Energy Consumption in Mid- and High-rise Residential Buildings The Myths and Realities of Real Building Energy Performance Warren Knowles P.Eng. January 19, 2011
Learning Objectives Understanding of: Energy consumption trends within new and older high-rise buildings (where energy is used / can be conserved). Impacts of design of the building enclosure on energy consumption. Relationship between enclosure air-tightness, suite compartmentalization, and ventilation strategies on energy consumption. How simple calibrated energy modeling can be used to assist with the design. How to comply with current energy code requirements including ASHRAE 90.1. How to improve performance characteristics of building enclosure assemblies.
BC Climate Action Plan By 2020: 33 % reduction in Greenhouse Gas Emissions Energy Efficient Building Strategy -20% energy use per household Clean Energy Act
City of Vancouver Greenest City Action Plan 2020 Goals: Carbon Neutral New Buildings 20% Reduction in Energy Consumption and Greenhouse Gas Emissions in Existing Buildings Buildings account for 55% of Greenhouse Gas Emissions How will we get there? Absolute Energy Intensity requirements (kwh/m2/yr) Incentives and other means
Multi-Unit High-Rise Residential Building Energy Study Energy consumption of over 60 mid- to highrise Multi-Unit Residential Buildings (MURBs) Constructed between 1974 and 2002 Half of study buildings underwent a full-scale building enclosure rehabilitation Allows for the assessment of actual energy savings from enclosure performance Pre- and post-rehabilitation R-values, airtightness characteristics are compared to energy consumption. Other building performance characteristics as a result of the enclosure improvements are assessed. CMHC SCHL
Energy Units Typical energy intensity units - kwh/m 2 /yr or GJ/m 2 /yr in Canada Gas is metered/billed in units of GJ, and electricity in units of kwh Both energy intensities are used in the study 1 kwh = 10 x 100 watt lights bulbs 1 hour 1 kj = Burning a match 1 GJ = 277.8 kwh (or ekwh)
Study Buildings Why High-rise MURBs? 55% of GHGs from Buildings in Vancouver High-rise MURBs largest emitters (COV) Not well understood
Study Buildings 39 mid and high rise residential buildings 4,400 residential suites 4,600,000 square feet of floor area $5,000,000 annual energy costs 44,000,000 kwh annual electricity use 173,000 GJ annual gas use
Design Characteristics Older Buildings Lower glazing percentage Framed walls Exposed concrete Punched windows
Design Characteristics 1990s Buildings Higher glazing percentage Concrete walls Framed wall Window wall and punched windows
Design Characteristics - More Recent Buildings High glazing percentage Metal panel cladding Concrete fins Window wall / spandrel panels
Top-down vs. Bottom-up Analysis Top down: Annual bulk energy billed known Suggests good overview Problems: Bottom-up: Metering varies (individual for electrical, vs. common for gas) Building features and activities Pools, elevators, fireplaces, lighting, etc. Seasonal conversion efficiencies not known Detailed information available Can identify anomalies or errors in billing data One building at a time Building systems known Modeling software available Occupant Behavior? Better weather data (smart metering data during cold rain events)
Monthly Energy Consumption Typical Building kwh Baseline Gas No Space Heat Baseline Suite Electricity No Space Heat
Estimated Monthly Heating kwh
Energy Intensity kwh/m 2 /yr 350 300 250 Average = 213 kwh/m 2 /yr Median = 217 kwh/m 2 /yr Average = 213 kwh/m 2 /yr Std Dev = 42 kwh/m 2 /yr Range = 144 to 299 kwh/m 2 /yr Common Electricity Suite Electricity Gas 200 150 100 50-8 11 44 9 52 42 61 63 18 7 62 12 26 19 33 32 20 45 29 17 43 60 31 28 6 14 3 39 2 57 30 41 24 1 40 59 21 36 58
