BFH The Path to Net Zero Energy Houses in Cold Climates

The Process of Progressions

Net Zero Energy

75% reduction

50% reduction

25% reduction

Current Practice

}  The Path to Net Zero

A Net Zero Energy House produces as much energy as it uses on an annual basis.

This presentation focusses on how to get there.

Reductions most cost-effective in this order

Air tightness measures

Increase insulation

Water conservation

Mechanicals

Renewables

}  Focus of measures in progressions

Capacity exceeds code requirements

Issues

Concerns

Challenges

Innovations on the horizon

}  NRCan targets/goals for Industry

Energy Intensity vs. House Size

Issues

Concerns

Challenges

}  Energy Intensity

Lighting 5% Appliances

13%

Water 17%

Space 65%

ERS80 (PRE-2012 R-2000)

Lighting 6%

Appliances 16%

Water 21%

Space 57%

ERS86 (conventional HVAC)

Series of challenges to reduce various loads

Reduce space heating load

Air tightness measures

Insulation Measures

Reduce water heating load

Fixtures

Drainwater Heat Recovery

Meeting DWH load becomes biggest challenge

Mechanicals designed around low temp hot water delivery

Minimal electrical loads @ fans/pumps

Small loads, can sacrifice efficiency @ blower

Electrical base loads

Primarily occupant driven

Builder has minimal impact

}  Energy End Use Patterns

Lighting 13%

Appliances 46%

Water 8%

Space 33%

Net Zero Energy (solar thermal option)

Note: Ventilation included in ‘Space’ component in charts, ranges from 2% of overall energy load in ERS80 to 9% in NZE

Lighting 10%

Appliances 44%

Water 20%

Space 26%

Net Zero Energy (non-solar thermal)

Revisit, Revise, Rethink

Measures taken in initial progressions impact the types of measures (and associated costs) further down the path to Net Zero Energy.

}  Energy Analysis & Financial Evaluation Work Flow

Excel worksheet

Revise ��to targets

IRR/ simple

payback

Costings Loads w/fuel equivalents

Energy contributions Incremental capital costs over baseline

Reductions in purchased fuel Contributions from Renewables

Offsets to purchased fuel (DWHR)

Select target reduction from baseline

Model for 25%, 50%, 75% ��and 100% reductions ��

from baseline

Select regionally appropriate assemblies to increase

insulation levels

Specify high performance mechanicals and renewables

Estimate regional fuel costs

Ramping it up

Air sealing & increasing insulation highest priorities for ERS80↓25% & ERS80↓50%

Mechanicals are the highest priorities for ERS80↓75%

Renewables are the highest priorities for NZE

}  Progressions

ERS 80 (Existing R2000)

• Performance Path, NSBC 2010, OBC 2012, NBC 2012 • NOTE: R2000 requires 1.5ACH @ 50Pa but ERS80 does not

ERS80↓25% ESNH

• Air sealing: key for production builders – close in on 1.5 ACH • Increase insulation -- Use exterior air barriers/rigid board ins. to help reduce ACH • Higher efficiency conventional mechanicals (incl. HRV)

ERS80↓50% R-2000

• Envelope: Further air sealing (1.0 ACH vs. 1.5 ACH), increase insulation, upgrade windows • Hot water conservation – DWHR • Higher efficiency, smaller space heating equipment • Integrated mechanicals?

ERS80↓75%

• Last push @ envelope: emerging high-efficiency materials/windows • Mechanicals: Integrated, renewables, match load, supply temps to delivery • DHW is the load challenge • Emerging technologies: air to water heat pumps, solar thermal concentrators, co-generation

Net Zero Energy

• Choose mechanicals to reduce electrical loads as well as heating loads • Reduce all possible electrical loading (LEDs, Energy Star appliances, motion detectors) • Site-generated electricity production to match anticipated loads

Like standard practice, only better

Exterior insulation

Combinations

Innovative materials

Assembly Issues

Brick ledge

Fasteners

Window bucks & details

Drainage plane

Construction Issues

Trades scheduling

Inspectors

}  Materials and Assemblies

Fig. 1

Fig. 2

Fig. 3


Tried & True

Air sealing interior VDR

Insulating with foam or fibre

Innovative

Quad glass with 2 suspended films, krypton fill

Vacuum Insulated panels: RSI 22.7/mm (R30/inch)

}  Materials and Assemblies


Integrated systems

Space and water heating/cooling

Space/water & ventilation

Flexibility of energy sources

What types?

