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HarmonAC - Vienna meeting –January 2010

Development and use of simulation toolsdedicated to energy audit of non-

residential buildingsStéphane Bertagnolio

Bertrand Fabry - Philippe André

University of Liège, Belgium

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TOC

• 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 theHarmonAC project: « Improved inspection and auditingtools »

• Simulation tools dedicated to benchmarking, inspection and audit of non-residential buildings

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TOC

• 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)

• Pre-audit (or Inspection): study of installed system, detailed analysis of global recorded energy consumption

• Detailed audit: quantitative evaluation of selected Energy Conservation Opportunities

• Investment grade audit: detailed technical and economical engineering study

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The sticky situation of the auditor

• Analysis of energyconsumption

• Identification of main energy consumers

• Identification of ECOs• Quantitative evaluation of

selected ECOs

Global and limitedinformation

• Monthly utility bills• (Uncomplete) as-built

data• On-site

measurements

Practicalconstrains

• Time• Money

Questions to answer

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Methodology

How simple simulation tools can help ?

• Benchmarking: first assessment of the building performance (comparison between actual and reference consumptions)

computation of reference performances• Pre-audit (or Inspection): study of installed system, detailed analysis

of global recorded energy consumptiondisaggregation of recorded energy consumption

• Detailed audit: quantitative evaluation of selected Energy Conservation Opportunities

comparison between ECOs, evaluation of energy savings

• Investment grade audit: detailed technical and economical engineering study

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TOC

• 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 theconsidered building

• SimAudit = simplified building energy simulation tool to be calibrated

Similar modeling bases

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Building zone model

• Simple multizone building model (simple hourly methodEN 13790)

• Water capacitance method (source: Trnsys)

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Sequential solving

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TOC

• Introduction• Methodology• Simulation Tools• Example of application• Conclusion

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Case study

• 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

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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%)

Due to heterogeneoususe 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 differentconsumers

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Use of simulation tools

• Benchmarking

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Use of simulation tools

• Model calibration

0 – 1: Parameters adjusted basingon as-built data

1 – 2: Electrical gains adjustedbasing 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%

Discrepancies due to variationsin building occupancy and use

-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 timefrom 75h to 55h per week)

2: increasing of air recirculation

3: air-to-air heat recovery system

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TOC

• Introduction• Methodology• Simulation Tools• Example of application• Conclusion

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Conclusion

• Two simplified building energy simulation tools withlimited number of parameters dedicated to audit

• « Benchmark »: code-compliant tool for benchmarkingpurposes

• « SimAudit »: simulation tool dedicated to inspection andevaluation of ECOs

www.harmonac.info

www.labothap.ulg.ac.be

Contact: stephane.bertagnolio@ulg.ac.be