Distribution of Space Heat Energy % of Total Building Energy Used for Space Heat % Total Energy Which h is Heat 60% 50% 40% 30% 20% 10% Electrical Heat Gas Heat Average of 37% of Energy is used for Space-Heating Average 37% of total building energy is used for heat Of this portion an average of 69% of this energy is from gas 0% 26 18 11 6 1 57 2 7 43 21 32 61 52 14 24 59 44 17 29 42 40 30 31 41 20 28 62 45 60 33 19 36 58 12 39 3 8 63 9 Building ID
Energy Consumption vs Year of Construction 350 Energy Consumption n - kwh/m 2 /yr 300 250 200 150 100 50 Total Energy Space Heat Energy - 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 Year of Construction
Fuel for Space Heat versus Age of Building kwh/m 2 /yr 160 Gas MAU or Fireplace Space Heat 140 Electric Resistance Space Heat Electric Space Heat Trend 120 Gas Space Heat Trend 100 80 60 40 20-1974 1975 1981 1984 1985 1985 1985 1986 1987 1989 1990 1990 1990 1990 1992 1992 1992 1993 1993 1993 1994 1994 1994 1994 1994 1995 1995 1995 1995 1995 1996 1996 1996 1997 1997 2001 2001 2002 2002
Space-Heat from Gas Sources % Total Building Heat which is Gas 100% 80% Average of 69%, Majority of Space-Heat Energy from Gas Sources MURBs with fireplaces in majority of suites Hydronic Gas Heat % Space Heat from Gas 60% 40% 20% 0% 11 42 62 61 44 6 18 17 43 7 28 40 29 32 1 2 57 26 8 33 14 31 3 59 30 52 63 60 9 20 39 12 24 41 21 58 45 36 19
Current Misconceptions about High-Rise Energy Use 258 kwh/m 2 128 kwh/m 2 Actual? >213 kwh/m 2 HOUSES HIGHRISES All of Canada BC buildings use approximately 92% of the Canadian average Appears that Common Area Gas Consumption (~50% of total energy use), may not have been included in SHEU data-set
Detailed Analysis Heat Transfer
Determining Thermals Resistance of Assemblies Model assemblies using THERM 5.2
Three-Dimensional Components Isothermal planes modeling technique Cladding (Stucco) Exterior Insulation (Mineral Wool) Steel Stud Interior Gypsum Wall Board Exterior Sheathing Steel Z-girts Stud Sill Track Concrete Floor Slab Stud Head Track 1) A cross-section is created on the horizontal blue plane. 2) Components that vary along the length of the wall are modeled using THERM and equivalent homogeneous materials are created. Horizontal Cross-section Vertical Cross Section 3) A cross-section is created on the vertical green plane. 4) The assembly is modeled on this plane using THERM and the equivlanet homogenous materials created in Step 2 are used in place of inhomogeous components as illustrated at left.
Three-Dimensional Components Verify with HEAT 3D and previous Guarded Hot-Box testing results HEAT 3D model of 6 Stainless Steel Clip Temperature Isotherms for 6 Stainless Steel Clip Temperature Isotherms through stainless clip horizontal cut
R-Values Down Jacket R 3-5 R 2 Acoustic Ceiling Tile
Framed Wall with Batt Insulation 3.5 Fibreglass R 12 or R14 Steel stud wall assembly with concrete slab R 3-4
Exterior Insulated Wall 3 XPS Insulation R 15 Exterior insulated wall assembly R 7.5
Concrete Wall R5 1 XPS Insulation Concrete wall with steel stud furring R14 3.5 Fibreglass R 7 (R3 without XPS Buildings 39 and 41)
U-Values Window U-value = Frame U x % Frame Area + Center of Glass U x % Glass Area + Edge of Glass U x % Edge of Glass Area U-value = 1/R-value
Why do We Use U-Values for Windows? Window Frame Material Aluminum Small Thermal Break Typical U-value Aluminum 0.39 Improved Thermal Break Insulated Vinyl or Fiberglass Typical R-value % Heat Flow through Framing 0.55 1.82 60% 0.39 2.58 45% 0.27 3.7 23% Because thermal performance is so poor?
Spandrel Panels Spandrels are poor thermal performers Thermal bridging of insulation by frames Effective R-value of spandrel panel assemblies are only slightly better than the windows themselves
U-Values What do we need? Current project original window sill detail
U-Values What do we need? Glazing = 0.24 Glazing + Frame = 0.37 Glazing + Frame + Flashing = 0.52 BC Energy Efficiency Act Requirement = 0.35 Building Design Requirement = 0.27
Shop Drawing Resubmission U value =? Moisture Management? IGU Durability?
