Do Heat Pump Clothes Dryers Make Sense for the U.S. Market (open access)

Do Heat Pump Clothes Dryers Make Sense for the U.S. Market

Heat pump clothes dryers (HPCDs) can be as much as 50percent more energy-efficient than conventional electric resistance clothes dryers, and therefore have the potential to save substantial amounts of electricity. While not currently available in the U.S., there are manufacturers in Europe and Japan that produce units for those markets. Drawing on analysis conducted for the U.S. Department of Energy's (DOE) current rulemaking on amended standards for clothes dryers, this paper evaluates the cost-effectiveness of HPCDs in American homes, as well as the national impact analysis for different market share scenarios. In order to get an accurate measurement of real energy savings potential, the paper offers a new energy use calculation methodology that takes into account the most current data on clothes washer cycles, clothes dryer usage frequency, remaining moisture content, and load weight per cycle, which is very different from current test procedure values. Using the above methodology along with product cost estimates developed by DOE, the paper presents the results of a life-cycle cost analysis of the adoption of HPCDs in a representative sample of American homes. The results show that HPCDs have positive economic benefits only for households with high clothes dryer usage or for households with …
Date: May 14, 2010
Creator: Meyers, Steve; Franco, Victor; Lekov, Alex; Thompson, Lisa & Sturges, Andy
Object Type: Article
System: The UNT Digital Library
Characterization of the role of Fhit in maintenance of genomic integrity following low dose radiation, in vivo and in vitro (open access)

Characterization of the role of Fhit in maintenance of genomic integrity following low dose radiation, in vivo and in vitro

The major goal of this study is to determine the effects of the Fhit pathway on low dose (< 0.1 Gy) ionizing radiation (IR)-induced genetic instability. Reduction of Fhit protein expression is observed in most solid tumors particularly in those tumors resulting from exposure to environmental carcinogens. Therefore, characterization of the role of the Fhit-dependent pathway in preventing low dose IR-induced genetic instability will provide useful parameters for evaluating the low dose IR-induced risk of mutagenesis and carcinogenesis. We pursued 3 specific aims to study our hypothesis that the Fhit-dependent pathways maintain genomic integrity through adjusting checkpoint response and repair genes expression following low dose IR. Aim 1: Determine whether Fhit interaction with RPA is necessary for Fhit to affect the cellular response to low dose IR. We combined the approaches of in vitro (GST pull-down and site-directed mutagenesis) and in vivo (observing the co-localization and immunoprecipitation of Fhit and RPA in Fhit knock out mouse cells transfected with mutant Fhit which has lost ability to interact with RPA in vitro). Aim 2: Determine the role of genes whose expression is affected by Fhit in low dose irradiated cells. We analyzed the distinct signature of gene expression in low dose …
Date: May 14, 2010
Creator: Wang, Ya
Object Type: Report
System: The UNT Digital Library
Two-photon double ionization of the helium atom by ultrashort pulses (open access)

Two-photon double ionization of the helium atom by ultrashort pulses

Two-photon double ionization of the helium atom was the subject of early experiments at FLASH and will be the subject of future benchmark measurements of the associated electron angular and energy distributions. As the photon energy of a single femtosecond pulse is raised from the threshold for two-photon double ionization at 39.5 eV to beyond the sequential ionization threshold at 54.4 eV, the electron ejection dynamics change from the highly correlated motion associated with nonsequential absorption to the much less correlated sequential ionization process. The signatures of both processes have been predicted in accurate \textit{ab initio} calculations of the joint angular and energy distributions of the electrons, and those predictions contain some surprises. The dominant terms that contribute to sequential ionization make their presence apparent several eV below that threshold. In two-color pump probe experiments with short pulses whose central frequencies require that the sequential ionization process necessarily dominates, a two-electron interference pattern emerges that depends on the pulse delay and the spin state of the atom.
Date: May 14, 2010
Creator: Palacios, Alicia; Horner, Daniel A.; Rescigno, Thomas N. & McCurdy, C. William
Object Type: Article
System: The UNT Digital Library
Comparison of Demand Response Performance with an EnergyPlus Model in a Low Energy Campus Building (open access)

