Energy Options for Residential Heating Juergen Korn, P.Eng.
Energy Options for Residential Heating: Heat balance An array of options and good heating systems Energy Costs Heating and construction type options Some technology to consider
HEATING: Why do we heat?
HEATING: Why do we heat? To maintain a relatively constant and comfortable indoor temperature despite wide fluctuations in temperature and conditions outside, and therefore heat output
HEATING: Why do we heat? To maintain a relatively constant and comfortable indoor temperature despite wide fluctuations in temperature and conditions outside, and therefore heat output To keep things dry
The Heat Balance Heat Input Fuel Volume x Energy Content x Efficiency Solar Gains = Heat Loss Lights, appliances, motors, people Walls, windows, doors, foundation Convection Internal Gains Conduction Air Leakage Ventilation Radiation Windows Latent Evaporation Cooling
Heat Loss: Directly impacts heating system size and type; Heating system output must match the home heat loss at the design temperature (-41 C in Whitehorse). plus ~20%, or far more
25 Options
27 Options
Elements of a Good Heating System Reliable and low maintenance High efficiency using the low cost fuel Inexpensive to purchase and install Provides a high level of comfort and even heat Low IAQ impact will not back draft
Elements of a Good Heating System Good temperature control Quick response time Zone control Simple to operate All ducting sealed not with duct tape Low environmental impact / risk CO2, smoke, soil contamination, renewable energy source
Combustion Appliances need special consideration Have been used for thousands of years All produce toxic gases and particulates Beware of exhaust fans - mind the depressurization Fuel spills, gas leaks Fire Ongoing maintenance and vigilance Moving parts break Cold chimneys don t work Sidewall venting is not ideal either Environmental impact / risk CO2, smoke Fuel prices may be unpredictable
Make up air
Controlled combustion air
Mechanical System Complexity Chasing every thermodynamic opportunity
Just Say No!!
Mechanical System Complexity Some lessons from Equilibrium Housing projects: Mechanical system complexity was one of the biggest, and most often reported, problems. Should we attempt to use every thermodynamic opportunity? Controls were a particular problem (did not work, were too complicated to understand, caused customer complaints). Builders felt that all the controls must be available from one supplier to ease maintenance, warranties, etc.
Complex Mechanical Systems Unanticipated interactions among mechanical components (instantaneous DHW heater would not fire since its inlet water, preheated by solar DHW, was too warm). Excessive floor space for mechanical systems At $1000 to $2000 /m2, how much space can be devoted to the mechanical system?
Non - Combustion Appliances Electric based heating Clean virtually no indoor air quality issues Highly versatile baseboards, furnaces, boilers, infloor, radiant panels, DHW, heat pumps, space heaters, Can be virtually no maintenance and 100% reliable Can be inexpensive to install Silent operation Few if any moving parts No chimneys Regulated energy price More strain on electrical grid
Energy Saving Potentials Properly installed modern heating appliances have little more potential for energy savings Heat pumps are an exception By far the greatest and most cost effective cost savings are by reducing heat loss
Residential Electrical Rates
Residential Electrical Rates > 95% of electricity is produced by hydro www.housing.yk.ca
Cost to Heat an Average Yukon Home:
Old Way of Seeing, for City of Whitehorse
Energy and heating system cost optimization Mark Carver, NRCan
Energy and heating system cost optimization
Winnipeg - Urban Ecology http://www.youtube.com/watch?v=tcql1nafjfi
Winnipeg - Urban Ecology
Toronto Now House
Riverdale Retrofit
Energy Saving Potentials Properly installed modern heating appliances have little potential for savings Heat pumps are an exception By far the greatest and most cost effective cost savings are by reducing heat loss
Heat Recovery Ventilation ( Minimum Efficiency in the City of Whitehorse = 64% @ -25C )
Heat Recovery Ventilators Temp = -20 C RH = 80 % Temp = -8 C RH = 100 % Temp = 20 C RH = 30 % Temp = 8 C Typical plate type HRV Efficiency = 70 % Temp Rise = 28 C RH = 5% Final RH = <3 % ( Minimum Efficiency in the City of Whitehorse = 64% @ -25C )
Air Source Heat Pumps: Mini-split or ducted Heating and cooling Electric ~ 200% efficient No combustion risk Reliable need cleaning Good to ~ -25 C or more
Ground Source Heat Pump:
Ground Source Heat Pump: Even great efficiency than cold climate air source heat pump No combustion Need to recharge the ground Poor value costly drilling, or trenching
Integrated Combo --
Electric hot water tank for space heating? In very low energy housing, yes! Very efficient Simple installation Reliable Two tanks can be combined for higher heating loads and solar thermal preheating No combustion issues
Passive Solar Windows: Windows can be net producers of energy There is an optimum glazing and window area for best annual energy efficiency What that area and glazing is we don t know Windows are very expensive relative to walls
Passive Solar Windows: Also, windows have a relatively short life (20 to 25 years) after which they have to be replaced. Overall, windows have poor cost-effectiveness (Value Indices) which suggests that passive solar may not be as important as first thought. use a good window, but one which also has a high Temperature Index (to resist condensation). I = [T Tc] / [Th Tc] x 100
Solar Energy Systems Reduced Solar Energy System Production due to: Snow cover on solar collectors and/or PV arrays. Low slope roof or panels can cause long periods of no energy production. Trees or other shading is more problematic than first anticipated and can be very expensive to deal with. Dormers and different roof heights can cause shading problems
Predicted vs. Actual PV production:
Yukon Government Micro-Generation Policy The incentive rate will apply to electricity exported to the grid and be set at $0.21/kWh on the Yukon s Integrated System (YIS) and $0.30/kWh in electrically isolated communities powered by diesel generation. This rate will be re-evaluated after two years. These rates are based on the latest analysis conducted by the utilities on avoided cost of new generation supply.
Photo Voltaics (PV) Solar Electricity Very reliable Grid connection is key < $5 per Watt installed and dropping At $0.21/kWh PV is about neutral value today At $0.30/kWh PV can be very cost effective Some Net Zero Energy homes are now using only PV
Solar Thermal:
Solar Thermal Plumbing Connections:
Solar contribution to hot water use compared to the number of 3 sq meter solar panels
Drain Water Heat Recovery Single stage DWHR Simple and cost effective 32 to 72 % heat recovery (steady state) Only works for showers Not for washing machines, baths, dishwashers Needs the height
Drain Water Heat Recovery Two stage DWHR Simple, more expensive than single stage Higher heat recovery than single stage Needs a little more space Only works for showers Not for washing machines, baths, dishwashers
Finally: Heating and heat loss are two sides of the same coin Very low heating loads opens opportunities for greatly simplified heating systems The house is a system all components influence others consider all the impacts of changes All moving parts eventually fail The more complex the system, the more likelihood of failure.
Finally: Building envelopes are permanent; heating appliances are not Building envelope improvements can yield far greater energy savings than improvements in heating systems Keep it small KEEP IT SIMPLE!!
April 17th - Construction and energy cost optimization
Any Questions??