Determining Thermals Resistance of Assemblies Model building in Google SketchUp Concrete Wall at Outside Corner Wall Full Height at Window Jamb Concrete Wall at Inside Corner Wall Under Window Concrete Wall Full Height Wall Full Height
Building 39 Typical Newer High-rise Enclosure Thermal Performance Effective Window R- value Effective Wall Area R- value Effective Roof R-value Enclosure R-value Pre Rehabilitation R- value hr ft 2 F/Btu (m 2 K/W) 1.58 (0.28) 2.95 (0.52) 21.25 (3.74) 2.06 (0.36) Enclosure R-value from energy consumption data 2.2
ASHRAE 90.1-2007 Compliance Prescriptive Path ASHRAE 90.1-2007 Compliance - Influence of Window Framing Type & IGU on Overall Enclosure R-value Overall Combined Wall and Win ndow Enclosure R-value 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 Compliant Enclosure Walls effective R-15.6, exterior insulated,clip supports, minimal exposed slab edges Non-Compliant Enclosure <R-3.75 R2.06 < R3.75 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% % Window Area Arranged in order from best to worst U-value Vinyl/Wood/Fiberglass - lowe/argon Triple IGUs, U-0.17 Vinyl/Wood/Fiberglass - lowe/argon Double IGUs, U-0.27 High Perf. Aluminum - lowe/argon Triple IGUs, U-0.29 High Perf. Aluminum - lowe/argon Double IGUs, U-0.39 High Perf. Aluminum - lowe/air Double IGUs, U-0.43 Typical Aluminum - low-e/air Double IGUs, U-0.49 Minimum ASHRAE 90.1-2007 Compliant, U-0.55 U-values from ASHRAE tables & NFRC published values
Building 19 Pre & Post Rehabilitation R-values Building #19 Pre and Post R-value Improvement Pre Rehabilitation Post Rehabilitation Assembly Description R-value Assembly Description R-value Walls (52%( of enclosure): Walls: Steel Stud w/ R-14 fiberglass. Exterior insulated, R-9.5 mineral Slab edges un-insulated, wool between steel z-girts. No 3.9 balconies stud cavity insulation. Slab 5.3 edge insulated, balconies uninsulated. Windows ( 27% of enclosure, Windows: 34% of wall area): High performance thermally Non-thermally broken broken aluminum frames. Soft- 1.37 aluminum frames. Clear glass, coat low-e, air filled IGUs with 2.16 air filled IGUs with aluminum aluminum spacers spacers Roof (21% of enclosure): Inverted assemblies with 3 14.3 Roof: Inverted assemblies with 4 18.3 extruded polystyrene extruded polystyrene. Overall l Building 2.92 Overall Building 4.26 Rehabilitation improved R-value by 46% (31% reduction in U-value) Rehabilitation Resulted in a Space-Heat Savings of Approximately 10%
Detailed R-value Calculations Pre- & Post-Rehabilitation R-values to assess space-heat savings Calculated U-values for every detail of each wall, roof, window assembly Calculated area-weighted U-values using detailed areas from sketch-up PRE R-2.92 POST R-4.26
Typical Enclosure R-values Study MURBs 4.5 4.0 Pre-Rehabilitation Post-Rehabilitation 4.3 4.1 Overall Enclosure R-Valu ue - hr ft 2 F/Btu 3.5 3.0 2.5 2.0 2.0 2.0 2.1 2.6 3.5 2.2 2.2 3.1 2.3 3.6 3.3 2.7 2.7 3.6 2.9 3.3 1.5 1.0 39 41 62 33 20 32 18 17 19 7 Building ID
Typical Building R-value / Glazing Percentages R-16 ASHRAE 90.1 16 prescriptive minimum R- value wall 14 Overall Enc clsosure R-value R-10 Exterior insulated wall with no balconies & minimal thermal bridging R-5 Typical practice accounting for thermal bridging 12 10 8 6 4 2 0 Typical MURB Enclosure R-value R-2 to R-5 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% % Window and Door Area R-2.5 High Performance Aluminum Windows R-1.3 Low Performance Aluminum Windows
Whole Building Modeling
Whole Building Energy Simulation FAST Facility Analysis and Simulation Tool (FAST) Developed by EnerSys Analytics Uses DOE-2 engine (same engine as equest, EE4) Customized for Multi-Unit Residential Buildings
