Malaviya National Institute of Technology Jaipur (India)

Comparison of simulation results and actual energy consumption in a

learning centre

Jyotirmay Mathur*, Vishal Garg**, Aviruch Bhatia*

* Energy Engineering Program, Mech. Engg. Dept.Malaviya national Institute of Technology Jaipur

and

**Centre for Research in Building ScienceIIIT Hyderabad

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Objective

6/16/2009 2

Identifying agreement between energy simulation and actual performance of buildings

Using calibrated simulation model to estimate the energy savings using ECMs [as per International Performance Measurement and Verification Protocol (IPMVP) - Option D]

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Ways to estimate Energy Savings

Agreed-upon stipulations

Engineering calculations

Metering and monitoring

Utility meter billing analysis

Computer simulations :without calibrated model v/s with calibrated

model

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Simulations for estimating energy savings

Calibrated simulation helps:When properties of materials, and other data are not known/have uncertaintySchedules are uncertainTakes care for variation of actual on site parameters from design values, inappropriate installation etc.

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Steps in calibration simulation

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Produce a calibrated simulation planCollect dataInput data and run modelEnergy simulation of modelCompare results with actual dataApply criteria for matching of resultsIdentify causes of variationRefine model by changing parametersEvaluate patterns in the differences between

simulation results and calibration dataCalculate energy savings using ECMs

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Case study: Building description

Satyam Learning Center (Hyderabad)The building is G+1(Ground + First) structure.External wall is composed of 190 mm brick with plaster Roof has a conventional 101.60 mm concrete slab with 20.30 mm plaster on upper sideGypsum board false ceiling is provided under the roof. Suspension height is 0.9 meterPercentage of glazing area is 7%.Packaged DX HVAC system with cooling set point 24 °C in conditioned zones.SLC is a learning centre with labs, cabins, cubicles, discussion rooms, library, toilets, pantry, electrical rooms, UPS rooms etc. with a high usage level of air conditioning.

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Location: Hyderabad

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Source: http://maps.google.com/maps Bahadurpally, Hyderabad, Andhra Pradesh, India latitude and longitude =17.387337,78.486328

Satyam Learning

Center (SLC)West Building

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

The Building: Satyam Learning Center

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Data collection Indoor Air TemperaturesOutdoor Air TemperatureSurface TemperatureOutdoor Air Relative HumiditySolar radiation (horizontal global)Roof Heat FluxesElectric Power Consumption

HVACUninterruptible power supply (UPS)Lighting systems

6/16/2009 9

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Simulation Model in DesignBuilder

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Malaviya National Institute of Technology Jaipur (India)

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Floor plan

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Malaviya National Institute of Technology Jaipur (India)

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Lighting power density

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S. No Name Area Lightm2 Nos Watt Total watt LPD (W- m-2)

1 Lab 1 149.13 40 40 1600 10.732 Lab 2 148.77 40 40 1600 10.763 HUB Room 6.37 - - 0 0.004 UPS Room 47.00 10 55 550 11.705 Discussion Room (N) 27.35 14 40 560 20.486 AHU (S) 11.78 4 55 220 18.687 Ladies Toilet 21.33 18 22 396 18.578 Cubicles 22.95 12 40 480 20.929 Cabin 3 10.85 4 40 160 14.74

10 Cabin 2 11.67 10 22 220 18.8611 Gents Toilet 21.33 16 22 352 16.5012 AHU (N) 11.15 4 55 220 19.7213 Stair 29.51 2 22 44 1.4914 Discussion Room (s) 28.28 10 40 400 14.1515 AHU (NW) 15.32 4 55 220 14.3616 Room office 15.32 7 22 154 10.0517 Passage 191.87 31 22 682 3.5518 Xerox Room 16.63 4 40 160 9.6219 Stair (S) 29.51 2 22 44 1.49

Malaviya National Institute of Technology Jaipur (India)

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Computer power density

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S. No Name Area Computerm2 Nos Watt Total watt CPD (W- m-2)

1 Lab 1 149.13 60 135 8100 54.322 Lab 2 148.77 60 135 8100 54.453 HUB Room 6.37 - - - -4 UPS Room 47.00 - - - -5 Discussion Room (N) 27.35 2 135 270 9.876 AHU (S) 11.78 - - - 0.007 Ladies Toilet 21.33 - - - 0.008 Cubicles 22.95 4 135 540 23.539 Cabin 3 10.85 1 135 135 12.44

10 Cabin 2 11.67 - - - -11 Gents Toilet 21.33 - - - -12 AHU (N) 11.15 - - - -13 Stair 29.51 - - - -14 Discussion Room (s) 28.28 1 135 135 4.7715 AHU (NW) 15.32 - - - -16 Roof office 15.32 1 135 135 8.8117 Passage 191.87 - - - -18 Xerox Room 16.66 - - - -19 Stair (S) 29.51 - - - -

Malaviya National Institute of Technology Jaipur (India)

