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Author: Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
Houses do not perform optimally or even as many codes and forecasts predict. For example, Walker et al. (1998a) found large variations in thermal distribution system efficiency, as much as a factor of two even between side-by-side houses with the same system design and installation crew. This and other studies (e.g., Jump et al. 1996) indicate that duct leakage testing and sealing can readily achieve a 25 to 30% reduction in installed cooling capacity and energy consumption. As another example, consider that the building industry has recognized for at least 20 years the substantial impact that envelope airtightness has on thermal loads, energy use, comfort, and indoor air quality. However, Walker et al. (1998a) found 50% variances in airtightness for houses with the same design and construction crews, within the same subdivision. A substantial reason for these problems is that few houses are now built or retrofitted using formal design procedures, most are field assembled from a large number of components, and there is no consistent process to identify problems or to correct them. Solving the problems requires field performance evaluations of houses using appropriate and agreed upon procedures. Many procedural elements already exist in a fragmented environment; some are ready now to be integrated into a new process called residential commissioning (Wray et al. 2000). For example, California's Title 24 energy code already provides some commissioning elements for evaluating the energy performance of new houses. A house consists of components and systems that need to be commissioned, such as building envelopes, air distribution systems, cooling equipment, heat pumps, combustion appliances, controls, and other electrical appliances. For simplicity and practicality, these components and systems are usually evaluated individually, but we need to bear in mind that many of them interact. Therefore, commissioning must not only identify the energy and non-energy benefits associated with improving the performance of a component, it must also indicate how individual components interact in the complete building system. For this paper, we limit our discussion to diagnostics in areas of particular concern with significant interactions: envelope and HVAC systems. These areas include insulation quality, windows, airtightness, envelope moisture, fan and duct system airflows, duct leakage, cooling equipment charge, and combustion appliance backdrafting with spillage. The remainder of this paper first describes what residential commissioning is, its characteristic elements, and how one might structure its process. Subsequent sections describe a consolidated set of practical diagnostics that the building industry can use now. Where possible, we also discuss the accuracy and usability of these diagnostics, based on recent laboratory work and field studies. We conclude by describing areas in need of research and development, such as practical field diagnostics for envelope thermal conductance and combustion safety. There are several potential benefits for builders, consumers, code officials, utilities, and energy planners of commissioning houses using a consistent set of validated methods. Builders and/or commissioning agents will be able to optimize system performance and reduce consumer costs associated with building energy use. Consumers will be more likely to get what they paid for and builders can show they delivered what was expected. Code officials will be better able to enforce existing and future energy codes. As energy reduction measures are more effectively incorporated into the housing stock, utilities and energy planners will benefit through greater confidence in predicting demand and greater assurance that demand reductions will actually occur. Performance improvements will also reduce emissions from electricity generating plants and residential combustion equipment. Research to characterize these benefits is underway.