Whole Building Energy Simulation FAST Define building through series of inputs Architectural Mechanical Space conditions
Whole Building Energy Simulation FAST Program calculates monthly gas and electricity consumption
Whole Building Energy Simulation FAST Model calibrations Define set of starting estimates for unknown input parameters Run simulation, compare simulation output to metered energy consumption (from bills) Adjust unknown inputs so that simulation output matches metered consumption
Whole Building Energy Simulation FAST Eg. Building 32: Suite Electricity Decreased space heating (lowered baseboard capacity) to calibrate simulation to metered data Uncalibrated Energy in kwh 250,000 200,000 Difference 20% 15% 10% Avg. Monthly Error: 35.4% 9.7% Ann. Error: 46.2% 150,000 5% 0% 100,000-5% Billed 50,000-10% -15% Simulated Difference 0-20% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Calibrated Energy in kwh 140,000 120,000 100,000 80,000 60,000 40,000 20,000 Difference 20% 15% 10% 5% 0% -5% -10% -15% Avg. Monthly Error:.0% 2.7% Ann. Error:.1% Billed Simulated Difference 0-20% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Whole Building Modeling, Building 33 Energy in kwh 300,000 250,000 200,000 150,000 100,000 50,000 0 Difference Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 20% 15% 10% 5% 0% -5% -10% -15% -20% Un-calibrated results (45.1% annual difference) Avg. Monthly Error: 35.5% 8.3% Ann. Error: 45.1% Billed Simulated Difference Energy in kwh 160,000 Difference 20% 140,000 15% 120,000 10% 100,000 5% 80,000 0% 60,000-5% 40,000-10% 20,000-15% 0-20% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Calibrated results (o.1 % annual difference) Avg. Monthly Error:.1% 2.9% Ann. Error:.1% Billed Simulated Difference
Building 33 Modeling, Gas Consumption 800 700 600 500 400 300 200 100 0 Natural Gas in GJ Difference Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 20% 15% 10% 5% 0% -5% -10% -15% -20% Un-calibrated results (24.1% annual difference) Avg. Monthly Error: 24.9%.8% Ann. Error: 24.1% Billed Simulated Difference 700 Natural Gas Difference 600 500 400 300 200 100 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Calibrated results (o.8 % annual difference) 20% 15% 10% 5% 0% -5% -10% -15% -20% Avg. Monthly Error: -.6% 1.2% Ann. Error:.8% Billed Simulated Difference
Distribution of Energy Consumption Building 33 Total building energy consumption = 164.4 kwh/m 2 /yr Equipment and Ammenity (Common), 28.3, 14% Elevators, 4.2, 2% Electric Baseboard Heating, 18.8, 9% Plug and Appliances (Suites), 18.7, 9% Fireplaces, 37.2, 19% Lights - Suite, 15.9, 8% Lights - Common, 3.7, 2% DHW, 32.9, 17% Ventilation Heating, 39.7, 20%
Distribution of Energy Consumption - Modern MURB Equipment and Ammenity (Common), 19.9, 9% Elevators, 2.7, 1% Electric Baseboard Heating, 29.1, 13% Plug and Appliances (Suites), 18.7, 9% Fireplaces, 24.1, 11% Lights -Suite, 15.9, 7% Lights -Common, 3.8, 2% Heat DHW, 20.7, 9% Modern MURB - >221.9 kwh/m 2 Ventilation Heating, 86.9, 39%
Impact of Nominal R-Values In Modeling Building 11 Annual Space Heat Consu umption, kwh/m 2 60.0 50.0 40.0 30.0 20.0 10.0 0.0 53.5 38.0 Baseline Pre Nominal Assumptions 29 % Difference in Space Heat Energy Consumption
Other Building Systems Calibrated models allow the assessment of other building systems Number of Su uites 200 180 160 140 120 100 80 60 Buildings 7, 11, 32, 33 Building 18 40 20 0 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 Peak Average Daily Domestic Hot Water Consumption, gpm Domestic Hot Water