How many?

Issues

Preplanning

Servicing non-conventional systems

Distribution systems

}  Mechanicals

Air handler

Hot water coil

Evaporator Coil (cooling) optional

Integrated Space Conditioning and Water Heating (forced air)

Air to Water Heat Pump (hydronic space conditioning and water heating)

Always cheaper to save a Watt than make a Watt

Reduce loads

Space heating

Water heating

Lighting

Appliances

Builder can only supply a house than can approach net zero energy

Energy usage dependent on occupant lifestyle

Preplanning

Solar thermal

PV

Micro co-generation

District energy

}  Renewables

What works in different areas

Assemblies & materials

Mechanicals

Airtightness

Labour/Trades

Fuel Costs/Perceptions

}  Regional Differences

Large/Mid-size Production or Custom

Scheduling issues

Labour/training issues

Client interaction

Market Dynamics

}  Builder Type – Economies of Scale

Internal Rate of Return vs. Payback

What is Payback •  The time required for the

return on an investment to “repay” the sum of the original investment.

What is Internal Rate of Return (IRR)? •  Tells you how well your

money is working for you compared to other investments or costs of borrowing.

•  Indicator of the efficiency,

quality or yield of an

investment.

}  Financial Valuation of Premiums

Internal Rate of Return: the point on the graph where the costs of the investment equal the benefits of the investment. Expressed as a percentage that represents how well your investment is working for you each year after you have taken care of all of your costs.

Planning Horizon (years)

All

cash

flow

s (+

/-)

Years after capital expenditure

Capital Expenditure

Simple Payback: the point on the graph where the cost of the investment is recovered. Expressed in years or months

Perceptions of Costs

Simple Payback:

“The quicker the better”

vs.

long-term investment

How to talk about IRR?

• IRR of 10% over 10 years for

NZE construction/mechanicals can

be compared to interest on the

increased mortgage principal

needed for the premium to be

paid over and above the baseline

construction and mechanicals

}  Communicating IRR to the Client

costs benefits

House Characteristics

325 m2 (3,500 s.f.) living space

2 storey house + finished basement

>15% glazing

Attached garage

Conventional mechanicals

}  ESNH/R-2000 Upgrade Package (Ottawa) 2-storey w/basement ERS80 Baseline

ID

Library Part Na... D1 10 D1 Entrance 10 D1 Entrance 10 D1 Garage 1 10 D1 Pocket 10 D2 10

Quantity 5 1 1 1 1 1

W x H Size 0.813x2.000 1.067x2.100 1.219x2.100 3.048x2.134 0.762x2.100 1.800x2.100

2D Symbol

3D Front View

Door Legend

12

4

12

10

A5 HOUSE 3 DOOR SCHEDULE 1:1

A5 HOUSE 3 REAR ELEVATION 1:64A5 HOUSE 3 FRONT ELEVATION 1:64

ID

Library Part Na... D1 10 D1 Entrance 10 D1 Entrance 10 D1 Garage 1 10 D1 Pocket 10 D2 10

Quantity 5 1 1 1 1 1

W x H Size 0.813x2.000 1.067x2.100 1.219x2.100 3.048x2.134 0.762x2.100 1.800x2.100

2D Symbol

3D Front View

Door Legend

12

4

12

10

A5 HOUSE 3 DOOR SCHEDULE 1:1

A5 HOUSE 3 REAR ELEVATION 1:64A5 HOUSE 3 FRONT ELEVATION 1:64

98

5.11

46

8.88

2.93

2.09

2.42

2.42

4.83

8.60

BEDROOM

BEDROOM

38mm x 140mm framing @400mm O.C. drywall

INTERIOR AREA:41.538 m2

BEDROOM

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

A3 HOUSE 3 UPPER FLOOR PLAN 1:64

Total heated space = 3,500 s.f.

