Lecture Objectives: Discuss accuracy of energy simulation and Introduce advance simulation tools Review the course topics Do the Course and Instructor Evaluation

Testing the Accuracy of Energy Simulations Comparison with measured data Cranfield test rooms (from Lomas et al 1994a)

BESTEST Building Energy Simulation TEST System of tests (~ 40 cases) - Each test emphasizes certain phenomena like external (internal) convection, radiation, ground contact Simple geometry Mountain climate COMPARE THE RESULTS

Example of best test comparison

Data Driven Modeling Empirical model For average year use TMY2 Load vs. dry bulb temperature Measured for a building in Syracuse, NY Model For average year use TMY2 =835890ton hour = 10.031 106 Btu

Advance Energy Modeling with coupled energy and airflow Example: Night Cooling/Hybrid Ventilation The IONICA Office Building, Cambridge, UK

Night Cooling/Hybrid Ventilation: Requires combined Energy and airflow modeling

Night Cooling/Hybrid Ventilation: The IONICA Office Building, Cambridge, UK

Available software Which software to use: - Depends on project requirements - If you have a choice: the one which passed BETEST Be ready to conduct additional analysis based on your modeling skills http://www.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm

Structure of All ES programs Graphical User Interface (GUI) Solver Interface for input data Interface for result presentation Preprocessor ASCI file Preprocessor Engine

ES programs Large variety DOE2 eQUEST (DOE2) BLAST ESPr TRNSYS http://www.buildingenergysoftwaretools.com/ DOE2 eQUEST (DOE2) BLAST ESPr TRNSYS EnergyPlus (DOE2 & BLAST)

eQUEST (DOE2) US Department of Energy & California utility customers eQUEST - interface for the DOE-2 solver DOE-2 - one of the most widely used ES program - recognized as the industry standard eQUEST very user friendly interface Good for life-cycle cost and parametric analyses Not very large capabilities for modeling of different HVAC systems Many simplified models Certain limitations related to research application - no capabilities for detailed modeling DOE3 – very similar

ESPr University of Strathclyde - Glasgow, Scotland, UK Detailed models – Research program Use finite difference method for conduction Simulate actual physical systems Enable integrated performance assessments Includes daylight utilization, natural ventilation, airflow modeling CFD, various HVAC and control models Detail model – require highly educated users Primarily for use with UNIX operating systems

http://www.esru.strath.ac.uk/Programs/ESP-r_overview.htm

TRNSYS Solar Energy Lab - University of Wisconsin Modular system approach One of the most flexible tools available A library of components Various building models including HVAC Specialized for renewable energy and emerging technologies User must provide detailed information about the building and systems Not free

https://sel.me.wisc.edu/trnsys/

EnergyPlus U S Department of Energy Newest generation building energy simulation program ( BLAST + DOE-2) Accurate and detailed Complex modeling capabilities Large variety of HVAC models Some integration wit the airflow programs Zonal models and CFD Detail model – require highly educated users Very modest interface Third party interface – very costly New interface: Open Studio,

https://energyplus. net/ https://www. openstudio. net/ https://beopt https://energyplus.net/ https://www.openstudio.net/ https://beopt.nrel.gov/

Modelica (Modelica Buildings Library) http://simulationresearch. lbl

THERM Two-Dimensional Building Heat-Transfer Modeling https://windows Thermal bridge analysis Window performance analysis

WUFI http://web.ornl.gov/sci/buildings/tools/wufi/ Heat and moisture analysis in building structural components

Matlab vs. Scilab http://www.scilab.org/ Many other free versions: Python …

Review Course Objectives 1. Identify basic building elements which affect building energy consumption and analyze the performance of these elements using energy conservation models. 2. Analyze the physics behind various numerical tools used for solving different heat transfer problems in building elements. 3. Use basic numerical methods for solving systems of linear and nonlinear equations. 4. Conduct building energy analysis using comprehensive computer simulation tools. 5. Evaluate the performance of building envelope and environmental systems considering energy consumption. 6. Perform parametric analysis to evaluate the effects of design choices and operational strategies of building systems on building energy use. 7. Use building simulations in life-cycle cost analyses for selection of energy-efficient building components.

There is a Building Energy System course that I teach in Spring 2017 If you likes this course: There is a Building Energy System course that I teach in Spring 2017