Other Building Systems 1.00 0.90 0.80 Power Density (W/sf) 0.70 0.60 0.50 0.40 0.30 0.20 0.10 Suite Lighting Suite Plug Loads 0.00 0 10 20 30 40 50 60 70 Building Number Suite Lighting and Plug Loads
Typical Building Model Created a typical building model to run simulations Typical Building Model Based on 13 Buildings Average of 39 Study Buildings Total Floor Area 121,922 ft² 118,655 Percent Area for Common Space 13% Number of Suites 110 113 Number of Storeys (above grade) 18 18 Height of Average Storey 8.7 ft Orientation from North 0 o Gross Exposed Wall Area, Wall 1 15580 ft² Gross Exposed Wall Area, Wall 2 15580 ft² Gross Exposed Wall Area, Wall 3 15580 ft² Gross Exposed Wall Area, Wall 4 15580 ft² Window Percentage, Wall 1 46% 47% Window Percentage, Wall 2 46% 47% Window Percentage, Wall 3 46% 47% Window Percentage, Wall 4 46% 47% Infiltration Rate (0.15 cfm/sf) 0.572 ACH Pre Post Overall Roof R-Value 12.7 13.3 o F-ft²-hr/Btu Overall Wall R-Value 3.6 5.5 o F-ft²-hr/Btu Overall Window U-Value 0.70 0.51 Btu/ o F-ft²-hr Window Solar Heat Gain Coefficient 0.67 0.39 Architectural Inputs
Distribution of Energy Consumption Typical MURB uses approximately 200 kwh/m 2 /yr Equipment and Ammenity (Common), 28.3, 14% Elevators, 4.2, 2% Electric Baseboard Heating, 18.8, 9% Plug and Appliances (Suites), 18.7, 9% Fireplaces, 37.2, 19% Lights - Suite, 15.9, 8% Lights - Common, 3.7, 2% DHW, 32.9, 17% Ventilation Heating, 39.7, 20%
Space Heat Consumption for locations across Canada 180 Annual Space Hea at Consumption, kwh/m 2 160 140 120 100 80 60 40 102.4 131.5 140.5 144.8 120.9 129.1 129.4 124.4 159.9 20 0 Ottawa Vancouver Calgary Edmonton Winnipeg Toronto Ottawa Montreal Halifax Whitehorse
Impact of Wall Performance on Space Heat Consumption
Window Influence on Total Building Energy Comparison of Different Window Performance Criteria on Total Building Energy Consumption Case Baseline Performance Standard (effective values) Average Pre Wall R-3.6 Roof R-12.7 Overall Product Performance Characteristics [W/(m 2 K] Total Heating [kwh/m 2 ] Total Bldg Energy [kwh/m 2 ] % Total Savings U-3.97, SHGC-0.67 83.2 187.1 0.0% Window U-3.97 SHGC-0.67 Window ASHRAE 90.1-2004 U-3.24, SHGC-0.4 83.3 187.2-0.1% ASHRAE 90.1-2007 U-3.1, SHGC-0.4 82.7 186.6 0.3% ASHRAE 189.1-2009 U-2.57, SHGC-0.4 79.1 183.0 2.2% BC EEA metal frame U-2.57, SHGC-0.4 79.1 183.0 2.2% BC EEA non-metal frame U-2.0, SHGC-0.4 75.0 178.8 4.4% Non-metal frame, low-e, U-0.96, SHGC-0.3 67.6 171.5 8.4% argon fill, triple glazed Lighting ASHRAE 90.1-2007 7.53 W/m 2 83.7 185.5 0.9% ASHRAE 189.1-2009 6.78 W/m 2 84.1 184.4 1.4%
Impact of Window Performance on Space Heat 120 Annual Space Heat Consumption, kwh/m 2 100 80 60 40 20 Electricity Gas 0 Baseline U = 0.45 SHGC = 0.4 U = 0.45 SHGC = 0.3 U = 0.27 SHGC = 0.4 U = 0.27 SHGC = 0.3 U = 0.17 SHGC = 0.3 U = 0.17 SHGC = 0.2 Post U-Value with Pre SHGC
Air Flow
Space Heat Loss Distribution Effect of Air Leakage Air Tight Enclosure Natural Air Leakage, 2.9, 3% Air Leaky Enclosure Open Windows Natural Air Leakage, 16.3, 16% Conduction, 47.9, 53% Mechanical Ventilation, 39.7, 44% Conduction, 47.9, 46% Mechanical Ventilation, 39.7, 38% kwh/m 2 /yr, % Total Space Heat Total Space Heat = 90.5 kwh/m 2 /yr kwh/m 2 /yr, % Total Space Heat Total Space Heat = 103.9 kwh/m 2 /yr
What if Good Enclosure & w/heat Recovery Ventilation? Air Tight Enclosure Air Leaky Enclosure Open Windows Conduction 5% Conduction, 2.3, 20% Natural Air Leakage, 2.5, 22% Mechanical Ventilation 24% Mechanical Ventilation, 6.5, 58% Natural Air Leakage 71% kwh/m 2 /yr, % Total Space Heat Total Space Heat = 11.2 kwh/m 2 /yr kwh/m 2 /yr, % Total Space Heat Total Space Heat = 30.3 kwh/m 2 /yr
