Net Zero Energy in Very Cold Climates

Habitat Studio has built over 40 houses with Energuide Ratings of 86 or better

Our minimum energy specification results in a Energuide rating of 82

Net Zero Energy

• Produces all of its own energy for Heating, DHW, Lighting and Appliances on site over the course of a year.

• Next to impossible without aggressive conservation

!

• 54000 C Heating Degree Days

• -340 C Design Temp

Habitat Studio NetZero Energy Houses so far

Riverdale NetZero Mill Creek NetZero

Belgravia NetZero Parkland NetZero

South Windsor Park NetZero Holyrood Near

NetZero Retrofit

Edmonton

Winnipeg

• 59000 C Heating Degree Days

• -350 C Design Temp

Parkland NetZero• LEED Platinum 4000 sqft two story with

finished basement, complex shape. 6 occupants

• 16,800 watts of PV, ground mounted with 2 way tracking

• 55% passive solar heated, 12% south glazing with 2 1/2” concrete floor

• Electric boiler with in floor distribution.

• Good solar site for house and array

net-zero.ca/

Habitat Studio Net Zero houses this year

Allen Residence

Shute Salvalaggio Residence Kennepohl Franchuk Residence

Kosowan Ferrero Residence

• Panelized factory built 2x8 Filled with 5" 2lb Spray foam & 2.25" fibreglass

• East west facing site

• Air source heat pump heating

• Air source heat pump hot water

• 16.3 kW photovoltaic system

• Landmark builds over 1000 homes per year

Landmark Group of Builders Ltd.

Net Zero in 10 easy steps

• Model the energy performance of your preliminary design

• Use the modelling results to optimize the building envelope and passive solar gain

• Reduce base loads

• Domestic hot water

• Lighting and appliances

!

• Evaluate air source heat pumps or geothermal and other renewables

• Size PV to meet remaining total loadEnergy Reduction

Renewable Energy Collection• Site assessment

• Preliminary design

• Optimize passive solar if available

• Finish detailed architectural and system design

Using modelling to optimize the cost of conservation measures

For Net Zero Energy at the Lowest Cost

Cost per kWh/year of energy collection*=Cost per kWh/year of energy

conservation

Cost per kilowatt-hour/year (kWh/a) of any energy conservation measure

Cost of the measure divided by energy saving in kilowatt-hours per year(kWh/a)=

*Current cost of PV in Edmonton is $3.00 to $3.50 for the capacity to generate

1 kWh/year

N.B. This works until you run out of roof space and it ignores the fact that there are primary energy consequences to exporting large amounts of energy

to the grid in summer and drawing it back in winter

• Conservation is the simplest, most economical and most reliable route to energy and greenhouse gas reduction - better than solar PV, solar hot water, better than geothermal

• Without aggressive conservation there’s not much point in planning for renewable energy collection

• The most benign energy available is the energy you don’t ever need.

Building a Better Building Envelope

• Very hard to fix the building envelope later

Preliminary Design

• Usual home design considerations- Job #1 is to build a great place to live.

• Keep living spaces on the south side to make best use of passive solar potential

• Try to accommodate space for PV generation

• Keep the shape simple and compact

Site Assessment

• Evaluate the Solar Potential

• Consider potential shading from buildings, trees, etc.

• Potential for renewable energy collection

• Passive solar is not often available on urban lots, but when it is, it makes net zero a lot easier.

S

January 15

Belgravia NetZero• 1900 sq. ft. with basement suite (TFA 1981sqft /184 m2 ),

currently one occupant

• Excellent solar site

• 7740 watts of PV- 5160 watts moveable, 2580 watts fixed

• 12.6% south glazing area, 2 1/2” concrete on floors

• Dead simple, very low cost electric baseboard heaters and DHW

• Incremental investment in conservation was partially paid for by savings on the mechanical system

• Has used ~5600kWh/a for heating, lighting, appliances, and DHW and generated 9600 kWh- a 4000 kWh surplus for two years in a row. (30kWh/m2 all in).

19°

53°

885 square feet

375 square feet

Roof shape and orientation

• When PV costs were $6.00 to $7.00 per installed peak watt we angled the roof to get as much output as possible from each module.

• Now with PV costing $3 to $3.50 per installed peak watt it makes more sense to accommodate as many modules as possible and accept lower output per module.

