Objectives of this Webinar Explain how to develop the energy models Review ASHRAE and its Appendices Review the Simulation Guidelines 3
ASHRAE Standard Similar to the RESNET Standard for residential and low-rise multifamily 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 Section 1: Purpose Section 2: Scope Section 3: Definitions, Abbreviations, and Acronyms Section 4: Administration and Enforcement
ASHRAE Standard 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 Example:
ASHRAE Standard Tables to know –Tables through (Building Envelope Requirements by Climate Zone) –Tables 6.8.1D, 6.8.1F and 7.8 (Minimum HVAC and DHW Equipment Efficiencies) –Tables and (Lighting power densities by space type) –Table 10.8 (M inimum Motor Efficiencies)
ASHRAE Standard 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
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 –AG walls: Steel-framed, R-13+R-7.5 c.i. –Floor perimeter: R-9.5 c.i. –Floors: Steel-joist, R-19, U –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 EER Pumps: 19 W/gpm, Outdoor reset (G ) –2: Packaged terminal heat pumps (6.8.1D) EER and 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 (G )
20 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
21 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
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
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
Performance Rating Baseline Building Performance (Base BP ) Proposed Building Performance (Prop BP ) Annual sum of predicted energy costs Performance Rating=100*(Base BP - Prop BP ) (Base BP ) On-site power generation cannot be used to meet the 15% Performance Target Some outside calculations permitted
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) 29 ASHRAE Space Type Lighting Power Densities (W/ft 2 ) Recommended Light Levels (Weighted Avg. Footcandles) ASHRAE Space Type Lighting Power Densities (W/ft 2 ) Recommended Light Levels (Weighted Avg. Footcandles) Apartments1.116Stairs - Active0.615 Storage, active0.820Restroom0.912 Storage,inactive0.38Office Food Preparation Conference/ meeting/ multipurpose Dining Area - For Family Dining Electrical/ Mechanical Lobby/Elevator1.316Workshop1.950 Corridor/ Transition 0.510Parking garage0.27
3.6 Lighting (In-Unit) Schedule: 2.34 hours per day Baseline:1.1 Watt/ft 2 Proposed:1.1 Watt/ft 2 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 ft 2 per Watt. Overall LPD can be used in simulation.
3.6 Lighting (In-Unit), continued 31 BR1 – 150 ft 2 BR2 – 150 ft 2 Bath – 50 ft 2 Kitchen ft 2 Living Room- 300 ft 2 Hall – 100 ft ft 2 x 1.1 Watts/ft 2 = 1045 Watts
3.6 Lighting (In-Unit), continued 32 BR1 – 150 ft 2 BR2 – 150 ft 2 Bath – 50 ft 2 Kitchen ft 2 Living Room- 300 ft 2 Hall – 100 ft 2 Unlit area – 100 ft 2, assume 110 W supplied by occupant Lit area – 200 ft 2, 100 W installed
3.6 Lighting (In-Unit), continued 33 BR1 – 150 ft 2 None (165W) BR2 – 150 ft 2 None (165W) Bath – 50 ft 2 37W Kitchen ft 2 57W Living Room- 300 ft 2 Hall – 100 ft 2 56W Unlit area – 100 ft 2, assume 110 W supplied by occupant Lit area – 200 ft 2, 100 W installed [ ] ÷ 950 = 0.73 W/ft 2
3.6 Lighting (Common Areas) Automatic Control Device Space TypePower Adjustment Percentage Occupancy sensorHallways/Corridors Stairwells All other spaces 25%(1) 35% 10%(2) Occupancy sensor and programmable timing control All spacesSame as with occupancy sensor only for the appropriate space type above, or per Table G3.2 ASHRAE Space Type Lighting Power Densities (W/ft 2 ) Hours of operation ASHRAE Space Type Lighting Power Densities (W/ft 2 ) Hours of operation Apartments Stairs - Active0.624 Storage, active0.84Restroom0.94 Storage,inactive0.32Office Food Preparation 1.24 Conference/ meeting/ multipurpose Dining Area - For Family Dining 2.14 Electrical/ Mechanical 1.54 Lobby/Elevator1.324Workshop1.94 Corridor/ Transition 0.524Parking garage0.224
3.6 Lighting (Exterior) Include all exterior lighting connected to the building’s utility meters. Use Table 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 Non-energy related Water Savings 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.
3.12 Ventilation & Infiltration General –Use the same infiltration algorithms in Baseline and Proposed (ACH, CFM/ft 2, 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 (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 rates by more than 50%. Bathroom exhaust: CFM continuous; CFM int. Kitchen exhaust: 5–7.5 ACH continuous; CFM int. ‘Whole-house’ ventilation: CFM=0.01*Area *(#BR+1) Ex ft 2 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 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 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 CFM, and in-line ventilating fans: 2.3 CFM/Watt –Bathroom and utility room fans of 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 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: 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.