ENERGY STARMultifamily High Rise Program

Using the Simulation Guidelines

July 2011

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Performance Path Components

• Prerequisites

• Performance Target

• Simulation Guidelines

• Performance Path Calculator

• Modeling Checklist

• Testing and Verification (T&V)

• Benchmarking using Portfolio Manager

Objectives of this Webinar

• Explain how to develop the energy models

• Review ASHRAE 90.1-2007 and its Appendices

• Review the Simulation Guidelines

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ASHRAE Standard 90.1-2007

• Similar to the RESNET Standard for residential and low-rise multifamily.

• 90.1 is the energy standard for buildings except low-rise residential buildings.

• Unlike RESNET, 90.1 is not automatically used in software to generate the baseline building. Only some software currently have this capability.

ASHRAE Standard 90.1-2007

• Section 1: Purpose

• Section 2: Scope

• Section 3: Definitions, Abbreviations, and Acronyms

• Section 4: Administration and Enforcement

ASHRAE Standard 90.1-2007

• Section 5: Building Envelope

• Section 6: Heating, Ventilating and Air Conditioning

• Section 7: Service Water Heating

• Section 8: Power

• Section 9: Lighting

• Section 10: Other Equipment

• Section 11: Energy Cost Budget Method

• Section 12: Normative References

ASHRAE Standard 90.1-2007

• Example:

ASHRAE Standard 90.1-2007

• Tables to know– Tables 5.5-1 through 5.5-8

(Building Envelope Requirements by Climate Zone)

– Tables 6.8.1D, 6.8.1F and 7.8(Minimum HVAC and DHW Equipment Efficiencies)

– Tables 9.4.5 and 9.6.1(Lighting power densities by space type)

– Table 10.8

(Minimum Motor Efficiencies)

ASHRAE Standard 90.1-2007

• Appendix A: Rated R-Value of Insulation and Assembly U-Factor Determinations

• Appendix B: Building Envelope Climate Criteria• Appendix C: Methodology for Building Envelope

Trade-Off Option in Section 5.6• Appendix D: Climatic Data• Appendix E: Informative References• Appendix F: Addenda Description Info• Appendix G: Performance Rating Method

Appendix A – R and U values

• Example: Using Table A3.4 of Appendix A, R-13 cavity insulation installed in 2x4, 16”oc wood-frame walls with R-5 continuous, results in an assembly U-value of 0.059.

Appendix B – Climate Zones

Appendix D – Climatic Data

• Your software may automatically select the correct heating and cooling design temperatures based on the nearest city to your location. If not, Table D-1 can be used.

Appendix G – Performance Rating

• G1 – General

• G2 – Simulation General Requirements

• G3 – Calculation of the Proposed and Baseline Building Performance– Table G3.1 Modeling Requirements– Table G3.1.1A Baseline HVAC System Types– Table G3.1.1B Baseline System Descriptions

Appendix G – Section G3

• Calculation of the Proposed and Baseline Building Performance– Table G3.1 Modeling Requirements– Table G3.1.1A Baseline HVAC System Types– Table G3.1.1B Baseline System Descriptions

Appendix G – Table G3.1

• Table G3.1 Modeling Requirements

Appendix G – Table G3.1, cont’d

• Baseline Envelope– Roof: Insulation entirely above deck; reflectivity of

0.30– Above-grade walls: Steel-framed– Floor perimeter: same as mass wall– Floors: Steel-joist– Vertical fenestration: area and orientation to equal

Proposed Design, but NOT to exceed 40% of the gross above-grade wall area

– Residential vs nonresidential

Appendix G – Table G3.1, cont’d

• Residential Baseline Envelope for Zone 3– Roof: Above deck, R-20 c.i., U-0.048– AG walls: Steel-framed, R-13+R-7.5 c.i.– Floor perimeter: R-9.5 c.i.– Floors: Steel-joist, R-19, U-0.052– Vertical fenestration: (SHGC-0.25, all frames)

