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Residential hot water distribution systems: Roundtablesession

Description: Residential building practice currently ignores the lossesof energy and water caused by the poor design of hot water systems. Theselosses include: combustion and standby losses from water heaters, thewaste of water (and energy) while waiting for hot water to get to thepoint of use; the wasted heat as water cools down in the distributionsystem after a draw; heat losses from recirculation systems and thediscarded warmth of waste water as it runs down the drain. Severaltechnologies are available that save energy (and water) by reducing theselosses or by passively recovering heat from wastewater streams and othersources. Energy savings from some individual technologies are reported tobe as much as 30 percent. Savings calculations of prototype systemsincluding bundles of technologies have been reported above 50 percent.This roundtable session will describe the current practices, summarizethe results of past and ongoing studies, discuss ways to think about hotwater system efficiency, and point to areas of future study. We will alsorecommend further steps to reduce unnecessary losses from hot waterdistribution systems.
Date: August 1, 2002
Creator: Lutz, James D.; Klein, Gary; Springer, David & Howard, Bion D.
Partner: UNT Libraries Government Documents Department

Estimating Energy and Water Losses in Residential Hot WaterDistribution Systems

Description: Residential single family building practice currently ignores the losses of energy and water caused by the poor design of hot water systems. These losses include; the waste of water while waiting for hot water to get to the point of use; the wasted heat as water cools down in the distribution system after a draw; and the energy needed to reheat water that was already heated once before. Average losses of water are estimated to be 6.35 gallons (24.0 L) per day. (This is water that is rundown the drain without being used while waiting for hot water.) The amount of wasted hot water has been calculated to be 10.9 gallons (41.3L) per day. (This is water that was heated, but either is not used or issued after it has cooled off.) A check on the reasonableness of this estimate is made by showing that total residential hot water use averages about 52.6 gallons (199 L) per day. This indicates about 20 percent of average daily hot water is wasted.
Date: February 26, 2005
Creator: Lutz, James
Partner: UNT Libraries Government Documents Department

Development of Standardized Domestic Hot Water Event Schedules for Residential Buildings

Description: The Building America Research Benchmark is a standard house definition created as a point of reference for tracking progress toward multi-year energy savings targets. As part of its development, the National Renewable Energy Laboratory has established a set of domestic hot water events to be used in conjunction with sub-hourly analysis of advanced hot water systems.
Date: August 1, 2008
Creator: Hendron, R. & Burch, J.
Partner: UNT Libraries Government Documents Department

LWRS Fuels Pathway: Engineering Design and Fuels Pathway Initial Testing of the Hot Water Corrosion System

Description: The Advanced LWR Nuclear Fuel Development R&D pathway performs strategic research focused on cladding designs leading to improved reactor core economics and safety margins. The research performed is to demonstrate the nuclear fuel technology advancements while satisfying safety and regulatory limits. These goals are met through rigorous testing and analysis. The nuclear fuel technology developed will assist in moving existing nuclear fuel technology to an improved level that would not be practical by industry acting independently. Strategic mission goals are to improve the scientific knowledge basis for understanding and predicting fundamental nuclear fuel and cladding performance in nuclear power plants, and to apply this information in the development of high-performance, high burn-up fuels. These will result in improved safety, cladding, integrity, and nuclear fuel cycle economics. To achieve these goals various methods for non-irradiated characterization testing of advanced cladding systems are needed. One such new test system is the Hot Water Corrosion System (HWCS) designed to develop new data for cladding performance assessment and material behavior under simulated off-normal reactor conditions. The HWCS is capable of exposing prototype rodlets to heated, high velocity water at elevated pressure for long periods of time (days, weeks, months). Water chemistry (dissolved oxygen, conductivity and pH) is continuously monitored. In addition, internal rodlet heaters inserted into cladding tubes are used to evaluate repeated thermal stressing and heat transfer characteristics of the prototype rodlets. In summary, the HWCS provides rapid ex-reactor evaluation of cladding designs in normal (flowing hot water) and off-normal (induced cladding stress), enabling engineering and manufacturing improvements to cladding designs before initiation of the more expensive and time consuming in-reactor irradiation testing.
Date: September 1, 2012
Creator: Garnier, Dr. John & McHugh, Dr. Kevin
Partner: UNT Libraries Government Documents Department

