posted Sep 6, 2011 1:16 PM by ASHRAE Saskatoon
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updated Sep 6, 2011 1:22 PM
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There will be no new Energy Answers columns until further notice. Please feel free to read any of the past columns here.
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posted Mar 1, 2011 8:05 PM by ASHRAE Saskatoon
If you could have only one instrument to help tune up a house's energy use, what would it be?
A thermocouple temperature sensor would be my choice.
Most of the energy consumption in houses is used to maintain a temperature difference. For instance, house temperature in winter is usually held around 22 C, the hot water around 55 C, the refrigerator at about 4 C, the freezer at -18 C, etc. If these values are not right, you may be wasting a considerable amount of energy.
For measuring temperature, my favourite device is a thermocouple based digital readout. The thermocouple has the advantage that it is quite rugged, can measure temperatures over a wide range, is not very sensitive to liquid water, and is relatively inexpensive. Thermocouples operate on the Seebeck effect. A junction of two dissimilar metals will generate a voltage if the junction is at a different temperature than the readout device. The readout device converts this voltage signal into a temperature. A schematic of the thermocouple and readout is shown in Figure 1. The voltage output from most thermocouples is quite small—about 40 microvolts per degree C-- thus a sensitive readout is needed.
Figure 1. Thermcouple wires and a temperature readout
For about $150 you can get a dual input thermocouple readout with decent accuracy. Omega.ca has an Omegaette HH300 model that uses type K thermocouples, and I have been satisfied with their performance over the years. Some other suppliers include Fluke, Extech, and Cole-Parmer.
Here are some temperatures that can be checked using a thermocouple:
Refrigerator temperature. The desirable temperature should be about 4 C. A higher temperature will increase food spoilage, and a lower temperature will increase energy use.
Freezer temperature. The desirable temperature should be about -18 C. As with a refrigerator, a higher temperature will increase food spoilage, and a lower temperature will increase energy use.
Room thermostat. Use the thermocouple readout to check that your thermostat is reading properly.
Water heater temperature. The water temperature should be about 55 C coming out of the unit. Higher temperatures will waste energy and can cause scalding, and lower temperatures increase the risk of legionella and other bacteria growing in the unit.
Oven temperatures. The thermocouple can be used to cross-check the temperature settings on the oven dial and prevent uncooked or burnt food.
Furnace exhaust temperatures. A high efficiency condensing natural gas furnace will have an exhaust gas temperature of about 50 C or lower. A low efficiency conventional natural draft gas furnace should have an exhaust gas temperature of about 175 C as the exhaust gas leaves the heat exchanger. (We have, however, measured some exhaust gas temperatures as high as 400 C in cases where the warm air flow through the furnace was seriously impeded by bad ductwork or a dirty air filter.) A high exhaust gas temperature is a ready indicator of low efficiency.
Air to Air Heat Exchanger (Heat Recovery Ventilator). Use the thermocouples to check out the temperatures at the inlets and outlets of the HRV. For example, if the outdoor air temperature is -10 C and the indoor air temperature is +22 C, the temperature of the outside air should be about +13.4 C after it has been passed through the HRV (this assumes that the sensible heat recovery effectiveness is about 70%). In addition, the temperature drop on the exhaust air side of the heat exchanger should be roughly equal to the temperature rise on the outside air side of the heat exchanger. For the above example the temperature rise of the outside air would be 11.4 -(-10) = 23.4 C. The temperature fall on the exhaust air side of the heat exchanger should also be about 23.4 C if the air flows on each side of the heat exchanger are equal. (This assumes that condensation effects can be neglected.) Thus the exhaust air temperature after it has been cooled should be about 22 -23.4 = -1.4 C. If the temperature rise and temperature fall values are quite different, the most likely reason is that the flows on each side of the exchanger are unequal. Adjust the flows to bring the HRV into balance.
