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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Homeowner Decision Making and Behavior Relating to Deep Home Retrofits

Existing homes present an enormous, largely untapped potential for energy savings. The U.S. Department of Energy (DOE), utilities, and other organizations around the country have launched many initiatives intended to achieve significant energy savings through home retrofits—or energy-saving home improvements. Retrofit programs vary in their specific objectives, the kind of homes or homeowners targeted, their approaches, the metrics for their “success,” and various measures of their effectiveness. Each initiative explicitly or implicitly reflects ideas or assumptions about “what it takes” for homeowners to participate in energy-saving retrofit programs, go through with audits, install recommended energy saving measures, and/or achieve desired or predicted energy savings. Yet, there is not enough research to identify with certainty the approaches likely to work best for a particular population in a particular setting. The interrelated tendencies to focus on actions homeowners take (e.g., via participation rates) and/or to make assumptions about homeowners’ motivations contributes to this knowledge gap. This report seeks to shrink this knowledge gap by focusing on homeowner decision making. In particular, it focuses on a set of homeowners who agreed to participate in a technical deep-home retrofit project wherein they would implement a variety of measures (at their own personal cost) and have the effectiveness of those measures monitored for a year after installation.

Wolfe, Amy K.↗
DOE OSTI2012

Case Study of the Maplewood Park Multifamily Retrofit for Energy Efficiency

Maplewood Park (Maplewood), a 110-unit multifamily apartment complex in Union City, Georgia, completed major renovations under the guidance of a third-party green building certification program in October 2012. Oak Ridge National Laboratory (ORNL) partnered with Southface Energy Institute (Southface) to use this project as a case study of energy retrofits in low-rise, garden-style, multifamily buildings in the southeastern United States. This report provides a comprehensive profile of this project including the project economics, findings of the building audit, and results of the analysis of energy retrofit measures specific to this project. With a main focus of energy retrofits, this report aims to discuss other aspects of multifamily building retrofit that would benefit future projects in terms of improved building audit process, streamlined tasks, and higher energy savings in low-rise, garden-style apartments. Maplewood received Low Income Housing Tax Credit (LIHTC) financing via the 2010 Georgia Qualified Allocation Plan (QAP). To be eligible for QAP funds in Georgia, all major renovations must incorporate energy-efficiency measures and adopt a third-party green building certification. Because of the unique demands of this financing, including requirements for long-term ownership, property owners were also especially motivated to invest in upgrades that will increase durability and comfort while reducing the energy cost for the tenants.

Kim, Euy-Jin↗
DOE OSTI2014

Evaluation of Crawlspace Retrofits in Multifamily Buildings

In 2011 and early 2012, Building Science Corporation (BSC) collaborated with Innova Services Corporation on a multifamily community unvented crawlspace retrofit project at Oakwood Gardens in Lansdale, Pennsylvania. BSC provided design consulting services and pre- and post-retrofit evaluation, testing, and data monitoring. The existing condition was a vented crawlspace with an uninsulated floor between the crawlspace and the dwelling units above. The crawlspace was therefore a critically weak link in the building enclosure and was ripe for improvement. Saving energy was the primary interest and goal, but the greatest challenge in this unvented crawlspace retrofit project was working through a crawlspace bulk water intrusion problem caused by inadequate site drainage, window well drainage, foundation wall drainage, and a rising water table during rainy periods. While the unvented crawlspace retrofit was effective in reducing heat loss, and the majority of the bulk water drainage problems had been resolved, the important finding was that some of the wood joists embedded in masonry pockets behind the brick veneer were showing signs of moisture damage.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

