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At least 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Control of airborne infectious disease in buildings: Evidence and research priorities

The evolution of SARS-CoV-2 virus has resulted in variants likely to be more readily transmitted through respiratory aerosols, underscoring the increased potential for indoor environmental controls to mitigate risk. Use of tight-fitting face masks to trap infectious aerosol in exhaled breath and reduce inhalation exposure to contaminated air is of critical importance for disease control. Administrative controls including the regulation of occupancy and interpersonal spacing are also important, while presenting social and economic challenges. Indoor engineering controls including ventilation, exhaust, air flow control, filtration, and disinfection by germicidal ultraviolet irradiation can reduce reliance on stringent occupancy restrictions. However, the effects of controls-individually and in combination-on reducing infectious aerosol transfer indoors remain to be clearly characterized to the extent needed to support widespread implementation by building operators. We review aerobiologic and epidemiologic evidence of indoor environmental controls against transmission and present a quantitative aerosol transfer scenario illustrating relative differences in exposure at close-interactive, room, and building scales. We identify an overarching need for investment to implement building controls and evaluate their effectiveness on infection in well-characterized and real-world settings, supported by specific, methodological advances. Finally, improved understanding of engineering control effectiveness guides implementation at scale while considering occupant comfort, operational challenges, and energy costs.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Data-Enabled Predictive Control for Building HVAC Systems

Model predictive control is widely used as a control technology for the computation of optimal control inputs of building heating, ventilating, and air conditioning (HVAC) systems. However, both the benefits and widespread adoption of model predictive control (MPC) are hindered by the effort of model creation, calibration, and accuracy of the predictions. In this paper, we apply the data-enabled predictive control (DeePC) algorithm for designing controls for building HVAC systems. The algorithm solely depends on input/output data from the system to predict future state trajectories without the need for system identification. The algorithm relies on the idea that a vector space of all input–output trajectories of a discrete-time linear time-invariant (LTI) system is spanned by time-shifts of a single measured trajectory, given the input signal is persistently exciting. Closed-loop simulations using EnergyPlus are performed to demonstrate the approach. The simulated building modeled in EnergyPlus is a modified commercial large office prototype building served by an air handling unit-variable air volume HVAC system. Temperature setpoints of zones are used as control variables to minimize the HVAC energy cost of the building considering a time-of-use electricity rate structure. Furthermore, sensitivity analysis is conducted to gain insights into the effect of parameter tuning on DeePC performance. Simulation results are used to illustrate the performance of the algorithm and compare the algorithm with model-based MPC and occupancy-based setpoint controller. Overall, DeePC achieves similar performance compared to MPC for lower engineering effort.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Measurement of the Tracer Gradient and Sampling System Bias of the Hot Fuel Examination Facility Stack Air Monitoring System

This report describes tracer gas uniformity and bias measurements made in the exhaust air discharge of the Hot Fuel Examination Facility at Idaho National Laboratory. The measurements were a follow-up on earlier measurements which indicated a lack of mixing of the two ventilation streams being discharged via a common stack. The lack of mixing is detrimental to the accuracy of air emission measurements. The lack of mixing was confirmed in these new measurements. The air sampling probe was found to be out of alignment and that was corrected. The suspected sampling bias in the air sample stream was disproved.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2011

