Design vs. Delivery:
              What goes right is also wrong!

Toronto Regional Green Building Festival 2007
Stephen P...
Big energy simulation benefits…BUT

                 • Can’t build and monitor
                   commercial buildings lik...
Variations from real performance

“It’s tough to make predictions, especially about the future.”
Yogi Berra

• Why?
   • R...
Variations are to be expected

• Weather patterns are changing;
• Building performance monitoring is not common;
  • Curre...
Simulate to identify trends
                                      Wall to Roof Ratio 1:2                                  ...
Common Commercial Building Tools

•       Commercial buildings require multi-zone analysis
        addressing the followin...
Fair and Consistent Evaluations

• ASHRAE 90.1-1999                           • MNECB/CS 1999
 •   Energy Cost Budget Meth...
Relative Comparison Method

   • Both MNECB and ASHRAE 90.1
     compare a proposed building and
     a reference building...
Major Simulation Variables

• Weather;
  •   1996 CWEC (Environment Canada) 30 year average used for EE4.
• Occupancy cond...
MNECB School Occupants & Fans
                                      MNECB Schedule D (School) Occupants

                 ...
BC School Occupants




Credit: EnerSys Analytics


                            11 of 16
Differing Service Amounts

ASHRAE 62.1 – 2004                               MNECB 1997
• Hours of use/day (BC): 14        ...
EE4/DOE-2 Software Conditions

• Nature of DOE-2 analysis:
  • Hourly time step
  • Air side space conditioning only – no ...
What to do next?
• For existing buildings;
  •    Measure occupancy times & patterns;
  •    Cross reference occupancy wit...
A good energy simulator….

• Sees the whole forest not just the
  trees;
• Has HVAC design experience,
  AND/OR strong kno...
Thank You




                    Stephen Pope, OAA, MRAIC
                Sustainable Building Design Specialist
 Natural...
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GBF2007 - Building Design vs Delivery - S. Pope

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GBF2007 - Building Design vs Delivery - S. Pope