Impact of Different Make-up Air Flow Rates Assumed flow rate of 50 cfm per suite 160 Annual Space Heat Cons sumption, kwh/m 2 140 120 100 80 60 40 20 77.4 75.7 74.0 71.5 69.8 68.2 66.5 64.1 62.6 25.1 25.1 25.2 25.3 25.3 25.4 25.4 25.5 25.6 26.7 24.0 44.2 125.0 Gas 0 100% of Nominal* 95% of Nominal 90% of Nominal 85% of Nominal 80% of Nominal 75% of Nominal 70% of Nominal 65% of Nominal 60% of Nominal Zero Modern
Understanding Energy Use in MURBs Domestic Hot Water is heated using Gas Air leakage of heated ventilation air through elevator and stairwell shafts Elevator pumping Ventilation air is heated using gas-fired make-up air unit (MUA) - To heat ventilation air for make-up air supply - To heat domestic hot water - To heat pool/hot-tubs - Suite fireplaces (if equipped) - Pilot lights for above - Interior lighting - Elevators - Ventilation fans and motors - Parking garage exhaust fans - Water distribution pumps - Baseboard heaters - Recreation areas/pool pumps - Exterior lighting - Communication - Controls Heated Ventilation air from corridor Electric Baseboard Heaters in all Suites Gas fireplaces in some Suites Air flow through open windows Air exhausted using bathroom/kitchen fans & windows Enclosure airleakage - Baseboard heaters - Lighting - Appliances - Miscellaneous Electric Loads - Plug loads - Exhaust fans Gas Boiler to heat pool & hot-tubs Rec. Areas Pool Suites Common Areas Parking Garage Typically Unheated Some Gas & Electric Heat at Common Areas Parking Garage Exhaust Fans
Air Flow within a Building Building 20
Air Pressure Differential in Study Building (43) 22 storey highrise - Pressure Beneath Suite Doors Floor 22 21 20 19 Theoretical 18 Average 17 Maximum 16 Linear (Theoretical) 15 Linear (Average) 14 12 Linear (Maximum) 11 10 9 8 7 6 5 4 3 2-15 -10-5 0 5 10 15 Pressure Differential (Pa) Measured air pressure across the corridor doors of suites in a 22 storey building
Make-Up air Considerations 1. We should be ventilating for health and comfort (not heat) 2. Corridors need a minimal amount of air for smoke/odour control but fresh air is needed in the suites. 3. Reconsider large rooftop MUA units & pressurized corridor supply for ventilation. 4. Provide fresh air-directly to suites 5. Compartmentalization is needed Further research of air flow within buildings required
Make-Up Air Investigation Investigation and analysis of condensation related problems at window-wall assemblies. Monitored environmental conditions and mechanical system conditions: Temperatures Relative Humidity CO 2 Operation of mechanical equipment including Heat pump Cloths dryer Exhaust Fans Make-up air at suite door
Make-Up Air Investigation
Actual Airflow Suite Number N601 N301 Baseline (no fans operational) Master Bathroom Fan Guest Bathroom Fan Common Bathroom Fan Kitchen Fan - Level 1 Kitchen Fan - Level 2 Kitchen Fan - Level 3 Dryer w/ Booster Fan ASHRAE Recommended (based on suite size = 0.3 ACH) % of ASHRAE Recommended @ Baseline % of ASHRAE Recommended with Continuous Master Bath Fan ASHRAE Recommended (based on # of occupants, 15cfm/person) % of ASHRAE Recommended @ Baseline % of ASHRAE Recommended with Continuous Master Bath Fan Control suite Air flow less affected by fan operation, hallway pressurization was not working ASHRAE recommendations based on suite area (accounts for 5-6 occupants) ASHRAE recommendations at 15 cfm per person for actual occupant loads 24 cfm 55 53 55 55 55 59 55 82 cfm 29% 67% 30 cfm 79% 183% 0 cfm 8 11 14 11 16 29 14 82 cfm 0% 10% 30 cfm 0% 27%
Other Considerations Fireplaces Occupants etc.