Author: Publisher: ISBN: Category : Languages : en Pages : 24
Book Description
Houses do not perform optimally or even as many codes and forecasts predict. For example, Walker et al. (1998a) found large variations in thermal distribution system efficiency, as much as a factor of two even between side-by-side houses with the same system design and installation crew. This and other studies (e.g., Jump et al. 1996) indicate that duct leakage testing and sealing can readily achieve a 25 to 30% reduction in installed cooling capacity and energy consumption. As another example, consider that the building industry has recognized for at least 20 years the substantial impact that envelope airtightness has on thermal loads, energy use, comfort, and indoor air quality. However, Walker et al. (1998a) found 50% variances in airtightness for houses with the same design and construction crews, within the same subdivision. A substantial reason for these problems is that few houses are now built or retrofitted using formal design procedures, most are field assembled from a large number of components, and there is no consistent process to identify problems or to correct them. Solving the problems requires field performance evaluations of houses using appropriate and agreed upon procedures. Many procedural elements already exist in a fragmented environment; some are ready now to be integrated into a new process called residential commissioning (Wray et al. 2000). For example, California's Title 24 energy code already provides some commissioning elements for evaluating the energy performance of new houses. A house consists of components and systems that need to be commissioned, such as building envelopes, air distribution systems, cooling equipment, heat pumps, combustion appliances, controls, and other electrical appliances. For simplicity and practicality, these components and systems are usually evaluated individually, but we need to bear in mind that many of them interact. Therefore, commissioning must not only identify the energy and non-energy benefits associated with improving the performance of a component, it must also indicate how individual components interact in the complete building system. For this paper, we limit our discussion to diagnostics in areas of particular concern with significant interactions: envelope and HVAC systems. These areas include insulation quality, windows, airtightness, envelope moisture, fan and duct system airflows, duct leakage, cooling equipment charge, and combustion appliance backdrafting with spillage. The remainder of this paper first describes what residential commissioning is, its characteristic elements, and how one might structure its process. Subsequent sections describe a consolidated set of practical diagnostics that the building industry can use now. Where possible, we also discuss the accuracy and usability of these diagnostics, based on recent laboratory work and field studies. We conclude by describing areas in need of research and development, such as practical field diagnostics for envelope thermal conductance and combustion safety. There are several potential benefits for builders, consumers, code officials, utilities, and energy planners of commissioning houses using a consistent set of validated methods. Builders and/or commissioning agents will be able to optimize system performance and reduce consumer costs associated with building energy use. Consumers will be more likely to get what they paid for and builders can show they delivered what was expected. Code officials will be better able to enforce existing and future energy codes. As energy reduction measures are more effectively incorporated into the housing stock, utilities and energy planners will benefit through greater confidence in predicting demand and greater assurance that demand reductions will actually occur. Performance improvements will also reduce emissions from electricity generating plants and residential combustion equipment. Research to characterize these benefits is underway.
Author: Maija Virta Publisher: CRC Press ISBN: 1000387631 Category : Technology & Engineering Languages : en Pages : 163
Book Description
Green buildings have become common in India and other countries in Asia. However, there is a concern regarding the performance of green buildings failing to meet the expectations of clients during the operation. One of the key reasons for this is poorly commissioned HVAC systems. In this publication we provide tools and knowhow for more efficient HVAC commissioning. It gives answers for four major questions: why commissioning is needed, how to perform proper commissioning, which key performance issues of common HVAC equipment need to be considered, and what kind of checklists are used during commissioning? It covers the entire commissioning process beginning with the owner’s project requirements and commissioning design reviews. Then, it explains procedures during installation and start-up of equipment followed by the functional performance testing, seasonal commissioning and 10 months’ operation review. This publication is developed by Indian Society of Heating, Refrigeration and Air Conditioning Engineers ISHRAE for Indian and Asian requirements in conjunction with the Federation of European HVAC Associations REHVA. The process steps described in this publication are in line with all major international building standards and green building certification schemes. Note: T&F does not sell or distribute the Hardback in India, Pakistan, Nepal, Bhutan, Bangladesh and Sri Lanka.
Author: Walter T. Grondzik Publisher: John Wiley & Sons ISBN: 0470112972 Category : Technology & Engineering Languages : en Pages : 146
Book Description
Commissioning is coming of age. Savvy building owners have adopted commissioning as an effective way to improve the facility acquisition process. Green building initiatives have embraced commissioning as a way of assuring quality in the delivery of high-performance buildings. This long-established quality control process for building mechanical systems is emerging as a broader construction management tool improving nearly all aspects of a project. What exactly is this thing called commissioning? Principles of Building Commissioning answers this fundamental question with the first all-inclusive, practical guide to the application of the principles of commissioning. The book clarifies the underlying philosophy of commissioning: the why, what, when, and who of this process. Shaped by the ASHRAE Guideline 0 view of the world of commissioning, Building Commissioning: Maps out the territory of commissioning Outlines its defining characteristics Explains its flow of processes Demystifies its documentation Making the fundamentals of commissioning accessible to all parties—building owners and operators, architects and engineers, users and suppliers—who may be called upon to join the commissioning team for a particular project, Building Commissioning serves as the professional's road map to the commissioning process, from the predesign phase through occupancy.