Modelling

• Good modelling is everything. Designing for net zero at an optimum cost is almost impossible without it. You're shooting in the dark

• Model early in the design process while it is still easy to make changes and before people get attached to particular configurations

• Model in house if possible, but if you can’t you can still learn a lot by playing with the input values in a model set up an expert evaluator.

• It seems like a lot of work, but can be done in a couple of hours after you’ve done it a few times.

Modelling Tools

• HOT2000 is tested, tried, and true. It is the basis for most Canadian labelling and rebate programs

• Passive House Planning Package (PHPP) is excellent. It gives very detailed feedback and lets you dial in the important details

Envelope Modelling/Optimization

• Determine Current PV cost or other benchmark energy price.

• Evaluate envelope upgrades with respect to cost per kWh/year of energy saved.

• Optimize envelope specifications: foundation,walls, roof, windows, air tightness.

• Extra conservation cost can often be offset by simpler mechanical systems

Net Zero in 10 easy steps

• Model energy performance of preliminary design

• Use the modelling results to optimize the building envelope and passive solar gain

• Reduce base loads

• Domestic hot water

• Lighting and appliances

!

• Examine / Model solar domestic hot water and heating

• Consider Air Source Heat Pumps or Geothermal

• Size PV to meet remaining total load

Energy Reduction

Renewable Energy Collection• Site assessment

• Preliminary design

• Finish detailed architectural and system design

Options for walls with better performance than 2x6 16” O.C.• 2x6 @ 24” O.C. (R 17.9 vs R16.5)

• 2x6 or 2x8 with high density foam -

• ICFs (Insulated Concrete Forms)

• SIPs (Structurally Insulated Panels

• 2x6 with 2x3 Strapping

• 2x8 24” O.C. with OVE details

• Double 2x4 walls - 10” to 16” thick

• Saskatchewan Double 2x4 wall

• 2x4 with Larsen trusses

• 2x6 with exterior rigid insulation foam or rigid Roxul-

• REMOTE walls - see CCHRC site for some great pamphlets

Considerations in choosing a wall system

• Lowest cost per effective R value

• Ease of getting ultra air tightness.

• Continuous insulation layer- no thermal thermal bridges

• Durability- vapour openness.

• Ease of construction

• not too disruptive of normal construction sequence

• minimal work from scaffolding

• As walls get thicker and tighter the sheathing gets colder. Moisture that gets into the walls from air leakage or diffusion will condense on cold sheathing.

• OSB is almost a vapour barrier. It slows drying significantly.

• Air leakage from inside the house can deposit lots of water in the wall.

Better insulated walls have a higher moisture risk

Good sources of info• Building Science Corporation http://www.buildingscience.com/documents/

bareports/ba-1316-moisture-management-for-high-r-value-walls/view

• CCHRC report on Moisture in REMOTE walls

• Air tightness of older-generation energy efficient houses in Saskatoon in Journal of Building Physics Volume 36 Issue 3, January 2013 (email pamerongen@habitat-studio.com for a .pdf)

High Density Spray Foam in a 2x6 wall

• R 24.8 (effective) for 2x6 24” O.C

• Less fussy

• Less labour

• Use less space

• Good air tightness with some remedial sealing

!

+!

-• Expensive

• No thermal break

• High embodied energy

• Less environmentally friendly- high GHG emissions from blowing agents

• Hard to renovate

• Not good for some small gaps

• Not as air tight as you would think

Riverdale Deep Wall!

• Lowest incremental cost to get R40+

• Follows normal construction sequence

• Can be very air tight

• Versatile

• Almost the same amount of dimension lumber as standard 2x6 @ 16” O.C.

• Minimal Waste

!

+• Extra labour

• Fussy air sealing

• Takes extra space

• Hard to renovate

!

-

Passive buildings need to have low thermal bridging.

• Both Construction Thermal Bridges and Geometric Thermal Bridges can be significant.

• At some point piling more insulation onto the surfaces doesn’t help much, and the joints and points need to be looked at.

©Passive House Institute US 2013 – Certified Passive House Consultant Training

and points need to be looked at.

7

Picture Credit: David White

Thermal Bridging Control• HOT2000 is responsive to thermal bridging control is a few

areas, but isn’t transparent.

• Effective R values depend on continuous insulation layers.