Comparison of Advanced Residential Water Heating Technologies in the United States

Description: Gas storage, gas tankless, condensing, electric storage, heat pump, and solar water heaters were simulated in several different climates across the US installed in both conditioned and unconditioned space and subjected to several different draw profiles. While many preexisting models were used, new models of condensing and heat pump water heaters were created specifically for this work.
Date: May 1, 2013
Creator: Maguire, J.; Fang, X. & Wilson, E.
Partner: UNT Libraries Government Documents Department

Saving Water Saves Energy

Description: Hot water use in households, for showers and baths as wellas for washing clothes and dishes, is a major driver of household energyconsumption. Other household uses of water (such as irrigatinglandscaping) require additional energy in other sectors to transport andtreat the water before use, and to treat wastewater. In California, 19percent of total electricity for all sectors combined and 32 percent ofnatural gas consumption is related to water. There is a criticalinterdependence between energy and water systems: thermal power plantsrequire cooling water, and water pumping and treatment require energy.Energy efficiency can be increased by a number of means, includingmore-efficient appliances (e.g., clothes washers or dishwashers that useless total water and less heated water), water-conserving plumbingfixtures and fittings (e.g., showerheads, faucets, toilets) and changesin consumer behavior (e.g., lower temperature set points for storagewater heaters, shorter showers). Water- and energy-conserving activitiescan help offset the stress imposed on limited water (and energy) suppliesfrom increasing population in some areas, particularly in drought years,or increased consumption (e.g., some new shower systems) as a result ofincreased wealth. This paper explores the connections between householdwater use and energy, and suggests options for increased efficiencies inboth individual technologies and systems. Studies indicate that urbanwater use can be reduced cost-effectively by up to 30 percent withcommercially available products. The energy savings associated with watersavings may represent a large additional and largely untappedcost-effective opportunity.
Date: June 15, 2006
Creator: McMahon, James E.; Whitehead, Camilla Dunham & Biermayer, Peter
Partner: UNT Libraries Government Documents Department

Development and testing of a photometric method to identify non-operating solar hot water systems in field settings.

Description: This report presents the results of experimental tests of a concept for using infrared (IR) photos to identify non-operational systems based on their glazing temperatures; operating systems have lower glazing temperatures than those in stagnation. In recent years thousands of new solar hot water (SHW) systems have been installed in some utility districts. As these numbers increase, concern is growing about the systems dependability because installation rebates are often based on the assumption that all of the SHW systems will perform flawlessly for a 20-year period. If SHW systems routinely fail prematurely, then the utilities will have overpaid for grid-energy reduction performance that is unrealized. Moreover, utilities are responsible for replacing energy for loads that failed SHW system were supplying. Thus, utilities are seeking data to quantify the reliability of SHW systems. The work described herein is intended to help meet this need. The details of the experiment are presented, including a description of the SHW collectors that were examined, the testbed that was used to control the system and record data, the IR camera that was employed, and the conditions in which testing was completed. The details of the associated analysis are presented, including direct examination of the video records of operational and stagnant collectors, as well as the development of a model to predict glazing temperatures and an analysis of temporal intermittency of the images, both of which are critical to properly adjusting the IR camera for optimal performance. Many IR images and a video are presented to show the contrast between operating and stagnant collectors. The major conclusion is that the technique has potential to be applied by using an aircraft fitted with an IR camera that can fly over an area with installed SHW systems, thus recording the images. Subsequent analysis of the images can determine ...
Date: June 1, 2012
Creator: He, Hongbo (University of New Mexico, Albuquerque, NM); Vorobieff, Peter V. (University of New Mexico, Albuquerque, NM); Menicucci, David (University of New Mexico, Albuquerque, NM); Mammoli, Andrea A. (University of New Mexico, Albuquerque, NM) & Carlson, Jeffrey J.
Partner: UNT Libraries Government Documents Department

Report on the analysis of field data relating to the reliability of solar hot water systems.

