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Comparison Between Predicted Duct Effectiveness from Proposed ASHRAE Standard 152P and Measured Field Data for Residential Forced Air Cooling Systems

Comparison Between Predicted Duct Effectiveness from Propose...

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ASHRAE 2003 Winter Meeting CD, Technical and Symposium Papers

作者： Siegel, Jeffrey A. McWilliams, Jennifer A. Walker, Iain S. Architectural Engineering Program Department of Civil Engineering University of Texas Austin TX Ener. Performance of Buildings Group Lawrence Berkeley Natl. Laboratory Berkeley CA

The proposed ASHRAE Standard 152P, "Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems" (ASHRAE 2002), has recently completed its second public review, Aspart of the standard development process, this study compares the forced air distribution system ratings to measured field results. Fifty-eight field tests were performed on cooling systems in eleven homes in the summers of 1998 and 1999, Seven of these houses had standard attics with insulation on the attic floor and a well-vented attic space. The other four houses had unvented attics where the insulation is placed directly under the roof deck, and the attic space is not deliberately vented. Each house was tested under a range of summer weather conditions at each particular site and, in some cases, the amount of duct leakage was intentionally varied. The comparison between predicted efficiencies and the measured results includes evaluation of the effects of weather, duct location, thermal conditions, duct leakage, and system capacity. The results showed that the difference between measured results and those calculated using proposed Standard 152P is about 5 percentage points on average if weather data, duct leakage, and air handler flow are well known. However, the accuracy of the standard is strongly dependent on having good measurements of duct leakage and system airflow. Given that the uncertainty in the measured results is typically also about 5 percentage points, the Standard 152P results are acceptably close to the measured data.

关键词： Air conditioning ducts

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Synergies between Sustainable Design and Constructability at the Pentagon

Synergies between Sustainable Design and Constructability at...

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Construction Research Congress, Winds of Change: Integration and Innovation in Construction, Proceedings of the Congress

作者： Pulaski, Michael Pohlman, Teresa Horman, Michael Riley, David Dept. of Architectural Engineering Pennsylvania State University 104 Engineering Unit A University Park PA 16801 Pentagon Renovation Program 100 Boundary Channel Rd. Arlington VA 22202

ISBN: (纸本)0784406715

Sustainable design and constructability are two keys for efficient design and construction that are often addressed separately from each other in projects. This paper examines the integration of these two initiatives on the Pentagon renovation. The examination exposes a synergistic relationship between sustainable design and constructability. This relationship strives to efficiently utilize resources and reduce waste in the project. The integrated organizational structure and design-build performance based contracting strategies at the Pentagon have assisted in the implementation of sustainable design and constructability. Connections between the two initiatives were found at the conceptual level, system level, materials level and in the design implementation process. Importantly, the analysis of the Pentagon reveals that the potential to improve the sustainability and the constructability of a project is enhanced when the two initiatives are integrated and approached in a combined fashion.

关键词： Construction industry

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Comparison between predicted duct effectiveness from proposed ASHRAE standard 152P and measured field data for residential forced air cooling systems

Comparison between predicted duct effectiveness from propose...

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Technical and Symposium Papers Presented At the 2003 Winter Meeting of The ASHRAE

作者： Siegel, Jeffrey A. McWilliams, Jennifer A. Walker, Iain S. Architectural Engineering Program Department of Civil Engineering University of Texas Austin TX United States Energy Performance of Bldg. Group Lawrence Berkeley National Lab. Berkeley CA United States

The proposed ASHRAE Standard 152P, "Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems" (ASHRAE 2002), has recently completed its second public review. As part of the standard development process, this study compares the forced air distribution system ratings to measured field results. Fifty-eight field tests were performed on cooling systems in eleven homes in the summers of 1998 and 1999. Seven of these houses had standard attics with insulation on the attic floor and a well-vented attic space. The other four houses had unvented attics where the insulation is placed directly under the roof deck, and the attic space is not deliberately vented. Each house was tested under a range of summer weather conditions at each particular site and, in some cases, the amount of duct leakage was intentionally varied. The comparison between predicted efficiencies and the measured results includes evaluation of the effects of weather;duct location, thermal conditions, duct leakage, and system capacity. The results showed that the difference between measured results and those calculated using proposed Standard 152P is about 5 percentage points on average if weather data, duct leakage, and air handler flow are well known. However, the accuracy of the standard is strongly dependent on having good measurements of duct leakage and system airflow. Given that the uncertainty in the measured results is typically also about 5 percentage points, the Standard 152P results are acceptably close to the measured data.

