ABSTRACT:There is currently no comprehensive model which considers multiple performance criteria in choosing HVAC systems. This dissertation aims at developing an integrated decision-making model for selecting HVAC systems based on various performance criteria, including technical performance, environmental performance, economic performance and LEED performance. An analytical hierarchy process (AHP) method is used as the basis of the decision-making model to generate the optimal HVAC system. The preference weightings of performance criteria are assigned to the hierarchy structure based on the preference of the decision-makers. The weightings of the performance criteria are further integrated with the performance indicators of alternatives to calculate an overall score for each HVAC alternative of interest. With the decision-making model, the alternatives are ranked by the overall scores and the alternative with the highest score indicates the optimal HVAC system based on its comprehensive performance and preferences of the decision makers. A case study is conducted to further test the validity of the methodology. Sensitivity analysis and consistency checks are conducted to track the sensibility and accuracy of the model. This dissertation also provides thoughts on the development of software for the decision-making model for the purpose of facilitating the programming process and reducing the complexity of the model inputs and outputs.

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.

This book presents various multi-criteria analysis methods for sustainability-oriented analysis and decision-making for energy systems, under various different conditions and scenarios. It presents methodologies to answer the questions relating to which of the options are the most sustainable among the alternatives, and how multi-criteria decision analysis methods can be used to select the most sustainable energy systems. A systematic innovative methodological framework is presented, which enables the most appropriate energy system to be selected under different conditions including: Scientific decision support tools for sustainable energy system selection; Fuzzy, grey, and rough sets based multi-criteria decision analysis; Decision-making models under uncertainties; and The combination of life cycle thinking and multi-criteria decision analysis This book is of interest to researchers, engineers, decision makers, and postgraduate students within the field of energy systems, sustainability, and multi-criteria decision analysis.

This book focuses on some of the most energy-consuming HVAC systems; illuminating huge opportunities for energy savings in buildings that operate with these systems. The main discussion is on, cutting-edge decision making approaches, and algorithms in: decision making under uncertainty, genetic algorithms, fuzzy logic, artificial neural networks, agent based modeling, and game theory. These methods are applied to HVAC systems, in order to help designers select the best options among the many available pathways for designing and the building of HVAC systems and applications. The discussion further evolves to depict how the buildings of the future can incorporate these advanced decision-making algorithms to become autonomous and truly ‘smart’.

Preface Selecting the proper HVAC (Heating, Ventilation, and Air Conditioning) equipment for your project is crucial for ensuring energy efficiency, comfort, and cost-effectiveness. This preface will provide an overview of key considerations and steps involved in choosing the right HVAC system for your specific needs. Understanding HVAC Systems HVAC systems are integral to maintaining indoor air quality and thermal comfort. They include components for heating, cooling, ventilation, and humidity control. Common types of HVAC systems include: Split Systems: Separate indoor and outdoor units, ideal for individual room control. Packaged Systems: All-in-one units, typically used in commercial applications. Heat Pumps: Efficient for both heating and cooling, suitable for moderate climates. Ductless Mini-Splits: Offer flexibility without ductwork, ideal for retrofits or specific zones. Key Considerations Project Scope and Requirements: Size and Layout: The size and layout of the space influence the type and capacity of the HVAC system needed. Larger or multi-story buildings may require more complex systems. Usage: Determine the primary use of the space (e.g., residential, commercial, industrial) and any specific needs such as server rooms, labs, or manufacturing areas. Climate: Local climate conditions significantly affect HVAC requirements. Hot and humid climates demand efficient cooling and dehumidification, while colder regions prioritize heating. Energy Efficiency: Look for systems with high Seasonal Energy Efficiency Ratio (SEER) and Heating Seasonal Performance Factor (HSPF) ratings. Energy-efficient systems reduce operating costs and environmental impact. Consider systems with variable speed technology for better energy management. Budget: Balance initial investment with long-term operational costs. High-efficiency systems may have higher upfront costs but lower ongoing expenses. Building Codes and Regulations: Ensure compliance with local building codes, standards, and regulations. This includes safety standards, energy efficiency mandates, and environmental regulations. Indoor Air Quality: Choose systems with good filtration and ventilation capabilities to maintain healthy indoor air quality, especially in spaces with high occupancy or specific air quality requirements. System Design and Integration: Proper design and integration with existing building systems (electrical, plumbing, etc.) are crucial for optimal performance. Consider consulting with HVAC professionals or engineers. Future Scalability: Plan for potential future expansions or modifications. Select systems that can be easily upgraded or expanded. Steps to Select the Proper HVAC Equipment Assess the Building Load: Conduct a load calculation to determine heating and cooling requirements. This includes considering insulation, windows, occupancy, and internal heat gains. Evaluate Different HVAC Systems: Compare various systems based on efficiency, capacity, and suitability for the project's specific needs. Consider Technological Features: Look for modern features such as smart thermostats, zoning capabilities, and remote monitoring for enhanced control and efficiency. Consult with Professionals: Engage HVAC contractors, engineers, or consultants to review your plans and provide expert recommendations. Review Manufacturer Warranties and Support: Choose reputable manufacturers that offer robust warranties and reliable customer support. Conclusion Selecting the proper HVAC equipment is a multifaceted process that requires careful consideration of the project's specific requirements, climate, energy efficiency, and budget. By following a systematic approach and leveraging professional expertise, you can ensure that your HVAC system will provide optimal performance, comfort, and cost-efficiency for your project.

This thesis investigates the use of building performance simulation tools as a method of informing the design decision of Net Zero Energy Buildings (NZEBs).