R. Judkoff

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• Masters In Architecture, Columbia University
• Chief Architectural Engineer emeritus at National Renewable Energy Laboratory

The authors present a novel method for using electrical meter data to synthesize realistic equipment use schedules that can improve models of electrical demand in buildings. Other methods exist for creating schedules based on historical data from a limited set of past field studies, but the method presented here is unique because it allows a modell...

Materials advances could help to reduce the energy and environmental impacts of buildings. Globally, buildings consume 30%-40% of primary energy and account for 25%-33% of CO2 emissions. This talk explores some foundational concepts about how energy is used in buildings, and also highlights areas where materials advances would be most beneficial fr...

ANSI/ASHRAE Standard 140, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs applies the IEA BESTEST building thermal fabric test cases and example simulation results originally published in 1995. These software accuracy test cases and their example simulation results, which comprise the first test suite adapte...

This report documents the design of a desiccant enhanced evaporative air conditioner (DEVAP AC) prototype and the testing to prove its performance. Previous numerical modeling and building energy simulations indicate a DEVAP AC can save significant energy compared to a conventional vapor compression AC (Kozubal et al. 2011). The purposes of this re...

This presentation discusses the goals of NREL Analysis Accuracy R&D; BESTEST-EX goals; what BESTEST-EX is; how it works; 'Building Physics' cases; 'Building Physics' reference results; 'utility bill calibration' cases; limitations and potential future work. Goals of NREL Analysis Accuracy R&D are: (1) Provide industry with the tools and technical i...

This publication summarizes building energy simulation test for existing homes (BESTEST-EX): instructions for implementing the test procedure, calibration tests reference results, and example acceptance-range criteria.

Businesses, government agencies, consumers, policy makers, and utilities currently have limited access to occupant-, building-, and location-specific recommendations for optimal energy retrofit packages, as defined by estimated costs and energy savings. This report describes an analysis method for determining optimal residential energy efficiency r...

A set of in-depth diagnostic test cases for multi-zone heat transfer was developed. These are designed to test the ability of building energy analysis tools to model multi-zone conduction, multi-zone shading, including automated building self-shading and modeling of internal windows between zones. A methodological advancement for this work, which e...

The authors developed a method for testing the reliability of models that predict retrofit energy savings, including their associated calibration methods. The test suite applies the new Building Energy Simulation Test for Existing Homes (BESTEST-EX) Methodology, developed by the National Renewable Energy Laboratory in consultation with home energy...

Focus Materials advances could help to reduce the energy and environmental impacts of buildings. Globally, buildings consume 30%–40% of primary energy and account for 25%–33% of CO2 emissions. Building energy consumption emanates from a variety of sources, some of which are related to the building envelope or fabric, some to the equipment in the bu...

Contract No. DE-AC36-99-GO10337NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness,...

This paper presents an overview of the International Energy Agency Solar Heating and Cooling Task 34 and Energy Conservation in Buildings and Community Systems Annex 43.

This document provides an example procedure for establishing acceptance-range criteria to assess results from software undergoing BESTEST-EX. This example method for BESTEST-EX is a modified version of the method described in HERS BESTEST.

BESTEST-EX is a method to test building energy software for use on residential buildings. This paper discusses how to establish acceptance range criteria based on a confidence interval approach. Another paper discusses the overall BESTEST-EX Methodology.

The U.S. Department of Energy tasked NREL to develop a process for testing the reliability of models that predict retrofit energy savings, including their associated calibration methods. DOE asked NREL to conduct the work in phases so that a test procedure would be ready should DOE need it to meet legislative requirements related to residential ret...

A set of validation test cases are presented for comparing the results of mid-level detailed ground-coupled heat transfer models typically used with whole-building energy simulation software to verified detailed numerical ground-coupled heat transfer models. A new validation methodology development is also presented that uses an analytical solution...

This report documents a set of diagnostic test cases for multi-zone heat transfer models. The methodology combines empirical validation, analytical verification, and comparative analysis techniques.

This report documents a set of idealized in-depth diagnostic test cases for use in validating ground-coupled floor slab heat transfer models. These test cases represent an extension to IEA BESTEST.

The objective of this report was to develop a validation methodology for building energy analysis simulations, collect high-quality, unambiguous empirical data for validation, and apply the validation methodology to the DOE-2.1, BLAST-2MRT, BLAST-3.0, DEROB-3, DEROB-4, and SUNCAT 2.4 computer programs. This report covers background information, lit...

