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Telluric and D.C. Resistivity Techniques Applied to the Geophysical Investigation of Basin and Range Geothermal Systems, Part II: A Numberical Model Study of the Dipole-Dipole and Schlumberger Resistivity Methods

Description: This paper is a two-dimensional numerical model study and comparison of the polar dipole-dipole and Schlumberger resistivity arrays. A catalog of dipole-dipole and Schlumberger apparent resistivity pseudo-sections is presented. It is concluded that: for the Schlumberger array, data can be accurately interpreted only if the resistivity structure is horizontally layered, and conductive bodies having a depth of burial greater than their width are not observed; for the dipole-dipole array, complex anomaly patterns unrelated in appearance to the causative structure result from simple models, hence, a familiarity with model results is essential to interpretation of these data.
Date: June 1, 1977
Creator: Beyer, J.H.
Partner: UNT Libraries Government Documents Department

Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse-gas Emissions

Description: The aim of commissioning new buildings is to ensure that they deliver, if not exceed, the performance and energy savings promised by their design. When applied to existing buildings, commissioning identifies the almost inevitable 'drift' from where things should be and puts the building back on course. In both contexts, commissioning is a systematic, forensic approach to quality assurance, rather than a technology per se. Although commissioning has earned increased recognition in recent years - even a toehold in Wikipedia - it remains an enigmatic practice whose visibility severely lags its potential. Over the past decade, Lawrence Berkeley National Laboratory has built the world's largest compilation and meta-analysis of commissioning experience in commercial buildings. Since our last report (Mills et al. 2004) the database has grown from 224 to 643 buildings (all located in the United States, and spanning 26 states), from 30 to 100 million square feet of floorspace, and from $17 million to $43 million in commissioning expenditures. The recorded cases of new-construction commissioning took place in buildings representing $2.2 billion in total construction costs (up from 1.5 billion). The work of many more commissioning providers (18 versus 37) is represented in this study, as is more evidence of energy and peak-power savings as well as cost-effectiveness. We now translate these impacts into avoided greenhouse gases and provide new indicators of cost-effectiveness. We also draw attention to the specific challenges and opportunities for high-tech facilities such as labs, cleanrooms, data centers, and healthcare facilities. The results are compelling. We developed an array of benchmarks for characterizing project performance and cost-effectiveness. The median normalized cost to deliver commissioning was $0.30/ft2 for existing buildings and $1.16/ft2 for new construction (or 0.4% of the overall construction cost). The commissioning projects for which data are available revealed over 10,000 energy-related problems, resulting ...
Date: July 16, 2009
Creator: Mills, Evan
Partner: UNT Libraries Government Documents Department

An Analysis of Energy Use on Community College Campuses

Description: This paper provides an analysis of energy use on community college campuses which justifies the introduction of a simple model for describing that energy use. The model is then applied to the data from 80 campuses to determine average values for the parameters of the model. The model can be used to measure the energy savings of conservation programs as well as the cost avoidance associated with those savings. Because the model explicitly takes into account variations in weather, it provides an essential tool for evaluating energy conservation programs.
Date: March 1, 1980
Creator: York, C. M.
Partner: UNT Libraries Government Documents Department


Description: Passage of the Toxic Substances Control Act (TSCA) last year emphasized the urgent need for the formulation of viable criteria and interim standards limiting the exposure of increasingly large segments of the U.S. population to environmental chemical toxicants. Unfortunately, current methods of developing these standards are both time-consuming and costly. The resulting need for a priori predictive techniques to assess the inherent potential of chemicals, such as the halocarbons found in chlorinated waters, for inducing adverse biological effects, has led to the use of a number of analytical methods designed primarily for screening large numbers of chemical compounds before they impose unacceptable environmental hazards, frequently of crisis proportions. Four of the techniques best adapted to dealing with the multifactorial environmental problems of chemical health effects will be briefly described: (1) quantitative structure/activity relationships (QSAR); (2) factor analysis (FA); (3) pattern recognition/artificial intelligence (PR/AI); and (4) molecular connectivity (MC). While it is clear that none provides easy answers, it would appear that the more recent areas of PR and MC both merit more intensive investigation as predictive tools. In particular, the relative simplicity of the MC approach and the possibility of substantially reducing the empirical component are attractive incentives for pursuing further work in this area.
Date: October 1, 1977
Creator: Kland, M.J.
Partner: UNT Libraries Government Documents Department