Skin temperature. Your skin temperature is usually about 30 C. If it is less than or equal to room temperature, you are likely dead, and you need read no further. Thermocouples can be fooled if not used properly. Here are some common errors with using thermocouples: 1 The junction of the thermocouple must be in thermal equilbrium with the temperature of the object being measured. Make sure that the thermocouple wire is in contact for at least an inch (25 mm) with the surface being measured. For instance, if you place only the tip of a thermocouple on your skin, the temperature will read about 25 C, which is clearly too low. If, however, you tape the thermocouple tip and an inch of wire near the tip to your skin, you will get a temperature of about 30 C, which is much more accurate. 2 Ensure that the insulation on the two wires is intact. If the wires are shorted at a place other than the tip, the thermocouple will give an inaccurate reading. 3 Periodically check the calibration of the thermocouple. An accurate check can be made by placing the thermocouple junction and about an inch of the wire into an ice bath. The ice bath should consist of a mixture of water and crushed ice. The thermocouple should read very close to 0 C. 4 Watch out for radiation sources, as they can give a false reading of temperature. For instance, a thermocouple that is exposed to direct sun outdoors will give an inaccurate reading of the air temperature. A radiation shield such as a toilet paper cardboard wrapped with aluminum foil will work well. A thermocouple inside an oven will give an inaccurate reading of temperature if the thermocouple is placed near the hot element.
Temperature is the probably the most important parameter in a dwelling. It pays to have a good temperature sensor.
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posted Feb 1, 2011 3:07 PM by ASHRAE Saskatoon
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updated Feb 1, 2011 3:29 PM
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Can you tell us more about the VerEco Net Zero Energy Home in Saskatoon?
The VerEco Net Zero Home in Saskatoon was opened in October of 2010. The house is on display at a local Museum until August of 2011, and then it will be moved to its final site and be placed on a basement. The house is a modest bungalow in size, with 1440 square feet on the main floor. Here’s a photo of the house. Figure 1. VerEco Net Zero Home Exhibit in Saskatoon
What are some notable features of the Net Zero Home?
1. The Net Zero home is likely the coldest NZ home in the world (In location, not in interior temperature). To my knowledge, no one in a colder climate has built such a house. Less than 1% of the world’s population lives in as cold a climate as in Saskatoon. If it can be done in Saskatoon, it can be done anywhere in the more populated and warmer parts of the planet. 2. The home may have the best insulated residential attic in the world. The attic has an R value using cellulose of about 110 in English units (RSI 19.5.) I used to think that my house, with R80 in the attic, was at the outer limit. Not so any more. The walls are double stud walls with about R60 blown in cellulose insulation. 3. The flat plate solar thermal panels are mounted vertically on the south wall. (Saskatoon is located at latitude 52 degrees North.) In addition some evacuated tube solar thermal panels are located vertically on the front of the deck on the west edge of the south side of the house. (These evacuated tube panels have not yet been connected to the heating system.) These locations for active solar panels give more design freedom, although at a penalty in energy performance. 4. Additional thermal mass is present in the floor tiles. The floor tiles are prefabricated concrete tiles with a thickness of 1.25 inches. The tiles serve three purposes—they provide a finished floor, they help moderate temperature swings from solar gains during the heating season, and they also help moderate temperature swings in the summer. 5. The house was pre-fabricated off site and moved in one piece to the exhibit area. Saskatchewan has quite generous rules as to the size of new homes that can be transported, and this 1440 square foot house was readily moved. For a short video showing the move, have a look at http://www.youtube.com/watch?v=cp34vBuRshQ6. The house is open six days a week for 10 months at a popular museum site. Especially important are the elementary school tours, as kids in Grade 7 science are taking material on energy, and the house tours will help a lot in explaining principles of energy and water efficient design. (We haven’t had all that much success educating adults in North America about sustainable housing, so perhaps getting people at an earlier age will help.) 8. A relatively inexpensive device (about $280 plus shipping) called a TED 5002-G allows one to monitor the house electrical consumption and photovoltaic generation over the internet. An electrician or experienced electrical person is needed to attach the TED unit to the main electrical panel. A view of the Dashboard output from the VerEco Home is shown on the wall mounted LED TV hooked to a computer in Figure 2. The TED unit collects historical data as well as instantaneous.
Figure 2. Interior View of the VerEco Home showing the wall-mounted LED TV with the TED Dashboard.
Figure 3. Dashboard for the TED-5002 G Unit
Figure 4. Meter showing the instantaneous electrical energy consumption of the house.
The TED unit also will graph the energy consumption and production for the house. In Figure 5 a graph of a 7 day interval is shown.
Figure 5. Graph of hourly energy consumption and PV production at the VerEco Home for January 12 to 19, 2011.