Materials advances could help to reduce the energy and environmental impacts of buildings. Globally, buildings use about 20% of primary energy and account for 20% of atmospheric emissions. Building energy consumption emanates from a variety of sources, some of which are related to the building envelope or fabric, some to the equipment in the buildi...

This report uses EnergyPlus simulations of each building in the 2003 Commercial Buildings Energy Consumption Survey (CBECS) to document and demonstrate bottom-up methods of modeling the entire U.S. commercial buildings sector (EIA 2006). The ability to use a whole-building simulation tool to model the entire sector is of interest because the energy...

This report summarizes the findings from research conducted at NREL to assess the technical potential for zero-energy building (ZEB) technologies and practices to reduce the impact of commercial buildings on the U.S. energy system. Commercial buildings currently account for 18% of annual U.S. energy consumption, and energy use is growing along w...

Advances in on-site renewable energy technology have brought the concept of zero-energy buildings within reach. Many single-story residential and commercial buildings have enough favorably oriented roof area to make achieving zero energy technically feasible, assuming no major solar obstructions exist and that energy efficiency has been aggressivel...

A method, and systems for implementing such method, for purifying and conditioning air of weaponized contaminants. The method includes wetting a filter packing media with a salt-based liquid desiccant, such as water with a high concentration of lithium chloride. Air is passed through the wetted filter packing media and the contaminants in are captu...

Commercial buildings have a significant impact on energy use and the environment. They account for approximately 18% (17.9 quads) of the total primary energy consumption in the United States (DOE 2005). The energy used by the building sector continues to increase, primarily because new buildings are added to the national building stock faster than...

Ideally, whole-building energy simulation programs model all aspects of a building that influence energy use and thermal and visual comfort for the occupants. An essential component of the development of such computer simulation models is a rigorous program of validation and testing. This paper describes a methodology to evaluate the accuracy of wh...

Paper discusses NREL's role in the participation of the design process of the Zion National Park Visitor Center Complex and the results documented from monitoring the energy performance of the building for several years. Paper includes PV system and Trombe wall description and lessons learned in the design, construction, and commissioning of the bu...

This report is part of a series of six case studies to develop, document, analyze, and evaluate the processes by which highly energy-efficient buildings can be reliably produced. NREL monitored the energy performance of the Visitor Center Complex at Zion National Park from September 1, 2000 to June 1, 2003. This evaluation was crucial to achieving...

Final report of energy performance analysis and design process evaluation for the Thermal Test Facility at the National Renewable Energy Laboratory.

This paper describes a new data set appropriate for empirical validation of whole-building energy simulation software. The data has been created using artificial and natural climate configurations in the empirically characterized ETNA (Essais Thermiques en climat Naturel et Artificiel) test cells of an electric utility in France. This data set incl...

This report documents an additional set of mechanical system test cases that are planned for inclusion in ANSI/ASHRAE STANDARD 140. The cases test a program's modeling capabilities on the working-fluid side of the coil, but in an hourly dynamic context over an expanded range of performance conditions. These cases help to scale the significance of d...

Because buildings consume more than 39% of the nation’s primary energy and more than 70% of the total electricity, it is essential that architects and engineers design buildings that use considerably less energy than existing buildings. Some owners and designers have made great strides to significantly change the way commercial buildings use energy...

The energy performance of six high-performance buildings around the United States was monitored in detail. The six buildings include the Visitor Center at Zion National Park; the National Renewable Energy Laboratory's Thermal Test Facility; the Chesapeake Bay Foundation's Merrill Center; The BigHorn Home Improvement Center; the Cambria DEP Office B...

To measure progress toward multi-year Building America research goals, cost and performance trade-offs are evaluated through a series of controlled field and laboratory experiments supported by energy analysis techniques that use test data to''calibrate'' energy simulation models. This report summarizes the guidelines for reporting such analytical...

In the autumn of 2002, 14 universities built solar houses on the National Mall in Washington, DC, in a student competition-the Solar Decathlon-demonstrating that homes call derive all the energy they need from the sun and celebrating advances in solar buildings. This paper describes recent progress in solar building technology that expands the desi...

A three-dimensional, finite-element, heat-transfer computer program was developed to study ground-coupled heat transfer from buildings. It was used in conjunction with the SUNREL whole-building energy simulation program to analyze ground-coupled heat transfer from buildings, and the results were compared with the simple ground-coupled heat transfer...