Description: This report presents the results of a preliminary study concerning the use of high speed turbomachinery in a solar-assisted Rankine cooling cycle. The use of Rankine cycles in solar powered cooling of buildings involves a solar collector to provide energy to heat and vaporize a working fluid. Energy is extracted from this vapor in an expansion engine that is used to drive an air conditioning vapor compressor. In a typical Rankine cycle, the maximum temperature at the inlet to the expander is limited to the temperature of the fluid leaving the solar collector. Because of the relatively low temperature capability associated with inexpensive collectors the efficiency of the Rankine cycle is generally low. This low efficiency results in low coefficient of performance values for the solar powered cooling system. In an effort to improve Rankine cycle efficiency, a solar-assisted approach was presented in NSF report RA-N-75-012, by Dr. Henry Curran. In this approach solar energy vaporizes the working fluid at a low temperature using solar collectors; the vapor is subsequently superheated to a higher temperature using fossil fuel, thereby allowing the potential of much improved Rankine cycle efficiency as compared to a typical cycle. Water was selected as the working fluid to avoid problems associated with chemical stability of organic fluids at high values of expander inlet temperature. A maximum steam temperature of 1100 F was suggested to achieve Rankine cycle efficiencies on the order of 25%. The solar-assisted Rankine cycle was shown by Dr. Curran to offer a substantial cost advantage over conventional absorption machinery. Key elements in achieving this performance improvement are the efficiency of the Rankine cycle vapor expander and the performance of the vapor cycle. In Dr. Curran's study, an expander efficiency of 82% and an air conditioning COP{sub vc} of 4.0 was assumed. Additionally, no ...
Date: December 1, 1976
Creator: Leech, J.
Partner: UNT Libraries Government Documents Department

Analysis of the Relationship Between Vehicle Weight/Size and Safety, and Implications for Federal Fuel Economy Regulation

Description: This report analyzes the relationship between vehicle weight, size (wheelbase, track width, and their product, footprint), and safety, for individual vehicle makes and models. Vehicle weight and footprint are correlated with a correlation coefficient (R{sup 2}) of about 0.62. The relationship is stronger for cars (0.69) than for light trucks (0.42); light trucks include minivans, fullsize vans, truck-based SUVs, crossover SUVs, and pickup trucks. The correlation between wheelbase and track width, the components of footprint, is about 0.61 for all light vehicles, 0.62 for cars and 0.48 for light trucks. However, the footprint data used in this analysis does not vary for different versions of the same vehicle model, as curb weight does; the analysis could be improved with more precise data on footprint for different versions of the same vehicle model. Although US fatality risk to drivers (driver fatalities per million registered vehicles) decreases as vehicle footprint increases, there is very little correlation either for all light vehicles (0.01), or cars (0.07) or trucks (0.11). The correlation between footprint and fatality risks cars impose on drivers of other vehicles is also very low (0.01); for trucks the correlation is higher (0.30), with risk to others increasing as truck footprint increases. Fatality risks reported here do not account for differences in annual miles driven, driver age or gender, or crash location by vehicle type or model. It is difficult to account for these factors using data on national fatal crashes because the number of vehicles registered to, for instance, young males in urban areas is not readily available by vehicle type or model. State data on all police-reported crashes can be used to estimate casualty risks that account for miles driven, driver age and gender, and crash location. The number of vehicles involved in a crash can act as a ...
Date: March 2, 2010
Creator: Wenzel, Thomas P.
Partner: UNT Libraries Government Documents Department


