SEEM Calibration for Multi-Family Buildings

1. SEEM Calibration forMulti-Family Buildings Regional Technical Forum September 18, 2012

2. Scope: Which Multi-Family Buildings? • Project constrained to multi-family buildings 3 stories or less. • Building types and prototypes: • Townhouse • Exterior access; shared walls • Woody walk-up • Exterior access; stacked flats; shared walls, floors, & ceilings • Double loaded corridor • Interior access; stacked flats; shared walls, floors, & ceilings

3. Woody walk-ups:

4. Double Loaded Corridor: Townhouse:

5. Background, Goals, & Recommendation • Multi-Family Building Measures with SEEM-estimated UES’s: • Weatherization (currently out-of-compliance) • New Construction (upcoming EnergyStar) • Goal: Calibrate SEEM94 model input assumptions to real-world billing data, per section 3.1.3.2 Model Calibration of the RTF’s Guidelines • Recommendations for Calibration • Set SEEM inputs for heating temperature setpoints to match calibration findings: • 68˚F (constant) for walk-up and corridor buildings • 66˚F (constant) for townhouses

6. RTF Guidelines 3.1.3.2 Model Calibration In most cases, calibrated engineering procedures will involve at least one stage of modeling in which baseline and efficient case energy consumption are estimated for the measure-affected end use. For example, the heating load for single family homes is estimated as part of the derivation of UES for ductless heat pump conversion. A simulation model is used to derive the heating end use for typical homes in different climate zones. Ideally, the model would be calibrated to measured heating end use for a sample of homes. If end use data are not available, the model should at least be calibrated to metered total use for the sample. Calibration should also be performed for samples that have adopted the measure, i.e., the efficient case. For measures that affect new buildings the calibration may be limited to the efficient case or to comparable buildings of recent vintage.

7. Process • Use building and operation characteristics of available billing study data • Measured and modeled data compared on an area-normalized basis (kWh/yr/ft2 ) • A single prototype is selected to match building types in the study data • Compare SEEM94 output to billing study results • Adjust input parameters only as appropriate • For example, cannot adjust insulation levels if they were definitively provided in the billings study. • Planned to adjust heating setpoint (within reason). • Compare again

8. Prototypes

9. Standardized Internal Gains Calculator • Developed based on NREL studies: • Hendron, R. January 2008. Building America Research Benchmark Definition. National Renewable Energy Lab. Contract # DE-AC36-99-GO10337. • http://www.nrel.gov/docs/fy08osti/42662.pdf • Inputs: • Heated Floor Area • # bedrooms • # units • # people • Appliances: old, new, EnergyStar? • Laundry: In-Unit or Common? • Cooking: gas or electric? • Water Heater Location: In-Unit or Common DHW • Lighting Power Density • Outputs: • Internal gains in Btu/hr

10. Gains Calculator • See workbook for more details • Future updates: possible tie-in to RBSA audited and metered findings

11. Available Studies • MF MCS 1994 • SBW Consulting. “Multifamily Metering Study. Impact Evaluation of the Model Conservation Standards.” Prepared for BPA. April 1994. • MF Wx 2007-2009 • SBW Consulting. “Impact Evaluation of Multifamily Weatherization Program. Program Years 2007-2009.” Prepared for Puget Sound Energy. May 2011. • New MF 2009 • Heller, Geraghty, and Oram, Ecotope. “Multifamily Billing Analysis - New Mid-Rise Buildings in Seattle.” December 2009 • ARRA-FG and ARRA-AV • Ecotope for King County House Authority. ARRA Verification Project. 2010.

12. Available Data (more details) • For even more details, please refer to calibration workbook

13. Results

14. Ballpark Check • Are the setpoints of 68F and 66F reasonable? • Portland area MF building study • Prepared for ETO: “Energy Consumption of Multifamily Units in Portland Metro Area.” Phillip Kelsven.Conservation Services Group. August 22, 2011 • Large billing data set showing 4 kWh/yr/ft2 of heating energy for electrically heated buildings. • Includes all existing buildings but characteristics unknown. • All buildings, so the population includes old and new alike – both poorly and well insulated envelopes • Check SEEM setpoint temperatures by guessing envelope characteristics • R-19 floor, R-19 ceiling, R-11 wall, U-0.62 window, 7ach50 per unit

15. In the Park? • Test simulations show setpoints of 68F & 66F are reasonable • As expected, simulations show that for the same set of insulation specs, the heating load decreases as adiabatic surface area increases • townhousewalk-upcorridor

16. Discussion • Prototypes modeled as one complete building and not individual units (or individually zoned units) • Lots of data on walk-ups but less so on the townhouses and corridor buildings • Available studies encompassed only electric resistance zonally heated buildings – can we extend to ducted gas and electric systems? • Internal gains are a bigger factor in MF than SF because density is higher – standardized calculator is a way to make the input less arbitrary

17. RTF Decision? • Proposed Motion: • Accept the use of SEEM 94 as calibrated for space heat energy consumption in multi-family buildings, 3 stories and less, when using the RTF’s prototypes and a thermostat setting of 68°F for the walk-up and corridor buildings and 66°F for townhouses (independent of heating system type).