•  Air tightness: 4.55 ACH

•  ATTIC: RSI 8.8/R50 blown cellulose

•  BELOW-GRADE WALLS: RSI 2.1/R12 fibreglass batt interior standoff wall

•  ABOVE-GRADE WALLS: RSI 3.9/R22 fibreglass batt

•  BELOW SLAB: RSI 1.8/R10

•  WINDOWS: Low-e, argon-filled, insulating spacers, vinyl frames

•  SPACE HEATING: 92% AFUE gas furnace

•  WATER HEATING: 67% AFUE 60 gal tank

•  VENTILATION: 60% sensible efficiency

}  ESNH/R-2000 Upgrade Package (Ottawa) 2-storey w/basement ERS80 Baseline

W

1

2

3

4

5

6

7

8

9

10

11

12

13

5.11 61 3.66

5.11 4.27

8.29

4.53

8.88

618.

881.

65UNEXCAVATED

LAUNDRY

FINISHEDSLAB ONGRADE

SLAB ON GRADE

38 mmx235mm floor joists @ 400mm

O.C. 18.5mm T&G plywood

FINISHED BASEMENTAREA:

INTERIOR AREA:37.5537m2

45.3768 m2

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

A1 HOUSE 3 FOUNDATION 1:64

5'-11" by 6'-11"

3'-6"

6'-11"

3'by

6'3'

by6'

2'-8" by 6'-7"

10' by 7'

4'

6'-1

1"

1

2

3

4

5

6

7

8

9

10

11

12

13

F

1

2

3

4

5

6

7

8

9

10

11

12

13

2.56 3.17

5.72

1.65

5.11

3.84

5.64

9.49

1.27 2.59 1.26 4.27

1.65

45

11.1

3

61

1.65

8.88

61

8.60

612.89

4.83

2.31

2.95

INTERIOR AREA:48.9119 m2

LIVING

GARAGE

9'1" CEILINGHEIGHT

38m

m x

140

mm

fram

ing

@

400m

m O

.C. d

ryw

all

KITCHEN

38 mmx235mm floor joists @ 400mm

O.C. 18.5mm T&G plywood

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

HOUSE 3

A2 HOUSE 3 MAIN FLOOR 1:64

Changes from ERS80

ESNH Envelope (ERS80↓25%):

•  Air tightness: 2.0 ACH


•  ABOVE-GRADE WALLS: RSI 3.9/R22 fibreglass batt plus 2” Type IV exterior (or 1.5” polyisocyanurate) 10” fdn wall for brick siding

•  BELOW-GRADE WALLS: RSI 3.9/R22 fibreglass batt interior standoff wall

•  BELOW SLAB: RSI 1.8/R10, no change from baseline

}  ESNH (ERS80↓25%) Package, Ottawa

Measure Upgrade Cost

GJ saved

RSI 10.6/R60 attic RSI 6.3/R32 above grade walls RSI 3.9/R22 below grade walls

$540 $6815 $818

46.47 GJ

86% AFUE Instantaneous gas DHW

Rental vs. $1100

7.90 GJ

75% Efficient HRV $300 -1.82 GJ

DWHR $500 2.63 GJ

Changes from ERS80

R2000 Envelope (ERS80↓50%):

•  AIR TIGHTNESS: 1.0 ACH


•  ABOVE-GRADE WALLS: RSI 3.9/R22 fibreglass batt plus 2.5” polyisocyanurate 10” fdn wall for brick siding

•  BELOW-GRADE WALLS: RSI 3.9/R22 fibreglass batt interior standoff wall plus 1.5” Type IV exterior