Description: Utilities are overseeing the installations of thousand of solar hot water (SHW) systems. Utility planners have begun to ask for quantitative measures of the expected lifetimes of these systems so that they can properly forecast their loads. This report, which augments a 2009 reliability analysis effort by Sandia National Laboratories (SNL), addresses this need. Additional reliability data have been collected, added to the existing database, and analyzed. The results are presented. Additionally, formal reliability theory is described, including the bathtub curve, which is the most common model to characterize the lifetime reliability character of systems, and for predicting failures in the field. Reliability theory is used to assess the SNL reliability database. This assessment shows that the database is heavily weighted with data that describe the reliability of SHW systems early in their lives, during the warranty period. But it contains few measured data to describe the ends of SHW systems lives. End-of-life data are the most critical ones to define sufficiently the reliability of SHW systems in order to answer the questions that the utilities pose. Several ideas are presented for collecting the required data, including photometric analysis of aerial photographs of installed collectors, statistical and neural network analysis of energy bills from solar homes, and the development of simple algorithms to allow conventional SHW controllers to announce system failures and record the details of the event, similar to how aircraft black box recorders perform. Some information is also presented about public expectations for the longevity of a SHW system, information that is useful in developing reliability goals.
Date: July 1, 2011
Creator: Menicucci, David F. (Building Specialists, Inc., Albuquerque, NM)
Partner: UNT Libraries Government Documents Department

Field Test of a DHW Distribution System: Temperature and Flow Analyses (Presentation)

Description: This presentation discusses a field test of a DHW distribution system in an occupied townhome. It includes measured fixture flows and temperatures, a tested recirculation system, evaluated disaggregation of flow by measured temperatures, Aquacraft Trace Wizard analysis, and comparison.
Date: May 13, 2010
Creator: Barley, C. D.; Hendron, B. & Magnusson, L.
Partner: UNT Libraries Government Documents Department

Validation of a Hot Water Distribution Model Using Laboratory and Field Data

Description: Characterizing the performance of hot water distribution systems is a critical step in developing best practice guidelines for the design and installation of high performance hot water systems. Developing and validating simulation models is critical to this effort, as well as collecting accurate input data to drive the models. In this project, the ARBI team validated the newly developed TRNSYS Type 604 pipe model against both detailed laboratory and field distribution system performance data. Validation efforts indicate that the model performs very well in handling different pipe materials, insulation cases, and varying hot water load conditions. Limitations of the model include the complexity of setting up the input file and long simulation run times. In addition to completing validation activities, this project looked at recent field hot water studies to better understand use patterns and potential behavioral changes as homeowners convert from conventional storage water heaters to gas tankless units. Based on these datasets, we conclude that the current Energy Factor test procedure overestimates typical use and underestimates the number of hot water draws. This has implications for both equipment and distribution system performance. Gas tankless water heaters were found to impact how people use hot water, but the data does not necessarily suggest an increase in usage. Further study in hot water usage and patterns is needed to better define these characteristics in different climates and home vintages.
Date: July 1, 2013
Creator: Backman, C. & Hoeschele, M.
Partner: UNT Libraries Government Documents Department

Analysis Model for Domestic Hot Water Distribution Systems: Preprint

Description: A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.
Date: November 1, 2011
Creator: Maguire, J.; Krarti, M. & Fang, X.
Partner: UNT Libraries Government Documents Department

Feasibility study and roadmap to improve residential hot water distribution systems