As can be seen from the graph, there is a period on January 15 and 16 when the energy consumption increases dramatically. During these periods, a worker was outside on the temporarily hoarded front porch, and was using a 220 volt construction heater. The high consumption for those periods is evident from the graph. The light coloured bars below the 0 axis are the PV production. The house has a 4.4 kW peak PV system tilted at an angle of 62 degrees from the horizontal. Note that between January 14 and 16 the PV production was minimal—this was caused by a combination of cloudy days and heavy snowfall which radically reduced the PV output. On January 17 the panels were cleared off with a roof rake and the PV production resumed. The TED 5002 G greatly helps in tracking the energy performance. The house sits on a crawl space, and during the open house there is no insulation in the floor. Thus roughly 2/3 of the heat loss from the house is into the crawl space. As can be seen from Figure 5, the total energy consumption of the house (there are no sources of heat such as a natural gas furnace or boiler) is very modest. (1 kilowatt = 3413 BTU/h).
The key to the outstanding performance of the house is the outstanding energy conservation design. With the greatly decreased loads, the renewable energy sources, ---passive solar gain, the active solar thermal and the photovoltaic panels--- are projected to generate enough energy to make the house Net Zero in annual energy consumption once the house is moved onto a basement.
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posted Dec 7, 2010 1:54 PM by ASHRAE Saskatoon
What should Canada be doing in revising its National Energy Codes for Residences and Buildings?
Recently Canada lost its bid for a seat on the prestigious Security Council of the United Nations. Part of the reason was our refusal to behave responsibly and take serious action against climate change. In life, if you want to be respected, you must do respectable things.
Building energy use is a major, major component of our total energy use. According to the ASHRAE treasurer in a recent speech to the Building Green Saskatchewan Conference in Regina in October 2010, buildings account for 40% of all energy use in the United States, and the buildings sector exceeds the transportation sector and the industrial sector.
A sustainable world will not be without sustainable buildings.
Canada has been a consistent laggard in the fight against climate change. This laggard behaviour is not the action of just one political party at the federal level. Both the current Conservatives and the previous Liberals did very little to address climate change. By contrast, most European nations aggressively pursued the Kyoto goal. Canada will miss the 2012 Kyoto Goal of a 6% reduction in energy use compared with 1990 by as much as 40%.
While Canada’s emissions have soared, Germany had chopped its greenhouse gas emissions by 18% as of 2006 compared with 1990, while the UK reduced its emissions by 15%. Canada, in shocking contrast, had increased its emissions by 33.8% over the same period according to Environment Canada numbers. This is shameful behaviour on Canada’s part.
As of 2006, Europe was averaging greenhouse gas emissions of 10.6 tonnes per capita per year, while Canada was using 23.2 tonnes or 119% more than Europeans.
Andrew Weaver, a climatologist at the University of Victoria, put it well: “We’re laggards and obstructionists.”
The following cartoon says it all. Other nations and jurisdictions are aggressively upgrading their minimum standards for energy efficiency. In the United Kingdom, all new houses built after 2016 will have to be net zero energy consumers.
What specific policies would you recommend for new buildings?
It is almost always less expensive to build new buildings to a higher energy standard than to retrofit them later. Upgrading wall insulation after the fact is very expensive, as adding more insulation to the walls of an existing building almost always entails changing the finish on either the inside or outside of the wall. For this reason, I am proposing the following real action plan:
1. All new residences in this country must have a minimum of R40 insulation in the walls as of 2012. Full stop. Canada is one of the coldest countries in the world, and yet our wall insulation values for new construction are set assuming that cheap energy and a limitless atmosphere to absorb carbon dioxide emissions will always be with us. (Sweden increased its minimum wall insulation value to R33.5 over 25 years ago.1) Attic, basement wall and window insulation values should be correspondingly increased. A maximum air leakage rate of 0.75 air changes per hour at 50 pascals should be set for all new houses, and all new houses should have a heat recovery ventilator with a minimum effectiveness of 75%
2. By 2016, all new houses in this country must be net zero ready. By net zero ready, I mean that they should be well enough insulated, sealed and HRV’d so that at a later date they could be energized by on-site solar thermal and solar photovoltaic panels. An even more stringent policy is in place in the United Kingdom, which requires that all new housing be Net Zero (and not Net Zero Ready) as of 2016.
Who would pay for the extra costs of this initiative? I estimate that the 2016 standard would cost an extra $4 billion dollars a year. This is small compared with the annual budget revenues of the federal government of $274 billion as of 2009-2010. If half of the costs were covered by the federal government, the incremental cost would be less than 1% of federal government revenues. The remaining costs could be covered by provincial governments, utilities and homeowners.