Other Considerations Impact of Fireplaces Why do we need them? 120 Annual Space Heat Cons nsumption, kwh/m 2 100 80 60 40 20 0 77.4 39.9 25.1 29.1 Gas Electricity Baseline Pre With Fireplaces Baseline Pre Without Fireplaces
Distribution of Energy Costs in MURBs Plug and Appliances (Suite), 18.7, 31% Electric Baseboard Heating, 24.8, 42% Total Consumed By Strata, 146.9, 71% Total Consumed By Owner, 59.5, 29% Equipment and Ammenity (Common), 28.3, 19% Lights (Suite), 15.9, 27% Elevators, 4.2, 3% Owner Paid Electric Baseboard Heating, 0.3, 0% Fireplaces, 37.7, 26% Lights (Common), 3.7, 3% Strata Paid DHW, 32.9, 22% Ventilation Heating, 39.7, 27%
Disconnect Between Consumption and Billing Average MURB Energy Distribution and Associated Cost 28% Suite Electricity = $408/yr (Occupant Paid) 21% Common Area Electricity = $323/yr (Strata Paid) 51% Gas Heat and Hot water = $455/yr (Strata Paid) Only 36% of Total Energy Cost is Directly Paid by Occupant 69% of Building Space Heat is from Gas (Paid by Strata) Occupants are only directly paying for 31% of space heating
How Do We Do Better?
Where Do We Want To Go? New Buildings to be Carbon Neutral by 2020 Biggest Opportunities in Existing Buildings
Getting to Best Performance Space Heating Reduce the loads Recover the heat
Impact of Cladding Attachment R-15 of Insulation Current Practice Better Even Better Most Efficient R-7.4 R-10.3 R-11.6 to 14.4 R-15.8
Retrofit and New Construction Enclosure Strategies 10 ASHRAE 90.1-2007 Compliance - Influence of Window Framing Type on Overall Enclosure R-value 9 Overall Combined Wall and Wind dow Enclosure R-value 8 7 6 5 4 3 2 1 ASHRAE 90.1-2007 Compliant Buildings Constructed with minimally compliant wall and window R-values Study Buildings - Metro Vancouver Average 50% glazing area Thermally Efficient Building Enclosures Constructed with high performance windows and well insulated walls 0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% % Window Area
Thermal Anatomy of a High Rise MURB R-12 Insulation in walls R-4 accounting for steel studs and slab edges R-1.8 Windows aluminum window wall, low-e, air fill R-20 Roof Insulation 65% Glazing R-Value % of Enclosure % Heat loss Walls 4 29 16.6 Windows 1.8 65 82.7 Roof 20 6 0.7 Overall R-Value 2.3 Strategy 1 Improve wall R-value to R10 Strategy 2 Improve window R-value to R3.5 Strategy 3 Reduce window area to 30%
Strategy 1 Improve wall R-value to R10 R-Value % of Enclosure % Heat loss Walls 10 29 7.4 Windows 1.8 65 91.9 Roof 20 6 0.8 Overall R-Value 2.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 Base Strategy 1
Strategy 2 Improve Window R-value to R3.5 R-Value % of Enclosure % Heat loss Walls 10 29 13.3 Windows 3.5 65 85.3 Roof 20 6 1.4 Overall R-Value 4.6 5.0 4.0 3.0 2.0 1.0 0.0 Base Strategy 1 Strategy 2
Strategy 3 Reduce Glazing to 30% R-Value % of Enclosure % Heat loss Walls 10 64 41.9 Windows 3.5 30 56.1 Roof 20 6 2.0 Overall R-Value 6.5 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 Base Strategy 1 Strategy 2 Strategy 3
Reduced Glazing Area
Improved Ventilation Strategies Corridor pressurized with small fans at each floor level
Combination Energy Efficiency Measures Simulated Scenario Model Inputs Baseline Post t Walls effective R-5.5 t Windows double glazed, air fill, low-e, aluminum frame; U = 0.51, SC = 0.45 t Air tightness Tight High Average, 0.15 cfm/ft 2 t Make-up air temperature setpoint 68 F t No heat recovery Good t Walls effective R-10 t Windows double glazed, argon fill, low-e, low conductive frame; U = 0.27, SC = 0.35 t Air tightness Tight Low Average, 0.05 cfm/ft 2 t Make-up air temperature setpoint 64 F t No heat recovery Best t Walls effective R-18.2 t Windows triple glazed, argon fill, low-e, low conductive frame; U = 0.17, SC = 0.23 t Air tightness Very Tight, 0.02 cfm/ft 2 t Make-up air temperature setpoint 60 F t 80% Heat Recovery