Description: Planning a rational energy future requires anticipating the environmental consequences of various technologies. This is difficult to do with precision as the effects of pollutants are often determined by interactions between and among complex physical (abiotic) and biological (biotic) systems. A given pollutant may affect human beings through direct exposure or indirectly through inducing changes to biological systems which humans need to utilize. The concentration of a toxin in the food chain or the destruction of organisms necessary for the maintenance of high quality water are examples of indirect effects. Pollutants can be transformed and/or degraded as they establish residence in various components of an ecosystem. Anticipation and amelioration of pollutant effects involves the integration of a vast range of data. This data includes: (1) physical and chemical characterization cf the pollutant as it enters the environment; (2) determining effects on the various components (biotic and abiotic) within the context of the functioning ecosystem of interest; (3) transformation in movements and/or degradation of the pollutant within that ecosystem and within specific organisms and physical components; and (4) determining a detailed biochemical and biological picture of the interactions of pollutants with particular organisms and/or their cellular components judged salient for various processes. The major programs described below are designed to answer parts of the above fundamental questions relevant to pollutants generated by energy related technologies. Their emphasis is on anticipating consequences to the biological components of various ecosystems. The work ranges from studies involving parts of a single cell (the membranes) to studies involving the whole ecosystem (in the pelagic zone of a lake). The programs take advantage of expertise and technical abilities present at LBL. Two small exploratory projects which were of brief duration and not related to anticipating biological effects of pollutants are included in this section. They concern ...
Date: October 1, 1980
Creator: Authors, Various
Partner: UNT Libraries Government Documents Department

Comments on the Joint Proposed Rulemaking to Establish Light-Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards

Description: I appreciate the opportunity to provide comments on the joint rulemaking to establish greenhouse gas emission and fuel economy standards for light-duty vehicles. My comments are directed at the choice of vehicle footprint as the attribute by which to vary fuel economy and greenhouse gas emission standards, in the interest of protecting vehicle occupants from death or serious injury. I have made several of these points before when commenting on previous NHTSA rulemakings regarding CAFE standards and safety. The comments today are mine alone, and do not necessarily represent the views of the US Department of Energy, Lawrence Berkeley National Laboratory, or the University of California. My comments can be summarized as follows: (1) My updated analysis of casualty risk finds that, after accounting for drivers and crash location, there is a wide range in casualty risk for vehicles with the same weight or footprint. This suggests that reducing vehicle weight or footprint will not necessarily result in increased fatalities or serious injuries. (2) Indeed, the recent safety record of crossover SUVs indicates that weight reduction in this class of vehicles resulted in a reduction in fatality risks. (3) Computer crash simulations can pinpoint the effect of specific design changes on vehicle safety; these analyses are preferable to regression analyses, which rely on historical vehicle designs, and cannot fully isolate the effect of specific design changes, such as weight reduction, on crash outcomes. (4) There is evidence that automakers planned to build more large light trucks in response to the footprint-based light truck CAFE standards. Such an increase in the number of large light trucks on the road may decrease, rather than increase, overall safety.
Date: October 27, 2009
Creator: Wenzel, Thomas P
Partner: UNT Libraries Government Documents Department

Telluric and D.C. Resistivity Techniques Applied to the Geophysical Investigation of Basin and Range Geothermal Systems, Part III: The Analysis of Data From Grass Valley, Nevada

Description: This paper contains a detailed interpretation of E-field ratio telluric, bipole-dipole resistivity mapping, and dipole-dipole resistivity data obtained in the course of geophysical exploration of the Leach Hot Springs area of Grass Valley, Nevada. Several areas are singled out as being worthy of further investigation of their geothermal potential. Comparison of the three electrical exploration techniques indicates that: the bipole-dipole resistivity mapping method is the least useful; the dipole-dipole resistivity method can be very useful, but is, for practical purposes, exceptionally expensive and difficult to interpret; the E-field ratio telluric method can be a highly successful reconnaissance technique for delineating structures and relating the resistivities of different regions within the survey area.
Date: June 1, 1977
Creator: Beyer, J.H.
Partner: UNT Libraries Government Documents Department