Validation of building energy simulation programs consists of a combination of empirical validation, analytical verification, and comparative analysis techniques. An analytical verification and comparative diagnostic procedure was developed to test the ability of whole-building simulation programs to model the performance of unitary space-cooling e...

This report describes the Building Energy Simulation Test for Heating, Ventilating, and Air-Conditioning Equipment Models (HVAC BESTEST) project conducted by the Tool Evaluation and Improvement International Energy Agency (IEA) Experts Group. The group was composed of experts from the Solar Heating and Cooling (SHC) Programme, Task 22, Subtask A. T...

As the Building America Program has grown to include a large and diverse cross section of the home building industry, accurate and consistent analysis techniques have become more important to help all program partners as they perform design tradeoffs and calculate energy savings for prototype houses built as part of the program. This document illus...

Two modular office units were tested at the National Renewable Energy Laboratory (NREL) to establish each unit's thermal performance. The two units were nearly identical in appearance, but one was built with structural insulating panels (SIP), and the other was built using standard frame construction. The primary objective of these tests was to com...

This paper is extracted from a full-length technical report that presents a detailed analysis of the differences in thermal performance between the SIP and frame units and describes the validation of the STEM method.

Minimizing energy consumption in residential buildings using passive solar strategies almost always calls for the efficient use of massive building materials combined with solar gain control and adequate insulation. Using computerized simulation tools to understand the interactions among all the elements facilitates designing low-energy houses. Fin...

In the United States, well over $100 billion is spent annually to provide energy to homes. Two tools that can help improve the energy efficiency of the nation's housing stock are home energy rating systems (HERS) and energy-efficient mortgages (EEMs). A home energy rating measures the energy efficiency of a house and recommends cost-effective energ...

An ASHRAE Standard Method of Test is being developed for systematically testing whole-building energy simulation models and diagnosing the sources of predictive disagreement. The procedure, ASHRAE Proposed Standard 140P, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs, uses the comparative testing approach....

Designing and constructing low-energy buildings (buildings that consume 50% to 70% less energy than code-compliant buildings) require the design team to follow an energy-design process that considers how the building envelope and systems work together. A design team must set energy efficiency goals at the beginning of the pre-design phase. Detailed...

The Thermal Test Facility (TTF) at the UD Department of Energy's National Renewable Energy Laboratory (NREL) was designed and constructed using an energy design process that optimizes the interaction between the building envelope and systems. To successfully realize a low-energy building, the design team made a cost-effective energy minimization on...

In 1991, the U.S. Department of Energy, in cooperation with the Department of Housing and Urban Development (HUD), initiated a collaborative process to define a residential energy efficiency rating program linked with energy-efficient mortgage (EEM) financing. During this process, the collaborative, consisting of a broad-based group representing st...

This paper summarizes a two volume National Renewable Energy Laboratory (NREL) report entitled "Home Energy Rating System Building Energy Simulation Test (HERS BESTEST)" (Judkoff and Neymark, 1995a). HERS BESTEST is a comparative validation method for evaluating the credibility of building energy software used by Home Energy Rating Systems. As NREL...

The Home Energy Rating System (HERS) Building Energy Simulation Test (BESTEST) is a method for evaluating the credibility of software used by HERS to model energy use in buildings. The method provides the technical foundation for ''certification of the technical accuracy of building energy analysis tools used to determine energy efficiency ratings,...

The Home Energy Rating System (HERS) Building Energy Simulation Test (BESTEST) is a method for evaluating the credibility of software used by HERS to model energy use in buildings. The method provides the technical foundation for ''certification of the technical accuracy of building energy analysis tools used to determine energy efficiency ratings,...

This is a report on the Building Energy Simulation Test (BESTEST) project conducted by the Model Evaluation and Improvement International Energy Agency (IEA) Experts Group. The group was composed of experts from the Solar Heating and Cooling (SHC) Programme, Task 12 Subtask B, and the Energy Conservation in Buildings and Community Systems (BCS) Pro...

A procedure was developed for systematically testing whole building energy simulation models and diagnosing the sources of predictive disagreements. Field trials of the method were conducted with a number of detailed state-of-the-art programs by researchers from nations participating in International Energy Agency (IEA) Task 12 and Annex 21. The te...