Building a 40% Energy Saving House in the Mixed-Humid Climate

This report describes a home that uses 40% less energy than the energy-efficient Building America standard - a giant step in the pursuit of affordable near-zero-energy housing through the evolution of five near-zero-energy research houses. This four-bedroom, two-bath, 1232-ft2 house has a Home Energy Rating System (HERS) index of 35 (a HERS rating of 0 is a zero-energy house, a conventional new house would have a HERS rating of 100), which qualifies it for federal energy efficiency and solar incentives. The house is leading to the planned construction of a similar home in Greensburg, Kansas, and 21 staff houses in the Walden Reserve, a 7000-unit "deep green" community in Cookville, Tennessee. Discussions are underway for construction of similar houses in Charleston, South Carolina, Seattle, Washington, Knoxville and Oak Ridge, Tennessee, and upstate New York. This house should lead to a 40% and 50% Gate-3, Mixed-Humid-Climate Joule for the DOE Building America Program. The house is constructed with structurally-insulated-panel walls and roof, raised metal-seam roof with infrared reflective coating, airtight envelope (1.65 air changes per hour at 50 Pascal), supply mechanical ventilation, ducts inside the conditioned space, extensive moisture control package, foundation geothermal space heating and cooling system, ZEHcor wall, solar water heater, and a 2.2 kWp grid-connected photovoltaic (PV) system. The detailed specifications for the envelope and the equipment used in ZEH5 compared to all the houses in this series are shown in Tables 1 and 2. Based on a validated computer simulation of ZEH5 with typical occupancy patterns and energy services for four occupants, energy for this all-electric house is predicted to cost only $0.66/day ($0.86/day counting the hookup charges). By contrast, the benchmark house would require $3.56/day, including hookup charges (these costs are based on a 2006 residential rates of $0.07/kWh and solar buyback at $0.15/kWh). The solar fraction for this home located in Lenoir City, Tennessee, is predicted to be as high as 41%(accounting for both solar PV and the solar water heater). This all-electric home is predicted to use 25 kWh/day based on the one year of measured data used to calibrate a whole-building simulation model. Based on two years of measured data, the roof-mounted 2.2 kWp PV system is predicted to generate 7.5 kWh/day. The 2005 cost to commercially construct ZEH5, including builder profit and overhead, is estimated at about $150,000. This cost - for ZEH5's panelized construction, premanufactured utility wall (ZEHcor), foundation geothermal system, and the addition of the walkout lower level, and considering the falling cost for PV - suggests that the construction cost per ft2 for a ZEH5 two-story will be even more cost-competitive. The 2005 construction cost estimate for a finished-out ZEH5 with 2632 ft2 is $222,000 or $85/ft2. The intention of this report is to help builders and homeowners make the decision to build zero-energy-ready homes. Detailed drawings, specifications, and lessons learned in the construction and analysis of data from about 100 sensors monitoring thermal performance for a one-year period are presented. This information should be specifically useful to those considering structural insulated panel walls and roof, foundation geothermal space heating and cooling, solar water heater and roof-mounted, photovoltaic, grid-tied systems.

14 SOLAR ENERGY↗
DOE OSTI2011

Nationwide Snapshot

The purpose of this effort was to create a nationwide snapshot of the current residential building practices in the United States, and to identify trends in building practices as they relate to building energy efficiency. Information on typical insulation levels, heating, ventilation, and air conditioning (HVAC) efficiencies, window profiles, and other residential building components and assemblies provided a foundation for (1) identifying trends in residential building practices over time, (2) assessing energy-efficiency improvements in single-family homes over time and correlating them with the applicable building energy codes if possible, and (3) identifying building energy code adoption and compliance needs. This report seeks to identify trends in the residential building practice from 1996 to 2009.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Extend EnergyPlus to Support Evaluation, Design, and Operation of Low Energy Buildings

During FY10-11, Pacific Northwest National Laboratory in collaboration with the EnergyPlus development team implemented the following high priority enhancements to support the simulation of high performance buildings: (1) Improve Autosizing of Heating, Ventilation, and Air Conditioning (HVAC) Components; (2) Life-Cycle Costing to Evaluate Energy Efficiency Upgrades; (3) Develop New Model to Capture Transformer Losses; (4) Enhance the Model for Electric Battery Storage; and (5) Develop New Model for Chiller-Tower Optimization. This report summarizes the technical background, new feature development and implementation details, and testing and validation process for these enhancements. The autosizing, life-cycle costing and transformer model enhancements/developments were included in EnergyPlus release Version 6.0, and the electric battery model development will be included in Version 7.0. The model development of chiller-tower optimization will be included in a later version (after Version 7.0).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Assessing and Reducing Miscellaneous Electric Loads (MELs) in Banks