An Assessment of Envelope Measures in Mild Climate Deep Energy Retrofits

Energy end-uses and interior comfort conditions have been monitored in 11 Deep Energy Retrofits (DERs) in a mild marine climate. Two broad categories of DER envelope were identified: first, bringing homes up to current code levels of insulation and airtightness, and second, enhanced retrofits that go beyond these code requirements. The efficacy of envelope measures in DERs was difficult to determine, due to the intermingled effects of enclosure improvements, HVAC system upgrades and changes in interior comfort conditions. While energy reductions in these project homes could not be assigned to specific improvements, the combined effects of changes in enclosure, HVAC system and comfort led to average heating energy reductions of 76percent (12,937 kWh) in the five DERs with pre-retrofit data, or 80percent (5.9 kWh/ft2) when normalized by floor area. Overall, net-site energy reductions averaged 58percent (15,966 kWh; n=5), and DERs with code-style envelopes achieved average net-site energy reductions of 65percent (18,923 kWh; n=4). In some homes, the heating energy reductions were actually larger than the whole house reductions that were achieved, which suggests that substantial additional energy uses were added to the home during the retrofit that offset some heating savings. Heating system operation and energy use was shown to vary inconsistently with outdoor conditions, suggesting that most DERs were not thermostatically controlled and that occupants were engaged in managing the indoor environmental conditions. Indoor temperatures maintained in these DERs were highly variable, and no project home consistently provided conditions within the ASHRAE Standard 55-2010 heating season comfort zone. Thermal comfort and heating system operation had a large impact on performance and were found to depend upon the occupant activities, so DERs should be designed with the occupants needs and patterns of consumption in mind. Beyond-code building envelopes were not found to be strictly necessary for the achievement of deep energy savings in existing uninsulated homes in mild marine climates, provided that other energy end-uses were comprehensively reduced. We recommend that mild climate DERs pursue envelopes in compliance with the 2012 International Energy Conservation Code (IECC) and pair these with high efficiency, off-the-shelf HVAC equipment. Enhanced building envelopes should be considered in cases where very low heating energy use (<1,000 kWh/year or <0.5 kWh/ft2-year) and enhanced thermal comfort (ASHRAE 55-2010) are required, as well as in those situations where substantial energy uses are added to the home, such as decorative lighting, cooling or smart home A/V and communication equipment.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Trial Demonstration of Area Lighting Retrofit: Yuma Border Patrol, Yuma Arizona

The Yuma Sector Border Patrol Area is a high flux lighting application in a high temperature environment, presenting a formidable challenge for light-emitting diodes (LEDs). This retrofit is an Energy Savings Performance Contract ENABLE project under the U.S. Department of Energy (DOE) Federal Energy Management Program. If high flux LED technology performs well in a region with high ambient temperature and solar radiation, it can perform well in most outdoor environments. The design process for the Yuma retrofit has already provided valuable knowledge to CBP and DOE. The LED lighting system selected for the retrofit is expected to reduce energy consumption 69% compared to the incumbent quartz metal halide (QMH) lighting system. If the LED lighting system is installed, GATEWAY will continue to document and disseminate information regarding the installation and long-term performance so that others may also gain valuable knowledge from the Yuma Sector Border Patrol Area lighting retrofit.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2013

Achieving a Net Zero Energy Retrofit - In a humid, temperate climate: Lessons from the University of Hawai'i at Manoa

The University of Hawaii at Manoa (UHM) partnered with the US Department of Energy (DOE) to develop and implement solutions to retrofit exiting buildings to reduce energy consumption by at least 30% as part of DOE’s Commercial Building Partnerships (CBP) Program.1 Kuykendall Hall, located on the UHM campus in Honolulu, was the focus of a CBP analysis and design collaboration among the University of Hawai’i, their consultants, and Lawrence Berkeley National Laboratory (LBNL). Kuykendall Hall consists of two 1960s-era wings – a four-story wing containing classrooms, and a seven-story tower containing offices – with a total floor area of approximately 76,000 square feet (ft2). The retrofit design, which uses local prevailing winds to aid ventilation and cooling and incorporates envelope and lighting elements that reduce the need for cooling, was initially on track to use about 50% less energy than the current building, exceeding the CBP’s 30% savings goal. With the addition of building-mounted solar electric panels, the retrofitted building is projected to achieve net-zero annual energy use. Achieving net-zero energy addressed an emerging challenge to the university – how to lower energy usage and reduce dependence on imported fossil fuel in the face of already-high energy prices that are forecast to double by 2040. Not only will the retrofit dramatically reduce Kuykendall Hall’s annual energy costs, but the project lays the groundwork for new campus policies and processes and low-energy design approaches and is building a campus knowledge base on low-energy practices. This project is a model of integrated design and building delivery that will be replicated in future projects on the campus.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2016

Quantifying the Financial Benefits of Multifamily Retrofits

Increasing the adoption of energy efficient building practices will require the energy sector to increase their understanding of the way that retrofits affect multifamily financial performance as well as how those indicators are interpreted by the lending and appraisal industries. This project analyzed building, energy, and financial program data as well as other public and private data to examine the relationship between energy efficiency retrofits and financial performance on three levels: building, city, and community. The project goals were to increase the data and analysis in the growing body of multifamily financial benefits work as well provide a framework for other geographies to produce similar characterization. The goals are accomplished through three tasks. Task one: A pre- and post-retrofit analysis of thirteen Chicago multifamily buildings. Task two: A comparison of Chicago income and expenses to two national datasets. Task three: An in-depth look at multifamily market sales data and the subsequent impact of buildings that undergo retrofits.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Wall Upgrades for Energy Retrofits: A Techno-Economic Study