The current proposed revisions to the energy part of the National Building Code of Canada are very disappointing. Although Canada has roughly the same population as California, we do not have the same mild climate. Why are we building houses to the same insulation standards?
Reference: 1. Energy in the Built Environment, Swedish Council for Building Research, Svensk Byggtjanst, Box 7852, S-1033 99, Stockholm, Sweden
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posted Nov 1, 2010 5:03 PM by ASHRAE Saskatoon President
What is your opinion about radiant floor heating for houses?
There are positives and negatives:
On the positive side, most people seem to like that type of heating, which almost always consists of pipes carrying a warm liquid placed in the floors. To distribute the heat from the pipes to the floor surface, a concrete layer is poured around the tubes; alternatively, heat fin plates, often of aluminum, are attached to the pipes. Various floor coverings such as ceramic tile or thin wood floors have been used as the top surface. Although not ideal, radiant floors can be covered with wall to wall carpets. (A higher water temperature will be needed to drive heat through the insulation that the carpet provides.)
Here are some of the advantages:
1. The radiant floors generally have a warmer floor surface temperature, which makes the floor more comfortable in the heating season. However, in a very low energy house not much space heating is required, and the floor will generally not be very warm.
2. There is an absence of noise from creaking radiators or convectors, and there are no drafts from forced air ducts.
3. There is no smell of burnt dust from higher temperature heating surfaces, and special cleaning of the floor is not needed.
4. Compared with conventional forced air systems with conventional fan motors, the electric power to drive the liquid pump is often only about 1/5 that of the power to distribute an equivalent amount of heat by forced air.
5. With some boilers or water heaters, the same heating source can be used for both space heating and domestic water heating.
6. The water temperatures in the radiant systems can be low, and with the right kind of boiler the low water temperatures can result in higher efficiencies. (The lower water temperatures can even allow the boilers or water heaters to condense–a good thing provided the boiler or water heater is designed to handle the condensation.)
Many homes in Europe use radiant floors. I have heard that in Germany radiant floors are the system of choice for new homes.
On the negative side, there are a number of challenges with radiant systems:
1. Generally there is a substantial cost premium to incorporate radiant floor heating into wood frame construction. The concrete topping, aluminum plates, heat distribution pipes and manifolds used for the floors make for a more expensive system than a forced air system. Concrete and aluminum are also relatively high embodied energy materials compared with wood. In a multi-storey house, you generally also need some insulation beneath the radiant floor systems for good temperature control, and that insulation adds to the cost.
2, The extra weight of the concrete topping can add costs to the structural system for the house. A 38 mm (1.5 inch) thick layer of concrete around the floor piping adds a dead load of about 15 to 20 pounds per square foot. This is significant relative to the live floor loads of about 30 to 40 pounds per square foot for typical residential floors.
3. There is no ventilation air distribution with the radiant heating systems; a separate ventilation system will be needed to ensure good indoor air quality. Forced air systems do not have that disadvantage, as the ducts can carry ventilation air as well as air for heating (and cooling.)
4. A well-insulated and house does not need a lot of space heating; as a consequence the floor surface temperature will not be very warm and the "warm floor" effect will be small. For instance, to provide 3 kW (10,200 BTU/hr) of heat to a well-insulated house with 100 square metre (1076 square foot)floor area with an indoor air temperature of 22 C, the floor surface temperature needs to be only 3.6 C [6.5 F] higher than 22C. This elevated temperature would only be needed on the coldest day of the yar.
5. Inexpensive condensing boilers with a long track record of durability and longevity are not yet available. A number of builders have used residential water heaters, but the efficiency of typical water heaters is not very high compared with condensing equipment. I have heard of severe condensation occurring in some water heaters that are used for space heating with radiant systems. The problem is that the return water temperature from the floor system is cold enough that continuous condensation occurs in the flue gas chimney of the water heater. The condensation drips down and splashes on the gas burners, creating carbon monoxide and potential air quality problems. As with any house using combustion equipment, I would recommend installing a carbon monoxide sensor. Some water heaters are certified for use as both space and water heaters, and these are a better choice.
6. Night setback of temperature in the house is more complicated with the concrete topped radiant floors, as the thermal mass of the concrete delays the temperature fall in the house following setback, and prolongs the amount of time for the house temperature to recover.
7. Temperature controls for radiant floor heating systems tend to be more complicated; sometimes the systems use an outdoor air reset temperature to vary the fluid temperature in the pipes according to outdoor conditions. Untrained repair people can have problems diagnosing such a system.