•  BELOW SLAB: RSI 1.8/R10, no change from baseline

}  R-2000 (ERS80↓50%) Package, Ottawa

Measure Upgrade Cost

GJ saved

RSI 10.6/R60 attic RSI 7.0/R40 above grade walls RSI 4.9/R28 below grade walls

$540 $15744 $2314

63.99 GJ

86% AFUE Instantaneous gas DHW

Rental vs. $1100

7.90 GJ

75% Efficient HRV $300 -1.82 GJ

DWHR $500 2.63 GJ

Main upgrades from ESNH (ERS80↓25%): Air tightness from 2.0 to 1.0 Below Grade Walls from RSI 3.9/R22 to RSI 4.9/R28 Above Grade Walls from RSI 6.3/R32 to RSI 7.0/R40

Reductions from ERS80

Space heating •  ERS80: 94% gas furnace ( AFUE) •  ESNH: no change from baseline •  R-2000: no change from baseline

Water heating •  ERS80: .67 AFUE gas (tank) •  ESNH: instantaneous gas water

heater 0.86 EF •  R-2000: instantaneous gas water

heater 0.92 EF Hot water load reduced by: •  ESNH: 33.05% •  ERS86: 33.15%

Ventilation •  ERS80: 60% EF HRV •  ESNH: 75% EF HRV •  R-2000: 75% EF HRV

}  ESNH/R-2000 Upgrade Package (Ottawa)

ERS 80 ESNH R-2000

Space heating

108.41 GJ 61.93 GJ 44.42 GJ

Water heating

23.92 GJ 16.01 GJ 15.99 GJ

Base loads 31.53 GJ 31.53 GJ 31.53 GJ

ACH@50Pa 4.55 2.0 1.0

Reductions from ERS80

Cost increase

•  ESNH – 25%

•  Envelope - $8,173

•  Mechanicals - $1,900

•  Package - $10,073

•  R-2000 – 50%

•  Envelope - $18,598

•  Mechanicals - $1,900

•  Package - $20,498

IRR/Simple Payback – 10 years with annualized capital costs over the 10 years

•  ESNH - none

•  R2000 - none

}  ESNH/R-2000 Upgrade Package (Ottawa)

$0"

$5,000"

$10,000"

$15,000"

$20,000"

$25,000"

Vancouver" Kamloops" GTA" Ottawa" Sudbury" Nova Scotia"

Estimated Median Cost Increase of Progression for ERS80↓50% (R-2000)!

$0"

$2,000"

$4,000"

$6,000"

$8,000"

$10,000"

$12,000"

Vancouver" Kamloops" GTA" Ottawa" Sudbury" Nova Scotia"

Estimated Median Cost Increase of Progression for ERS80↓25% (ESNH)!

ERS80↓75%


214 m2 (2,300 s.f.) living space

2-storey slab-on-grade

No garage

3.76kW p Photovoltaics (PV)

(16 * 235W modules)

4 flat-plate solar thermal collectors

}  Denim Homes/Nova Scotia Power Demonstration House: ERS96

ERS80↓75%

Final ERS = 96

Total heated space = 2,300 s.f.


•  ABOVE-GRADE WALLS: RSI 7.4/R42 wet sprayed cellulose & 75mm (1.5 inches) rigid board

•  BELOW SLAB: RSI 4.4/R25 Type III

•  WINDOWS: Low-e, argon-filled, insulating spacers, vinyl frames,

•  SPACE CONDITIONING: Air-Source Heat Pump, with Solar Thermal in-floor

•  WATER HEATING: Solar, DWHR, electric boost

•  VENTILATION:

•  High efficiency HRV


This house features selective glazing. The south and west facing windows are double-pane units to take advantage of passive solar gain. The north facing windows, which don’t contribute to solar gain, are triple-pane units.

