Architecture Commons^™

The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu

Durham School of Architectural Engineering and Construction: Faculty Publications

A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively …

Teaching Sustainable Design Using Bim And Project-Based Energy Simulations, Zhigang Shen, Wayne Jensen, Tim Wentz, Bruce Fischer

Durham School of Architectural Engineering and Construction: Faculty Publications

The cross-disciplinary nature of energy-efficient building design has created many challenges for architecture, engineering and construction instructors. One of the technical challenges in teaching sustainable building design is enabling students to quantitatively understand how different building designs affect a building’s energy performance. Concept based instructional methods fall short in evaluating the impact of different design choices on a buildings’ energy consumption. Building Information Modeling (BIM) with energy performance software provides a feasible tool to evaluate building design parameters. One notable advantage of this tool is its ability to couple 3D visualization of the structure with energy performance analysis without requiring …

Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The study introduces the motivation, presents the simplified modeling methodology, and illustrates the model and simulating structure. A preliminary evaluation of the method is conducted with two simple simulations. The proposed “node-branch-state” modeling approach could be easily modified, expanded and integrated into a detailed …

Ann Based Load Identification And Forecasting System For The Built Environment, Hosen Hasna

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

"Phantom Loads" cause energy waste in homes and the built environment as a whole. Consumers spend more than $3 billion a year on "Phantom Load" in the United States alone. The goal of this work is to conserve energy by increasing consumer awareness on their energy usage and appropriate tools which in turn will be reducing and /or eliminating phantom loads and mismanagement of the load in the built environment. A further goal is to improve upon existing power distribution systems in the built environment with limited hardware additions to increase energy conservation. This work investigates remote identification of load …

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal., Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …

A Virtual Supply Airflow Rate Meter In Rooftop Air Conditioning Units, Daihong Yu

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Virtual sensing technology aims to estimate difficult to measure, expensive, or new quantities by using multifarious mathematical models along with non-invasive and low-cost measurements. Such embedded intelligence is a key to improving the performance of building systems in terms of functionality, safety, energy efficiency, environmental impacts, and costs. Considering the progress that has been achieved over many various fields (e.g., process controls, automobiles, avionics, autonomous robots, telemedicine) within the last two decades, numerous intelligent features have been incorporated and enabled that would otherwise not be possible or economical.

To identify the potential opportunities and research/development needs of virtual sensing technology …

A Virtual Supply Airflow Rate Meter In Rooftop Air Conditioning Units, Daihong Yu

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Virtual sensing technology aims to estimate difficult to measure, expensive, or new quantities by using multifarious mathematical models along with non-invasive and low-cost measurements. Such embedded intelligence is a key to improving the performance of building systems in terms of functionality, safety, energy efficiency, environmental impacts, and costs. Considering the progress that has been achieved over many various fields (e.g., process controls, automobiles, avionics, autonomous robots, telemedicine) within the last two decades, numerous intelligent features have been incorporated and enabled that would otherwise not be possible or economical.

To identify the potential opportunities and research/development needs of virtual sensing technology …

Lv-11-C031: Measured Levels Of Hospital Noise Before, During, And After Renovation Of A Hospital Wing, And A Survey Of Resulting Patient Perception, Cassandra H. Wiese, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Acoustic conditions in hospitals can negatively influence a patient’s physical and psychological health. This paperreports on noise levels measured before, during, and after renovation of a hospital wing in an Omaha, Nebraska, facility thatregularly receives unsatisfactory noise scores on patient satisfaction surveys. Sound pressure levels were logged every 10seconds over four-day periods in three different locations: at the nurses' station, in the hallway, and in a nearby patient’sroom. The resulting data have been analyzed in terms of A-weighted equivalent sound levels (LAeq) as well as variousexceedance levels (Ln). Results indicate that sound levels did not change much due to the …

Industry-Experienced Graduate Student Program: Innovative Collaboration In Architectural Engineering At The University Of Nebraska–Lincoln, Clarence E. Waters, Steve Alvine, Michelle L. Eble-Hankins

Durham School of Architectural Engineering and Construction: Faculty Publications

In 2001, the Architectural Engineering Department at the University of Nebraska–Lincoln, along with industry partners, established an industry-experienced graduate student program. The program was developed to bring experienced design professionals to collaborate with the industry while pursuing a Ph.D. in architectural engineering. This program is designed to be mutually beneficial to industry partners, -graduate students, the University of Nebraska–Lincoln Architectural Engineering Department, and the building industry at large. The first doctoral candidate in the program graduated, and significant collaborative work was completed for the industry partner. All parties to this initial offering are pleased with the outcome and believe the …