8. Radiant heated concrete floors don’t work all that well with direct gain passive solar heating systems. On a cold night the radiant floor will have to be warm to deliver heat to the house. When the sun comes out and starts delivering passive solar heat, the house thermostat will call for the pump to stop delivering heat to the radiant floor. Even though the heat flow is cut off, there is a lot of stored heat in the concrete floor, and that heat combined with the passive solar heat contribution can overheat the space. I noticed this phenomenon in a newly built commercial building here in Saskatoon with a radiant floor and a large passive solar aperture. In February there was so much heat available from both the radiant floor and the passive solar contribution that the staff had to open an outside door, because the air conditioner was not set up to run when the outdoor temperature was cold.
9. It is generally more difficult to incorporate air conditioning or cooling with a radiant floor system. Some work has gone on with passing chilled water through the piping systems, but there are questions about the efficacy of that approach. A possible problem is that the floor surface temperature can go below the dew point temperature and mold will occur under carpets, furniture, cardboard boxes, etc. I would proceed with extreme caution with chilled floors, particularly in any location subject to high humidity.
10 Radiant floor systems can be very expensive to repair. One example I have heard of is an older radiant floor system in a church near Vancouver, B.C. To save money, iron pipes were used in the radiant heating system under the extensive ceramic tile floors. Several of the iron pipes have started leaking after about 20 years, and a major cost will have to be incurred to replace the entire floor system.
11 Some types of plastic piping used in radiant floor systems have had problems. At least two plastic piping systems have had major class action lawsuits associated with leaks.
For the house that my wife and I designed, I looked into radiant floor heating, but decided against it. There was a substantial cost premium, and that cost along with the fact that we wanted hardwood floors which are not very compatible with leaking pipes made us choose a forced air system.
In general I prefer to see dollars spent on improving the building envelope through better windows, thermal insulation, and air sealing rather than on heating systems. All of these expenditures on conservation will also improve thermal comfort.
However, for those who have the money and inclination, radiant floor systems can be a satisfactory heating system. They have the best cost-effectiveness when used with concrete slab-on-grade construction in buildings that don’t need air conditioning. Just don’t skimp on the underfloor insulation and be very careful about solid concrete thermal bridges to the outdoors. The property of concrete that makes it a relatively good conductor of heat from the radiant floor piping also makes it a very good source of perimeter heat loss from concrete slabs.
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posted Oct 6, 2010 2:12 PM by ASHRAE Saskatoon
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updated Oct 6, 2010 3:13 PM
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How
much insulation should you put into a new house?
There are several possible answers to that
question. A lot depends on your estimate
of the future cost of energy and on your concern for the environment. 1. Here is the “Deep Green” option. Install enough insulation for net zero annual energy use.
Putting enough insulation in a house to result in a net zero house results in a lot of insulation in Canadian houses. R100 attics, for instances, have been used in some net zero houses in Edmonton and Saskatoon. Although this approach may seem radical, consider that in the United Kingdom that all new houses starting in 2016 will have to be net zero in energy consumption. California has plans to make all new
housing as of 2020 in the net zero annual energy category.
In
our house in Saskatoon built in 1992, we put R80 insulation in the attic, R60
in the walls and R35 in the basement floor. We also used triple glazed windows
with two low e coatings, argon gas, and low conductivity spacer bars. I have no
regrets about making this investment. Gary Proskiw, a seasoned mechanical
engineer based in Winnipeg, recently completed a study with Anil Parekh of
NRCan regarding the appropriate insulation levels to use in Net Zero Energy
houses in Canada. They looked at the appropriate insulation levels to use for
Net Zero Energy houses in four climate
areas in Canada—Vancouver, Winnipeg, Toronto and Yellowknife.