• Passive House Planning Package (PHPP) requires detailed input and gives good feedback on the consequences of thermal bridging.

• Eliminating thermal bridging will reduce heat loss substantially whether you can calculate it or not.

• Air tightness is by far the cheapest energy reduction investment you can make

• Air test results of 0.6ACH 50 or better are achievable in wood frame buildings.

• Keeping uncontrolled air leakage out wall assemblies enhances durability

• New vapour open air sealing products and techniques are one of the biggest benefits of the Passive House approach.

Windows

Courtesy of the US DOE

Windows and doors are the single biggest source of transmission heat loss - often 40% or more of the total building heat loss.

Window Shopping- features to look for

• Low conductivity (Low U value/high R value) glass

• High solar heat gain coefficient (on the south)

• Low conductivity (Low U value/high R value) frames

• Slim profile frames- typically the glass will have a better U value than the frame

• Low conductivity spacer bars

• Good airtightness- preferably triple weather stripping

• Durable

• A few large windows (less frame and framing) will use less energy and cost less than more small windows of the same total area.

Heat Recovery Ventilators

• Any air tight building requires a continuous supply of fresh air. Heating ventilation air can require up to 20% of the total heating energy

• HRV’s are an essential component of high performance housing

• Most HRV’s have relatively low efficiency. ( ~55 to 65%)

• High efficiency HRV’s (80 to 95%) are a good investment and have a short payback.

Total Annual Heating Energy Reduction(kWh/year)

Domestic Water HeatingCoolingLighting and Appliances*Net Annual space Heating

*Including passive solar and internal gains and heat pump C.O.P.

• Low flow shower heads

• Efficient Hot Water Tanks

• Water conserving dishwasher

• Water conserving clothes washer

• Grey water heat recovery

Domestic Hot-Water Energy Reduction

• Energy Efficient Appliances

• refrigerator

• clothes washer

• No Dryer

• Range/ Pressure cooker

• Energy Efficient Lighting

• compact fluorescents

• LEDs

• task lighting

• day lighting

• Energy Efficient Motors

• ventilation

• heating

• Phantom Load Control

• The Energy Detective(TED) monitor

Electrical Load Reduction

Riverdale NZ Heating Schematic

Solar Thermal Space Heating

7- Zen 28S Collectors

• Can be very expensive if you size it to meet a high percentage of the winter load.

• Not enough energy available when you need it most

• Can be very complicated

• Potential to harvest more useful energy per sq. ft than PV (~20 kWh/sq.ft./year)

• Incremental cost at Riverdale~ $50000 per unit

Fresh Air from

Outdoors

Exhaust Air to

Outdoors

Exhaust Air from Bathrooms &

Kitchen

Return Airfrom

House

Fan Coil

Heated / CooledAir to House

7 Solar Heating

Collectors

Domestic Hot Water

Domestic Cold Water from Mains

Drain Water Heat

Recovery

Electric Heating Element

Fan Coil Pump

2 THeatPump

Ground LoopsGL1. 41 m under garageGL2. 55 m around foundation

Daily Heat Storage Tank

Seasonal Heat Storage Tank

Tempering Valve

17,000 litreswater

300 litres water

Cold Waterto Interior

Uses

Heat Recovery Ventilator

Fan

Fan

Dwg M1. Riverdale NetZero House Mechanical Systems Layoutver 3d Drawn and developed by: David Morrow, Hydraft Development Services

Peter Amerongen, Habitat Studio and WorkshopMonitoring Instrumentation: Gordon Howell, Howell-Mayhew Engineering

Date: 2008 August 02

55°C to 80°C

5°C to 90°C6 GJ of heat

Fresh Air to House

Fan

Daily Storage Tank Bypass Valves

Fan Coil Bypass Valves

Seasonal Storage Tank Bypass Valves

Drainback Tank

30 litres water

Surface area:

