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At least 1,009 records · Page 56

Advocating for view and daylight in buildings: Next steps

With the exponential growth in population and commensurate increased density in urban cities, access to daylight and views to nature is being severely curtailed in buildings. In parallel, increasingly urgent demands to sharply reduce building energy use and associated greenhouse gas emissions are being made to mitigate climate change. There are many challenges and performance tradeoffs associated with the building facade (i.e., daylight and view versus solar and glare control); increased prioritization of health and well-being as a fundamental human requirement could adversely affect building energy-efficiency. Given the current state of knowledge on the effects of daylight and view on health and well-being in buildings, we identify critical needs in research, tools and technologies that if satisfied may enable more effective use of daylight and view in buildings within the constraints of climate change. Lack of knowledge regarding the complex causal mechanisms of window views on human factors is a severely limiting factor in forward progress. Current models and methods to derive bidirectional scattering distribution functions (BSDFs) will need to be modified. Developers of energy-efficient window technologies will need more guidance to shape product development. Advanced window technologies and integrated design can enable attainment of both health and well-being and net zero energy goals, but considerable work will be needed to make such options turnkey and broadly available.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Reducing the cost of home energy upgrades in the US: An industry survey

Decarbonizing the US residential building stock requires a substantial acceleration in home energy upgrades. Numerous barriers exist to accelerating adoption of efficient and electric building technologies, but foremost among these is high upfront costs. This study uses an industry survey delivered to a sample of home energy professionals to examine promising cost reduction strategies across a range of project types, including HVAC, water heating, and envelope/insulation projects. The survey included quantitative and qualitative questions to collect evidence on the estimated cost reduction potential of these strategies and their likelihood of use in the construction industry. The 167 survey respondents included contractors, energy consultants, architects, manufacturers, and others with experience in delivering energy upgrades in single-family and multifamily buildings in the US. Results show that significant cost reductions are achievable by minimizing additional infrastructure costs (such as replacing electric panels), streamlining project planning/management, and deploying innovations that simplify installation. We find that for a typical deep retrofit project, including heat pumps for space and water heating in addition to envelope upgrades, the strategies could result in a total installed cost reduction of nearly 50%, dramatically improving the customer economics of such a project. This research makes a novel contribution to the literature on strategies to reduce the costs of residential retrofits. We discuss how our study's insights on the highest-value cost reduction strategies for home energy upgrades can further accelerate their uptake in the US housing stock.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Communities of the Future: Accelerating Zero Energy District Master Planning: Preprint

Zero energy districts aggregate multiple buildings and optimize energy efficiency, district thermal energy, and renewable energy generation among those buildings so that on-site renewable energy can offset the energy use at a district scale. Zero energy districts have the potential to dramatically improve the economic competitiveness, resiliency, environmental quality, and energy independence of communities. The U.S. Department of Energy (DOE) Zero Energy Districts Accelerator (ZEDA) brings together district developers, planners, owners, national experts, and key stakeholders to develop the energy master planning documents needed for zero energy district development and replication. Through this effort, DOE is working with pioneering leaders to understand and address barriers to achieving zero energy districts. Each district partner will complete detailed energy master plans that provide the framework necessary to achieve ambitious energy goals. These complex projects represent billions of dollars of investment and are creating the communities of the future. ZEDA partners are using best-practice approaches to realize energy performance goals for the entire building and district life cycle. Their successful strategies will be documented and made available to promote replication in cities around the world that are setting aggressive energy goals. This paper introduces zero energy districts, reviews the structure of ZEDA, discusses the value of energy master planning, presents barriers to zero energy districts and how these are being addressed by zero energy district pioneers, and suggests pathways for wide-scale replication.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Communities of the Future: Accelerating Zero Energy District Master Planning