• Nonmetal framing: U-0.65• Metal framing (curtainwall/storefront): U-0.60• Metal framing (entrance door): U-0.90• Metal framing (all other): U-0.65

Appendix G – Tables G3.1.1A & B

• Baseline HVAC System Types & Descriptions

Appendix G – Table G3.1.1B

• Baseline HVAC System Descriptions– 1: Hot-water boiler(s) and PTACs (6.8.1D&F)

• 80% AFUE-82% Et and 9.3-11.0 EER• Pumps: 19 W/gpm, Supply @180F, Return @130F• Outdoor reset (G3.1.3.4)

– 2: Packaged terminal heat pumps (6.8.1D)• 9.1-10.8 EER and 2.8-3.0 COP• 6.8.1D Example:12.3-(0.213*Capacity/1000) EER• Auxiliary heat only when outdoor temp is < 40F

– Supply Fan Power: CFM X 0.3 (G3.1.2.9)

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Simulation Guidelines

• I – Definitions

• 1 – Scope (page 5)

• 2 – Objectives (page 5)

• 3 – Modeling Guidelines (pages 5-27)

• Appendix A: List of Standards

• Appendix B: Description of Performance Path Calculator

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Modeling Guidelines

– 3.1 General Approach

– 3.2 Performance Rating

– 3.3 Simulation Program

– 3.4 Opaque Assemblies

– 3.5 Vertical Fenestration

– 3.6 Lighting

– 3.7 Thermal Blocks

– 3.8 HVAC

– 3.9 Domestic Hot Water

– 3.10 Plug Loads

– 3.11 Elevator Loads

– 3.12 Ventilation & Infiltration

– 3.13 HVAC Distribution Losses

– 3.14 Fan Motor Energy

– 3.15 Pumps

– 3.16 Energy Rates

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3.1 General Approach

• Baseline, Proposed & As-Built Components

• End uses that do not exist

• Code-compliant

• Model as verified on-site

• Some measured data (ie. envelope leakage) are part of program requirements, but are not updated in the model

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3.1 General Approach

• What to include and exclude

• Include all residential spaces

• Include all building related end-use loads

• Include or exclude commercial/retail

• Exclude credit for systems to be installed by owner or occupant

• Schedules - lighting, temperature

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3.2 Performance Rating

• Baseline Building Performance (BaseBP)

• Proposed Building Performance (PropBP)

• Annual sum of predicted energy costs

• Performance Rating=100*(BaseBP - PropBP)

(BaseBP)

• On-site power generation cannot be used to meet the 15% Performance Target

• Some outside calculations permitted

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3.3 Simulation Program

• Must meet the requirements of Appendix G, Section G2.2.

• Examples: DOE-2, eQUEST, TRACE, HAP and EnergyGauge.

3.4 Opaque Assemblies

• Baseline walls, floors, roofs use Tables 5.5

• Proposed Design follows 90.1 Appendix A

• Existing Buildings

• Treat these as windows:– Through-wall AC sleeves– Doors that are more than 50% glass

• Floor perimeter edges & balconies

• Weighted U-values accepted

• De-rate continuous exterior insulation

3.5 Vertical Fenestration

• Distributed on each face of the Baseline building in the same proportion as the Proposed Design, without exceeding 40% of gross above-grade wall area.

• Baseline window framing material*– Wood-frame buildings>>nonmetal frames– All other buildings>>metal frames

• NFRC or official certification from installer– Assembly U-factor, not center of glass

• Automatically-controlled shades or blinds and permanent shading devices

*Indicates a deviation from ASHRAE

3.6 Lighting (General)

• Power = lamp (bulb) + ballast

• Model lighting power as installed, not based on maximum rated fixture wattage.*– ASHRAE: Max 100W, with 26W CFL 100W– EPA: Max 100W, with 26W CFL 28W

• No credit for plug-in lighting

• Credit for efficient lighting, but not insufficient lighting

3.6 Lighting (footcandles)

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ASHRAE Space Type

Lighting Power

Densities (W/ft2)