This study analyzes utility bill data for 36 mobile homes retrofitted by Colorado Division of Housing Weatherization Assistance Program according to criteria developed specifically for mobile homes by the National Renewable Energy Laboratory (NREL). The post-retrofit energy savings were determined using PRISM, a regression method that provides weat...

This article evaluates both the performance of two mobile homes built to meet recently proposed federal energy performance standards and the standards themselves. Topics include test methods, results, thermal exposure infrared scan results; regulators, thermal characteristics of test homes, real life conditions, factory observations, the future of...

This Research Update presents the status of the Existing Buildings Research program of the Office of Building Technologies of the US Department of Energy for the period 1989-199 1. This program covers research on energy efficiency improvements for the residential and commercial buildings in this country. ne Existing Buildings Research program has c...

Thermal testing of two manufactured homes was performed at the National Renewable Energy Laboratory`s (NREL`s) Collaborative Manufactured Buildings Facility for Energy Research and Testing (CMFERT) environmental enclosure in the winter and spring of 1991. The primary objective of the study was to directly measure the thermal performance of the two...

This article describes mobile home retrofits for energy conservation as developed by the Collaborative Manufactured-Building Facility for Energy Research and Training (CMFERT). These techniques were developed in specially adapted warehouses in simulated wind conditions and consequently subjected to field training and testing. Results of the testing...

For several years the Solar Energy Research Institute has been testing the effectiveness of mobile home weatherization measures, with the support of the US DOE Office of State and Local Assistance Programs Weatherization Assistance Program, the DOE Office of Buildings and Community Systems, the seven states within the federal Weatherization Region...

The Solar Energy Research Institute (SERI) was funded by the Department of Energy's Office of Buildings and Community Systems (DOE OBCS) in FY 1987 and 1988 to investigate cost effective ways to weatherize mobile homes constructed prior to the enactment of HUD Thermal Standards in 1976. In FY 1987 SERI studied the effectiveness of a variety of infi...

This article presents a synopsis of work conducted over a number of years at the Solar Energy Research Institute (SERI) related to the validation of building energy analysis simulation programs. The work described was supported by the U.S. Department of Energy, Solar Buildings and Conservation Divisions, and more recently has also been sponsored un...

For the past several years the United States Department of Energy (DOE) Passive and Hybrid Solar Division has sponsored work to improve the reliability of computerized building energy analysis simulations. Under the auspices of what has come to be called the Class A Monitoring and Validation program, the Solar Energy Research Institute (SERI) has e...

A residential test building at the SERI Interim Field Site was monitored at the Class-A level during the spring of 1982. The building was also modeled on three building energy analysis simulations - DOE2.1A, Blast 3.0 and SERIRES - using measured weather data from the test period and the location. The measured energy performance data, and that pred...

A multizone infiltration monitoring system (MIMS) using a single tracer gas has been developed. MIMS measures zonal infiltration and exfiltration as well as interzonal air movement rates. The system has been used at the 4-zone test house at the SERI interim field site, and this paper presents preliminary results. The present system can determine zo...

Four building energy analysis codes are compared using two direct gain building models with Madison, WI, and Albuquerque, NM, typical meteorological year (TMY) data. Annual heating and cooling loads are compared and analyzed with respect to two previous studies. The results from all four codes disagree significantly.

The design and construction of a 100% passive solar building utilizing a clerestory and a trombe wall are described. The use of three selectively absorptive and emissive coverings on the trombe wall outer surface are investigated. One of the coverings and its laminating adhesive are tested for degradation after a year of exposure under normal opera...

An analytical verification technique for building energy analysis codes has been developed. For this technique, building models are developed that can be both solved analytically and modeled using the analysis codes. The output of the codes is then compared with the analytical solutions. In this way, the accuracy of selected mechanisms in the codes...

Four building energy analysis codes are compared using two direct gain building models with Madison TMY weather data. Hourly temperature profiles and annual heating and cooling loads are compared and discussed. An analytic verification technique is described and used to investigate performance of the four codes. An anomaly is discovered in one of t...

A software package for passive solar design analysis was developed. This package is based on the Los Alamos Scientific Laboratories Solar/Load Ratio (LASL SLR) method, and utilizes the most current features of this method. Further algorithms allow calculation of solar radition on a tilted, shaded aperture at any azimuth. This offers increased flexi...