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Location
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Recommended Attic
Insulation Levels
R value
(hr-ft2- F/BTU)
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Yellowknife
8500 Heating Degree Days C
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80+
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Winnipeg
5900 Heating Degree Days C
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80
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Toronto
3650 Heating Degree Days C
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80
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Vancouver
2925 Heating Degree Days C
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60 to 80
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RSI
1 = R 5.678
As expected, somewhat higher insulation levels are recommended
for colder locations. These insulation levels were chosen by using the
following criterion:
Here is a quote from the Proskiw and Parekh paper:
“To improve a building’s energy
performance, NZEH designers have two options at their disposal - various types of
conservation measures and renewable energy systems. Conservation measures have
several advantages: they are well understood, generally have an established
track record of performance, are relatively economic and are (for the most
part) durable. They can also be applied to virtually any house without major
modifications to the design or impact on the occupant’s lifestyle. Adding
moderate levels of conservation measures tends to initially produce significant
savings at modest incremental cost. However, as the level of conservation
increases, the rate of further savings declines and the costs increase. This
trend continues until a point is reached at which the cost of saving energy
using conservation is greater than the cost of producing new energy from
renewables. At this point, the designer should direct further energy
investments into renewable energy sources, even though their cost may be high
since they are still less expensive than the competing conservation
alternatives.” This
same approach was used by the designers of the Riverdale Net Zero Home in
Edmonton, who ended up with similar insulation levels. The first time that I
heard of this rigorous approach [adding insulation until the cost of energy
saved was equal to the cost of the energy from renewable energy
(photovoltaics)] was at a design charrette for the Riverdale Net Zero Home.
The
one weakness with this approach is that while insulation, properly installed,
has a nearly infinite life, photovoltaics, inverters, and solar thermal collectors do not. Thus, if anything, one would likely want to put some more insulation than those levels indicated in the above table.
The slightly more correct economic approach would be to choose the insulation levels that would result in the lowest net present value of the expenditures for insulation, renewable energy equipment, and heating equipment over the life of the house. Why this alternative? The key reason is that while insulation, properly installed, has no moving parts and nothing to wear out, will last for the life of the house, the renewable energy equipment and heating equipment must be replaced periodically.
Another side benefit of high insulation levels is that the cost of the heating system can usually be reduced. High insulation levels equal small heating systems. This approach has been championed by the Passive House (PassivHaus) movement in Europe, where over 10,000 homes have been built to this high standard. In Northern Europe, the standard heating system is often an expensive boiler. By eliminating the boiler, significant cost savings are possible.
For an excellent set of videos by a Net Zero Energy builder in Edmonton, Peter Amerongen, have a look at Youtube. http://www.youtube.com/watch?v=nxDUe4qnZtg
The videos show a lot of details that have been developed to keep the incremental costs for Net Zero houses at a minimum. To quote Peter Amerongen ,”Better housing will always cost more (initially, ed), but if we don’t focus on doing it efficiently and making the right decisions, it could be extraordinarily expensive.” Anyone involved with Net Zero housing in Canada must see these videos. Peter’s company has now completed at least three net zero energy houses in Edmonton.
2. Green Option. Select insulation levels to match the price of certified “green electricity” from your local utility.
In Saskatchewan, for example, one can purchased certified green electricity for an incremental cost of 2.5 cents per kilowatt-hour. Certified green electricity in Saskatchewan comes from Wind generation. Conventional grid electricity is about 11 cents per kWh.
3. Model National Energy Code Option
Back in the mid-90s, a model national energy code for Canada was developed. At the present time, the code is being rewritten. Hopefully the new code will more seriously address climate change and the peak oil issue than the last edition.
4. Local jurisdiction Minimum Code Values
A number of jurisdictions in Canada now mandate minimum insulation standards for new housing, and others just leave it up to the local market.
When serious national objectives are at stake, Canada in the past has not “left it up to the local market.” We now have national regulations on automobile fuel efficiency and appliance energy use. I see no reason why buildings should be exempt.
Canada will seriously miss its Kyoto target of a 6% reduction in energy use compared with 1990, in large part because of an absence of initiatives by the federal government.
Nicholas Werth recently did a study for the UK government about climate change. He concluded that a carbon tax of $200 US per tonne of carbon dioxide emissions would be needed to seriously reduce greenhouse gas emissions. At present in Europe, carbon is trading at about $20 per tonne. A ten-fold increase in the charges will be needed to bring about needed reductions in fossil fuel use.
Increased insulation levels are a simple, proven, and relatively inexpensive way to address carbon emissions and greenhouse gas emissions. Let’s get on with it.
References:
OPTIMIZATION OF NET ZERO ENERGY HOUSES
By Gary Proskiw, P. Eng., Proskiw Engineering Ltd. (pel@mts.net; 204 633-1107)
Anil Parekh, P. Eng., Natural Resources Canada BEST 2 - Energy Efficiency - Session EE3-3 |
posted Sep 7, 2010 9:29 AM by ASHRAE Saskatoon
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updated Sep 7, 2010 9:47 AM
]
Will site-generated photovoltaic energy ever be price competitive with grid electricity in Canada?
Answer.