Recommended Light Levels

(Weighted Avg. Footcandles)

ASHRAE Space Type

Lighting Power

Densities (W/ft2)

Recommended Light Levels

(Weighted Avg. Footcandles)

Apartments 1.1 16 Stairs - Active 0.6 15

Storage, active 0.8 20 Restroom 0.9 12

Storage,inactive 0.3 8 Office 1.11 35

Food Preparation

1.2 40Conference/meeting/multipurpose

1.3 30

Dining Area - For Family Dining

2.1 23Electrical/Mechanical

1.5 30

Lobby/Elevator 1.3 16 Workshop 1.9 50

Corridor/Transition

0.5 10 Parking garage 0.2 7

3.6 Lighting (In-Unit)

• Schedule: 2.34 hours per day

• Baseline:1.1 Watt/ft2

• Proposed:1.1 Watt/ft2 where none specified

• Where specified, the actual installed lighting power density (LPD) shall be modeled.

• If supplemented by lighting via receptacles, hardwired fixtures can provide illumination at a rate of no more than 2 ft2 per Watt.

• Overall LPD can be used in simulation.

3.6 Lighting (In-Unit), continued

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BR1 – 150 ft2

BR2 – 150 ft2

Bath – 50 ft2

Kitchen - 200 ft2

Living Room- 300 ft2

Hall – 100 ft2

950 ft2 x 1.1 Watts/ft2 = 1045 Watts

3.6 Lighting (In-Unit), continued

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BR1 – 150 ft2

BR2 – 150 ft2

Bath – 50 ft2

Kitchen - 200 ft2

Living Room- 300 ft2Hall – 100 ft2

Unlit area –100 ft2, assume 110 W supplied by occupant

Lit area –200 ft2, 100 W installed

3.6 Lighting (In-Unit), continued

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BR1 – 150 ft2

None (165W)

BR2 – 150 ft2

None (165W)

Bath – 50 ft2

37W

Kitchen - 200 ft2

57W

Living Room- 300 ft2Hall – 100 ft2

56W

Unlit area –100 ft2, assume 110 W supplied by occupant

Lit area –200 ft2, 100 W installed

[165+37+165+56+57+110+100] ÷ 950 = 0.73 W/ft2

3.6 Lighting (Common Areas)

Automatic Control Device

Space Type Power Adjustment Percentage

Occupancy sensor Hallways/CorridorsStairwellsAll other spaces

25%(1)35%10%(2)

Occupancy sensor and programmable timing control

All spaces Same as with occupancy sensor only for the appropriate space type above, or per Table G3.2

ASHRAE Space Type

Lighting Power

Densities (W/ft2)

Hours of operation

ASHRAE Space Type

Lighting Power

Densities (W/ft2)

Hours of operation

Apartments 1.1 2.34 Stairs - Active 0.6 24

Storage, active 0.8 4 Restroom 0.9 4

Storage,inactive 0.3 2 Office 1.11 10

Food Preparation

1.2 4Conference/meeting/multipurpose

1.3 10

Dining Area - For Family Dining

2.1 4Electrical/Mechanical

1.5 4

Lobby/Elevator 1.3 24 Workshop 1.9 4

Corridor/Transition

0.5 24 Parking garage 0.2 24

3.6 Lighting (Occupancy Sensors)

• Appendix G, Table G3.2: 10% savings• EPA: 25-35%*• Ex. Baseline Stairs: 0.6 Watt/ft2, 24 hrs

Proposed Stairs: 0.6 Watt/ft2, 15.6 hrs

or 0.39 Watt/ft2, 24 hrs

Automatic Control Device

Space Type Power Adjustment Percentage

Occupancy sensor Hallways/CorridorsStairwells

10% 25%10% 35%

3.6 Lighting (Exterior)

• Include all exterior lighting connected to the building’s utility meters.

• Use 90.1-2007 Table 9.4.5 for Baseline.