关键词： Air conditioning ducts

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Predicting particle deposition on HVAC heat exchangers

Predicting particle deposition on HVAC heat exchangers

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作者： Siegel, Jeffrey A. Nazaroff, William W. Architectural Engineering Program Department of Civil Engineering University of Texas Austin TX 78712-1076 United States Dept. of Civ./Environ. Engineering University of California Berkeley CA 94720-1710 United States

Particles in indoor environments may deposit on the surfaces of heat exchangers that are used in heating, ventilation and air conditioning (HVAC) systems. Such deposits can lead to performance degradation and indoor air quality problems. We present a model of fin-and-tube heat-exchanger fouling that deterministically simulates particle impaction, gravitational settling, and Brownian diffusion and uses a Monte Carlo simulation to account for impaction due to air turbulence. The model predicts that -1. The amount that the model underpredicts the measured data increases at higher velocities and especially for larger particles, although the model shows good qualitative agreement with the measured deposition fractions. Discontinuities in the heat-exchanger fins are hypothesized to be responsible for the increase in measured deposition. The model and experiments reported here are for isothermal conditions and do not address the potentially important effects of heat transfer and water phase change on deposition. © 2003 Elsevier Ltd. All rights reserved.

关键词： Indoor air pollution

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Modeling immune building systems for bioterrorism defense

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Journal of architectural engineering 2003年第2期9卷 86-95页

作者： Kowalski, Wladyslaw Bahnfleth, William Musser, Amy Indoor Environment Center Dept. of Architectural Engineering Pennsylvania State Univ. University Park PA 16802 Architectural Engineering Program Univ. of Nebraska Omaha NE 68182-0681

This paper presents the results of research on the performance of air-cleaning and air-disinfection systems used for protecting buildings against intentional releases of biological agents. The air-cleaning technologies addressed include dilution ventilation, filtration, and ultraviolet germicidal irradiation. A 40-story commercial office building is modeled using typical occupancy levels and leakage rates for doors, walls, and floors. A steady-state single-zone model is used to predict steady-state conditions resulting from the use of various levels of air cleaning. A transient single-zone model is used to predict transient indoor concentrations from which inhaled doses and estimated casualties are predicted. A transient multizone model is used to evaluate contaminant dispersion and estimate potential casualties. Three design-basis attack scenarios are simulated using various biological weapon agents. Predicted casualties are estimated using an epidemiological model of the dose response curves for each of the agents. The effect of increasing levels of air cleaning is examined under the attack scenarios to evaluate their effectiveness. Results indicate that high levels of protection are possible for building occupants with moderate and affordable levels of air cleaning when filtration is combined with ultraviolet germicidal irradiation. Results also suggest that diminishing returns occur when increased levels of air cleaning are applied. It is hypothesized that the maximum useful size of any air-cleaning system is defined and limited by building physical characteristics alone. © ASCE.

关键词： Buildings

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Effect of learning on line-of-balance scheduling

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International Journal of Project Management 2001年第5期19卷 265-277页

作者： Arditi, David Tokdemir, Onur Behzat Suh, Kangsuk Department of Civil and Architectural Engineering Construction Engineering and Management Program Illinois Institute of Technology 3201 South Dearborn Street Chicago IL 60616 United States

An approach to formulate learning rates and include them in line-of-balance (LOB) calculations is proposed in this paper. Learning rates are generated by modifying historical learning rates of typical construction activities and by incorporating the impact of relevant factors such as, number of operations in one unit, activity complexity, and job and management conditions. Fuzzy set theory is used to develop production rules to treat both factual and uncertain information. An S-type membership function is used to interpret the fuzzy data and produce adjustment factors that are in turn used to modify consecutive learning rates, until an adjusted learning rate is obtained. The adjusted learning rate is then used to calculate expected worker-hours and activity durations at each unit of production (e.g., a floor in a high-rise building, a mile of pavement work, etc.). A final LOB diagram is generated using this information. Different pairs of curves represent the start and the finish times of each activity in sets of units that make use of different numbers of crews. Learning reduces project duration and resource requirements. The proposed approach demonstrates the potential for formalizing the inclusion of learning effects into the LOB scheduling of repetitive-unit construction. © 2001 Elsevier Science Ltd and IPMA. All rights reserved.

