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Modeling particle loss in ventilation ducts

Description: Empirical equations were developed and applied to predict losses of 0.01-100 {micro}m airborne particles making a single pass through 120 different ventilation duct runs typical of those found in mid-sized office buildings. For all duct runs, losses were negligible for submicron particles and nearly complete for particles larger than 50 {micro}m. The 50th percentile cut-point diameters were 15 {micro}m in supply runs and 25 {micro}m in return runs. Losses in supply duct runs were higher than in… more
Date: April 1, 2003
Creator: Sippola, Mark R. & Nazaroff, William W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

FIELD EVALUATION OF IMPROVED METHODS FOR MEASURING THE AIR LEAKAGE OF DUCT SYSTEMS UNDER NORMAL OPERATING CONDITIONS IN 51 HOMES

Description: Duct leakage in forced-air distribution systems has been recognized for years as a major source of energy losses in residential buildings. Unfortunately, the distribution of leakage across homes is far from uniform, and measuring duct leakage under normal operating conditions has proven to be difficult. Recently, two new methods for estimating duct leakage at normal operating conditions have been devised. These are called the nulling test and the Delta-Q test. Small exploratory studies have bee… more
Date: October 18, 2003
Creator: Francisco, Paul W.; Palmiter, Larry; Kruse, Erin & Davis, Bob
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Glovebox Dismantlement and Equipment Protection in Contaminated Environments

Description: It has been revealed from the experiences of Decontamination and Decommissioning (D&D) activities that even a small improvement in performance can result in significant risk reduction and cost savings. For example, Race Scan Ear Mic System, which was originally developed for communications between racecar drivers and crews in loud environments, has been successfully applied to D&D work and proved to enhance worker safety and communications. Glovebox dismantlement is an important and cos… more
Date: February 27, 2003
Creator: Kitamura, Akihiro; Stallings, Ellen & Wilburn, Dianne W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Minimum Leakage/Low Cost Duct Connections

Description: Leaky and disconnected joints in HVAC air distribution systems are extremely widespread. The average efficiency of duct systems in homes in the US is approximately 55% with approximately 60% of the loss due to duct leakage. Beyond the energy and emissions penalties caused by these leaks, leaky systems have detrimental comfort, health, and safety effects. The health and safety effects include the delivery of combustion products into the homes due to leakage induced depressurization. Current duct… more
Date: August 1, 2003
Creator: Proctor, John
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental and Numerical Investigation of Impinging Jet Flow in Square Ducts Intersecting at 90 Degrees

Description: An experimental and numerical investigation has been conducted on flow through two square ducts with a 2:1 hydraulic diameter ratio joined at a right angle. Measurements of the velocity field were acquired using a laser Doppler velocimeter at various planar locations throughout the ducts at a nominal Reynolds number of 68,000. Pressure drop measurements were taken for 3 Reynolds numbers between 46,000 and 93,000. Computational fluid dynamics (CFD) analyses were performed using STAR-CD to determ… more
Date: October 20, 2003
Creator: Corson, David & Vassallo, Peter
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Analysis of U.S. residential air leakage database

Description: The air leakage of a building envelope can be determined from fan pressurization measurements with a blower door. More than 70,000 air leakage measurements have been compiled into a database. In addition to air leakage, the database includes other important characteristics of the dwellings tested, such as floor area, year built, and location. There are also data for some houses on the presence of heating ducts, and floor/basement construction type. The purpose of this work is to identify house … more
Date: July 1, 2003
Creator: Chan, Wanyu R.; Price, Phillip N.; Sohn, Michael D. & Gadgil, Ashok J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Advanced Duct Sealing Testing

Description: Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have typically shown that these seals tend to fail over extended periods of time. The Lawrence Berkeley Na… more
Date: August 1, 2003
Creator: Sherman, Max H. & Walker, Iain S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laboratory Evaluation of the Delta Q Test for Duct Leakage

Description: Using a residential-size duct system in a controlled laboratory setting, the repeatability and accuracy of the Delta Q test for air leakage in residential duct systems have been measured. More than 100 Delta Q tests were performed. These were compared with results using fan pressurization and also with results of a procedure (Delta Q Plus) that uses leakage hole-size information to select the leakage pressures to be used in the Delta Q algorithm. The average error in supply or return leakage fo… more
Date: May 1, 2003
Creator: Andrews, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Evaluation of Gas Filled Plenum (GFP) Insulation for Ducts

Description: Forced-air heating and cooling system ducts are often located outside conditioned space in US houses. For these systems to perform efficiently it is important that these ducts be well insulated. Common practice is to use a glass fiber wrap around the ducts--either field applied or more commonly, integrated into a flexible duct. Most duct insulation has an R-value of 4.2, with R6 and R8 ducts also occasionally used. With glass fiber insulation being about R4 per inch (RSI 0.28/cm), this adds 2 t… more
Date: January 26, 2003
Creator: Walker, Iain S. & Guillot, Cyril
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Improving air handler efficiency in residential HVAC applications

Description: In continuing the development of energy efficiency standards, consideration has turned to air handlers used for heating and air conditioning of consumer residences. These air handlers have typical efficiencies of about 10% to 15% due to poor electric motor performance and aerodynamically poor fans and fan housings. This study was undertaken to examine some of these performance issues, under carefully controlled laboratory conditions, to support potential regulatory changes. In addition, this st… more
Date: August 1, 2003
Creator: Walker, Iain S.; Mingee, Michael D. & Brenner, Douglas E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experimental Evaluation of Gas Filled Plenum (GFP) Insulation for Ducts