Driving Demand for Home Energy Improvements: Motivating residential customers to invest in comprehensive upgrades that eliminate energy waste, avoid high utility bills, and spur the economy

Description: Policy makers and program designers in the U.S. and abroad are deeply concerned with the question of how to scale up energy efficiency to a level that is commensurate both to the scale of the energy and climate challenges we face, and to the potential for energy savings that has been touted for decades. When policy makers ask what energy efficiency can do, the answers usually revolve around the technical and economic potential of energy efficiency - they rarely hone in on the element of energy demand that matters most for changing energy usage in existing homes: the consumer. A growing literature is concerned with the behavioral underpinnings of energy consumption. We examine a narrower, related subject: How can millions of Americans be persuaded to divert valued time and resources into upgrading their homes to eliminate energy waste, avoid high utility bills, and spur the economy? With hundreds of millions of public dollars flowing into incentives, workforce training, and other initiatives to support comprehensive home energy improvements, it makes sense to review the history of these programs and begin gleaning best practices for encouraging comprehensive home energy improvements. Looking across 30 years of energy efficiency programs that targeted the residential market, many of the same issues that confronted past program administrators are relevant today: How do we cost-effectively motivate customers to take action? Who can we partner with to increase program participation? How do we get residential efficiency programs to scale? While there is no proven formula - and only limited success to date with reliably motivating large numbers of Americans to invest in comprehensive home energy improvements, especially if they are being asked to pay for a majority of the improvement costs - there is a rich and varied history of experiences that new programs can draw upon. Our ...
Date: September 20, 2010
Creator: Fuller, Merrian C.
Partner: UNT Libraries Government Documents Department

Home Network Technologies and Automating Demand Response

Description: Over the past several years, interest in large-scale control of peak energy demand and total consumption has increased. While motivated by a number of factors, this interest has primarily been spurred on the demand side by the increasing cost of energy and, on the supply side by the limited ability of utilities to build sufficient electricity generation capacity to meet unrestrained future demand. To address peak electricity use Demand Response (DR) systems are being proposed to motivate reductions in electricity use through the use of price incentives. DR systems are also be design to shift or curtail energy demand at critical times when the generation, transmission, and distribution systems (i.e. the 'grid') are threatened with instabilities. To be effectively deployed on a large-scale, these proposed DR systems need to be automated. Automation will require robust and efficient data communications infrastructures across geographically dispersed markets. The present availability of widespread Internet connectivity and inexpensive, reliable computing hardware combined with the growing confidence in the capabilities of distributed, application-level communications protocols suggests that now is the time for designing and deploying practical systems. Centralized computer systems that are capable of providing continuous signals to automate customers reduction of power demand, are known as Demand Response Automation Servers (DRAS). The deployment of prototype DRAS systems has already begun - with most initial deployments targeting large commercial and industrial (C & I) customers. An examination of the current overall energy consumption by economic sector shows that the C & I market is responsible for roughly half of all energy consumption in the US. On a per customer basis, large C & I customers clearly have the most to offer - and to gain - by participating in DR programs to reduce peak demand. And, by concentrating on a small number of relatively sophisticated energy ...
Date: December 1, 2009
Creator: McParland, Charles
Partner: UNT Libraries Government Documents Department

Methods for Analyzing Electric Load Shape and its Variability

Description: Current methods of summarizing and analyzing electric load shape are discussed briefly and compared. Simple rules of thumb for graphical display of load shapes are suggested. We propose a set of parameters that quantitatively describe the load shape in many buildings. Using the example of a linear regression model to predict load shape from time and temperature, we show how quantities such as the load?s sensitivity to outdoor temperature, and the effectiveness of demand response (DR), can be quantified. Examples are presented using real building data.
Date: May 12, 2010
Creator: Price, Philip
Partner: UNT Libraries Government Documents Department

Improved Modeling and Understanding of Diffusion-Media Wettability on Polymer-Electrolyte-Fuel-Cell Performance