Ab-10-018: The Effects Of Noise From Building Mechanical Systems With Tonal Components On Human Performance And Perception (1322-Rp), Erica E. Ryherd, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This study investigated the effects of noise from building mechanical systems with tonal components on human task performance and perception. Six different noise conditions based on in-situ measurements were reproduced in an office-like setting; all were set to approximately the same sound level (47 dBA) but could have one particular tonal frequency (120 Hz, 235 Hz, or 595 Hz) at one of two tonal prominence ratios (5 or 9). Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately 1 hour to each noise condition. Results show that the noise …

Ab-10-017: Combined Effects Of Noise And Temperature On Human Comfort And Performance (1128-Rp), Dale Tiller, Lily M. Wang, Amy Musser, Matthew Radik

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper summarizes results from an experiment designed to investigate the combined effects of noise and temperature on human thermal comfort and task performance. Thirty subjects (16 females, 14 males) were exposed to all combinations of five thermal conditions (PMV +1 [79.6°F:26.4°C], PMV +0.5 [75.8°F:24.3°C], PMV 0 [72.1°F:22.3°C], PMV -0.5 [68.3°F:20.2°C], and PMV -1 [64.6°F:18.1°C]), three RC noise levels (RC-30, RC-40, and RC-50), and two sound qualities (neutral and rumbly): all sounds mimicked noise from building ventilation systems. After a one-hour adaptation period at each condition, subjects rated their thermal comfort using the ASHRAE Thermal Comfort Scale and the Tenant …

Ab-10-019: Human Performance And Perception-Based Evaluations Of Indoor Noise Criteria For Rating Mechanical System Noise With Time-Varying Fluctuations (1322-Rp), Lily M. Wang, Cathleen C. Novak

Durham School of Architectural Engineering and Construction: Faculty Publications

The goal of this study was to investigate the effects of noise from building mechanical systems with time-varying fluctuations on human task performance and perception, and to determine how well current indoor noise rating methods account for this performance and perception. Six different noise conditions with varying degrees of time-varying fluctuations, many focused in the low frequency rumble region, were reproduced in an office-like setting. Thirty participants were asked to complete typing, grammatical reasoning, and math tasks plus subjective questionnaires, while being exposed for approximately one hour to each noise condition. Results show that the noise conditions with higher sound …

Ab-10-C037: Effects Of Noise From Building Mechanical Systems On Elementary School Student Achievement, Lauren M. Ronsse, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This project seeks to determine what relationship, if any, exists betweenbackground noise levels in elementary classrooms due to the building mechanicalsystems and student performance on achievement tests. Previous research inclassroom acoustics has clearly identified that lower background noise levelsresult in higher speech intelligibility which is crucial for the learning process;however, there is a lack of data correlating lower noise levels to improved studentachievement scores. For this study, background noise level measurements were madein 14 elementary schools in a public school system in Council Bluffs, Iowa, USA.The measurements were made in unoccupied classrooms with the central buildingmechanical systems activated. Second and …

Active Noise Barrier Minimizing Pressure Gradient, Carl Hart, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Minimization of the sound pressure field within the shadow zone of a noise barrier is achieved by reducing the pressure gradient along a line, at the top of a barrier, via active noise control. The noise control effectiveness of a barrier is increased by this strategy, especially for specific system configurations. The proposed method was evaluated by numerical simulation. Results indicate that system orientation has little effect on minimizing the pressure gradient at the top of the barrier when the error sensors are invisible to the primary noise disturbance. Highly effective control within the shadow zone and close to the …

Noise Propagation Through Open Windows Of Finite Depth Into An Enclosure, Caleb Sieck, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

Predicting the insertion loss of an opening backed with an enclosed space is important for building noise control. Recent research in sound transmission through apertures of finite depth in infinite rigid baffles has included the effects of propagating and evanescent modes within the aperture in order to extend models to higher frequencies. The present study extends the model to the case of the aperture backed by a cavity as opposed to sound radiating into half-space. The role of coupling between the aperture modes, radiation modes, and cavity modes in the transmission was investigated. The results were compared to those of …

Feasibility Study Of Solar Driven Underground Cooling System, Michel E. Shafik

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

In the United States the peak electrical use occurs during the summer. In addition, the building sector consumes a major portion of the annual electrical energy consumption. One of the main energy consuming components in the building sector is the Heating, Ventilation, and Air-Conditioning (HVAC) systems. This research studies the feasibility of implementing a solar driven underground cooling system that could contribute to reducing building cooling loads. The developed system consists of an Earth-to-Air Heat Exchanger (EAHE) coupled with a solar chimney that provides a natural cool draft to the test facility building at the Solar Energy Research Test Facility …

Evaluation Of A Virtual Refrigerant Charge Sensor, Woohyun Kim, James E. Braun, Haorong Li