  1. 1. Design vs. Delivery: What goes right is also wrong! Toronto Regional Green Building Festival 2007 Stephen Pope, OAA, MRAIC CETC Sustainable Buildings and Communities 24 October, 2007
  2. 2. Big energy simulation benefits…BUT • Can’t build and monitor commercial buildings like we do test houses! • Simulation shows the cross system impacts of building services in a whole building environment – identifies revenge effects of performance changes; • BUT…real utility bills often vary from simulated performance; • Simulation process needs to be understood to correctly interpret the results; 2 of 16
  3. 3. Variations from real performance “It’s tough to make predictions, especially about the future.” Yogi Berra • Why? • Real conditions change from design conditions; • Different tools give different solutions; • Tools are taken up without adequate training – Canadian simulation industry is very small; • Simulations are often improperly prepared. • What can be done? • Recognize the assumptions used in energy simulation software; • Use the right tool for the job; • Understand the limitations of the tools; • Establish quality assurance processes for design with simulation inputs; • Use simulation in supportive design environments like the Integrated Design Process. 3 of 16
  4. 4. Variations are to be expected • Weather patterns are changing; • Building performance monitoring is not common; • Currently we monitor based on complaints; • How does one know how many people are in the building, at what times of day and for how long? • Documenting all possible variables is exceptionally difficult, expensive, and often unnecessary; • Only sensitive variables need documentation… but different building types have different sensitivities; • Tools take short-cuts; • Trade-offs are made between ease of use and accuracy of representation. • Measuring protocols may not match reality…… • Equipment rating conditions are very different from operating conditions. 4 of 16
  5. 5. Simulate to identify trends Wall to Roof Ratio 1:2 Wall to Roof Ratio 2:1 16,750 16,750 16,250 16,250 MJ/annum MJ/annum 15,750 15,750 15,250 15,250 14,750 14,750 14,250 14,250 W:R=1:2 FWR 17% - 85% W:R=1:2 Window U / SC W:R=2:1 Window U/SC W:R=2:1 FWR 17%-85% W:R=1:2 Wall Insul RSI 1.8-8.0 W:R=1:2 Roof Ins RSI 2.1-15 W:R=2:1 Wall RSI 1.8-8 W:R=2:1 Roof RSI 2.1-15 15,620 m2 regional high school – Screening Tool School archetype 5 of 16
  6. 6. Common Commercial Building Tools • Commercial buildings require multi-zone analysis addressing the following systems: • heating ventilating and air conditioning; • service water heating; • electric power distribution and metering provisions; • electric motors and belt drives, and; • lighting. • Simulation tools commonly used in Canada: • DOE-2; EE4 (DOE-2.1E); eQuest (DOE-2.2); Ecotect; TAS; TRNSYS; Energy Plus; IES <VE>; ESP-r. • Commercial HVAC sizing tools: • TRACE (Trane); HAP (Carrier) • US DOE Tools listing (345 individual tools): • http://www.eere.energy.gov/buildings/tools_directory/ 6 of 16
  7. 7. Fair and Consistent Evaluations • ASHRAE 90.1-1999 • MNECB/CS 1999 • Energy Cost Budget Method Article • Statement of Intent (page ii) 11.1.2 • “In general, the purpose of • “The energy cost budget and the performance compliance the design energy cost procedure is not to develop calculations are applicable an accurate prediction of only for determining annual energy use for space compliance with this heating. Rather, the purpose is standard. They are not to develop fair and predictions of actual energy consistent evaluations of the consumption or costs of the effects of deviations (in proposed design after whatever direction) from construction. …” MNECB prescriptive • 90.1-2004 similar. requirements.” 7 of 16
  8. 8. Relative Comparison Method • Both MNECB and ASHRAE 90.1 compare a proposed building and a reference building; • Both buildings operated under standardized conditions; • Similar equipment is ignored; • Elevators – note changes w/ 90.1 Appendix G. • BUT…building design follows multiple additional standards; • ASHRAE 55 – 2004 (Comfort); • ASHRAE 62.1 – 2004 (Ventilation); • Local building code imperatives. 8 of 16
  9. 9. Major Simulation Variables • Weather; • 1996 CWEC (Environment Canada) 30 year average used for EE4. • Occupancy conditions; • Occupant densities; • Schedules; • Occupancy hours; • Plug loads. • Service per person; • Ventilation air; • Hot water. • Heating, Ventilation, and Cooling system representations; • Limited number of HVAC systems in MNECB / EE4 – interpretation required; • If correct systems are present, controls options may not be available. • Geometric building entries. • MNECB conditions (EE4) – no building self-shading, no off-site shading. 9 of 16
  10. 10. MNECB School Occupants & Fans MNECB Schedule D (School) Occupants 1.1 1 Weekdays 0.9 Portion of Total Capacity 0.8 Weekend 0.7 & Holiday 0.6 Week Day 0.5 Fans 0.4 0.3 0.2 0.1 0 1 3 5 7 9 11 13 15 17 19 21 23 Hour 10 of 16
  11. 11. BC School Occupants Credit: EnerSys Analytics 11 of 16
  12. 12. Differing Service Amounts ASHRAE 62.1 – 2004 MNECB 1997 • Hours of use/day (BC): 14 • Hours of use/day: 16 • Occupant Density • Occupant Density: • Classroom: age +9 yrs – 2.9 m2/occ • All classrooms – 8 m2/occ • Lecture class – 1.5 m2/occ • Lecture Hall (fixed seats) – 0.7 m2/occ • Ventilation Air (L/s/occ) • Ventilation Air (L/s/occ): • Classroom age +9 yrs – 6.7 L/s/occ • All classrooms – 8.0 L/s/occ • Lecture class – 4.3 L/s/occ • Lecture Hall (fixed seats) – 4.0 L/s/occ • 100 m2 classroom • 100 m2 classroom: • Lecture class; • All classrooms the same; • 65 occupants; • 13 occupants; • 280 L/s outdoor air. • 100 L/s outdoor air. 12 of 16
  13. 13. EE4/DOE-2 Software Conditions • Nature of DOE-2 analysis: • Hourly time step • Air side space conditioning only – no radiant effects; • Evenly mixed air temperature – no stratification; • Pure systems – single system per zone, schedules at zone; • Sequential: Loads; Systems; Plant; Economics – system interactions incompletely captured; • Adiabatic environment – each zone isolated unless links are created. • Specific EE4 limitations • No geometric relationships; • Ventilation based on occupancy class (not population), floor area, and fan schedules; • Window analysis based on U-value and solar heat gain coefficient only (not able to model spectrally selective glass); • Infiltration excluded – set at 1/10th current good practice. 13 of 16
  14. 14. What to do next? • For existing buildings; • Measure occupancy times & patterns; • Cross reference occupancy with utility data. • Develop simulation models reconciled with real data. • Use reconciled simulation models to test benefits of proposed efficiency upgrades. • For new buildings & major retrofits: • Design using the Integrated Design Process; • IDP provides quality assurance on design; • Design sessions take place in facilitated workshops with energy simulation support. • Owner participates “live” on the design team; • Owner hires energy simulator directly; • Remove potential for conflicts between design approaches; • If possible, simulate occupancy with custom schedules representing real occupancy patterns. 14 of 16
  15. 15. A good energy simulator…. • Sees the whole forest not just the trees; • Has HVAC design experience, AND/OR strong knowledge of how the simulation software models work – interprets well; • Understands building science behind window, wall, and roof performance; • Looks for cross system impacts of individual efficiency measures. • Documents assumptions and inputs. 15 of 16
  16. 16. Thank You Stephen Pope, OAA, MRAIC Sustainable Building Design Specialist Natural Resources Canada / CANMET Energy Technology Centre Sustainable Buildings & Communities / Commercial Buildings Section 580 Booth St., 13th Flr, D5, Ottawa ON K1A 0E4 tel. (613) 947-9823 cell (613) 324-1642, fax (613) 996-9909 email - spope@nrcan.gc.ca, web - http://www.sbc.nrcan.gc.ca 16 of 16

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