• If it’s not specified in Proposed, it’s not modeled in Baseline either.

• Building façade lighting penalty; no credit

• Due to the required photosensors, model exterior lighting for only 12 hours/day.

3.7 Thermal Blocks

• Unlike Appendix G, the EPA permits dwelling units that have different orientation and/or are adjacent to different types of surfaces (e.g. roof or slab) to be aggregated*. This is not required.

• However, common spaces, utility areas and other non-living areas must be modeled as separate thermal blocks.

• The thermal block configuration must remain identical between the Baseline Building and Proposed Design building models.

*Indicates a deviation from ASHRAE

3.8 HVAC

• Conditioning of spaces must match in both models. • Typical living spaces must be modeled as heated

and cooled, regardless of what is installed in those spaces.

• Do NOT model cooling in corridors and utility spaces if the spaces are NOT cooled in the Proposed Design.*

• The Baseline HVAC system shall be modeled as per Appendix G, as described in previous slides.  

• The Baseline equipment capacities shall be oversized by 15% for cooling and 25% for heating.

3.8 HVAC, continued

• The same modeling method and/or efficiency units must be used in the Baseline Building and Proposed Design model.

• Setpoint temperature of 72ºF and setback temperature of 70ºF shall be used for heating.

• Setpoint temperature of 78ºF and setback temperature of 80ºF shall be used for cooling.

• The hourly thermostat schedule is provided in the Simulation Guidelines.

3.9.1 Domestic Hot Water

• Equipment Type and Efficiency– Unlike HVAC, Baseline DHW system type,

capacity and fuel shall be the same as specified in the Proposed Design.

– If a combined heating & hot water system is proposed, separate stand-alone systems for both heating and hot water must be modeled as the Baseline system.

– See Table 7.8 for Baseline DHW efficiencies– Unfired storage tanks: R-12.5 insulation

3.9.2 Domestic Hot Water, cont’d

• Baseline Hot Water Demand– Based on number of bedrooms in buildings,

occupancy demographics, and the use of EPACT 1992 plumbing fixtures (2.5 gpm).

– 12, 25, or 44 gallons per day per person, based on low, medium or high-usage.

– Example: 50 unit low-income building, with 100 bedrooms, 100 occupantsX44=4400 gpd

• Proposed Hot Water Demand is based on lower flow fixtures and any ENERGY STAR clothes washers and/or dishwashers.

3.9 Domestic Hot Water, cont’d

• 3.9.3 Non-energy related Water Savings

• 3.9.4 Hot Water Distribution System– Same piping area in both models– Hot water setpoint of 120°F in both models– If a hot water recirculation system is present

in Proposed Design, it must also be included in the Baseline.

3.10 Receptacles and Plug Loads

3.11 Elevator Loads

• Use number of stories and units in Proposed Design with chart below to determine electricity consumption of Baseline elevator.

• 10% of elevator energy usage shall be added to space heat gains.

• Use same value for Proposed or to take credit, follow guidance in Simulation Guidelines.Default Elevator Energy Usage Table

ClassHYDRAULIC (1-6 stories)

GEARED TRACTION

(7-20 stories)

GEARLESS TRACTION

(21+ stories)1: UP TO 6 DWELLING UNITS 1.91 NA NA2: 7 TO 20 DWELLING UNITS 2.15 NA NA3: 21 TO 50 DWELLING UNITS 2.94 3.15 NA4: MORE THAN 50 DWELLING UNITS 4.12 4.55 7.57

Annual Energy Consumption (MWh)

3.12 Ventilation & Infiltration

• General– Use the same infiltration algorithms in Baseline

and Proposed (ACH, CFM/ft2, etc)– Software defaults for infiltration may be used in

non-dwelling unit spaces– Exhaust ventilation can be combined with

infiltration in the model– Measured infiltration rates are not used in the

As-Built model, but must meet Prerequisites.– ASHRAE 62.2-2007 (apartments), 62.1 (other)

3.12 Ventilation & Infiltration

Baseline Building• Ventilation rates shall be modeled in the Baseline using the

same rates as the Proposed Design, without exceeding ASHRAE 62.2-2007 rates by more than 50%.

