January 2010. Building zone model. • Simple multizone building model (simple
hourly method. EN 13790). • Water capacitance method (source: Trnsys) ...
Development and use of simulation tools dedicated to energy audit of nonresidential buildings Stéphane Bertagnolio Bertrand Fabry - Philippe André
University of Liège, Belgium HarmonAC - Vienna meeting – January 2010
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Introduction Methodology Simulation Tools Example of application Conclusion
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Introduction • Initially developed in the frame of the AUDITAC project • Development continued in the frame of the WP7 of the HarmonAC project: « Improved inspection and auditing tools » • Simulation tools dedicated to benchmarking, inspection and audit of non-residential buildings
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TOC • • • • •
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Introduction Methodology Simulation Tools Example of application Conclusion
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Methodology •
Benchmarking: first assessment of the building performance (comparison between actual and reference consumptions)
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Pre-audit (or Inspection): study of installed system, detailed analysis of global recorded energy consumption
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Detailed audit: quantitative evaluation of selected Energy Conservation Opportunities
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Investment grade audit: detailed technical and economical engineering study
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The sticky situation of the auditor
Questions to answer
Global and limited information • •
Monthly utility bills (Uncomplete) as-built data On-site measurements
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Analysis of energy consumption Identification of main energy consumers Identification of ECOs Quantitative evaluation of selected ECOs
Practical constrains • •
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Time Money
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Methodology How simple simulation tools can help ? •
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Benchmarking: first assessment of the building performance (comparison between actual and reference consumptions) Æ computation of reference performances Pre-audit (or Inspection): study of installed system, detailed analysis of global recorded energy consumption Æ disaggregation of recorded energy consumption Detailed audit: quantitative evaluation of selected Energy Conservation Opportunities Æ comparison between ECOs, evaluation of energy savings Investment grade audit: detailed technical and economical engineering study HarmonAC - Vienna meeting – January 2010
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TOC • • • • •
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Introduction Methodology Simulation Tools Example of application Conclusion
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1st Simulation Tool • SimBench • Used to compute reference performance • Mono-zone simulation of the actual building coupled to a “typical” reference HVAC system • System characteristics based on standards :PrEN13779 / PrEN13053 SIMBENCH
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2nd Simulation Tool • SimAudit •
Used to disaggregate recorded energy consumptions and to evaluate the selected ECOs • Mono-zone or Multi-zone Simulation of the actual building and the actual HVAC system • Calibration of the model to recorded energy consumptions
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Simulation Tools • SimBench = CEN code compliant simulation of the considered building • SimAudit = simplified building energy simulation tool to be calibrated Æ Similar modeling bases
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Building zone model • Simple multizone building model (simple hourly method EN 13790) • Water capacitance method (source: Trnsys)
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Sequential solving
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TOC • • • • •
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Introduction Methodology Simulation Tools Example of application Conclusion
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Case study • • • • • •
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Office building in Brussels (Belgium) : 26700 m² H shape, N-S oriented Light frontage composed of 1000 double-glazing modules CAV system coupled to local heating/cooling induction units Very high ventilation flow rate : 2.4 ACH 1100 occupants : 10 hours/day and 5 days/week
HarmonAC - Vienna meeting – January 2010
Recorded data • 30 years monthly fuel oil consumptions - Slope (50 kW/K) ~ Building global
heat transfer coef. (52 kW/K) - High dispersion (correlation factor: 66%) Æ Due to heterogeneous use of the HVAC system (and solar gains)
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Recorded data • 2 years monthly (total) electricity consumptions
- No seasonal effect
- Impossible to identify the different consumers
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Use of simulation tools • Benchmarking
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Use of simulation tools • Model calibration 0 – 1: Parameters adjusted basing on as-built data 1 – 2: Electrical gains adjusted basing on visual observations 2 – 3: Modification of performance of primary HVAC components
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Use of simulation tools • Analysis and Disaggregation
- Slope (55 kW/K) ~ Recorded value (50
kW/K) - Better correlation factor: 98% ÆDiscrepancies due to variations in building occupancy and use 20
-Important part due to appliances and lighti - Chiller : about 10 % of the total
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Use of simulation tools • Evaluation of retrofit options 1: better fresh air management (decreasing of operating time from 75h to 55h per week) 2: increasing of air recirculation 3: air-to-air heat recovery system
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TOC • • • • •
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Introduction Methodology Simulation Tools Example of application Conclusion
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Conclusion • Two simplified building energy simulation tools with limited number of parameters dedicated to audit • « Benchmark »: code-compliant tool for benchmarking purposes • « SimAudit »: simulation tool dedicated to inspection and evaluation of ECOs www.harmonac.info www.labothap.ulg.ac.be Contact:
[email protected]
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