21 m2

Cold Waterto Exterior

Uses

WM-cmWM-dh

Tsolar-in Tsolar-outTfc-in

Tfc-out

T1

T3

T4

T5

T8

House Temperature

Outdoor Temperature

T6

a

b V1

HX3

HX2

HX1

E1

V3a

V4 a

b

V5b

a

V7

a

b

V6 ab

P2

F1

F2F3

Fsolar

Ffc

HX4

Tempered Water to Showers

WM-cx

Solar Collector

Pump

P1

Solar SupplyHeat Meter

HM-ss

a V2

b

Vent

T2

c

V8

a

b

c

GL1

Daily Storage

Tank Bypass Valves

Seasonal Storage

Tank Bypass Valves

GL2

Heat Pump Pump

Fan CoilHeat Meter

HM-fc

b

Heat from solar collectorsSolar heat to daily tankSolar heat to seasonal tankPotable waterStored heat from seasonal tankStored heat to fan coilStored heat to daily tankStored heat to heat pumpConcentrated heat from heat pumpHeat to/from ground loops

Cold Water Pre-Heat

HX5

T7

Colour Legend for Heating Loops:

P3

Nearest Nuclear Fusion Furnace

Notes:1. Ground loops intended to provide space cooling only.2. Heat pump supplements the moving of heat if

required:a) from seasonal tank to fan coil by taking the

seasonal tank from 25°C down to 5°C;b) from seasonal tank to daily tank; andc) from fan coil to ground loops for space cooling.

3. Manual valve sets V7 and V8a) “a” is mainly used to create backpressure so loop

remains pressured while serving thenon-pressurised tank;

b) “a” & “b” are used for seasonal selection of ground loops for cooling;

c) “c” is for isolation only – it is normally open.

Net Zero in 10 easy steps

• Model the energy performance of your preliminary design

• Use the modelling results to optimize the building envelope and passive solar gain

• Reduce base loads

• Domestic hot water

• Lighting and appliances

!

• Consider Air Source Heat Pumps or Geothermal

• Size PV to meet remaining total loadEnergy Reduction

Renewable Energy Collection• Site assessment

• Preliminary design

• Optimize passive solar if available

• Finish detailed architectural and system design

• The energy harvested by Air Source Heat Pumps is 100% renewable - solar energy with no direct sun.

• It is possible to get C.O.P.’s* of 2 or better in Edmonton or Winnipeg.

• C.O.P. drops off as temperature get colder.

• Mitsubishi ‘Hyperheat’ units have shown C.O.P.’s of greater than 1.0 at temperatures as low as -30℃

• They can make or break the attempt to get to net zero energy.

0"

5"

10"

15"

20"

25"

30"

35"

40"

45"

50"

1" 13"

25"

37"

49"

61"

73"

85"

97"

109"

121"

133"

145"

157"

169"

181"

193"

205"

217"

229"

241"

253"

265"

277"

289"

301"

313"

325"

337"

349"

361"

Series1"

Edmonton Heating Degree Days 2013

Mitsubishi ‘Hyperheat’ cutoff (~-25℃)

*C.O.P. - Coefficient of Performance C.O.P. of 2 indicates 2 units of energy out for

every 1 unit of electricity in.

Air Source Heat Pump Operating Range

Heating and ventilating with a small mini split air source heat pump

*Needs EGH 86 or better envelope

Mini split outdoor unit

Fresh air fromoutside

Fresh air to house

Exhaust stale air out Mini split indoor unit c/w blower

Stale air exhaust from kitchen,

bathrooms and laundry

Transition supply duct

Controller to sync mini split fan with thermostat and post heater

10kW Thermolec Post Heater

HRV

12" round duct to supply heating and fresh air to house. 500CFM at < 0.36 in.WG

12 " return air from house

Mini splits vs Central systems

• Ductless mini splits can save heating system dollars if the loads are small enough to be met with point source heating and electric baseboard back up.

• Big central ASHP’s like the Mitsubishi Zuba Central will add ~$8000 to heating system costs.

• Even at that price central systems can pay for themselves in offset PV costs. For example, if it saves 3000kWh/year if will offset $10,500 worth of PV and also need less roof space.

Air Source Heat Pumps for Domestic Hot Water

• Relatively low cost $1500-2000 • Provide a small summer cooling

benefit • Work well in tandem with Air

Source Heat Pump or Geothermal heating.

• Will shrink the size of the PV array

• Annual COP of ~1.50 to1.75 is possible

• Provides a small amount of summer cooling

!

+!

- • Will increase winter heating load • Noisy

Photovoltaic Electricity (PV)

! • Requires lots of roof space- 100 sq. ft. to generate 1500 kWh/ year - more if you have shading

• Expensive ~ $3.00 to $3.50 per installed watt of peak capacity. Typical NZ system $30,000 to $40,000(Each installed watt in Edmonton will produce 1.1 kWh per year.)