Description: Residential building practice currently ignores the losses of energy and water caused by the poor design of hot water systems. These losses include: the waste of water while waiting for hot water to get to the point of use; the wasted heat as water cools down in the distribution system after a draw; and the energy to reheat water that was already heated once before. A feasibility study and an action plan for a proposed research project involving residential hot water distribution systems is being developed. The feasibility study will use past work to estimate of hot water and energy loses caused by current hot water distribution systems in residences. Proposed research project, or roadmap, will develop recommendations for improvements to residential hot water distribution systems. The roadmap addresses the technical obstacles and gaps in our knowledge that prevent water and energy reductions and market adoption of water- and energy-efficient technologies. The initial results of the feasibility study are presented here along with a discussion of a roadmap to improve the efficiency of residential hot water distribution systems.
Date: March 31, 2004
Creator: Lutz, James D.
Partner: UNT Libraries Government Documents Department

Inversion of synthetic aperture radar interferograms for sourcesof production-related subsidence at the Dixie Valley geothermalfield

Description: We used synthetic aperture radar interferograms to imageground subsidence that occurred over the Dixie Valley geothermal fieldduring different time intervals between 1992 and 1997. Linear elasticinversion of the subsidence that occurred between April, 1996 and March,1997 revealed that the dominant sources of deformation during this timeperiod were large changes in fluid volumes at shallow depths within thevalley fill above the reservoir. The distributions of subsidence andsubsurface volume change support a model in which reduction in pressureand volume of hot water discharging into the valley fill from localizedupflow along the Stillwater range frontal fault is caused by drawdownwithin the upflow zone resulting from geothermal production. Our resultsalso suggest that an additional source of fluid volume reduction in theshallow valley fill might be similar drawdown within piedmont faultzones. Shallow groundwater flow in the vicinity of the field appears tobe controlled on the NW by a mapped fault and to the SW by a lineament ofas yet unknown origin.
Date: July 1, 2006
Creator: Foxall, B. & Vasco, D.W.
Partner: UNT Libraries Government Documents Department

Enhancement of Solar Energy Representation in the GCAM Model

Description: The representation of solar technologies in a research version of the GCAM (formerly MiniCAM) integrated assessment model have been enhanced to add technologies, improve the underlying data, and improve the interaction with the rest of the model. We find that the largest potential impact from the inclusion of thermal Concentrating Solar Power plants, which supply a substantial portion of electric generation in sunny regions of the world. Drawing on NREL research, domestic Solar Hot Water technologies have also been added in the United States region where this technology competes with conventional electric and gas technologies. PV technologies are as implemented in the CCTP scenarios, drawing on NREL cost curves for the United States, extrapolated to other world regions using a spatial analysis of population and solar resources.
Date: February 1, 2010
Creator: Smith, Steven J.; Volke, April C. & Delgado Arias, Sabrina
Partner: UNT Libraries Government Documents Department

Analysis of chlorinated polyvinyl chloride pipe burst problems :Vasquez residence system inspection.

Description: This report documents the investigation regarding the failure of CPVC piping that was used to connect a solar hot water system to standard plumbing in a home. Details of the failure are described along with numerous pictures and diagrams. A potential failure mechanism is described and recommendations are outlined to prevent such a failure.
Date: October 1, 2005
Creator: Black, Billy D.; Menicucci, David F. & Harrison, John (Florida Solar Energy Center)
Partner: UNT Libraries Government Documents Department

Cold-Climate Solar Domestic Hot Water Systems Analysis

Description: The Solar Heating and Lighting Sub-program has set the key goal to reduce the cost of saved energy [Csav, defined as (total cost, $)/(total discounted savings, kWh_thermal)] for solar domestic water heaters (SDWH) by at least 50%. To determine if this goal is attainable and prioritize R&D for cold-climate SDWH, life-cycle analyses were done with hypothetical lower-cost components in glycol, drainback, and thermosiphon systems. Balance-of-system (BOS, everything but the collector) measures included replacing metal components with polymeric versions and system simplification. With all BOS measures in place, Csav could be reduced more than 50% with a low-cost, selectively-coated, glazed polymeric collector, and slightly less than 50% with either a conventional selective metal-glass or a non-selective glazed polymer collector. The largest percent reduction in Csav comes from replacing conventional pressurized solar storage tanks and metal heat exchangers with un-pressurized polymer tanks with immersed polymer heat exchangers, which could be developed with relatively low-risk R&D.
Date: November 1, 2005
Creator: Burch, J.; Salasovich, J. & Hillman, T.
Partner: UNT Libraries Government Documents Department