Author: Charles Nehme Publisher: Charles Nehme ISBN: Category : Technology & Engineering Languages : en Pages : 73
Book Description
Introduction The purpose of this guide is to provide a comprehensive set of best practices for HVAC (Heating, Ventilation, and Air Conditioning) installations. These practices are designed to ensure optimal system performance, energy efficiency, safety, and customer satisfaction. Whether you are an HVAC contractor, installer, or technician, adhering to these guidelines will help you deliver high-quality installations that meet or exceed industry standards. Planning and Design Load Calculation: Perform accurate load calculations using recognized methods such as Manual J for residential and Manual N for commercial buildings to ensure the system is appropriately sized. System Selection: Choose HVAC systems that match the load requirements and consider factors such as energy efficiency ratings (SEER, EER, HSPF), environmental impact (refrigerant type), and client preferences. Ductwork Design: Design ductwork to minimize pressure losses and ensure balanced airflow. Use Manual D for residential duct design and ensure proper sizing and layout to prevent issues like hot and cold spots. Installation Best Practices Site Preparation: Ensure the installation site is clean, accessible, and complies with local building codes. Verify that there is sufficient space for equipment and maintenance access. Proper Mounting and Leveling: Mount and level all HVAC equipment correctly to prevent operational issues and enhance longevity. Use appropriate mounting hardware and check levels using a spirit level. Refrigerant Piping: Size and install refrigerant piping according to manufacturer specifications to prevent pressure drops and ensure efficient refrigerant flow. Insulate refrigerant lines to prevent heat loss or gain. Electrical Connections: Ensure all electrical connections are secure and comply with the National Electrical Code (NEC). Verify correct voltage and amperage, and install appropriate circuit protection devices. Duct Sealing and Insulation: Seal all duct joints with mastic or UL 181-rated tape to prevent air leakage. Insulate ducts in unconditioned spaces to improve energy efficiency. Ventilation Requirements: Install ventilation systems according to local codes and standards such as ASHRAE 62.2 for residential ventilation. Ensure proper placement of intake and exhaust vents to optimize air quality and system performance. Commissioning and Testing System Startup: Follow manufacturer guidelines for system startup procedures. Verify that all components are functioning correctly and that there are no abnormal noises or vibrations. Airflow Measurement: Measure and adjust airflow to meet design specifications. Use tools like anemometers or balometers to ensure balanced and adequate airflow throughout the system. Refrigerant Charge Verification: Verify that the refrigerant charge is correct using superheat and subcooling methods. Adjust the charge if necessary to ensure optimal system performance and efficiency. Maintenance and Documentation Maintenance Plan: Develop a maintenance plan that includes regular inspections, filter changes, and system tune-ups. Educate the customer on the importance of routine maintenance to prolong the system’s lifespan and maintain efficiency. Customer Education: Provide the customer with a detailed user manual and a walkthrough of the system’s features and maintenance requirements. Ensure they understand how to operate the thermostat, change filters, and recognize signs of potential issues. Documentation: Keep detailed records of all installation steps, system specifications, and any modifications made during the process. This documentation will be invaluable for future maintenance and troubleshooting. Safety and Compliance Code Compliance: Ensure that all installations comply with local building codes, safety regulations, and manufacturer guidelines. This includes securing necessary permits and passing all required inspections. Safety Protocols: Follow all safety protocols during installation, such as using appropriate personal protective equipment (PPE), ensuring proper ventilation when working with refrigerants, and maintaining a clean and hazard-free work area. Environmental Considerations: Dispose of old equipment and refrigerants responsibly, following EPA guidelines and local regulations. Consider recommending environmentally friendly options to customers, such as high-efficiency systems and eco-friendly refrigerants. Quality Assurance Final Inspection: Conduct a thorough final inspection of the entire HVAC system, checking for correct installation, proper operation, and compliance with all specifications. Customer Satisfaction: Ensure the customer is satisfied with the installation. Address any concerns or questions they may have before concluding the job. Warranty and Support: Provide information on warranties and support services. Ensure the customer knows who to contact in case of any future issues or questions. By adhering to these best practices, HVAC professionals can ensure high-quality installations that provide reliable, efficient, and safe heating and cooling solutions for their customers.