Simulated Space Heat Consumption Scenarios 120.0 Annual Space Heat Cons sumption, kwh/m 2 100.0 80.0 60.0 40.0 20.0 102.4 95.6 Better windows, walls and air-tightness 67.4 Ventilation Heat-Recovery 45.0 38.2 9.7 0.0 Baseline Pre Baseline Post Good Best Good, Without Fireplaces Best, Without Fireplaces
Total Building Energy Use Can get ~100 kwh/m 2 /yr with ventilation and enclosure upgrades only Further improvements from Domestic Hot Water, Lighting, Appliances, Controls etc. 250 Annual Energy Consumption, kwh/m 2 200 150 100 50 96.0 89.7 110.3 109.8 73.8 97.5 72.1 76.9 81.3 60.8 74.2 39.4 Gas Electricity 0 Baseline Pre Baseline Post Good Best Good, Without Fireplaces Best, Without Fireplaces
How Do We Get To Net Zero? 35 R-Values 30 t Consumption, kwh/m 2 Annual Suite Electric Space Heat 25 20 15 10 5 U = 0.45, 50% WWR U = 0.45, 40% WWR U = 0.45, 30% WWR U = 0.45, 20% WWR U = 0.27, 50% WWR U = 0.27, 40% WWR U = 0.27, 30% WWR U = 0.27, 20% WWR U = 0.17, 50% WWR U = 0.17, 40% WWR U = 0.17, 30% WWR U = 0.17, 20% WWR 0 0 5 10 15 20 25 30 35 40 45 50 Wall Effective R-Value R (hr-ft 2 -F/Btu)
Near Net Zero Effective Control of Air Flow 40 Annual Suite Electric Space Heat Consumption, kwh/m 2 35 30 25 20 15 10 5 Enclosure 1: Windows U-0.17, 30% WWR, Walls R-18.2 Enclosure 2: Windows U-0.45, 40% WWR, Walls R-15.6 Typical Building Simulated Air Leakage Rate 0 0 0.2 0.4 0.6 0.8 1 Air Leakage Rate, cfm/sf
Final Thoughts - Energy Efficiency & Moisture Problems Increased risk of moisture problems in more energy efficient buildings Consider future maintenance and renewal costs Systemic Low-e corrosion within proprietary triple IGUs after 5 years Failure of thermo-cladding
Need for a New Approach
Integrated Design Process Courtesy of Bunting Coady Architects
A New Approach for the Design of Buildings
A New Approach for the Design of Buildings
A New Approach for the Design of Buildings
A New Approach for the Design of Buildings
Discussion
Further Information / Background Information CMHC Reports / Guides Homeowner Protection Office Bulletins and Guides Builder Insight No. 7 Building Enclosure Design Guide
BC Energy Efficiency Act - Windows Low-rise Requirements Product Maximum U-Value W/(m 2 K) BTU/(hr ft 2 K) Effective Date Vinyl and fibreglass windows and sliding doors Tested with CSA A440.2-04 or NFRC 100-2004 Third party testing (SCC or NFRC accredited labs) Permanent certification label, temporary U-value label Exempts heritage buildings 2.0 0.35 March 1, 2009 Wood windows and sliding glass doors 2.0 0.35 January 1, 2011 Metal windows and sliding glass doors 2.57 0.45 2.0 0.35 June 1, 2009 January 1, 2011 Skylights (for low-rise and high-rise) 3.1 0.54 March 1, 2009
BC Energy Efficiency Act - Windows High-rise Requirements Product Maximum U-Value W/(m 2 K) BTU/(hr ft 2 K) Effective Date Metal framed curtain wall, window wall and storefront products Windows with framing materials other than metal, with or without metal reinforcing or cladding 2.57 0.45 January 1, 2011 2.0 0.35 January 1, 2011 Exempts products installed in buildings that are compliant with ASHRAE 90.1 (04 or 07) Option for U-value certificate in lieu of labels Flexibility provided for structural windows
Improved Ventilation Strategies Corridor pressurized with small fans at each floor level
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