Homes built before 1992, when the U.S. Department of Energy’s (DOE) Building Energy Codes Program was established, represent approximately 68% of the residential building stock in the country. Up to 43% of these homes have little to no insulation in the walls and have very high air leakage rates of 10 or more air changes per hour at 50 pascals of pressure (ACH50). These issues can represent a substantial portion of unnecessary money spent on utility bills for homeowners, especially in the colder climates. There is a significant need for cost-effective, reliable retrofit methods for these homes that include air, moisture, and vapor controls which are considered best practices for high-performance new home construction. Well-tested and documented wall retrofit systems can help to achieve substantial energy savings and also improve durability, comfort, health, and resilience. In 2018, DOE’s Building Technologies Office awarded Pacific Northwest National Laboratory, Oak Ridge National Laboratory, and the University of Minnesota funding to complete a 3-year project to compare a range of residential wall retrofit systems that prioritized affordability, durability and energy savings potential. In addition to these core criteria, the ease-of-construction and the wide-scale applicability of the solutions also were considered. In this project, the research team identified, constructed, tested, simulated, and analyzed the feasibility and economics of 16 wall retrofit assemblies (14 test configurations and two baseline configurations).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Low-cost Retrofit Kit for Integral Reciprocating Compressors (IRCs) to Reduce Emissions and Enhance Efficiency

Methane emissions from natural gas engines within the oil and gas industry pose a significant environmental challenge, contributing approximately 34.1 MMTCO2 eq to the total of 239 MMTCO2 eq of methane emissions in 2021, according to the EPA report. In response to this pressing issue, a collaborative effort involving the University of Oklahoma and key industry partners—WAGO Automation, Mid Continental Rental, Elipsa, and Perscient—has resulted in the development of a retrofit kit designed to reduce emissions from integral reciprocating compressors (IRCs), which are integrated compressors and engines. The retrofit kit developed comprises an Air Management System (AMS), Integrated Sensors, and a Cloud-Connected Control Unit with Graphical User Interface (GUI)/Human-Machine Interface (HMI). This solution enhances operational efficiency, reduces emissions, and expands the operational envelope of IRCs in the natural gas industry. The project successfully completed all tasks, including the installation of a full-size IRC at a designated site in Oklahoma, the development of an optimized AMS, integration of sensors, and implementation of a data acquisition system. Significant achievements include a notable reduction in CH 4 emissions, up to 84% at specific loads, and the successful deployment of the retrofit kit in diverse field conditions. The system's capabilities were enhanced through the creation of a feedback control algorithm for the AMS using a correlation matrix illustrating relationships between engine parameters, and the design of a predictive and preventive maintenance platform. The project concluded with the deployment of the entire retrofit kit to another location, confirming its effectiveness in reducing emissions and enhancing IRC performance. The comprehensive solution offers valuable benefits for IRCs, making them invaluable assets in the natural gas industry.

03 NATURAL GAS↗
DOE OSTI2016

Evaluation of Crawlspace Retrofits in Multifamily Buildings

In 2011 and early 2012, Building Science Corporation (BSC) collaborated with Innova Services Corporation on a multifamily community un-vented crawlspace retrofit project at Oakwood Gardens in Lansdale, Pennsylvania. BSC provided design consulting services and pre- and post-retrofit evaluation, testing, and data monitoring.The existing condition was a vented crawlspace with an un-insulated floor between the crawlspace and the dwelling units above. The crawlspace was therefore a critically weak link in the building enclosure and was ripe for improvement. Saving energy was the primary interest and goal, but the greatest challenge in this un-vented crawlspace retrofit project was working through a crawlspace bulk water intrusion problem caused by inadequate site drainage, window well drainage, foundation wall drainage, and a rising water table during rainy periods.While the un-vented crawlspace retrofit was effective in reducing heat loss, and the majority of the bulk water drainage problems had been resolved, the important finding was that some of the wood joists embedded in masonry pockets behind the brick veneer were showing signs of moisture damage.