关键词： Project management

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Parametric study of charging inlet diffuser performance in stratified chilled water storage tanks with radial diffusers: Part 1-model development and validation

Parametric study of charging inlet diffuser performance in s...

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2001 ASHRAE Annual Meeting

作者： Musser, Amy Bahnfleth, William P. Architectural Engineering Program University of Nebrask-Omaha Omaha NE United States

A computational fluid dynamics (CFD) model has been developed to simulate the flow and heat transfer near a lower radial inlet diffuser in a cylindrical stratified chilled water storage tank during charging. The model was used to perform parametric simulations of inlet diffuser performance in full-scale tanks during thermocline formation, from which first-order correlation relating thermal performance to tank and diffuser design parameters were derived Part I describes the development of the CFD model and its validation. Part 2 reports the results of the parametric study. The two-dimensional, transient model was implemented in a commercial finite element code. The model has been validated with field-measured data from two full-scale tanks. Laminar analysis predicted field-measured temperature profiles well, even under ostensibly transitional conditions, provided that variations in inlet temperature during the field tests were accurately modeled These results suggest that turbulence has a secondary effect on the development of thermoclines within the range of parameters considered and that laminar models may be useful for modeling performance of full-scale tanks over a wide range of inlet parameters. The fully developed temperature profile was found to be insensitive to the velocity distribution assumed at the inlet.

关键词： Water tanks

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An integrative curriculum in architectural engineering technology

An integrative curriculum in architectural engineering techn...

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2001 ASEE Annual Conference and Exposition: Peppers, Papers, Pueblos and Professors

作者： Davis, Daniel Fuller, James Petry, Elizabeth University of Hartford Arch. Engineering Technology Program University of Hartford Architectural Engineering Technology University of Hartford

In an effort to improve the architectural engineering Technology curriculum at the University of Hartford, educators and practitioners are working in collaboration. As design professionals, we are approaching the challenges of an integrative curriculum as we would an architectural design project. The goals of the 'new' design curriculum are to improve student learning through effective implementation of practice. The curriculum promotes critical thinking, problem solving skills, and creativity. Realistic issues are integrated into the design studios - real programs, real sites, cost estimating, and scheduling. We are integrating 'the basics' architectural history, architectural theory, drawing, and technical courses (such as structures and environmental systems) with design. In the design studio courses, we are attempting to find balance and connection, and increase the awareness of the interrelationships between these areas of study for the students. Faculty, practitioners, and students know that learning in a compartmental fashion has never been that successful. We look towards this new integrative design studio approach as a better way to prepare our students for the demands of professional life.

关键词： Curricula

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Relevance of Research Methods for the Design of Urban Open Public Spaces for Persons with Visual Impairments

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Proceedings of the Human Factors and Ergonomics Society Annual Meeting 2000年第8期44卷 52 - 55页

作者： Marta Dischinger Vera Helena Moro Bins Ely Lecturer at the Architecture Department of the Federal University of Santa Catarina BrazilResearch Student at the Architectural Design Department Chalmers Technological University Production Engineering Program – Federal University of Santa Catarina Brazil

In spite of the advances in high technological research creating devices to support spatial orientation of visually impaired persons, they still confront a difficult situation in public urban spaces, which are seldom accessible to them. Design solutions aiming to improve their accessibility means to enhance their perception and understanding of space, to increase their possibilities of orientation and of taking independent decisions, and also to enable them participate in the city life. For a design of this kind it is necessary to understand their rights as citizens, and their particular needs and problems arising from the reduction, or absence of vision. To reach understanding of the problem, from another frame of reference that is not visual, it is essential to develop special research methods to analyse urban spaces, and to obtain first-hand information about spatial experiences of visually impaired persons.

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Relevance of research methods for the design of urban open public spaces for persons with visual impairments

Relevance of research methods for the design of urban open p...

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Proceedings of the XIVth Triennial Congress of the International Ergonomics Association and 44th Annual Meeting of the Human Factors and Ergonomics Association, 'Ergonomics for the New Millennnium'

作者： Dischinger, Marta Ely, Vera Helena Moro Bins Architecture Department Federal University of Santa Catarina Brazil Architectural Design Department Chalmers Technological University Sweden Cx Postal 10060 88062-970 Florianopolis SC Brazil Production Engineering Program Federal University of Santa Catarina Brazil Rua prof. Marcos Cardoso Filho 597 88037-040 Florianopolis SC Brazil

关键词： Ergonomics

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