Miscellaneous electric loads (MELs) are loads outside of a building's core functions of heating, ventilating, air conditioning, lighting, and water heating. MELs are a large percentage of total building energy loads. This report reviews methods for reducing MELs in Banks. Reducing MELs in a bank setting requires both local and corporate action. Corporate action centers on activities to prioritize and allocate the right resources to correct procurement and central control issues. Local action includes branch assessment or audits to identify specific loads and needs. The worksheet at the end of this guide can help with cataloging needed information and estimating savings potential. The following steps provide a guide to MEL reductions in Bank Branches. The general process has been adapted from a process developed for office buildings the National Renewable Energy Laboratory (NREL, 2011).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

A Guide to Building Commissioning

Commissioning is the process of verifying that a building's heating, ventilation, and air conditioning (HVAC) and lighting systems perform correctly and efficiently. Without commissioning, system and equipment problems can result in higher than necessary utility bills and unexpected and costly equipment repairs. This report reviews the benefits of commissioning, why it is a requirement for Leadership in Energy and Environmental Design (LEED) certification, and why building codes are gradually adopting commissioning activities into code.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2012

Maximizing Thermal Efficiency and Optimizing Energy Management [Fact Sheet]

Researchers at the Thermal Test Facility (TTF) on the campus of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in Golden, Colorado, are addressing maximizing thermal efficiency and optimizing energy management through analysis of efficient heating, ventilating, and air conditioning (HVAC) strategies, automated home energy management (AHEM), and energy storage systems.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Case Studies of Duct Retrofits and Guidelines for Attic and Crawl Space Duct Sealing

The U.S. Department of Energy (DOE) is fully committed to research for developing the information and capabilities necessary to provide cost-effective residential retrofits yielding 50% energy savings within the next several years. Heating, ventilation, and air conditioning (HVAC) is the biggest energy end use in the residential sector, and a significant amount of energy can be wasted through leaky ductwork in unconditioned spaces such as attics and crawl spaces. A detailed duct sealing case study is presented for one house along with nine brief descriptions of other duct retrofits completed in the mixed-humid climate. Costs and estimated energy savings are reported for most of the ten houses. Costs for the retrofits ranged from $\$$0.92/ft 2 to $\$$1.80/ft 2 of living space and estimated yearly energy cost savings due to the duct retrofits range from 1.8% to 18.5%. Lessons learned and duct sealing guidelines based on these ten houses, as well as close work with the HVAC industry in the mixed-humid climate of East Tennessee, northern Georgia, and south-central Kentucky are presented. It is hoped that the lessons learned and guidelines will influence local HVAC contractors, energy auditors, and homeowners when diagnosing or repairing HVAC duct leakage and will be useful for steering DOE s future research in this area.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2012

Building Diagnostic Market Deployment (Final Report)