Measure ERS

Benchmark (NS Code) 80

Improved Envelope

Renewables 96

Mechanicals •  Air-to-Air heat pump

(primary heating & cooling)

•  Solar thermal and two drainwater heat recovery (DWHR) units

•  Radiant heating system in floor is fed by excess from DWHR and two solar thermal collectors

ERS80↓75%

Wall Detail

Double 2x4 stud wall on 2x10 plate

Staggering eliminates thermal bridging

Rainscreen detail

Foil-faced rigid board to interior provides air barrier

Wet-spray cellulose stays in place, can have higher density, higher R-value per unit thickness

Headers are filled with RSI 7/R40 high-density spray foam


Fibre-cement siding 3/8” vertical PT lath @

800mm (24”) o.c. (rainscreen) Housewrap

7/16” sheathing Double 2x4 staggered stud walls @ 800mm (24”)

o.c. on 2x10 plates RSI6.3/R36 wet-spray cellulose

RSI 1.3/R7.5 foil-faced rigid insulation Drywall, taped and sealed

Staggered Double Stud Wall, Corner Detail

Getting to Net Zero Energy


301m2 (3,237 s.f.)

2storey with walkout basement

Attached garage

8.3 kWp Photovoltaics (PV)

(36 * 190W modules)

(8 * 190W modules)

2 evacuated tube solar thermal collectors

}  BC Green Dream Home



Thermal Envelope = ERS85

Ceiling RSI 10.6 (R-60)

Main walls RSI 7.5 (R-44)

Foundation walls RSI 7.5 (R-44)

Slab RSI 3.5 (R-20)

Windows 3-pane, low-E 10 (soft coat), 13mm argon fill, insulating spacers, vinyl frames

0.68 ACH@50Pa (0.5ACH target)

Mechanicals

Space heating: Geothermal

Water Heating Solar DHW + HP preheat, DWHR, secondary electric boost as required

Ventilation: HRV

Space Cooling: Geothermal


Measure ERS Estimated MJ

Benchmark (Envelope) 85 90,390

Improved Mechanicals 38,265

Renewables 101 (6,720)

Attic Insulation: 75mm (3 inches) urethane foam

400mm (16 inches) blown cellulose

Footing to Rafter ICF construction: Total 273mm (10 ¾ inches) foam


Geothermal (5.1 COP per

manufacturer) feeds space

heating and pre-heats DHW

Solar thermal and drainwater

heat recovery (DWHR) unit reduce hot water load

Secondary electric tank boosts

DHW

Annual DHW energy

requirement = 4000 kWh

Solar contributes 2100 kWh-e

DWHR contributes 460 kWh-e


Drainwater Heat Recovery

Secondary

Primary

Geothermal Heat Pump Desuperheater

Solar Water Heating System

Solar DHW Array


Electrical load Lighting, appliances, electronics, exterior

CMHC default: 24 kWh/day

Actual Load: 11.5 kWh/day

PV: 8.3 kWpeak capacity

Modelled energy production

9940 kWh/yr

Monitored energy production

(Jun-Sep 2010) = -0.4% under

model


6.8 kW Roof Mounted Array

1.5 kW Bi-Facial Balcony Array

Solar DHW Array


PV optimized by using shadow modelling to determine array placement and ‘string’ arrangement.

Innovative ‘bi-facial’ PV panels used in vertical installation as balcony guard.

All energy used and produced is monitored.


1 1 1 1

1 1 1 1 1 2 2 2 3 3 3

2 2 2 3 3 2 3 2 3

3 2 3

4 4 4 4 4 4 4 4 4

X X

XX

Strings 1 & 2 è (18 modules) Inverter 1 Strings 3 & 4 è (18 modules) Inverter 2

Photo courtesy: www.greendreamhome.ca


33% Cost Increase over ERS80 baseline:

Envelope: $40,000

Mechanicals $10,000

PV: $50,000

Package: $100,000

Finish package = $200,000

Construction Cost = $600,000

Land cost = $150,000

ROI/payback unknown


Photos courtesy: www.greendreamhome.ca

BFH The Path to Net Zero Energy Houses in Cold Climates

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Transcript of BFH The Path to Net Zero Energy Houses in Cold Climates