Since 1999, GARD Analytics has been part of a USDOE research team that has developed and is continually adding new capabilities to the EnergyPlus building energy simulation software. EnergyPlus models heating, cooling, lighting, ventilating, and other energy flows as well as water in buildings. While originally based on the most popular features and capabilities of BLAST and DOE-2, EnergyPlus includes many innovative simulation capabilities such as time steps of less than an hour, modular systems and plants integrated with heat balance-based zone simulation, multi-zone air flow, thermal comfort, water use, natural ventilation, and photovoltaic systems. Tools like EnergyPlus are a key component in sustainable whole building design.
GARD’s role has been to test and validate each new public release version of the software, develop utility software programs, provide e-mail support to users, develop training materials, and provide user training through workshops and webinars.
Testing and validating new release versions of the software is done through use of the following test suites, some of which are industry standards and some of which have been developed by GARD.
Building Thermal Envelope and Fabric Load Tests from ANSI/ASHRAE Standard 140-2007, Section 5.2 — Comparative tests for building envelope with 1-zone and 2-zone buildings run using two different EnergyPlus solution algorithms: conduction transfer functions (CTF) and conduction finite difference (CondFD)
HVAC Equipment Performance Tests CE100 to CE200 from ANSI/ASHRAE Standard 140–2007, Sections 5.3.1 and 5.3.2 — Comparative and analytical tests with steady-state DX cooling equipment applied to a 1-zone building and simulated using two different EnergyPlus equipment models: window air conditioner and unitary furnace with DX cooling
HVAC Equipment Performance Tests, Part 2, CE300 thru CE545 from ANSI/ASHRAE Standard 140-2007, Sections 5.3.3 and 5.3.4 — Comparative tests with seasonal DX cooling equipment with outside air options applied to a 1-zone building and modeled using two different EnergyPlus equipment models: unitary air-to-air heat pump and unitary furnace with DX cooling
Fuel-Fired Furnace Performance Tests HE100 thru HE230 from ANSI/ASHRAE Standard 140–2007, Section 5.4 — Comparative tests of a seasonal gas furnace applied to a 1-zone building
ASHRAE 1052-RP Toolkit – Building Fabric Analytical Tests — Analytical tests for building envelopes using a 1-zone building
IEA BESTEST In-Depth Ground Coupled Heat Transfer Tests Related to Slab-on-Grade Construction — Comparative tests for foundation heat transfer applied to a 1-zone building
IEA BESTEST Multi-Zone Non-Airflow In-Depth Diagnostic Cases: MZ320 – MZ360 — Comparative tests of a 6 zone building to test accuracy of tracking heat transfer between zones, shading from external objects, and internal windows
IEA Airflow Test Cases including Multi-Zone — Comparative and analytical tests for tracking airflow between zones driven by wind, temperature difference, and both combined in a 1-zone and 3-zone building
IEA Mechanical Equipment and Control Strategies — Comparative and empirical tests to test the ability to predict energy consumption and performance of HVAC components in chilled-water and hot-water systems
IEA Home Energy Rating System (HERS BESTEST) from ANSI/ASHRAE Standard 140-2011 (draft) — Comparative tests to test the accuracy of modeling various features of a single-story house including passive solar features
HVAC Equipment Component Test Suite — Comparative tests of steady-state water-cooled chiller and hot water boiler to test accuracy compared to manufacturer data
Global Energy Balance Test Suite — Comparative tests of steady-state building with internal gains modeled with a window air-conditioner, chiller and boiler
GARD Analytics also has developed several utility software programs for EnergyPlus including:
- IDF Editor – a utility to aid in preparing EnergyPlus input data files. The IDF Editor is a dynamic self-configuring input file editor which automatically updates the input structure to match the current data dictionary.
- EP-Launch – EP-Launch features include input file selection, input file editing, weather file selection, simulation execution, and output file viewing.
- ExpandObjects – Used to convert simplified HVAC input into the more complex native EnergyPlus input objects.
- DOE-2 to EnergyPlus Translator – a FORTRAN utility which translates portions of DOE-2 input files into an EnergyPlus IDF.
- Tabular Reports – Added predefined and user definable verification and summary reports in IP and SI units similar to those available in DOE-2 including time dependent valuation (TDV) to support California’s Title 24.
- HVAC Diagram – a utility program to generate HVAC system and equipment diagrams using the user provided input for the various components which are available within EnergyPlus to help the user build-up systems.
- ConvertESOMTR – a utility to convert output reporting into IP units.
- Utility Tariffs – a set of objects to model utility rates and tariffs in a flexible simple approach.
- MathDiff –a Python script which mathematically compares a pair of CSV data files which have been created as output from EnergyPlus. MathDiff allows batch-oriented comparison of large data sets to identify whether changes are within specified tolerances of percentage and absolute differences.
- ParametricPreprocessor – used to create a series of resulting IDF files from a single source IDF file that contains parametric objects and expressions
- EP-Compare – used to compare the tabular results of several simulations including the ABUPS (Annual Building Energy Performance Summary) report
In its role of providing user support, GARD has reviewed hundreds of EnergyPlus input files describing buildings being designed and retrofitted, providing guidance and solving problems related to modeling building geometry, material properties, HVAC system design, and HVAC system controls.
GARD has responsibility for developing and conducting a series of EnergyPlus training workshops and webinars which are a valuable tool to enhance user skills. Since 2002, GARD has organized more than 40 events with over 700 attendees, and Dr. Witte of GARD has taught nearly all of them.