Operational faults are pervasive across the commercial buildings sector, wasting energy and increasing energy costs by up to about 30% (Mills 2009, Liu et al. 2003, Claridge et al. 2000, Katipamula and Brambley 2008, and Brambley and Katipamula 2009). Automated fault detection and diagnostic (AFDD) tools provide capabilities essential for detecting and correcting these problems and eliminating the associated energy waste and costs. The U.S. Department of Energy's (DOE) Building Technology Program (BTP) has previously invested in developing and testing of such diagnostic tools for whole-building (and major system) energy use, air handlers, chillers, cooling towers, chilled-water distribution systems, and boilers. These diagnostic processes can be used to make the commercial buildings more energy efficient. The work described in this report was done as part of a Cooperative Research and Development Agreement (CRADA) between the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL) and KGS Building LLC (KGS). PNNL and KGS both believe that the widespread adoption of AFDD tools will result in significant reduction to energy and peak energy consumption. The report provides an introduction and summary of the various tasks performed under the CRADA. The CRADA project had three major focus areas: (1) Technical Assistance for Whole Building Energy Diagnostician (WBE) Commercialization, (2) Market Transfer of the Outdoor Air/Economizer Diagnostician (OAE), and (3) Development and Deployment of Automated Diagnostics to Improve Large Commercial Building Operations. PNNL has previously developed two diagnostic tools: (1) whole building energy (WBE) diagnostician and (2) outdoor air/economizer (OAE) diagnostician. WBE diagnostician is currently licensed non-exclusively to one company. As part of this CRADA, PNNL developed implementation documentation and provided technical support to KGS to implement the tool into their software suite, Clockworks. PNNL also provided validation data sets and the WBE software tool to validate the KGS implementation. OAE diagnostician automatically detects and diagnoses problems with outdoor air ventilation and economizer operation for air handling units (AHUs) in commercial buildings using data available from building automation systems (BASs). As part of this CRADA, PNNL developed implementation documentation and provided technical support to KGS to implement the tool into their software suite. PNNL also provided validation data sets and the OAE software tool to validate the KGS implementation. Finally, as part of this CRADA project, PNNL developed new processes to automate parts of the re-tuning process and transfer those process to KGS for integration into their software product. The transfer of DOE-funded technologies will transform the commercial buildings sector by making buildings more energy efficient and also reducing the carbon footprint from the buildings. As part of the CRADA with PNNL, KGS implemented the whole building energy diagnostician, a portion of outdoor air economizer diagnostician and a number of measures that automate the identification of re-tuning measures.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Imagine Homes New Construction Occupied Test House

This report summarizes the research findings of a long-term monitoring plan to evaluate the performance of an energy-efficient home constructed in 2010 in San Antonio, Texas. Monitoring of the energy use, energy generation, and temperature conditions for this project occurred between July 2010 and October 2011. The heating, ventilation, and air conditioning system effectively maintained acceptable temperatures and humidity levels in peak cooling and heating and non-peak operating periods. Discrepancies were found between modeled and actual energy use values, with actual space cooling energy use closest to the corresponding modeled value. Energy consumption predicted for lighting, appliances, and miscellaneous electrical loads was significantly higher than measured amounts, and energy consumption predicted for cooling was significantly lower than measured amounts. A high amount of the 1,600 kWh of PV-generated electricity produced annually was sent to the electric grid every month. The solar thermal DHW system was the main source of hot water for most of the year and performed well; during summer, electrical use by the backup system was rare.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Retrofit of a Multifamily Mass Masonry Building in New England

Merrimack Valley Habitat for Humanity (MVHfH) has partnered with Building Science Corporation to provide high performance affordable housing for 10 families in the retrofit of an existing brick building (a former convent) into condominiums. The research performed for this project provides information regarding advanced retrofit packages for multi-family masonry buildings in Cold climates. In particular, this project demonstrates safe, durable, and cost-effective solutions that will potentially benefit millions of multi-family brick buildings throughout the East Coast and Midwest (Cold climates). The retrofit packages provide insight on the opportunities for and constraints on retrofitting multifamily buildings with ambitious energy performance goals but a limited budget. The condominium conversion project will contribute to several areas of research on enclosures, space conditioning, and water heating. Enclosure items include insulation of mass masonry building on the interior, airtightness of these types of retrofits, multi-unit building compartmentalization, window selection, and roof insulation strategies. Mechanical system items include combined hydronic and space heating systems with hydronic distribution in small (low load) units, and ventilation system retrofits for multifamily buildings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Measure Guideline: Implementing a Plenum Truss for a Compact Air Distribution System