Comparison of Demand Response Performance with an EnergyPlus Model in a Low Energy Campus Building

We have studied a low energy building on a campus of the University of California. It has efficient heating, ventilation, and air conditioning (HVAC) systems, consisting of a dual-fan/dual-duct variable air volume (VAV) system. As a major building on the campus, it was included in two demand response (DR) events in the summers of 2008 and 2009. With chilled water supplied by thermal energy storage in the central plant, cooling fans played a critical role during DR events. In this paper, an EnergyPlus model of the building was developed and calibrated. We compared both whole-building and HVAC fan energy consumption with model predictions to understand why demand savings in 2009 were much lower than in 2008. We also used model simulations of the study building to assess pre-cooling, a strategy that has been shown to improve demand saving and thermal comfort in many types of building. This study indicates a properly calibrated EnergyPlus model can reasonably predict demand savings from DR events and can be useful for designing or optimizing DR strategies.
Date: May 14, 2010
Creator: Dudley, Junqiao Han; Black, Doug; Apte, Mike; Piette, Mary Ann & Berkeley, Pam
Object Type: Article
System: The UNT Digital Library
Solar access of residential rooftops in four California cities (open access)

Solar access of residential rooftops in four California cities

Shadows cast by trees and buildings can limit the solar access of rooftop solar-energy systems, including photovoltaic panels and thermal collectors. This study characterizes residential rooftop shading in Sacramento, San Jose, Los Angeles and San Diego, CA. Our analysis can be used to better estimate power production and/or thermal collection by rooftop solar-energy equipment. It can also be considered when designing programs to plant shade trees. High-resolution orthophotos and LiDAR (Light Detection And Ranging) measurements of surface height were used to create a digital elevation model of all trees and buildings in a well-treed 2.5-4 km{sup 2} residential neighborhood. On-hour shading of roofing planes (the flat elements of roofs) was computed geometrically from the digital elevation model. Values in future years were determined by repeating these calculations after simulating tree growth. Parcel boundaries were used to determine the extent to which roofing planes were shaded by trees and buildings in neighboring parcels. For the subset of S+SW+W-facing planes on which solar equipment is commonly installed for maximum solar access, absolute light loss in spring, summer and fall peaked about two to four hours after sunrise and about two to four hours before sunset. The fraction of annual insolation lost to …
Date: May 14, 2010
Creator: Levinson, Ronnen; Akbari, Hashem & Pomerantz, Melvin
Object Type: Article
System: The UNT Digital Library
Quantitative Analysis of the Principal-Agent Problem in Commercial Buildings in the U.S.: Focus on Central Space Heating and Cooling (open access)

Quantitative Analysis of the Principal-Agent Problem in Commercial Buildings in the U.S.: Focus on Central Space Heating and Cooling

We investigate the existence of the principal-agent (PA) problem in non-government, non-mall commercial buildings in the U.S. in 2003. The analysis concentrates on space heating and cooling energy consumed by centrally installed equipment in order to verify whether a market failure caused by the PA problem might have prevented the installation of energy-efficient devices in non-owner-occupied buildings (efficiency problem) and/or the efficient operation of space-conditioning equipment in these buildings (usage problem). Commercial Buildings Energy Consumption Survey (CBECS) 2003 data for single-owner, single-tenant and multi-tenant occupied buildings were used for conducting this evaluation. These are the building subsets with the appropriate conditions for assessing both the efficiency and the usage problems. Together, these three building types represent 51.9percent of the total floor space of all buildings with space heating and 59.4percent of the total end-use energy consumption of such buildings; similarly, for space cooling, they represent 52.7percent of floor space and 51.6percent of energy consumption. Our statistical analysis shows that there is a usage PA problem. In space heating it applies only to buildings with a small floor area (&lt;_50,000 sq. ft.). We estimate that in 2003 it accounts for additional site energy consumption of 12.3 (+ 10.5 ) TBtu (primary …
Date: May 14, 2010
Creator: Blum, Helcio & Sathaye, Jayant
Object Type: Report
System: The UNT Digital Library
List of Contractors to Support Anthrax Remediation (open access)