Description: A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure -- saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the steepness of the capillary pressure -- saturation relationship. The model is also used to examine the impact of a microporous layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the water-injection sites into the more porous gas-diffusion layer.
Date: March 5, 2010
Creator: Weber, Adam
Partner: UNT Libraries Government Documents Department

Chemical Emissions of Residential Materials and Products: Review of Available Information

Description: This report is prepared in the context of a larger program whose mission is to advance understanding of ventilation and indoor air quality in U.S. homes. A specific objective of this program is to develop the scientific basis ? through controlled experiments, monitoring and analysis ? for health risk-based ventilation standards. Appropriate and adequate ventilation is a basic element of a healthy home. Ventilation provides outdoor air and in the process removes indoor odors and contaminants including potentially unhealthful chemicals emitted by indoor materials, products and activities. Ventilation traditionally was assured to occur via infiltration of outdoor air through cracks and other leakage pathways in the residential building envelope. As building air tightness is improved for energy efficiency, infiltration can be reduced to inadequate levels. This has lead to the development of standards requiring mechanical ventilation. Though nominally intended to ensure acceptable indoor air quality, the standards are not explicitly tied to health risk or pollutant exposure targets. LBNL is currently designing analyses to assess the impact of varying ventilation standards on pollutant concentrations, health risks and energy use. These analyses require information on sources of chemical pollutant emissions, ideally including emission rates and the impact of ventilation on emissions. Some information can be obtained from recent studies that report measurements of various air contaminants and their concentrations in U.S. residences. Another way to obtain this information is the bottom-up approach of collecting and evaluating emissions data from construction and interior materials and common household products. This review contributes to the latter approach by summarizing available information on chemical emissions from new residential products and materials. We review information from the scientific literature and public sources to identify and discuss the databases that provide information on new or low-emission materials and products. The review focuses on the primary chemical or ...
Date: September 15, 2010
Creator: Willem, Henry & Singer, Brett
Partner: UNT Libraries Government Documents Department

Industrial Energy Audit Guidebook: Guidelines for Conducting an Energy Audit in Industrial Facilities

Description: Various studies in different countries have shown that significant energy-efficiency improvement opportunities exist in the industrial sector, many of which are cost-effective. These energy-efficiency options include both cross-cutting as well as sector-specific measures. However, industrial plants are not always aware of energy-efficiency improvement potentials. Conducting an energy audit is one of the first steps in identifying these potentials. Even so, many plants do not have the capacity to conduct an effective energy audit. In some countries, government policies and programs aim to assist industry to improve competitiveness through increased energy efficiency. However, usually only limited technical and financial resources for improving energy efficiency are available, especially for small and medium-sized enterprises. Information on energy auditing and practices should, therefore, be prepared and disseminated to industrial plants. This guidebook provides guidelines for energy auditors regarding the key elements for preparing for an energy audit, conducting an inventory and measuring energy use, analyzing energy bills, benchmarking, analyzing energy use patterns, identifying energy-efficiency opportunities, conducting cost-benefit analysis, preparing energy audit reports, and undertaking post-audit activities. The purpose of this guidebook is to assist energy auditors and engineers in the plant to conduct a well-structured and effective energy audit.
Date: October 7, 2010
Creator: Hasanbeigi, Ali & Price, Lynn
Partner: UNT Libraries Government Documents Department

Assessment of Energy Savings Potential from the Use of Demand Controlled Ventilation in General Office Spaces in California

Description: A prototypical office building meeting the prescriptive requirements of the 2008 California building energy efficiency standards (Title 24) was used in EnergyPlus simulations to calculate the energy savings potential of demand controlled ventilation (DCV) in five typical California climates per three design occupancy densities and two minimum ventilation rates. The assumed minimum ventilation rates in offices without DCV, based on two different measurement methods employed in a large survey, were 38 and 13 L/s per occupant. The results of the life cycle cost analysis show DCV is cost effective for office spaces if the typical minimum ventilation rate without DCV is 38 L/s per person, except at the low design occupancy of 10.8 people per 100 m2 in climate zones 3 (north coast) and 6 (south Coast). DCV was not found to be cost effective if the typical minimum ventilation rate without DCV is 13 L/s per occupant, except at high design occupancy of 21.5 people per 100 m2 in climate zones 14 (desert) and 16 (mountains). Until the large uncertainties about the base case ventilation rates in offices without DCV are reduced, the case for requiring DCV in general office spaces will be a weak case. Under the Title 24 Standards office occupant density of 10.8 people per 100 m2, DCV becomes cost effective when the base case minimum ventilation rate is greater than 42.5, 43.0, 24.0, 19.0, and 18.0 L/s per person for climate zone 3, 6, 12, 14, and 16 respectively.
Date: January 1, 2010
Creator: Hong, Tianzhen & Fisk, William
Partner: UNT Libraries Government Documents Department