Zero energy districts aggregate multiple buildings and optimize energy efficiency, district thermal energy, and renewable energy generation among those buildings so that on-site renewable energy can offset the energy use at a district scale. Zero energy districts have the potential to dramatically improve the economic competitiveness, resiliency, environmental quality, and energy independence of communities. The U.S. Department of Energy (DOE) Zero Energy Districts Accelerator (ZEDA) brings together district developers, planners, owners, national experts, and key stakeholders to develop the energy master planning documents needed for zero energy district development and replication. Through this effort, DOE is working with pioneering leaders to understand and address barriers to achieving zero energy districts. Each district partner will complete detailed energy master plans that provide the framework necessary to achieve ambitious energy goals. These complex projects represent billions of dollars of investment and are creating the communities of the future. ZEDA partners are using best-practice approaches to realize energy performance goals for the entire building and district life cycle. Their successful strategies will be documented and made available to promote replication in cities around the world that are setting aggressive energy goals. This paper introduces zero energy districts, reviews the structure of ZEDA, discusses the value of energy master planning, presents barriers to zero energy districts and how these are being addressed by zero energy district pioneers, and suggests pathways for wide-scale replication.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Evaluating the energy impact potential of energy efficiency measures for retrofit applications: A case study with U.S. medium office buildings

Quantifying the energy savings of various energy efficiency measures (EEMs) for an energy retrofit project often necessitates an energy audit and detailed whole building energy modeling to evaluate the EEMs; however, this is often cost-prohibitive for small and medium buildings. In order to provide a defined guideline for projects with assumed common baseline characteristics, this paper applies a sensitivity analysis method to evaluate the impact of individual EEMs and groups these into packages to produce deep energy savings for a sample prototype medium office building across 15 climate zones in the United States. We start with one baseline model for each climate zone and nine candidate EEMs with a range of efficiency levels for each EEM. Three energy performance indicators (EPIs) are defined, which are annual electricity use intensity, annual natural gas use intensity, and annual energy cost. Then, a Standard Regression Coefficient (SRC) sensitivity analysis method is applied to determine the sensitivity of each EEM with respect to the three EPIs, and the relative sensitivity of all EEMs are calculated to evaluate their energy impacts. For the selected range of efficiency levels, the results indicate that the EEMs with higher energy impacts (i.e., higher sensitivity) in most climate zones are high-performance windows, reduced interior lighting power, and reduced interior plug and process loads. However, the sensitivity of the EEMs also vary by climate zone and EPI; for example, improved opaque envelope insulation and efficiency of cooling and heating systems are found to have a high energy impact in cold and hot climates.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Estimating the Energy, Economic, and Durability Benefits of Installing an Air Barrier System in Commercial Buildings

Uncontrolled heat, air, and moisture transfer through the building enclosure has a significant impact on energy usage, comfort, indoor air quality, and building enclosure durability. Air leakage in commercial buildings in the U.S. accounts for about one quad (one quadrillion Btu) of energy annually, costing approximately $10 billion. As the thermal resistance of commercial building enclosures continues to improve, the relative contribution of air leakage to heating and cooling loads is increasing. A wide variety of air barrier technologies and construction practices to reduce the air leakage in buildings are available to the architect and designer. To promote more energy-efficient and durable building enclosure design, advances in easy-to-use tools for determining the impact of air leakage are needed. Oak Ridge National Laboratory (ORNL), the Air Barrier Association of America (ABAA), and the National Institute of Standards and Technology (NIST) partnered to develop an online calculator that estimates the potential energy, cost savings (due to energy use reduction), and moisture transport due to improvements in airtightness. The calculator estimates the energy and cost savings potential based on the pre-and post-retrofit air leakage rates for prototype commercial buildings. The tool does not include the energy and hygrothermal impacts of air intrusion or air that flows into and out of the building enclosure from the same side. This article reports on the development of the Energy Savings and Moisture Transfer Calculator. This online tool aims to fill this void, is based on the best science available, and is easy to use.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

High-resolution hourly surrogate modeling framework for physics-based large-scale building stock modeling

Surrogate modeling can play a key role in reducing high computational burdens for large-scale physics-based modeling and uncertainty quantification. With the rapid development of large-scale building stock energy modeling, surrogate modeling has also begun to be widely applied in this field; however, most existing surrogate models lack hourly time resolution for regional-scale modeling, which is essential for understanding building demand profiles and grid impacts. Further, there is generally a lack of necessary data and feature engineering frameworks specific to building modeling for efficiently managing large datasets and complex computations. Furthermore, this paper proposes a modeling framework for large-scale (city-/region-scale), high-resolution, high-fidelity surrogate building stock energy models. Our developed framework consists of six modules: (1) building stock energy modeling (ComStock TM and ResStock TM ), (2) data engineering for large simulation data, (3) high performance computing workflow, (4) feature engineering, (5) machine learning model development, and (6) model performance evaluation. Two case studies apply the developed framework in both residential and commercial building stock analysis to demonstrate its computational efficiency and surrogate modeling accuracies. Results show that surrogate models, when efficiently trained using the HPC workflow module, reach a high level of modeling accuracy for two case studies.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Metrics for Interzonal Dispersion Assessment of Airborne SARS-CoV-2 Within Office Buildings