List of Contractors to Support Anthrax Remediation

This document responds to a need identified by private sector businesses for information on contractors that may be qualified to support building remediation efforts following a wide-area anthrax release.
Date: May 14, 2010
Creator: Judd, Kathleen S. & Lesperance, Ann M.
Object Type: Report
System: The UNT Digital Library
Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain (open access)

Measuring solar reflectance Part I: Defining a metric that accurately predicts solar heat gain

Solar reflectance can vary with the spectral and angular distributions of incident sunlight, which in turn depend on surface orientation, solar position and atmospheric conditions. A widely used solar reflectance metric based on the ASTM Standard E891 beam-normal solar spectral irradiance underestimates the solar heat gain of a spectrally selective 'cool colored' surface because this irradiance contains a greater fraction of near-infrared light than typically found in ordinary (unconcentrated) global sunlight. At mainland U.S. latitudes, this metric RE891BN can underestimate the annual peak solar heat gain of a typical roof or pavement (slope {le} 5:12 [23{sup o}]) by as much as 89 W m{sup -2}, and underestimate its peak surface temperature by up to 5 K. Using R{sub E891BN} to characterize roofs in a building energy simulation can exaggerate the economic value N of annual cool-roof net energy savings by as much as 23%. We define clear-sky air mass one global horizontal ('AM1GH') solar reflectance R{sub g,0}, a simple and easily measured property that more accurately predicts solar heat gain. R{sub g,0} predicts the annual peak solar heat gain of a roof or pavement to within 2 W m{sup -2}, and overestimates N by no more than 3%. R{sub g,0} …
Date: May 14, 2010
Creator: Levinson, Ronnen; Akbari, Hashem & Berdahl, Paul
Object Type: Article
System: The UNT Digital Library
Treatment of Anthrax Disease Frequently Asked Questions (open access)

Treatment of Anthrax Disease Frequently Asked Questions

This document provides a summary of Frequently Asked Questions (FAQs) on the treatment of anthrax disease caused by a wide-area release of Bacillus anthracis spores as an act bioterrorism. These FAQs are intended to provide the public health and medical community, as well as others, with guidance and communications to support the response and long-term recovery from an anthrax event.
Date: May 14, 2010
Creator: Judd, Kathleen S.; Young, Joan E.; Lesperance, Ann M. & Malone, John D.
Object Type: Report
System: The UNT Digital Library
Scenario Analysis of Peak Demand Savings for Commercial Buildings with Thermal Mass in California (open access)

Scenario Analysis of Peak Demand Savings for Commercial Buildings with Thermal Mass in California

This paper reports on the potential impact of demand response (DR) strategies in commercial buildings in California based on the Demand Response Quick Assessment Tool (DRQAT), which uses EnergyPlus simulation prototypes for office and retail buildings. The study describes the potential impact of building size, thermal mass, climate, and DR strategies on demand savings in commercial buildings. Sensitivity analyses are performed to evaluate how these factors influence the demand shift and shed during the peak period. The whole-building peak demand of a commercial building with high thermal mass in a hot climate zone can be reduced by 30percent using an optimized demand response strategy. Results are summarized for various simulation scenarios designed to help owners and managers understand the potential savings for demand response deployment. Simulated demand savings under various scenarios were compared to field-measured data in numerous climate zones, allowing calibration of the prototype models. The simulation results are compared to the peak demand data from the Commercial End-Use Survey for commercial buildings in California. On the economic side, a set of electricity rates are used to evaluate the impact of the DR strategies on economic savings for different thermal mass and climate conditions. Our comparison of recent simulation …
Date: May 14, 2010
Creator: Yin, Rongxin; Kiliccote, Sila; Piette, Mary Ann & Parrish, Kristen
Object Type: Article
System: The UNT Digital Library
Measuring solar reflectance Part II: Review of practical methods (open access)