Implications of Wide-Area Geographic Diversity for Short- Term Variability of Solar Power

Description: Worldwide interest in the deployment of photovoltaic generation (PV) is rapidly increasing. Operating experience with large PV plants, however, demonstrates that large, rapid changes in the output of PV plants are possible. Early studies of PV grid impacts suggested that short-term variability could be a potential limiting factor in deploying PV. Many of these early studies, however, lacked high-quality data from multiple sites to assess the costs and impacts of increasing PV penetration. As is well known for wind, accounting for the potential for geographic diversity can significantly reduce the magnitude of extreme changes in aggregated PV output, the resources required to accommodate that variability, and the potential costs of managing variability. We use measured 1-min solar insolation for 23 time-synchronized sites in the Southern Great Plains network of the Atmospheric Radiation Measurement program and wind speed data from 10 sites in the same network to characterize the variability of PV with different degrees of geographic diversity and to compare the variability of PV to the variability of similarly sited wind. The relative aggregate variability of PV plants sited in a dense 10 x 10 array with 20 km spacing is six times less than the variability of a single site for variability on time scales less than 15-min. We find in our analysis of wind and PV plants similarly sited in a 5 x 5 grid with 50 km spacing that the variability of PV is only slightly more than the variability of wind on time scales of 5-15 min. Over shorter and longer time scales the level of variability is nearly identical. Finally, we use a simple approximation method to estimate the cost of carrying additional reserves to manage sub-hourly variability. We conclude that the costs of managing the short-term variability of PV are dramatically reduced by geographic ...
Date: August 23, 2010
Creator: Mills, Andrew & Wiser, Ryan
Partner: UNT Libraries Government Documents Department

Duct Leakage Modeling in EnergyPlus and Analysis of Energy Savings from Implementing SAV with InCITeTM

Description: This project addressed two significant deficiencies in air-handling systems for large commercial building: duct leakage and duct static pressure reset. Both constitute significant energy reduction opportunities for these buildings. The overall project goal is to bridge the gaps in current duct performance modeling capabilities, and to expand our understanding of air-handling system performance in California large commercial buildings. The purpose of this project is to provide technical support for the implementation of a duct leakage modeling capability in EnergyPlus, to demonstrate the capabilities of the new model, and to carry out analyses of field measurements intended to demonstrate the energy saving potential of the SAV with InCITeTM duct static pressure reset (SPR) technology. A new duct leakage model has been successfully implemented in EnergyPlus, which will enable simulation users to assess the impacts of leakage on whole-building energy use and operation in a coupled manner. This feature also provides a foundation to support code change proposals and compliance analyses related to Title 24 where duct leakage is an issue. Our example simulations continue to show that leaky ducts substantially increase fan power: 10percent upstream and 10percent downstream leakage increases supply fan power 30percent on average compared to a tight duct system (2.5percent upstream and 2.5percent downstream leakage). Much of this increase is related to the upstream leakage rather than to the downstream leakage. This does not mean, however, that downstream leakage is unimportant. Our simulations also demonstrate that ceiling heat transfer is a significant effect that needs to be included when assessing the impacts of duct leakage in large commercial buildings. This is not particularly surprising, given that ?ceiling regain? issues have already been included in residential analyses as long as a decade ago (e.g., ASHRAE Standard 152); mainstream simulation programs that are used for large commercial building energy analyses ...
Date: March 1, 2010
Creator: Wray, Craig & Sherman, Max
Partner: UNT Libraries Government Documents Department