Author: Mark P. Modera Publisher: ASTM International ISBN: 0803120230 Category : Air flow Languages : en Pages : 304
Book Description
Discusses the measurement and control of air moving inside buildings and between the inside and outside in 17 papers and discussions from a symposium in Dallas/Fort Worth in October 1993. After an overview of the subject, covers air movement, ventilation, and indoor air quality; window air leakage;
Author: American Society of Heating, Refrigerating and Air-Conditioning Engineers Publisher: ISBN: Category : Air conditioning Languages : en Pages : 26
Author: Publisher: ISBN: Category : Languages : en Pages : 5
Book Description
This case study focusing on a residence in northern California was undertaken as a demonstration of the potential of a systems approach to HVAC retrofits. The systems approach means that other retrofits that can affect the HVAC system are also considered. For example, added building envelope insulation reduces building loads so that smaller capacity HVAC system can be used. Secondly, we wanted to examine the practical issues and interactions with contractors and code officials required to accomplish the systems approach because it represents a departure from current practice. We identified problems in the processes of communication and installation of the retrofit that led to compromises in the final energy efficiency of the HVAC system. These issues must be overcome in order for HVAC retrofits to deliver the increased performance that they promise. The experience gained in this case study was used to optimize best practices guidelines for contractors (Walker 2003) that include building diagnostics and checklists as tools to assist in ensuring the energy efficiency of ''house as a system'' HVAC retrofits. The best practices guidelines proved to be an excellent tool for evaluating the eight existing homes in this study, and we received positive feedback from many potential users who reviewed and used them. In addition, we were able to substantially improve the energy efficiency of the retrofitted case study house by adding envelope insulation, a more efficient furnace and air conditioner, an economizer and by reducing duct leakage.
Author: Miljana Horvat Publisher: ISBN: Category : Exterior walls Languages : en Pages : 0
Book Description
In the Canadian climate, the performance of wood-frame building envelopes is affected directly by moisture management as well as by the quality of design, construction workmanship, and maintenance. Trapped moisture reduces the thermal performance of the envelope and can lead to mould growth that deteriorates building materials and contaminates the indoor-air. The means to evaluate the impact of these factors on the overall performance of the envelope are limited. Computer models that exist are still, for the most part, reserved for researchers or have not been validated to a sufficient comfort level for the designer. Till now large scale testing that would provide realistic results have been limited due to the lack of facilities and the lack of evaluation procedures. This research project develops a protocol that facilitates the evaluation of the performance of light-frame building envelopes. The protocol evaluates the building envelope as a system under the following main issues: air-tightness, moisture management performance, thermal performance, energy performance, structural stability of building envelope, acoustic performance, fire response performance and quality of workmanship. It sets the internal and external loads that affect that performance and develops a procedure for evaluation. The evaluation protocol includes performance criteria, associated standards, and compliance evaluation methods. The second part of this study involves developing an assessment tool that uses data generated by the above evaluation procedure. This assessment tool is designed to provide a fast check of the building envelope system compliance against performance requirements. Intended to be comprehensive and user-friendly for professionals, this tool can also be used by producers and exporters of factory-made houses in Canada to examine existing designs and to verify the performance of new designs. The validation of the protocol and the assessment tool is done by evaluating the performance of five different building envelope assemblies: one modular prefabricated house designed and built in conformance with the requirements of NBC and Québec Energy Code (A-standard house), one modular prefabricated house designed to conform to requirements of Novoclimat program (A-Novoclimat house), one panellised high performance house (M-Thermo house) and two Advanced houses: NOVTEC Advanced house and Innova Advanced house. The results of validation show that the protocol and the assessment tool are effectively used to establish the performance profiles of these five case studies, demonstrating in each case the adequacy of each parameter. The results also demonstrate that the protocol provides a means of comparing the relative performance of respective parameters across case studies.