• Supply is out of sync with demand - grid dependant.

!• Very simple installation, durable, almost no

maintenance • Can be added later if roof space is available • With grid tie it doesn’t matter that supply and

demand are out of sync. • “PV is a rock the makes electricity” Martin

Holladay

!

+

!

-

Mosaic Centre Case Study• New 30,000 square foot office building in south Edmonton

• Beautiful, healthy, nurturing, affordable place to work for the Mosaic Group of Companies.

• Headquarters for Oil Country Engineering Services Ltd

• Includes a daycare, co-working spaces, a wellness centre, and an incubator for other greener businesses

• Natural daylight in all work spaces.

• Project environmental goals

• Net zero energy

• LEED Platinum Certification

• Living Building Challenge

Process

• Energy modeller was hired before the architect

• Achieving the project goals using conventional fixed price contracting was going to be unaffordable

• Early commitment to Integrated Project Delivery

• Careful team building prior to design.

• Open documentation of project successes and failures. http://themosaiccentre.ca/

Mosaic Centre IPD

• Early involvement of key participants

• Shared risk and reward based on project outcome

• Joint project control

• Reduced liability exposure

• Jointly developed and validated targets

Bullitt Center

Mosaic Centre: In pursuit of Net Zero*

* For the whole report: http://themosaiccentre.ca/wp-content/uploads/2014/09/2013-06-13-ReNu-C3-Report-3.pdf

Mosaic Centre: In pursuit of Net Zero

• More efficient servers and monitors

• Shaved lighting loads

• Reduced cooling load

• Utilizing waste heat from servers for heating

• Geothermal heating and cooling

• Higher efficiency PV

The IES run on versionC3 IES shows consumption for that design to be ~185,000 kWk/a. So they kept hunting. Solutions include:

• Project is under budget and 4 months ahead of schedule. Due to be complete in February 2015.

• There have been mistakes, a few of which would normally have been very costly and time consuming. The IPD team pulled together and corrected them quickly at a fraction of the expected cost.

• Premier quality, net zero energy building, being built at a premium of 5 to 10% over the cost of standard market space.

Results

• Savings from reduced lighting, heating and cooling loads did result in some reductions in equipment cost that have helped to pay for the envelope upgrades

Passive House • Started about 20 years ago when some Bo Adamson a German engineer

and Wolfgang Feist a physicist set out to reduce heating and cooling energy to a level (about a 90% reduction) that would be sustainable and leave room for the developing world to catchup.

• Building on the 1970’s work of Harold Orr (The Saskatchewan Conservation House) and William Shurcliff in the US, with stereotypical German thoroughness they built a heating and cooling demand spread sheet that accounted for everything.

• There are now ~30,000 Passive House buildings worldwide, several thousand in the US and a few dozen in Canada.

• Annual heating and cooling energy demand limited to 15 kWh/m²

• 0.6 Air Changes per hour

• 120 kWh/m² primary energy demand.

Passive House Metrics

Buildings designed and built to the passive house standard are among the most energy efficient, the healthiest, the most comfortable and durable buildings ever built.

The drive to meet this standard has powered innovation in building science, building techniques and building components. These innovations include:

• Very high efficiency HRVs

• Very high performance windows and doors

• Highly effective air sealing products and techniques

• Vapour open sheathing materials

• Highly insulated , thermal bridge free, vapour-open assemblies

• Hygrothermal analysis software

• Fine grained, detailed energy analysis tools (PHPP) now with a Sketchup interface

• House area is ~ 1600 sq. ft with a finished basement(TFA=246m2)

• 15kWh/m2 if .35 ACH50

• Thanks to Jim Zeibin and David Zeibin Architect

Cottonwood Passive House

U value w/m

R value

Concrete Foundation wall 0.113 50

Double stud exterior wall 0.076 75Truss roof 0.058 98Floor slab 0.119 48Windows InternormAir tightness target 0.3ACH50

HRVUltimateAir DX 300

Cottonwood Specifications

• Hard to meet the target with single family housing here in the frozen north, but your building will be better for the attempt.

• Multifamily is doable.

• PHIUS is about to roll out a climate specific standard, that will be more achievable here.

• Training: great courses available from CanPHI West and PHIUS

www. habitat-studio.com