In July 1998, USDOE and China's Ministry of Science and Technology (MOST) signed a Statement of Work to develop a demonstration energy-efficient office building and demonstration center in Beijing that will eventually house the Administrative Center for China's Agenda 21 (ACCA21). The statement calls for the Chinese side to be responsible for the b...

The BigHorn Home Improvement Center in Silverthorne, Colorado was one of the first commercial buildings in the United States to integrate extensive high-performance design into a retail space. After monitoring and evaluation by NREL, the BigHorn Center was found to consume 54% less source energy and have 53% lower energy costs than typical retail b...

The National Park Service (NPS) applied a whole-building design process developed at the National Renewable Energy Laboratory (NREL) to create a building that performs more than 70% better than a comparable code-compliant building at no additional construction cost. This whole-building design process involves a committed design team, including the...

Validation of Building Energy Simulation Programs consists of a combination of empirical validation, analytical verification, and comparative analysis techniques (Judkoff 1988). An analytical verification and comparative diagnostic procedure was developed to test the ability of whole-building simulation programs to model the performance of unitary...

The objective of this project is to assess the accuracy of building energy analysis tools that have incorporated detailed models for predicting ground-coupled heat transfer related to floor slab and basement constructions. An executive summary is to be found in the main report.

The Solar Energy Research Institute (SERI) is developing a procedure for the validation of Building Energy Analysis Simulation Codes (BEAS). These codes are being used increasingly in the building design process, both directly and as the basis for simplified design tools and guidelines. The importance of the validity of the BEAS in predicting build...

This paper focuses on implementation of daylighting into the Bighorn Center, a collection of home improvement retail spaces in Silverthorne, Colorado, which were constructed in three phases. Daylighting was an integral part of the design of the Phase 3 building. Energy consultants optimized the daylighting design through detailed modeling using an...

The Thermal Test Facility (TTF) at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, was designed and constructed using a whole-building energy design approach. This approach treats a building as a single unit, not as a shell containing many separate systems. It relies on the use of energy simulation tools for optimization throug...

SERI is developing a procedure for the validation of Building Energy Analysis Simulation Codes (BEAS). These codes are being used increasingly in the building design process, both directly and as the basis for simplified design tools and guidelines. The importance of the validity of the BEAS in predicting building energy performance is obvious when...

One quarter of all homes eligible for federal Low-Income Weatherization Assistance are mobile homes-the building type most notorious as energy sieves. Eligible or not, mobile homes tend to be inhabited by people who can least afford the mobile homes disproportionately high fuel bills. To top it off, a lack of hard data about the effectiveness of va...

Under the auspices of the DOE Passive/Hybrid Solar Division Class A Monitoring and Validation Program, SERI has engaged in several areas of research in fiscal year 1982. This research has included: (1) development of a validation methodology, (2) development of a performance monitoring methodology designed to meet the specific data needs for valida...

Accurate and meaningful energy savings calculations are essential for the evaluation of residential energy efficiency programs sponsored by the U.S. Department of Energy (DOE), such as the Building America Program (a public-private partnership designed to achieve significant energy savings in the residential building sector). The authors investigat...

Evaporative cooling systems have been criticized for their water use and acclaimed for their low energy consumption, especially when compared to typical cooling systems. In order to determine the overall effectiveness of cooling systems, both water and energy need to be considered; however, there must be a metric to compare the amount of energy use...

Zion National Park in Utah has experienced substantial growth in the number of visitors to the park, leading to a negative impact on visitor experience and the surrounding environment. To reduce environmental impact and improve visitor experience, National Park Service (NPS) staff planned the development of a new Visitor Center Complex. Saving and...

In addition to impacting non-renewable energy supplies, buildings world wide contribute to climate change by being responsible for the release of carbon dioxide, either directly through combustion of carbon-based fuels or indirectly through electricity consumption from carbon fuels. Engineers and architects have an obligation to design for sustaina...

The validation procedure for building Energy Analysis simulation Codes (BEAS) is divided into three parts. In the first, Comparative Study, each BEAS is divided into three parts. In the first, Comparative Study, each BEAS analyzes the same building using the same set of weather data input files. The second part, Analytical Verification, is useful i...

The Validation Test House at the Solar Energy Research Institute in Golden, Colorado, is being used to collect performance data for analysis/design tool validation as part of the DOE Passive Solar Class A Performance Evaluation Program. This site handbook describes in detail the construction, instrumentation, and test configuration of the building...