Development of a Remote External Repair Tool for Damaged or Defective Polyethylene Pipe

Description: Current procedures for repairing polyethylene (PE) gas pipe require excavation, isolation, and removal of the damaged section of pipe followed by fusing a new section of pipe into place. These techniques are costly and very disruptive. An alternative repair method was developed at Timberline Tool with support from Oregon State University (OSU) and funding by the U. S. Department of Energy National Energy Technology Laboratory (DOE/NETL). This project was undertaken to design, develop and test a tool and method for repairing damaged PE pipe remotely and externally in situ without squeezing off the flow of gas, eliminating the need for large-scale excavations. Through an iterative design and development approach, a final engineered prototype was developed that utilizes a unique thermo-chemical and mechanical process to apply a permanent external patch to repair small nicks, gouges and punctures under line pressure. The project identified several technical challenges during the design and development process. The repair tool must be capable of being installed under live conditions and operate in an 18-inch keyhole. This would eliminate the need for extensive excavations thus reducing the cost of the repair. Initially, the tool must be able to control the leak by encapsulating the pipe and apply slight pressure at the site of damage. Finally, the repair method must be permanent at typical operating pressures. The overall results of the project have established a permanent external repair method for use on damaged PE gas pipe in a safe and cost-effective manner. The engineered prototype was subjected to comprehensive testing and evaluation to validate the performance. Using the new repair tool, samples of 4-inch PE pipe with simulated damage were successfully repaired under line pressure to the satisfaction of DOE/NETL and the following natural gas companies: Northwest Natural; Sempra Energy, Southwest Gas Corporation, Questar, and Nicor. However, initial ...
Date: June 30, 2006
Creator: Green, Kenneth H.; Rochefort, Willie E.; Wannenmacher, Nick; Clark, John A. & Harris, Kevin
Partner: UNT Libraries Government Documents Department


Description: This report reviews the water vapor nitrogen (WVN) process for removing sodium from stainless steel equipment, with emphasis on the basis for selecting final operating parameters. the process includes vapor treatment with 5% water at 160 F to 190 F, hot water rinsing, and hot gas drying.
Date: November 15, 1977
Creator: M, CRIPPEN
Partner: UNT Libraries Government Documents Department

Tool for Generating Realistic Residential Hot Water Event Schedules: Preprint

Description: The installed energy savings for advanced residential hot water systems can depend greatly on detailed occupant use patterns. Quantifying these patterns is essential for analyzing measures such as tankless water heaters, solar hot water systems with demand-side heat exchangers, distribution system improvements, and recirculation loops. This paper describes the development of an advanced spreadsheet tool that can generate a series of year-long hot water event schedules consistent with realistic probability distributions of start time, duration and flow rate variability, clustering, fixture assignment, vacation periods, and seasonality. This paper also presents the application of the hot water event schedules in the context of an integral-collector-storage solar water heating system in a moderate climate.
Date: August 1, 2010
Creator: Hendron, B.; Burch, J. & Barker, G.
Partner: UNT Libraries Government Documents Department

Hot Water Distribution System Program Documentation and Comparison to Experimental Data