The trend in pricing is encouraging, with declining prices for PV and increasing prices for grid based electricity, particularly in those provinces (Alberta, Saskatchewan, Ontario, and Nova Scotia) where a large part of the electricity is generated by fossil fuels, primarily coal.
In my province of Saskatchewan, the utility is predicting a doubling in the retail price of electricity over the next decade from the current price of about $0.11 per kilowatt hour.
The cost of photovoltaic generated energy, however, continues to decline. Prices are being tracked by a web site called Solarbuzz.com.
As of May 2010, the Solarbuzz web site says that in the United States, residential PV has a cost of $0.35 US per kWh and industrial PV has a price of $0.19 per kWh. Back in 2000, the residential price of PV was $0.40 per kWh. There are not many commodities that are cheaper now than 10 years ago. PV is an exception.
One of the encouraging trends with PV systems is a rule of thumb used in manufacturing. Every time that you double the volume of production of a product, you can reduce the unit cost by about 10%.
According to the Wikipedia web site, the worldwide volume of production of PV has been increasing by 48% a year since 2002. As of 2008, the worldwide cumulative installations of PV were 15,200 megawatts.
The current world use of all forms of electricity is 15 Terawatts, or 15,000,000 megawatts. With the current PV installations at about 15, 200 megawatts, PV still provides far less than 0.1% of the world’s electricity supply. The potential for growth is enormous.
Have you seen any recent Canadian installations of PV?
In May this year I visited a friend’s acreage near Ottawa. He had just connected up his 10 kilowatt peak system to the Ontario Grid. A picture of the installation is shown in Figure 1. Figure 1. A 10 kilowatt peak photovoltaic installation near Ottawa
The system is ground mounted, as there was insufficient room on the roof or walls of his house. The system cost will be paid back in about 6 years assuming there are no equipment problems. In Ontario, the owner of a small system will receive a price of 80.5 cents per kilowatt hour that is generated. Ontario is offering these incentives as a means of kick-starting a PV industry.
The modules are facing due south at a tilt angle of 37 degrees. Ottawa is located at 45 degrees latitude. The 37 degree tilt angle was based on the optimum fixed angle for year round production according to the RETSCREEN computer program. In winter there will be times when the snow must be manually removed from the panels.
Have you seen any larger PV installations in Canada?
While in the Ottawa area, I visited the very large PV installation in Galetta, near Arnprior. This system, developed by EdF-EN has a peak production of 23,400 kilowatts located on a 200 acre farmsite. This is apparently the largest PV installation in Canada. The panels use thin film technology. On these larger systems, the owner gets a reduced price of 42 cents per kilowatt hour on a 20 year contract. A photo of some of the panels is shown in Figure 2.
Figure 2. Part of the largest PV installation in Canada. The Arnprior Solar Installation.
What implications do these projects have for house design? 1. Solar PV will, over the life of most houses in Canada, become one of the least cost electricity sources.
2. All new residences should be designed to be solar ready with a south facing roof or wall surface that has unobstructed access to the sun for about 4 hours on either side of solar noon.
3. All new subdivisions should be laid out so that solar access is possible for all dwellings.
4. Solar rights legislation is needed to prevent neighbouring homeowners obstructing one’s solar panels by growing trees or otherwise obstructing the access to the sun’s rays. Japan has legislated solar rights.
5. Let’s get on with it. |
posted May 18, 2010 11:08 AM by ASHRAE Saskatoon
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updated May 18, 2010 11:16 AM
]
A Tale of Two Buildings
While in Edmonton on March 15 and 16, 2010, I had a chance to see two interesting buildings.
Grandin Green The first was a multifamily residential building built in 2000. The building is a 55 unit co-operative built on the north edge of the North Saskatchewan River valley close to downtown. Communitas of Edmonton was the Developer. The building faces south. It was completed in 2001.
I received a tour of the building thanks to Brian Scott and Lynn Hanley of Communitas in the evening of March 15, and was so intrigued I returned the next day to take some photos. Here is a photo from the south.
Grandin Green from the South
Further descriptions of the building are available at
This building is quite energy efficient compared with its peers. It consumes about 195 kWh/ m per year. For comparison, a survey of Saskatchewan high rise apartments found an average annual consumption of 410 kWh/sq.m per year. Grandin Green is thus using about 52% less energy on an equivalent floor area basis in roughly the same climate zone as the Saskatchewan multi-family buildings.
This energy efficiency translates into a dollar saving of about $150 per month per suite.
