Model Validation and Testing: The Methodological Foundation of ASHRAE Standard 140; Preprint

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 whole-building energy simulation programs. The methodology is also used to identify and diagnose differences in simulation predictions that may be caused by algorithmic differences, modeling limitations, coding errors, or input errors. The methodology has been adopted by ANSI/ASHRAE Standard 140 (ANSI/ASHRAE 2001, 2004), Method of Test for the Evaluation of Building Energy Analysis Computer Programs. A summary of the method is included in the ASHRAE Handbook of Fundamentals (ASHRAE 2005). This paper describes the ANSI/ASHRAE Standard 140 method of test and its methodological basis. Also discussed are possible future enhancements to Standard 140 and related research recommendations

Home energy rating system building energy simulation test (HERS BESTEST): Volume 1, Tier 1 and Tier 2 tests user's manual

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,'' as called for in the Energy Policy Act of 1992 (Title I, subtitle A,l Section 102, Title II, Part 6, Section 271). Certification is accomplished with a uniform set of test cases that facilitate the comparison of a software tool with several of the best public-domain, state-of-the-art building energy simulation programs available in the United States. This set of test cases represents the Tier 1 and Tier 2 Tests for Certification of Rating Tools as described in DOE 10 CFR Part 437 and the HERS Council Guidelines for Uniformity (HERS Council). A third Tier of tests not included in this document is also planned

Building Energy Simulation Test for Existing Homes (BESTEST-EX) (Presentation)

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 information needed to improve the accuracy and consistency of analysis methods; (2) Reduce the risks associated with purchasing, financing, and selling energy efficiency upgrades; and (3) Enhance software and input collection methods considering impacts on accuracy, cost, and time of energy assessments. BESTEST-EX Goals are: (1) Test software predictions of retrofit energy savings in existing homes; (2) Ensure building physics calculations and utility bill calibration procedures perform up to a minimum standard; and (3) Quantify impact of uncertainties in input audit data and occupant behavior. BESTEST-EX is a repeatable procedure that tests how well audit software predictions compare to the current state of the art in building energy simulation. There is no direct truth standard. However, reference software have been subjected to validation testing, including comparisons with empirical data

Development and Analysis of Desiccant Enhanced Evaporative Air Conditioner Prototype

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 research were to build DEVAP prototypes, test them to validate the numerical model, and identify potential commercialization barriers

Building Energy Simulation Test for Existing Homes (BESTEST-EX) Methodology: Preprint

The test suite represents a set of cases applying the new Building Energy Simulation Test for Existing Homes (BESTEST-EX) Methodology developed by NREL. (Judkoff et al. 2010a). The NREL team developed the test cases in consultation with the home retrofit industry (BESTEST-EX Working Group 2009), and adjusted the test specifications in accordance with information supplied by a participant with access to large utility bill datasets (Blasnik 2009)

Methodology for Validating Building Energy Analysis Simulations

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, literature survey, validation methodology, comparative studies, analytical verification, empirical validation, comparative evaluation of codes, and conclusions

Solar Energy Research Institute Validation Test House Site Handbook

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

Comparative Study of Four Passive Building Energy Simulations DOE 2.1, BLAST, SUNCAT 2.4, DEROB-III

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 the codes, and the analytic verification technique is used to test a modified version of this code

IEA BESTEST Multi-Zone Non-Airflow In-Depth Diagnostic Cases: Preprint

This paper documents a set of in-depth diagnostic test cases for multi-zone heat transfer models that do not include the heat and mass transfer effects of airflow between zones. The multi-zone non-airflow test cases represent an extension to IEA BESTEST (Judkoff and Neymark 1995a)

Side-by-Side Thermal Tests of Modular Offices: A Validation Study of the STEM Method

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 compare the thermal performance of buildings using SIP and standard frame construction. Both units were tested under carefully controlled steady-state conditions in the NREL large-scale environmental enclosure. They were then moved outdoors where Short-Term Energy Monitoring (STEM) tests were performed, and long-term heating and cooling energy use was measured. A secondary objective was to evaluate the accuracy of the NREL STEM method by comparing the results of outdoor STEM tests to steady-state indoor test results. STEM is a method developed by NREL to determine key thermal parameters of a building in-situ, based on a 3-day test sequence. The indoor test facility also provided the opportunity to investigate the phenomenon of infiltration heat recovery in a real building, under carefully controlled conditions, to evaluate the stability of the concentration decay method of tracer gas-based infiltration monitoring, and to compare the blower-door method with the tracer-gas technique in determining infiltration.This project was a cooperative effort with the Structural Insulated Panel Association, the Modular Building Institute, All-American Modular (AAM, the manufacturer of the units), and GE Capitol (the owner of the units). Richard Harmon, the president of AAM, requested NREL's assistance in exploring the feasibility of converting his manufacturing process to SIP construction. His engineering staff needed to assess which comfort and energy benefits might be associated with this new technology. AAM manufactured the two units, and NREL tested the modules for 8 months