Description: In 2003, the California Energy Commission s (CEC s) Public Interest Energy Research (PIER) program funded Oak Ridge National Laboratory (ORNL) to create a computer program to analyze hot water distribution systems for single family residences, and to perform such analyses for a selection of houses. This effort and its results were documented in a report provided to CEC in March, 2004 [1]. The principal objective of effort was to compare the water and energy wasted between various possible hot water distribution systems for various different house designs. It was presumed that water being provided to a user would be considered suitably warm when it reached 105 F. Therefore, what was needed was a tool which could compute the time it takes for water reaching the draw point to reach 105 F, and the energy wasted during this wait. The computer program used to perform the analyses was a combination of a calculational core, produced by Dr. Keith A. Woodbury, Professor of Mechanical Engineering and Director, Alabama Industrial Assessment Center, University of Alabama, and a user interface based on LabVIEW, created by Dr. Roberto Lenarduzzi of ORNL. At that time, the computer program was in a relatively rough and undocumented form adequate to perform the contracted work but not in a condition where it could be readily used by those not involved in its generation. Subsequently, the CEC provided funding through Lawrence Berkeley National Laboratory (LBNL) to improve the program s documentation and user interface to facilitate use by others, and to compare the program s results to experimental data generated by Dr. Carl Hiller. This report describes the program and provides user guidance. It also summarizes the comparisons made to experimental data, along with options built into the program specifically to allow these comparisons. These options were necessitated by ...
Date: September 1, 2007
Creator: Baskin, Evelyn; Craddick, William G; Lenarduzzi, Roberto; Wendt, Robert L & Woodbury, Professor Keith A.
Partner: UNT Libraries Government Documents Department

Geology and Geothermal Potential North of Wells, Nevada

Description: The geology north of Wells, Nevada is dominated by approximately 2150 m of Tertiary lacustrine siltstones and conglomerates. The sediments are cut by a high-angle, range-bounding fault and several associated step faults. Hydrothermal alteration and silicification are associated with the high-angle faults. Two ages of Quaternary sediments locally overlie the Tertiary sediments. Lithologic and well log analyses define numerous potential aquifers in the Tertiary sediments. The shallowest of these aquifers is overlain by a tuffaceous siltstone which appears to act as an aquitard for hot water moving through the aquifers. Three possible subsurface hydrologic models can be constructed to explain the spatial relationships of the thermal water near Wells. Cost-effective steps taken to expedite geothermal development in the area might include deepening of an existing domestic well in the city of Wells to at least 180 m in order to penetrate the tuffaceous siltstone aquitard, running borehole logs for all existing wells, and conducting a shallow temperature-probe survey in the Tertiary sediments north of Wells.
Date: November 1, 1982
Creator: Jewell, Paul W.
Partner: UNT Libraries Government Documents Department

Water as a Reagent for Soil Remediation

Description: SRI International conducted experiments in a two-year, two-phase process to develop and evaluate hydrothermal extraction technology, also known as hot water extraction (HWE) technology, for remediating petroleum-contaminated soils. The bench-scale demonstration of the process has shown great promise, and the implementation of this technology will revolutionize the conventional use of water in soil remediation technologies and provide a standalone technology for removal of both volatile and heavy components from contaminated soil.
Date: March 6, 2003
Creator: Jayaweera, Indira S.; Marti-Perez, Montserrat; Diaz-Ferrero, Jordi & Sanjurjo, Angel
Partner: UNT Libraries Government Documents Department

Manufactured Residential Utility Wall System (ResCore),

Description: This paper describes the design and development of a manufactured residential utility wall system referred to as ResCore. ResCore is a self contained, manufactured, residential utility wall that provides complete rough-in of utilities (power, gas, water, and phone) and other functions (exhaust, combustion make-up air, refrigerant lines, etc.) to serve the kitchen, bath, utility, and laundry rooms. Auburn University, Department of Industrial Design faculty, students, supported by a team of graduate student researchers and the project`s advisory team, developed the ResCore. The project was accomplished through a research subcontract from the U.S. Department of Energy administered by the Oak Ridge National Laboratory. The ResCore wall system features a layered manufacturing technique that allows each major component group: structural, cold water, hot water, drain, gas, electric, etc. to be built as a separate subassembly and easily brought together for final assembly. The two structural layers are reinforced with bridging that adds strength and also permits firm attachment of plumbing pipes and other systems to the wall frame.
Date: December 31, 1997
Creator: Wendt, Robert; Lundell, Clark & Lau, Tin Man
Partner: UNT Libraries Government Documents Department