• Bathroom exhaust: 20-30 CFM continuous; 50-75 CFM int.• Kitchen exhaust: 5–7.5 ACH continuous;100-150 CFM int.• ‘Whole-house’ ventilation: CFM=0.01*Area + 7.5 *(#BR+1)• Ex. 1000 ft2 3 BR unit requires 40 CFM of continuous ventilation.

2 bathrooms designed for 20 CFM continuous exhaust could simultaneously meet the whole-house requirement. Alternatively, one kitchen with a 100 CFM tenant operated fan could be set on a timer to provide at least 40 CFM each hour.

3.12 Ventilation & Infiltration

Baseline Building

• The combined modeled rate of mechanical and natural ventilation and infiltration in dwelling units shall be no less than 0.35 ACH or 15 CFM per person.

• For common spaces: both outdoor air supply and exhaust systems shall be equipped with motorized dampers to automatically shut when the systems or spaces served are not in use.

• No heat recovery shall be modeled, unless it is required by local code or Appendix G.

• No demand control ventilation shall be modeled unless required by local or national code.

3.12 Ventilation & Infiltration

Proposed Design• Ventilation rates shall be modeled based on design and

design must meet ASHRAE 62-2007 Prerequisites.• The combined modeled rate of mechanical and natural

ventilation and infiltration in dwelling units shall be no less than 0.35 ACH or 15 CFM per person.

• Specified mechanical ventilation is permitted to exceed ASHRAE 62-2007 recommendations by more than 50%; there will, however, be an energy penalty associated with that over-ventilating.

3.13 HVAC Distribution Losses

• Do not model piping or duct losses.• Do take credit for properly sealing central stack

ventilation ductwork.– Prerequisite: 10 CFM50 per floor per shaft– Use duct blaster to pressurize shaft– Take CFM50, and divide by number of floors– If less than 10 per floor, take credit– Add 10 CFM per floor per shaft to design CFM in

Baseline– Add measured value to design CFM in Proposed

3.14 Fan Motor Energy

• Baseline Building– PTAC/PTHP fan power: 0.3 Watts/CFM– Ex. 400 CFM fan consumes 120 Watts– Other fan power=(bhp x 746)/motor efficiency– Range hoods up to 500 CFM, bathroom and

utility fans 90-500 CFM, and in-line ventilating fans: 2.3 CFM/Watt

– Bathroom and utility room fans of 10-80 CFM: 1.2 CFM/Watt

3.14 Fan Motor Energy

• Proposed Design– Use fan brake horsepower & motor efficiency– Ex. ¼ HP fan consumes 187 Watts– ENERGY STAR qualified range hoods, ceiling

and inline exhaust fans– Demand controlled ventilation: CO sensors in

garages can earn performance credit in the model for reduced operating times.

– Intermittent fans: assume 2 hours per day in both models.

3.15 Pumps

• Baseline HVAC pumps follow Appendix G.• Baseline pump motors follow Table 10.8.• Proposed use actual pump parameters but

get credit for motor efficiency and controls.• If the pump motor is not included in

ASHRAE 90.1 Section 10, it does not have to be modeled explicitly. If modeled, its parameters shall be the same in the Baseline and Proposed Design.

3.16 Energy Rates

• Use state average energy prices, available here: www.eia.doe.gov

• The same rate schedule should be used in all simulations.

• May use actual rates if modeling demand reduction measures.

• Savings associated with sub-metering must not be included in the performance rating.

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Performance Path Components

PrerequisitesPerformance TargetSimulation Guidelines

• Performance Path CalculatorModeling ChecklistTesting and Verification (T&V)Benchmarking using Portfolio Manager

The End

Questions?

Contact:

MFHR@energy star.gov

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