High ventilation rate is increasingly considered as a mitigation strategy in the rapid spread of COVID-19 in existing buildings in addition to other options like UVGI and added filtration. However, this and other similar measures may also impact energy use and the efficiency of the buildings in which they are installed. Without concrete metrics, the impact of all these potential changes to the system cannot be properly assessed relative to the other impacts the measures might have, including additional energy use, added operation and maintenance costs, and reduced system life. Multizone airflow and contaminant transport simulations involving parameters such as infiltration rate, system configuration, and level of occupancy can provide critical information on relative risk distribution within a building. In this study, prototype airflow models are used to assess the degree to which ventilation-related measures can mitigate the spread of a virus like SARS-CoV-2 in a similar way that prototype energy models are used to study energy efficiency measures. A new detailed medium-sized office building prototype model is developed using the CONTAM software to represent contaminant transport in buildings like those modeled by the U.S. Department of Energy’s detailed medium office prototype model. The goal of this study is to generate a set of suitable metrics that will give a whole-building picture of airborne SARS-CoV-2 virus distributions across the different zones of the building under different parameters and scenarios.

DeGraw, Jason↗

Small Commercial Building Re-tuning: A Primer

To help building owners and managers address issues related to energy-efficient operation of small buildings, DOE has developed a Small Building Re-tuning training curriculum. This "primer" provides additional background information to understand some of the concepts presented in the Small Building Re-tuning training. The intent is that those who are less familiar with the building energy concepts will review this material before taking the building re-tuning training class.

building energy↗

Commercial Building Energy Asset Score Program Overview and Technical Protocol (Version 1.1)

The U.S. Department of Energy (DOE) is developing a voluntary national scoring system for commercial buildings to help building owners and managers assess a building’s energy-related systems independent of operations. The goal of the score is to facilitate cost-effective investment in energy efficiency improvements of commercial buildings. The system, known as the Commercial Building Energy Asset Score, will allow building owners and managers to compare their building infrastructure against peers and track building upgrades over time. The system will also help other building stakeholders (e.g., building investors, tenants, financiers, and appraisers) understand the relative efficiency of different buildings in a way that is independent from operations and occupancy. This report outlines the technical protocol used to generate the energy asset score, explains the scoring methodology, and provides additional details regarding the energy asset scoring tool. The alternative methods that were considered prior to developing the current approach are described in the Program Overview and Technical Protocol Version 1.0.

Building Energy Use↗

High Efficiency Heat Pumps Can Pave the Path for Building Decarbonization in Cold Climates: Preprint

Heat pumps play an instrumental role in buildings decarbonization strategies. Recent advances in heat pump systems employ variable-speed compressor technology and electronically commutated fan motors. Inherently, the heating capacity and efficiency of heat pumps decrease with falling outdoor temperatures. Compared to single-speed heat pumps, variable speed systems can maintain higher heating and cooling efficiencies over a wider range of outdoor temperatures. The goal of this multi-phase project was to determine the energy savings of a high efficiency, variable-speed, air-source, split system heat pump designed for cold climate applications. The first project phase was to evaluate the performance of the heat pump in the laboratory under varying outdoor conditions in heating and cooling modes. The second phase was to translate the laboratory-measured performance into lookup tables for EnergyPlus hourly building simulation engine. Then, two sets of annual building simulations were performed using typical meteorological year weather from the Chicago-O'Hare airport for three different building types (a single-family residence, a strip mall, and a low-rise office building). The first set simulated a standard efficiency heat pump while the second set utilized the phase two performance tables to model a high efficiency heat pump. The high efficiency heat pump produced significant annual heating energy savings in all three buildings. The variable speed compressor and fan control also contributed to cooling energy savings. The simulated annual energy savings ranged from 22% to 35% over their respective baseline. The project's findings helped a Midwest electric utility, Commonwealth Edison (ComEd), design new incentives around high efficiency heat pumps.

cold climate heat pump↗

Commercial Building Energy Asset Score System: Program Overview and Technical Protocol (Version 1.0)

