maintenance. Case Studies: Real-world examples and lessons learned from successful implementations. Future of HVAC Systems: Exploration of technological advancements, emerging trends, and the future outlook of the HVAC industry. Overview of HVAC Systems HVAC systems are integral to modern buildings, providing thermal comfort and maintaining indoor air quality. These systems regulate temperature, humidity, and air circulation, ensuring that indoor environments remain conducive to the occupants' activities. The choice of an HVAC system can significantly impact energy consumption, operational costs, and environmental footprint, making it a critical decision in the design and management of buildings. Importance of Choosing the Right System Selecting the appropriate HVAC system involves balancing multiple factors such as building size, usage patterns, climate conditions, budget constraints, and energy efficiency goals. Chilled water and DX systems each offer unique benefits and challenges, and their suitability can vary widely depending on the specific application. Understanding the strengths and limitations of each system is essential for making informed decisions that align with both short-term needs and long-term objectives. Goals of the Book The primary goals of this book are to: Provide a clear and detailed comparison of chilled water and DX systems. Highlight the key factors influencing system selection and performance. Present practical insights and real-world examples to guide decision-making. Explore future trends and innovations in the HVAC industry. By achieving these goals, the book aims to be a valuable resource for professionals involved in the design, implementation, and management of HVAC systems, ultimately contributing to more efficient, sustainable, and cost-effective building solutions.




Proceedings of the 11th International Symposium on Heating, Ventilation and Air Conditioning (ISHVAC 2019)


Book Description

This book presents selected papers from the 11th International Symposium on Heating, Ventilation and Air Conditioning (ISHVAC 2019), with a focus on HVAC techniques for improving indoor environment quality and the energy efficiency of heating and cooling systems. Presenting inspiration for implementing more efficient and safer HVAC systems, the book is a valuable resource for academic researchers, engineers in industry, and government regulators.




HVAC System


Book Description

In this book, various aspects of heating, ventilation, and air-conditioning (HVAC) systems are investigated. HVAC systems are milestones of building mechanical systems that provide thermal comfort for occupants accompanied with indoor air quality. HVAC systems can be classified into central and local systems according to multiple zones, location, and distribution. Primary HVAC equipment includes heating equipment, ventilation equipment, and cooling or air-conditioning equipment. Central HVAC systems are located away from buildings in a central equipment room and deliver the conditioned air by a delivery ductwork system. Central HVAC systems contain all-air, air-water, or all-water systems. Two systems should be considered as central such as heating and cooling panels and water-source heat pumps.




Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning


Book Description

Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proceedings provide readers with a good general overview of recent advances in different aspects of HVAC systems and related research. As such, they offer a unique resource for further research and a valuable source of information for those interested in the subject. The proceedings are intended for researchers, engineers and graduate students in the fields of Heating, Ventilation and Air Conditioning (HVAC), indoor environments, energy systems, and building information and management. Angui Li works at Xi’an University of Architecture and Technology, Yingxin Zhu works at Tsinghua University and Yuguo Li works at The University of Hong Kong.







HVAC Systems


Book Description

HVAC Systems is intended for HVAC engineers, designers facilities engineers, plant engineers, cheif engineers, utility engineers, energy managers, energy management technicians, energy auditors, HVAC mechanics and operating personel, refrigeration mechanics and air and water balancing technicians. The book takes you on a guided tour of the various HVAC systems and their components. It uses numerous drawings and examples to show you how the components and systems should operate, how to test the systems for actual operating conditions and how to improve operation and performance. This is an exceptional source book packed with useful checklists, equations, tables, charts, curves, forms and definitions.