Comparative Analysis of Modeling Studies on China's Future Energy and Emissions Outlook

Description: The past decade has seen the development of various scenarios describing long-term patterns of future Greenhouse Gas (GHG) emissions, with each new approach adding insights to our understanding of the changing dynamics of energy consumption and aggregate future energy trends. With the recent growing focus on China's energy use and emission mitigation potential, a range of Chinese outlook models have been developed across different institutions including in China's Energy Research Institute's 2050 China Energy and CO2 Emissions Report, McKinsey & Co's China's Green Revolution report, the UK Sussex Energy Group and Tyndall Centre's China's Energy Transition report, and the China-specific section of the IEA World Energy Outlook 2009. At the same time, the China Energy Group at Lawrence Berkeley National Laboratory (LBNL) has developed a bottom-up, end-use energy model for China with scenario analysis of energy and emission pathways out to 2050. A robust and credible energy and emission model will play a key role in informing policymakers by assessing efficiency policy impacts and understanding the dynamics of future energy consumption and energy saving and emission reduction potential. This is especially true for developing countries such as China, where uncertainties are greater while the economy continues to undergo rapid growth and industrialization. A slightly different assumption or storyline could result in significant discrepancies among different model results. Therefore, it is necessary to understand the key models in terms of their scope, methodologies, key driver assumptions and the associated findings. A comparative analysis of LBNL's energy end-use model scenarios with the five above studies was thus conducted to examine similarities and divergences in methodologies, scenario storylines, macroeconomic drivers and assumptions as well as aggregate energy and emission scenario results. Besides directly tracing different energy and CO{sub 2} savings potential back to the underlying strategies and combination of efficiency and abatement policy ...
Date: September 1, 2010
Creator: Zheng, Nina; Zhou, Nan & Fridley, David
Partner: UNT Libraries Government Documents Department

Optical People Counting for Demand Controlled Ventilation: A Pilot Study of Counter Performance

Description: This pilot scale study evaluated the counting accuracy of two people counting systems that could be used in demand controlled ventilation systems to provide control signals for modulating outdoor air ventilation rates. The evaluations included controlled challenges of the people counting systems using pre-planned movements of occupants through doorways and evaluations of counting accuracies when naive occupants (i.e., occupants unaware of the counting systems) passed through the entrance doors of the building or room. The two people counting systems had high counting accuracy accuracies, with errors typically less than 10percent, for typical non-demanding counting events. However, counting errors were high in some highly challenging situations, such as multiple people passing simultaneously through a door. Counting errors, for at least one system, can be very high if people stand in the field of view of the sensor. Both counting system have limitations and would need to be used only at appropriate sites and where the demanding situations that led to counting errors were rare.
Date: December 26, 2009
Creator: Fisk, William J. & Sullivan, Douglas
Partner: UNT Libraries Government Documents Department

Infiltration Effects on Residential Pollutant Concentrations for Continuous and Intermittent Mechanical Ventilation Approaches

Description: The prevailing residential ventilation standard in North America, American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62.2, specifies volumetric airflow requirements as a function of the overall size of the home and the number of bedrooms, assumes a fixed, minimal amount of infiltration, and requires mechanical ventilation to achieve the remainder. The standard allows for infiltration credits and intermittent ventilation patterns that can be shown to provide comparable performance. Whole-house ventilation methods have a substantial effect on time-varying indoor pollutant concentrations. If alternatives specified by Standard 62.2, such as intermittent ventilation, are used, short-term pollutant concentrations could exceed acute health standards even if chronic health standards are met.The authors present a methodology for comparing ASHRAE- and non-ASHRAE-specified ventilation scenarios on relative indoor pollutant concentrations. We use numerical modeling to compare the maximum time-averaged concentrations for acute exposure relevant (1-hour, 8-hour, 24-hour ) and chronic exposure relevant (1-year) time periods for four different ventilation scenarios in six climates with a range of normalized leakage values. The results suggest that long-term concentrations are the most important metric for assessing the effectiveness of whole-house ventilation systems in meeting exposure standards and that, if chronic health exposure standards are met, acute standards will also be met.
Date: June 1, 2010
Creator: Sherman, Max; Logue, Jennifer & Singer, Brett
Partner: UNT Libraries Government Documents Department