Measuring solar reflectance Part II: Review of practical methods

A companion article explored how solar reflectance varies with surface orientation and solar position, and found that clear sky air mass 1 global horizontal (AM1GH) solar reflectance is a preferred quantity for estimating solar heat gain. In this study we show that AM1GH solar reflectance R{sub g,0} can be accurately measured with a pyranometer, a solar spectrophotometer, or an updated edition of the Solar Spectrum Reflectometer (version 6). Of primary concern are errors that result from variations in the spectral and angular distributions of incident sunlight. Neglecting shadow, background and instrument errors, the conventional pyranometer technique can measure R{sub g,0} to within 0.01 for surface slopes up to 5:12 [23{sup o}], and to within 0.02 for surface slopes up to 12:12 [45{sup o}]. An alternative pyranometer method minimizes shadow errors and can be used to measure R{sub g,0} of a surface as small as 1 m in diameter. The accuracy with which it can measure R{sub g,0} is otherwise comparable to that of the conventional pyranometer technique. A solar spectrophotometer can be used to determine R*{sub g,0}, a solar reflectance computed by averaging solar spectral reflectance weighted with AM1GH solar spectral irradiance. Neglecting instrument errors, R*{sub g,0} matches R{sub g,0} …
Date: May 14, 2010
Creator: Levinson, Ronnen; Akbari, Hashem & Berdahl, Paul
Object Type: Article
System: The UNT Digital Library
Business Continuity Planning Resources for Small- and Medium-Sized Businesses (open access)

Business Continuity Planning Resources for Small- and Medium-Sized Businesses

This document/memo summarizes existing resources and guidance on business continuity planning for small- to medium-sized businesses. DTRA will share this information with large commercial businesses who identified the need to help their suppliers and other key collaborators prepare business continuity plans in order to speed recovery from a wide-area bioterrorism incident.
Date: May 14, 2010
Creator: Judd, Kathleen S. & Lesperance, Ann M.
Object Type: Report
System: The UNT Digital Library
Toward the Holy Grail of Perfect Information: Lessons Learned Implementing an Energy Information System in a Commercial Building (open access)

Toward the Holy Grail of Perfect Information: Lessons Learned Implementing an Energy Information System in a Commercial Building

Energy information systems (real-time acquisition, analysis, and presentation of information from energy end-uses) in commercial buildings have demonstrated value as tools for improving energy efficiency and thermal comfort. These improvements include characterization through benchmarking, identification of retrofit opportunities, anomaly detection to inform retro-commissioning, and feedback to occupants to encourage shifts in behavior. Energy information systems can play a vital role in achieving a variety of ambitious sustainability goals for the existing stock of commercial buildings, but their implementation is often fraught with pitfalls. In this paper, we present a case study of an EIS and sub-metering project executed in a representative commercial office building. We describe the building, highlight a few of its problems, and detail the hardware and software technologies we employed to address them. We summarize the difficulties encountered and lessons learned, and suggest general guidelines for future EIS projects to improve performance and save energy in the commercial building fleet. These guidelines include measurement criteria, monitoring strategies, and analysis methods. In particular, we propose processes for: - Defining project goals, - Selecting end-use targets and depth of metering, - Selecting contractors and software vendors, - Installing and networking measurement devices, - Commissioning and using the energy information …
Date: May 14, 2010
Creator: Kircher, Kevin; Ghatikar, Girish; Greenberg, Steve; Watson, Dave; Diamond, Rick; Sartor, Dale et al.
Object Type: Article
System: The UNT Digital Library
Findings from Seven Years of Field Performance Data for Automated Demand Response in Commercial Buildings (open access)

Findings from Seven Years of Field Performance Data for Automated Demand Response in Commercial Buildings