This Measure Guideline presents the steps to implement a compact duct system inside an attic bulkhead (plenum truss) of a one-story, slab-on-grade (SOG) home. In a compact duct design, ductwork runs are reduced in length to yield a smaller and more compact duct system. Less energy will be lost through ductwork if the ducts are contained within the thermal enclosure of the house. These measures are intended for the production builder working to meet the 2012 International Energy Conservation Code (IECC) requirements and keep the ductwork within the thermal enclosure of the house. This measure of bringing the heating, ventilation and air conditioning (HVAC) equipment and ductwork within the thermal enclosure of the house is appropriate for the builder wishing to avoid cathedralizing the insulation in the attic space (i.e., locating it at the underside of the roof deck rather than along the attic floor) or adding dropped soffits.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Simplified Space Conditioning in Low-Load Homes: Results from Pittsburgh, Pennsylvania, New Construction Unoccupied Test House

Field testing was performed in a new construction unoccupied test house in Pittsburgh, Pennsylvania. Four air-based heating, ventilation, and air conditioning distribution systems--a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, a system with transfer fans to the bedrooms, and a system with no ductwork to the bedrooms--were evaluated during heating, cooling, and midseason conditions. The relative ability of each system was assessed with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability, respectively.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Performance Verification of Production-Scalable Energy-Efficient Solutions: Winchester/Camberley Homes Mixed-Humid Climate

Winchester/Camberley Homes with the Building America program and its NAHB Research Center Industry Partnership collaborated to develop a new set of high performance home designs that could be applicable on a production scale. The new home designs are to be constructed in the mixed humid climate zone four and could eventually apply to all of the builder's home designs to meet or exceed future energy codes or performance-based programs. However, the builder recognized that the combination of new wall framing designs and materials, higher levels of insulation in the wall cavity, and more detailed air sealing to achieve lower infiltration rates changes the moisture characteristics of the wall system. In order to ensure long term durability and repeatable successful implementation with few call-backs, this report demonstrates through measured data that the wall system functions as a dynamic system, responding to changing interior and outdoor environmental conditions within recognized limits of the materials that make up the wall system. A similar investigation was made with respect to the complete redesign of the heating, cooling, air distribution, and ventilation systems intended to optimize the equipment size and configuration to significantly improve efficiency while maintaining indoor comfort. Recognizing the need to demonstrate the benefits of these efficiency features, the builder offered a new house model to serve as a test case to develop framing designs, evaluate material selections and installation requirements, changes to work scopes and contractor learning curves, as well as to compare theoretical performance characteristics with measured results.

2X6 WALLS↗
DOE OSTI2014

Performance Evaluation of Advanced Retrofit Roof Technologies Using Field-Test Data Phase Three Final Report, Volume 1

This article presents various metal roof configurations that were tested at Oak Ridge National Laboratory in Tennessee, U.S.A. between 2009 and 2013, and describes their potential for reducing the attic-generated space conditioning loads. These roofs contained different combinations of phase change material, rigid insulation, low emittance surface and above-sheathing ventilation, with standing-seam metal panels on top. These roofs were designed to be installed on existing roofs decks, or on top of asphalt shingles for retrofit construction. All the tested roofs showed the potential for substantial energy savings compared to an asphalt shingle roof, which was used as a control for comparison. The roofs were constructed on a series of adjacent attics separated at the gables using thick foam insulation. The attics were built on top of a conditioned room. All attics were vented at the soffit and ridge. The test roofs and attics were instrumented with an array of thermocouples. Heat flux transducers were installed in the roof deck and attic floor (ceiling) to measure the heat flows through the roof and between the attic and conditioned space below. Temperature and heat flux data were collected during the heating, cooling and swing seasons over a 3 year period. Data from previous years of testing have been published. Here, data from the latest roof configurations being tested in year 3 of the project are presented. All test roofs were highly effective in reducing the heat flows through the roof and ceiling, and in reducing the diurnal attic temperature fluctuations.

above sheating ventilation↗