The Economic Value of PV and Net Metering to Residential Customers in California

Description: In this paper, we analyze the bill savings from PV for residential customers of the California's two largest electric utilities, under existing net metering tariffs as well as under several alternative compensation mechanisms. We find that economic value of PV to the customer is dependent on the structure of the underlying retail electricity rate and can vary quite significantly from one customer to another. In addition, we find that the value of the bill savings from PV generally declines with PV penetration level, as increased PV generation tends to offset lower-priced usage. Customers in our sample from both utilities are significantly better off with net metering than with a feed-in tariff where all PV generation is compensated at long-run avoided generation supply costs. Other compensation schemeswhich allow customers to displace their consumption with PV generation within each hour or each month, and are also based on the avoided costs, yield similar value to the customer as net metering.
Date: May 17, 2010
Creator: Darghouth, Naim; Barbose, Galen & Wiser, Ryan
Partner: UNT Libraries Government Documents Department

Assessing the Performance of LED-Based Flashlights Available in the Kenyan Off-Grid Lighting Market

Description: Low cost rechargeable flashlights that use LED technology are increasingly available in African markets. While LED technology holds promise to provide affordable, high quality lighting services, the widespread dissemination of low quality products may make it difficult to realize this potential. This study includes performance results for three brands of commonly available LED flashlights that were purchased in Kenya in 2009. The performance of the flashlights was evaluated by testing five units for each of the three brands. The tests included measurements of battery capacity, time required to charge the battery, maximum illuminance at one meter, operation time and lux-hours from a fully charged battery, light distribution, and color rendering. All flashlights tested performed well below the manufacturers? rated specifications; the measured battery capacity was 30-50percent lower than the rated capacity and the time required to fully charge the battery was 6-25percent greater than the rated time requirement. Our analysis further shows that within each brand there is considerable variability in each performance indicator. The five samples within a single brand varied from each other by as much as 22percent for battery capacity measurements, 3.6percent for the number of hours required for a full charge, 23percent for maximum initial lux, 38percent for run time, 11percent for light distribution and by as much as 200percent for color rendering. Results obtained are useful for creating a framework for quality assurance of off-grid LED products and will be valuable for informing consumers, distributors and product manufacturers about product performance.
Date: March 2, 2010
Creator: Tracy, Jennifer; Jacobson, Arne & Mills, Evan
Partner: UNT Libraries Government Documents Department

Parametric System Curves: Correlations Between Fan Pressure Rise and Flow for Large Commercial Buildings

Description: A substantial fraction of HVAC energy use in large commercial buildings is due to fan operation. Fan energy use depends in part on the relationship between system pressure drop and flow through the fan, which is commonly called a "system curve." As a step toward enabling better selections of air-handling system components and analyses of common energy efficiency measures such as duct static pressure reset and duct leakage sealing, this paper shows that a simple four-parameter physical model can be used to define system curves. Our model depends on the square of the fan flow, as is commonly considered. It also includes terms that account for linear-like flow resistances such as filters and coils, and for supply duct leakage when damper positions are fixed or are changed independently of static pressure or fan flow. Only two parameters are needed for systems with variable-position supply dampers (e.g., VAV box dampers modulating to control flow). For these systems, reducing or eliminating supply duct leakage does not change the system curve. The parametric system curve may be most useful when applied to field data. Non-linear techniques could be used to fit the curve to fan pressure rise and flow measurements over a range of operating conditions. During design, when measurements are unavailable, one could use duct design calculation tools instead to determine the coefficients.
Date: May 19, 2010
Creator: Sherman, Max & Wray, Craig
Partner: UNT Libraries Government Documents Department