Riverdale NetZero Project Summary of Costs and Expected Performance Natural Resources Canada Sustainable Buildings and Communities Edmonton, Ottawa 2009 January 07 Gordon Howell, P.Eng. 2008-2009
Progressively Detailed Analysis We are moving towards a better understanding of the costs and the performance of the Riverdale NetZero house. Performance is compared to standard construction in Edmonton. Upgrade costs depend on the point of comparison. are compared to standard Habitat Studio & Workshop practices (R28, R50, 3G windows, high efficiency furnace & water heater, HRV, airtight). include builder mark-up and GST. More analysis work still to be done. This is a summary of what we ve done so far. All numbers are for each side of the duplex. We welcome any questions, suggestions, comments and challenges to anything we present. 2
Riverdale NetZero Energy Home Edmonton 2008 duplex 1844 ft2 per side 2519 ft2 including basement 3 bedrooms 3
4 2008 December 30, 12h47, -20 C
The Journey to Net Zero Energy - cheapest to most expensive Electrical fixtures and appliances electrical Water fixtures and appliances water Building envelope heating } Ultra-high efficiency technologies Passive solar home heating??? Active solar thermal for domestic water heating??? } Active solar thermal for space heating??? Solar air heating??? Heat pump: geothermal, air, water??? Heating technologies Solar photovoltaics??? Microwind??? } Electricity technologies 5
Design Challenge Where do we find the minimum construction cost to achieve net zero? We need large amounts of energy efficiency and large amounts of renewable energy Cost of NZE home Total upgrade cost of NZE home Cost of home s renewable energy?? Optimum cost point Where is it? Cost of home s efficiency energy 6 Amount of energy efficiency or renewable energy needed to achieve net zero energy
#1. Domestic Electricity Electricity consumption reduced by 50% for an upgrade cost of $1800 (est) Energy efficient appliances, ECM ventilation motors Energy efficient lighting (compact fluorescent, LEDs) Task lighting (halogen) Daylighting Phantom load control Annual savings: $550 (4600 kwh, 4200 kg of emissions $0.40/ann-kWh) Return on Investment: 30% /year (simple) (=3+ year payback) Fridge Clothes dryer Dishwasher LED lighting 7 CF lighting
#2. Domestic Water Heating Drain water heat recovery Fuel consumption for water heating reduced 75% for an upgrade cost of $1750 Water efficient shower heads, faucets, dishwasher, clothes washer Drain water heat recovery Annual energy savings: $260 (6200 kwh, 46,000 DHW litres, 1500 kg of emissions $0.28/ann-kWh) Return on Investment: 15% /year (need to include savings in total water volume too) Shower heads and faucets Dish washer Clothes washer 8
#3. Building Envelope Fuel consumption for space heating reduced by 70% for an upgrade cost of $12,000 Ultra high insulation levels EG 86 High performance windows Ultra low air leakage rate High efficiency heat recovery ventilator (does not internal house heat gains) Ceiling R-100 cellufibre Double-stud 2x4 walls with R-56 cellufibre Annual savings: $1000 (25,000 kwh, 5900 kg $0.47/ann-kWh) Return on Investment: 9.6% /year Heat recovery ventilator 80% efficient Basement walls R-54 9 South windows R-7.3 R-8.3 North windows R-10 Air tight envelope 0.59 AC/h
#4. Passive solar for space heating all south windows EG 93 Provides 40% of our space heating Upgrade cost: $2,400 for additional concrete mass Annual value of passive solar heat: $185 (4400 kwh, 1000 kg) Economics are integrated with building envelope, not easy to determine (yet) 10
EG 96 Upgrade cost: $36,700 (net of $5k of learning we made) Annual savings: $175 (4150 kwh, 1000 kg, $8.84/ann-kWh) [$580 including eliminating gas connection fees] Return on Investment: 0.5% /year [1.6%] #5. Active solar thermal Drainback collectors: 21 m2, vertical Domestic water heat storage: 300 litres Space heat storage: 17,000 litres 11 Provides 83% of domestic water heating and 21% of space heating
12 Complete Heating System Schematic As-built
Drainback tank in bedroom Major components Solar collector array 7 collectors DWH tank 300 litres Space heating tank 17,000 litres Fan coil Heat exchangers in large tank 13
17,000 Litre Solar Storage Tank Concrete tank Some insulation 14 Tank with partial R50 insulation (walls and ceiling, R20 under floor)
Utility Room Solar Plumbing Layout When completed, the piping will be insulated and colour-coded with direction arrows. Fan coil 15
#1. Solar collection loop heat first to DWH tank then to space heating tank 16
#2. Domestic water heating drain water heat recovery heat exchanger in big tank keep DWH tank at 30 C min. use instantaneous water heater 17
#3a. Space heat transfer loop first from the space heating tank to the fan coil 18
#3b. Space heat transfer loop then from the DW heating tank to the fan coil 19
#3c. DW heat transfer loop from the space heating tank to the DW heating tank 20
#4. Ground cooling loops under the garage slab around the foundation manual valves 21
#5. Solar-assisted heat pump accesses an additional 2 GJ (500 kwh) of heat in the space heating tank by taking the tank from 30 C down to +5 C Each cycle is worth $60 in reduced electricity purchases HP purchase cost is $4k, which = $9.73/ann-kWh for one cycle per year 22
EG 100.3 Upgrade cost: ~$54,000 Annual savings: ~$760 (6200 kwh, 5800 kg, $8.69/ann-kWh) Return on Investment: 1.4% /year #6. Solar PV system for electricity 33 m2, 5.6 kw, 53 tilt 23 Provides 7% of domestic water heating, 16% of space heating and 108% of electricity consumption
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1. Solar array 2. Solar inverter 3. Disconnect switches 25
Electrical Room Solar Inverter Layout Simple Compact Quiet No maintenance 26
Riverdale NetZero Energy Home Edmonton 2008 27 Upgrade cost: $113,000 Annual savings: $2800 (36,000 kwh, ~16,000 kg) Return on Investment: 2.5% to 12% /year depending on government policies on fossil-fuel subsidies, environmental emissions and green loans
Results: Annual Home Energy Bills Natural gas bill: $0 no gas line needed, saves $410 per year in connection fees (in 2008) Electricity costs: surplus ~$40 ranging from $150 surplus to $100 deficit per year depending on homeowner electricity consumption choices plus normal electricity grid connection fees of $180 (in Edmonton) 28
Riverdale NetZero Project Summary of Costs and Expected Performance Download this presentation and others from www.hme.ca/presentations www.riverdalenetzero.ca For more information on see www.hme.ca/eq Gordon Howell, P.Eng. Howell-Mayhew Engineering 1995-2009 Edmonton Phone: +1 780 484 0476 E-mail: ghowell@hme.ca 29