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Occupancy Data

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S. No Name Area Occupancym2 Nos people per sq meter

1 Lab 1 149.13 61 0.412 Lab 2 148.77 61 0.413 HUB Room 6.37 - 0.00 4 UPS Room 47.00 - 0.00 5 Discussion Room (N) 27.35 3 0.116 AHU (S) 11.78 - 0.007 Ladies Toilet 21.33 1 0.058 Cubicles 22.95 4 0.179 Cabin 3 10.85 1 0.09

10 Cabin 2 11.67 - 0.0011 Gents Toilet 21.33 1 0.0512 AHU (N) 11.15 - 0.00 13 Stair 29.51 1 0.0314 Discussion Room (s) 28.28 5 0.1815 AHU (NW) 15.32 - 0.00 16 Room office 15.32 2 0.1317 Passage 191.87 1 0.0118 Xerox Room 16.63 - 0.0019 Stair (S) 29.51 - 0.00

Malaviya National Institute of Technology Jaipur (India)

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Sample Daily variations

Averaging is required due to practical limitations of entering schedulesCare to be taken for holidays/half days/special days

0

2

4

6

8

10

12

14

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Day-1

Day-2

Day-3

Day-4

Day-5

Malaviya National Institute of Technology Jaipur (India)

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UPS consumption schedule

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Lighting schedule

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Occupancy schedule for simulation

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Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Weather data for simulation

ISHRAE Weather file has been used by changing DBT and RH as per onsite measurement.

Non availability of direct solar radiation data (on-site) and variation of actual solar radiation from the ISHRAE weather file is also cause of some mismatch.

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Malaviya National Institute of Technology Jaipur (India)

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Calibration of SLC model

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Run Change Made to model MBE (%) CV (RMSE) (%)

1 Base Model -11.13 12.66

2 Adjust COP from 2.4 to 1.8 3.86 -8.18

3 Roof insulation R-value adjusted from 50.8 mm to

63.5 mm

2.91 7.69

Index ASHRAE 14 (%)

IPMVP (%)

FEMP (%)

SLC Calibrated model (%)

MBE month ±5 ±20 ±15 +2.91

CV (RMSE month) ±15 ±5 ±10 +7.69

Malaviya National Institute of Technology Jaipur (India)

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Total electricity consumption

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Over all Result for Total consumptionMBE month 2.91%

CV (RMSE) 7.69%

Malaviya National Institute of Technology Jaipur (India)

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Lighting consumption

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Over all Result for Lighting ConsumptionMBE month 3.03%

CV (RMSE) 4.03%

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UPS consumption

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Over all Result for UPS consumptionMBE month 4.78%

CV (RMSE) 5.29%

Malaviya National Institute of Technology Jaipur (India)

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Cooling consumption

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Over all Result for cooling consumptionMBE month 1.91%

CV (RMSE) 11.85%

Malaviya National Institute of Technology Jaipur (India)

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Some causes of deviation

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Hourly averages for monthly schedules of lighting,

equipment load

Occupancy was a derived information.

Variation in weather conditions, problems with direct solar

radiation data.

Variation/non-availability of thermo- physical properties of

materials

Complete details of HVAC system not available

De-rating/performance deterioration of HVAC systems

Information related to air infiltration not available

Malaviya National Institute of Technology Jaipur (India)

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Use of calibrated model

For projecting energy savings through ECMs

Example of cool roof coating:-

Malaviya National Institute of Technology Jaipur (India)

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Annual total energy consumption

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Malaviya National Institute of Technology Jaipur (India)

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End use energy savings

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Room Electricity Lighting Cooling Total

kWh kWh kWh kWh

Gray Roof 79318.36 26886.72 146192.68 252397.8

Cool Roof 79318.36 26886.72 133348.43 239553.5

Difference 0 0 12844.25 12844.26

Percent Diff. over Gray roof

0.00% 0.00% 8.78% 5.09%

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Heat flux from roof

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Cost/benefit analysis of Cool Roof

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Total Area of SLC Roof 840.90 Sq mTotal Area for coating 760.00 Sq mCost of Cool Paint 322.80 Rs./Sq mTotal Initial cost for coating 245328.00 Rs.Annual Saving 12844.26 kWhCost of Electricity 8.00 Rs. /kWhAnnual Saving 102754.08 Rs. /yearLife of coating 5 Years

Simple Payback 2.39IRR of ECM with 4 year life 24.39%IRR of ECM with 5 year life 31.05%

Year 0 1 2 3 4 5

Cash Flow -245328.00102754.

1102754.

1102754.

1 102754.1102754.

1

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Conclusions

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• Close agreement between simulation results and actual energy consumption of buildings can be achieved.

• Calibration of simulation model is important in retrofitting projects/post-occupancy analysis.

Malaviya National Institute of Technology Jaipur (India)

Jyotirmay Mathur

Thanks!!

Contact:

jyotirmay.mathur@gmail.comacknowledgements: LBNL, USAID, SPM thermoshield