Description: Forced-air heating and cooling system ducts are often located outside conditioned space in US houses. For these systems to perform efficiently it is important that these ducts be well insulated. Common practice is to use a glass fiber wrap around the ducts--either field applied or more commonly, integrated into a flexible duct. Most duct insulation has an R-value of 4.2, with R6 and R8 ducts also occasionally used. With glass fiber insulation being about R4 per inch (RSI 0.28/cm), this adds 2 t… more
Date: January 26, 2003
Creator: Walker, Iain S. & Guillot, Cyril
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Experiments measuring particle deposition from fully developed turbulent flow in ventilation ducts

Description: Particle deposition in ventilation ducts influences particle exposures of building occupants and may lead to a variety of indoor air quality concerns. Experiments have been performed in a laboratory to study the effects of particle size and air speed on deposition rates of particles from turbulent air flows in galvanized steel and internally insulated ducts with hydraulic diameters of 15.2 cm. The duct systems were constructed of materials typically found in commercial heating, ventilating and … more
Date: August 1, 2003
Creator: Sippola, Mark R. & Nazaroff, William W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Register Closing Effects on Forced Air Heating System Performance

Description: Closing registers in forced air heating systems and leaving some rooms in a house unconditioned has been suggested as a method of quickly saving energy for California consumers. This study combined laboratory measurements of the changes in duct leakage as registers are closed together with modeling techniques to estimate the changes in energy use attributed to closing registers. The results of this study showed that register closing led to increased energy use for a typical California house ove… more
Date: November 1, 2003
Creator: Walker, Iain S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Case study field evaluation of a systems approach to retrofitting a residential HVAC system

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 accom… more
Date: September 1, 2003
Creator: Walker, Iain S.; McWiliams, Jennifer A. & Konopacki, Steven J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Duct leakage impacts on VAV system performance in California large commercial buildings

Description: The purpose of this study is to evaluate the variability of duct leakage impacts on air distribution system performance for typical large commercial buildings in California. Specifically, a hybrid DOE-2/TRNSYS sequential simulation approach was used to model the energy use of a low-pressure terminal-reheat variable-air-volume (VAV) HVAC system with six duct leakage configurations (tight to leaky) in nine prototypical large office buildings (representing three construction eras in three Californ… more
Date: October 1, 2003
Creator: Wray, Craig P. & Matson, Nance E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Corrosion of Exhaust and Filtration Equipment in a Radioactive Waste Incinerator

Description: Condensation in the exhaust gas system of an incinerator burning low activity radioactive wastes led to numerous corrosion developments and rapid failure of the discharge filters. The problem was traced to insufficient reheat of the exhaust gases following scrubbing. Rust particulate and moisture loaded the filters, leading to water accumulation, chloride cracking of the filter housings, and plugging and tearing of the filter media itself. To mitigate the problem, the exhaust gas temperature wa… more
Date: October 31, 2003
Creator: Jenkins, C. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluation of PEGIT Duct Connection System

Description: Most air duct system components are assembled in the field and are mechanically fastened by sheet metal screws (for sheet metal-to-sheet metal) or by drawbands (for flex duct-to-sheet metal). Air sealing is separate from this mechanical fastening and is usually achieved using tape or mastic products after mechanical fastening. Field observations have shown that mechanical fastening rarely meets code or manufacturers requirements and that sealing procedures are similarly inconsistent. To address… more
Date: August 1, 2003
Creator: Walker, Iain S.; Brenner, Douglas E.; Sherman, Max H. & Dickerhoff, Darryl J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A HISTORY OF ASHRAE STANDARDS 152P.

Description: The American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) has been developing a standard test method for evaluating the efficiency of ducts and other types of thermal distribution systems in single-family residential buildings. This report presents an overview of the structure, function, and historical development of this test method.
Date: October 31, 2003
Creator: Andrews, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Thermal Performance of Unvented Attics in Hot-Dry Climates: Results from Building America; Preprint

Description: Unvented attics have become a more common design feature implemented by Building America partners in hot-dry climates of the United States. More attention is being focused on how this approach affects heating and cooling energy consumption. By eliminating the ridge and eave vents that circulate outside air through the attic and by moving the insulation from the attic floor to the underside of the roof, an unvented attic become a semi-conditioned space, creating a more benign environment for spa… more
Date: January 1, 2003
Creator: Hendron, R.; Farrar-Nagy, S.; Anderson, R.; Reeves, P. & Hancock, E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Duct thermal performance models for large commercial buildings

Description: Despite the potential for significant energy savings by reducing duct leakage or other thermal losses from duct systems in large commercial buildings, California Title 24 has no provisions to credit energy-efficient duct systems in these buildings. A substantial reason is the lack of readily available simulation tools to demonstrate the energy-saving benefits associated with efficient duct systems in large commercial buildings. The overall goal of the Efficient Distribution Systems (EDS) projec… more
Date: October 1, 2003
Creator: Wray, Craig P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Effect of Airflow and Heat Input Rates on Duct Efficiency.

Description: Reducing the airflow and heat input rates of a furnace that is connected to a duct system in thermal contact with unconditioned spaces can significantly reduce thermal distribution efficiency. This is a straightforward theoretical calculation based on the increased residence time of the air in the duct at the lower flow rate, which results in greater conduction losses. Experimental tests in an instrumented residential-size duct system have confirmed this prediction. Results are compared with th… more
Date: May 28, 2003
Creator: Andrews, J. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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