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents a thorough evaluation of a method for determining refrigerant charge that employs low-cost, non-invasive measurements (i.e., surface mounted temperature measurements). The method could be used as part of a protocol for verified service providers (VSPs) in AC diagnostic tune-up or refrigerant charge, air flow (RCA) verification programs. Ultimately, the method could be embedded within a portable virtual refrigerant charge gauge for a technician’s use or permanently installed on the AC unit. The accuracy of the virtual refrigerant charge sensor method is evaluated in this paper using laboratory data for a number of different systems and over a …

Trees And Ice Storms: The Development Of Ice Storm–Resistant Urban Tree Populations (Second Edition), Richard J. Hauer, Jeffrey O. Dawson, Les P. Werner

USDA Forest Service / UNL Faculty Publications

Severe ice storms occur every year in the United States and Canada, particularly in the midwestern and eastern regions of the United States. Along with fires and wind, ice storms are a frequent and major natural disturbance factor in eastern deciduous forests. Likewise ice storms are responsible for deaths and injuries of people and cause dramatic damage and tree loss to urban forests. Ice storms annually result in millions of dollars in loss, and potentially billions of dollars in losses for extreme and widespread ice storms. Damage to electric distribution systems, blocked roadways, and property damage from fallen trees and …

Or-05-6-4: Relating Human Productivity And Annoyance To Indoor Noise Criteria Systems: A Low Frequency Analysis, Erica Eileen Bowden, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

A number of indoor noise criteria systems are used to quantify the background noise in a built environment, including Noise Criteria (NC), Balanced Noise Criteria (NCB), Room Criteria (RC), Room Criteria Mark II (RC Mark II), A-weighted Equivalent Sound Pressure Level (L_Aeq), and others. An on-going debate exists in the acoustical community over which criterion is the most appropriate to use in the variety of ambient noise situations encountered. In an effort to quantitatively support the use of individual criterion, this project subjectively correlates these various criteria with human task performance and perception. Eleven subjects participated in a …

Mechanical Damping System For Structures, Jay A. Puckett, Patrick S. Mcmanus, Homer R. Hamilton Iii

Durham School of Architectural Engineering and Construction: Faculty Publications

A mechanical damping system for a structure is provided. The mechanical damping system comprises a tubular impact frame secured to the structure. A support frame is secured to the structure with the support frame spaced from the impact frame. An elongated member is provided having a first end and a second end. The first end is secured within the support frame and the second end is free from connection and extends into the impact frame. At least one impact mass is secured to the second end of the elongated member, the impact mass movable within and contactable with the impact …

Comparison Of Radiated Power From Structurally Different Violins, Lily M. Wang, Courtney B. Burroughs

Durham School of Architectural Engineering and Construction: Faculty Publications

The acoustic power has been determined from intensity measurements on three structurally different violins: a Scherl and Roth student violin, Hutchins' SUS29S, and Hutchins' mezzo violin SUS 100. While each violin was bowed with an open-frame mechanical bowing machine, the intensity measurements were made by scanning each side of the bowing machine with an intensity probe. One-third octave band sound power levels of the acoustic radiation from each of the three instruments as each of the four open strings is bowed show that the structurally different mezzo violin produces greater power at low frequencies when the lowest (G) string is …

Motorized Insulated Damper Assembly For Furnace Systems, William Max Kirk, Timothy Wentz

Durham School of Architectural Engineering and Construction: Faculty Publications

A damper unit is provided that is adapted to be positioned in a furnace duct line. The damper unit has a housing which is in communication with a fresh air source and a furnace system. The housing has a damper blade which is moveable between an open position which allows air flow through the housing and a closed position which prevents air flow through the housing. The blade is coupled with a Solenoid so that when the Solenoid is activated the blade is moved to an open position allowing air flow through the housing. Further, a fan is located in …

Urban Geology—A Need And A Challenge, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Urban land uses are rapidly converting open land into intensively used land. Generally, in planning those uses, a comprehensive study has included everything except an evaluation of the land in three dimensions. Geologists are eminently well equipped to supply the missing data, but they must also be aware of the needs of the urban community and the kinds of information needed by planners if they are to write reports usable by planners. Urban and environmental geology is a newly expanding field in the use of geologic data to help solve some urban problems in the planning stage. It is likely …

Hog Houses For Nebraska, O. W. Sjogren, I. D. Wood

Nebraska Agricultural Experiment Station: Historical Circulars

The material contained in this bulletin is a culmination of several years' study and investigation of the different types of hog houses used in Nebraska. It is realized that the plans given will not suit all conditions that may arise, but an effort has been made to bring out the essential factors so that the plans may serve as a guide in planning a house suited to particular conditions.

Hog Houses For Nebraska, O. W. Sjogren, I. D. Wood

Nebraska Agricultural Experiment Station: Historical Circulars

The material contained in this bulletin is a culmination of several years' study and investigation of the different types of hog houses used in Nebraska. It is realized that the plans given will not suit all conditions that may arise, but an effort has been made to bring out the essential factors so that the plans may serve as a guide in planning a house suited to particular conditions.