affordable housing↗
DOE OSTI2026

Heat Pump Retrofits for Central Plant Hydronic Heating Systems: A Software Toolkit for Screening and Design

Retrofitting existing central plants with high-efficiency heat pump technologies can play a crucial role in achieving long-term planning goals. Modern heat pump technologies are able to use waste heat recovery to meet a building's heating demand, but there is a lack of accessible tools designed for non-HVAC experts, such as building owners, to quickly and easily conduct what-if analysis, e.g., estimating retrofit costs and payback period for their partial or full equipment replacement. This paper introduces an open-source software toolkit designed to facilitate the initial screening and decision-making of heat pump retrofits in existing central plants using a building's yearly load profile from metered or utility bill data. The toolkit evaluates the technical and economic viability of replacing traditional central plant equipment with various options including water-to-water or air-to-water heat pumps, which can provide efficient and lower-cost heating and cooling. It allows users to compare current central plant configurations with retrofit scenarios, assessing energy consumption, life-cycle costs, and environmental impact. The toolkit offers (1) a web-based tool designed for user-friendly access by a broad audience and (2) Python-based source code for researchers and engineers conducting parametric studies and design parameter optimization. The toolkit compares a typical central plant configuration to a configuration that uses a heat pump to supply hydronic heating and cooling. The output metrics include energy consumption and output of each equipment, life-cycle cost analyses and metrics, and environmental impact of the system.

Excell, L↗
DOE OSTI2026

A Probabilistic Approach to Load Modeling for Central HVAC Systems in Large Commercial Buildings for Retrofit Decisions Under Uncertainty

Retrofitting central HVAC systems in large commercial buildings with advanced technologies like heat recovery chillers (HRCs) offers a significant opportunity to enhance energy efficiency. However, analyzing these retrofits is challenging with traditional whole-building simulation tools, which require intensive calibration and struggle to model innovative system configurations and controls. To overcome these limitations, this study proposes a load profilebased retrofit analysis framework that provides better decisions under uncertainty. The main focus of this paper is the development of a probabilistic load profile model that can be used in the framework by using exploratory data analysis (EDA) of measured building data to properly quantify its inherent variability. A non-parametric Gaussian Process (GP) model was employed to capture the time- and weather-dependent characteristics of the heating load while explicitly modeling its uncertainty. The model's effectiveness is demonstrated through strong predictive performance on unseen data and physically interpretable insights into load behavior. This data-driven, probabilistic load profile serves as a robust and flexible input for subsequent system simulations, enabling a more confident and statistically sound analysis of retrofit potential.

Ham, S W↗
NASA NTRS2005

A Demonstration of a Retrofit Architecture for Intelligent Control and Diagnostics of a Turbofan Engine

A retrofit architecture for intelligent turbofan engine control and diagnostics that changes the fan speed command to maintain thrust is proposed and its demonstration in a piloted flight simulator is described. The objective of the implementation is to increase the level of autonomy of the propulsion system, thereby reducing pilot workload in the presence of anomalies and engine degradation due to wear. The main functions of the architecture are to diagnose the cause of changes in the engine s operation, warning the pilot if necessary, and to adjust the outer loop control reference signal in response to the changes. This requires that the retrofit control architecture contain the capability to determine the changed relationship between fan speed and thrust, and the intelligence to recognize the cause of the change in order to correct it or warn the pilot. The proposed retrofit architecture is able to determine the fan speed setting through recognition of the degradation level of the engine, and it is able to identify specific faults and warn the pilot. In the flight simulator it was demonstrated that when degradation is introduced into an engine with standard fan speed control, the pilot needs to take corrective action to maintain heading. Utilizing the intelligent retrofit control architecture, the engine thrust is automatically adjusted to its expected value, eliminating yaw without pilot intervention.

Litt, Jonathan S.↗
DOE OSTI2012

Advancing Residential Energy Retrofits

To advance the market penetration of residential retrofits, Oak Ridge National Laboratory (ORNL) and Southface Energy Institute (Southface) partnered to provide technical assistance on nine home energy retrofits in metropolitan Atlanta with simulated source energy savings of 30% to 50%. Retrofit measures included duct sealing, air infiltration reductions, attic sealing and roofline insulation, crawlspace sealing, HVAC and water heating equipment replacement, and lighting and appliance upgrades. This paper will present a summary of these measures and their associated impacts on important home performance metrics, such as air infiltration and duct leakage. The average estimated source energy savings for the homes is 33%, and the actual heating season average savings is 32%. Additionally, a case study describing expected and realized energy savings of completed retrofit measures of one of the homes is described in this paper.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Need for Systematic Retrofit Analysis in Multifamily Buildings

