NREL Develops Diagnostic Test Cases to Improve Building Energy Simulation Programs (Fact Sheet)

Technical Report · Thu Dec 01 00:00:00 EST 2011

DOI:https://doi.org/10.2172/1031950· OSTI ID:1031950

This technical highlight describes NREL research to develop a set of diagnostic test cases for building energy simulations in order to achieve more accurate energy use and savings predictions. The National Renewable Energy Laboratory (NREL) Residential and Commercial Buildings research groups developed a set of diagnostic test cases for building energy simulations. Eight test cases were developed to test surface conduction heat transfer algorithms of building envelopes in building energy simulation programs. These algorithms are used to predict energy flow through external opaque surfaces such as walls, ceilings, and floors. The test cases consist of analytical and vetted numerical heat transfer solutions that have been available for decades, which increases confidence in test results. NREL researchers adapted these solutions for comparisons with building energy simulation results. Testing the new cases with EnergyPlus identified issues with the conduction finite difference (CondFD) heat transfer algorithm in versions 5 and 6. NREL researchers resolved these issues for EnergyPlus version 7. The new test cases will help users and developers of EnergyPlus and other building energy tools to identify and fix problems associated with solid conduction heat transfer algorithms of building envelopes and their boundary conditions. In the long term, improvements to software algorithms will result in more accurate energy use and savings predictions. NREL researchers plan to document the set of test cases and make them available for future consideration by validation standards such as ASHRAE Standard 140: Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs. EnergyPlus users will also have access to the improved CondFD model in version 7 after its next scheduled release.

• Research Organization: National Renewable Energy Lab. (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Building Technologies Program
• DOE Contract Number: AC36-08GO28308
• OSTI ID: 1031950
• Report Number(s): DOE/GO-102011-3230; TRN: US201202%%73
• Resource Relation: Related Information: Building America: Technical Highlight, Building Technologies Program (BTP)
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ALGORITHMS
BOUNDARY CONDITIONS
COMMERCIAL BUILDINGS
COMPUTER CODES
ENERGY ANALYSIS
EVALUATION
FLOORS
HEAT TRANSFER
NATIONAL RENEWABLE ENERGY LABORATORY
ROOFS
SIMULATION
TESTING
VALIDATION
WALLS
BUILDING ENERGY EFFICIENCY
ENERGY SIMULATION SOFTWARE
BUILDING ENVELOPES
Energy Efficiency and Renewable Energy
Electricity, Resources, and Buildings Systems
Buildings