California is a leader in automating demand response (DR) to promote low-cost, consistent, and predictable electric grid management tools. Over 250 commercial and industrial facilities in California participate in fully-automated programs providing over 60 MW of peak DR savings. This paper presents a summary of Open Automated DR (OpenADR) implementation by each of the investor-owned utilities in California. It provides a summary of participation, DR strategies and incentives. Commercial buildings can reduce peak demand from 5 to 15percent with an average of 13percent. Industrial facilities shed much higher loads. For buildings with multi-year savings we evaluate their load variability and shed variability. We provide a summary of control strategies deployed, along with costs to install automation. We report on how the electric DR control strategies perform over many years of events. We benchmark the peak demand of this sample of buildings against their past baselines to understand the differences in building performance over the years. This is done with peak demand intensities and load factors. The paper also describes the importance of these data in helping to understand possible techniques to reach net zero energy using peak day dynamic control capabilities in commercial buildings. We present an example in which …
Date: May 14, 2010
Creator: Kiliccote, Sila; Piette, Mary Ann; Mathieu, Johanna & Parrish, Kristen
Object Type: Article
System: The UNT Digital Library
Heat Pump Water Heaters and American Homes: A Good Fit? (open access)

Heat Pump Water Heaters and American Homes: A Good Fit?

Heat pump water heaters (HPWHs) are over twice as energy-efficient as conventional electric resistance water heaters, with the potential to save substantial amounts of electricity. Drawing on analysis conducted for the U.S. Department of Energy's recently-concluded rulemaking on amended standards for water heaters, this paper evaluates key issues that will determine how well, and to what extent, this technology will fit in American homes. The key issues include: 1) equipment cost of HPWHs; 2) cooling of the indoor environment by HPWHs; 3) size and air flow requirements of HPWHs; 4) performance of HPWH under different climate conditions and varying hot water use patterns; and 5) operating cost savings under different electricity prices and hot water use. The paper presents the results of a life-cycle cost analysis of the adoption of HPWHs in a representative sample of American homes, as well as national impact analysis for different market share scenarios. Assuming equipment costs that would result from high production volume, the results show that HPWHs can be cost effective in all regions for most single family homes, especially when the water heater is not installed in a conditioned space. HPWHs are not cost effective for most manufactured home and multi-family installations, …
Date: May 14, 2010
Creator: Franco, Victor; Lekov, Alex; Meyers, Steve & Letschert, Virginie
Object Type: Article
System: The UNT Digital Library
Economics of Condensing Gas Furnaces and Water Heaters Potential in Residential Single Family Homes (open access)

Economics of Condensing Gas Furnaces and Water Heaters Potential in Residential Single Family Homes

Residential space and water heating accounts for over 90percent of total residential primary gas consumption in the United States. Condensing space and water heating equipment are 10-30percent more energy-efficient than conventional space and water heating. Currently, condensing gas furnaces represent 40 percent of shipments and are common in the Northern U.S. market. Meanwhile, manufacturers are planning to develop condensing gas storage water heaters to qualify for Energy Star? certification. Consumers, installers, and builders who make decisions about installing space and water heating equipment generally do not perform an analysis to assess the economic impacts of different combinations and efficiencies of space and water heating equipment. Thus, equipment is often installed without taking into consideration the potential life-cycle economic and energy savings of installing space and water heating equipment combinations. Drawing on previous and current analysis conducted for the United States Department of Energy rulemaking on amended standards for furnaces and water heaters, this paper evaluates the extent to which condensing equipment can provide life-cycle cost-effectiveness in a representative sample of single family American homes. The economic analyses indicate that significant energy savings and consumer benefits may result from large-scale introduction of condensing water heaters combined with condensing furnaces in U.S. …
Date: May 14, 2010
Creator: Lekov, Alex; Franco, Victor & Meyers, Steve
Object Type: Article
System: The UNT Digital Library
A Benchmark Comparison of Monte Carlo Particle Transport Algorithms for Binary Stochastic Mixtures (open access)

A Benchmark Comparison of Monte Carlo Particle Transport Algorithms for Binary Stochastic Mixtures

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Date: May 14, 2010
Creator: Brantley, P
Object Type: Article
System: The UNT Digital Library