Multifamily housing offers high potential for energy savings through retrofits. A comprehensive energy audit with systematic evaluation of alternative energy measures is one of the key steps to realizing the full energy savings potential. However, this potential often remains unrealized when the selection of measures is (1) based on a one-size-fits-all approach originating from accustomed practices, (2) intended merely to meet code-compliance requirements, and/or (3) influenced by owner renter split incentive. In such cases, the benefits of comprehensive energy auditing are disregarded in view of the apparent difficulty in diagnosing multifamily buildings, evaluating alternative measures, and installing customized sets of measures. This paper highlights some of the barriers encountered in a multifamily housing retrofit project in Georgia and demonstrates the merits of systematic retrofit analysis by identifying opportunities for higher energy savings and improved comfort and indoor air quality that were missed in this project. The study uses a whole-building energy analysis conducted for a 10-unit, low-rise, multifamily building of a 110-unit apartment complex. The analysis projected a 24% energy savings from the measures installed in the building with a payback period of 10 years. Further analysis with a systematic evaluation of alternative measures showed that without compromising on the objectives of durability, livability, and appearance of the building, energy savings of up to 34% were achievable with a payback period of 7 years. The paper concludes by outlining recommendations that may benefit future retrofit projects by improving the audit process, streamlining tasks, and achieving higher energy savings.

Malhotra, Mini↗
DOE OSTI2014

An actuarial approach to retrofit savings in buildings

An actuarial method has been developed for determining energy savings from retrofits from energy use data for a number of buildings. This method should be contrasted with the traditional method of using pre- and post-retrofit data on the same building. This method supports the U.S. Department of Energy Building Performance Database of real building performance data and related tools that enable engineering and financial practitioners to evaluate retrofits. The actuarial approach derives, from the database, probability density functions (PDFs) for energy savings from retrofits by creating peer groups for the user’s pre post buildings. From the energy use distribution of the two groups, the savings PDF is derived. This provides the basis for engineering analysis as well as financial risk analysis leading to investment decisions. Several technical issues are addressed: The savings PDF is obtained from the pre- and post-PDF through a convolution. Smoothing using kernel density estimation is applied to make the PDF more realistic. The low data density problem can be mitigated through a neighborhood methodology. Correlations between pre and post buildings are addressed to improve the savings PDF. Sample size effects are addressed through the Kolmogorov--Smirnov tests and quantile-quantile plots.

Subbarao, Krishnappa↗
DOE OSTI2016

Building America Case Study: Quantifying the Financial Benefits of Multifamily Retrofits, Chicago, Illinois

Increasing the adoption of energy efficient building practices will require the energy sector to increase their understanding of the way that retrofits affect multifamily financial performance as well as how those indicators are interpreted by the lending and appraisal industries. This project analyzed building, energy, and financial program data as well as other public and private data to examine the relationship between energy efficiency retrofits and financial performance on three levels: building, city, and community. The project goals were to increase the data and analysis in the growing body of multifamily financial benefits work as well provide a framework for other geographies to produce similar characterization. The goals are accomplished through three tasks: Task one: A pre- and post-retrofit analysis of thirteen Chicago multifamily buildings. Task two: A comparison of Chicago income and expenses to two national datasets. Task three: An in-depth look at multifamily market sales data and the subsequent impact of buildings that undergo retrofits.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Extract useful information from building permits data to profile a city’s building retrofit history

Building retrofit is one of the key strategies for cities to reduce energy use and GHG emissions. The historical information about changes to buildings is crucial to infer the buildings’ current energy system efficiency levels and to identify candidate buildings for retrofit. In general, a building permit is required before the start of any construction activity of a building, such as changing building structure, remodeling, or installing new equipment. Moreover, many large cities provide public datasets of building permits in history. Therefore, the permits are a potentially good resource for mining information on the city’s retrofit history. In this study, we use the permit dataset from the city of San Francisco as a case study. Location and time information from the dataset is also used to depict the retrofit timeline of each building and the whole building stock. The type of work of the permit is inferred from the descriptive text by a machine learning model. At last, the limitations of the current permit dataset and potential improvements on the permit data management are discussed to better utilize the information in the future.

Zhang, Wanni↗