Some of the innovative features of the building include the following:
-Unobstructed South orientation - An innovative floor plan that provides each of the four suites on each floor with a generous south view -Use of Visionwall windows with their high R value, relatively good solar transmittance, excellent durability, and very good sound isolation -External shading of some of the south windows by the balconies to limit solar gain in the cooling season -Minimal windows on the north side of the building, which contains the elevator, some bedrooms, and not much of a view -Compartmentalization of the suites to minimize the stack effect and accompanying air leakage. Cross transfer of cooking odours, tobacco smoke, etc. is also greatly reduced. -A peel and stick membrane attached to the outside of the exterior gypsum board to ensure a well-sealed exterior envelope -Individual heat recovery ventilators in each suite, which ensure ventilation of each room in the suite. In addition, space is saved in the penthouse because large central equipment is no longer needed. -Mid-efficiency boilers
A view of the east entrance of the building is shown in Figure 2.
East Entrance of Grandin Green
A view of the north side of the building is shown in the following photo.
View from the Northeast
Water consumption in the building was 114 cubic metres per suite per year, a 47% reduction from the average of 216 cubic metres per suite per year for a group of 88 multi-family buildings across Canada.
In a comparison of energy use of innovative multi-family buildings across Canada, Grandin Green was found to use 36 watt-hours of energy per square meter of floor area per heating degree day. This value was slightly lower than that of three other large multi-family buildings built incorporating energy efficiency features.
The innovative features for the building were financed in an equally innovative manner. As noted in the CMHC report, “The incremental costs associated with the many innovations embodied in the building were financed through a “green” loan of approximately $20,000 per suite. The monthly interest charges per suite for the green loan are offset by the monthly energy savings.”
Some retrofits that were recommended in the CMHC Innovative Buildings Report were the use of condensing boilers, which are now (2010) more readily available, ECM motors (brushless direct current) on the heat recovery ventilators and fan coils (now also more readily available), and changes to the basement parking lot temperature setting and the common hallway ventilation.
Grandin Green is a most impressive building. Natural Resources Canada through the Commercial Buildings Incentive Program was one of the sponsors for energy innovation in the building.
A new multi-family complex, Station Pointe, is to be built in Northwest Edmonton by Communitas. The complex will build on the strengths of Grandin Green.
Art Gallery of Alberta The Art Gallery of Alberta opened in January 2010. A picture of the building from the northwest is presented in the following figure.
Art Gallery of Alberta in Downtown Edmonton
The appearance of the building reminds me of a comment, “It’s the kind of thing you like if you like that kind of thing.”
According to an Edmonton Journal article on March 16, 2010, the building cost $88 million dollars and has an exhibition space of 30,000 square feet. Assuming that the building has an equal amount of area for administration, programs, common areas, gift shop, restaurant, etc., the price per square foot is about $1500 per square foot. For comparison, new institutional buildings of a conventional nature cost roughly about one fifth that amount these days in Canada.
The gallery was closed at the time we wanted to visit, but I did take a quick look inside. Here is picture of the entrance doors:
Entrance Doors for the Art Gallery
A couple of things struck me about the “building science” aspect of the building. As you can see from the doors, they consist of single pieces of thick glass. There is no weather-stripping at the vertical joint of the two doors, and you can see daylight under the right hand door.
The chief architect for the building is Randall Stout of Los Angeles. I wonder if he has visited Edmonton in winter.
While looking at the building, I saw some workers tearing up part of the steps for the new building. The step treads and risers are not concrete but a type of cut stone. If you look carefully in the picture you can see that they have broken one of the treads while opening up the assembly.
Workers repairing the steps for the building
I asked why they were doing the work. The answer was as follows: There are pipes carrying warm glycol that pass underneath the steps. The purpose of the pipes is to melt snow. The glycol system is not working and they are trying to find the problem.
As a former researcher, I tend to look a lot at evidence and draw conclusions.
Here are a few: 1. The building envelope is incredibly complicated. We have difficulty in constructing regular buildings that don’t leak water and have condensation problems. An art gallery typically has to maintain a high interior relative humidity to meet accreditation standards, which adds to condensation problems. 2. Certain aspects of the building such as the single glazed front doors with no weather-stripping are very poorly detailed and highly inappropriate for a cold climate like Edmonton, where the annual average temperature is about +2 degrees C. 3. Using a glycol loop to melt snow is a very energy intensive operation. Most buildings in that climate seem to do fine with manual shoveling of snow. □ |
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