The U.S. Department of Energy (DOE) is developing a national voluntary energy asset score system that includes an energy asset score tool to help building owners evaluate their buildings with respect to the score system. The goal of the energy asset score system is to facilitate cost-effective investment in energy efficiency improvements of commercial buildings. The system will allow building owners and managers to compare their building infrastructure against peers and track building upgrade progress over time. The system can also help other building stakeholders (e.g., building operators, tenants, financiers, and appraisers) understand the relative efficiency of different buildings in a way that is independent from their operations and occupancy. This report outlines the technical protocol used to generate the energy asset score, explains the scoring methodology, and provides additional details regarding the energy asset score tool. This report also describes alternative methods that were considered prior to developing the current approach. Finally, this report describes a few features of the program where alternative approaches are still under evaluation.

building energy use↗

From Zero Energy Buildings to Zero Energy Districts

Some U.S. cities are planning advanced districts that have goals for zero energy, water, waste, and/or greenhouse gas emissions. From an energy perspective, zero energy districts present unique opportunities to cost-effectively achieve high levels of energy efficiency and renewable energy penetration across a collection of buildings that may be infeasible at the individual building scale. These high levels of performance are accomplished through district energy systems that harness renewable and wasted energy at large scales and flexible building loads that coordinate with variable renewable energy supply. Unfortunately, stakeholders face a lack of documented processes, tools, and best practices to assist them in achieving zero energy districts. The National Renewable Energy Laboratory (NREL) is partnering on two new district projects in Denver: the National Western Center and the Sun Valley Neighborhood. We are working closely with project stakeholders in their zero energy master planning efforts to develop the resources needed to resolve barriers and create replicable processes to support future zero energy district efforts across the United States. Initial results of these efforts include the identification and description of key zero energy district design principles (maximizing building efficiency, solar potential, renewable thermal energy, and load control), economic drivers, and master planning principles. The work has also resulted in NREL making initial enhancements to the U.S. Department of Energy's open source building energy modeling platform (OpenStudio and EnergyPlus) with the long-term goal of supporting the design and optimization of energy districts.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Zero Energy Schools: Designing for the Future: Zero Energy Ready K-12 Schools

Designing, building, and operating zero energy ready K-12 schools provides benefits for districts, students, and teachers. Optimizing energy efficiency is important in any building, but it's particularly important in K-12 schools. Many U.S. school districts struggle for funding, and improving a school building's energy efficiency can free up operational funds that may then be available for educational and other purposes.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Multi-Year Program Plan - Building Regulatory Programs

This document presents DOE’s multi-year plan for the three components of the Buildings Regulatory Program: Appliance and Equipment Efficiency Standards, ENERGY STAR, and the Building Energy Codes Program. This document summarizes the history of these programs, the mission and goals of the programs, pertinent statutory requirements, and DOE’s 5-year plan for moving forward.

Appliance and Equipment Efficiency Standards↗

Regional Shelter Analysis – External Gamma Radiation Exposure Methodology

During normal operations, buildings can protect their occupants from outdoor hazards, including nuclear fallout and other external gamma radiation hazards. Purposeful sheltering can increase this protection. The physics of building protection against external gamma radiation is relatively well understood and we can characterize the protection afforded by individual buildings. However, an operationally efficient, regional-scale methodology to account for building protection effects has not previously been available. Such a method is necessary because (a) the overwhelming majority of the US population is indoors at any given time and (b) a regional-level building protection methodology could better estimate populations truly at risk in emergencies, support improved decision-making (shelter vs. evacuation decisions), and help guide resources towards those most at risk. The Regional Shelter Analysis (RSA) methodology provides a comprehensive, yet operationally efficient method for population-based risk analyses. Specifically, it accounts for (a) building protection distributions (within and among different buildings) and (b) population postures (how people are distributed within and outside of buildings). The RSA method could support a common operating picture by providing user specific results that have the resolution appropriate for individual user’s needs while still being consistent with the information being provided to the other users. The method employs existing building and population databases and is compatible with most modern exposure and injury assessment tools. This report presents the RSA methodology and discusses general operational considerations, with a focus on external gamma radiation exposures. To place this work in the context of prior efforts and current initiatives, a focused literature review is provided that identifies the relevant literature, scientific findings, and datasets from a variety of scientific fields. Other reports in this series will discuss (a) the inhalation exposure pathway and (b) specific RSA implementations.

54 ENVIRONMENTAL SCIENCES↗