A group of U.S. Senate chiefs of staff from Wisconsin, Connecticut, West Virginia, Indiana, Alaska, New Hampshire, & Mississippi visited CCHRC in August to see our facility and research. Their visit to Alaska focused on energy and climate change.
Is it just us, or is this summer going fast?
As the daylight wanes to only 18 hours a day, we are getting situated to capture this heat at the Sustainable Village. The solar collectors are up on the northeast and southeast homes, which both have three 4-foot-by-10-foot collectors mounted on the south-facing wall just under the roof. The system will feed heat into radiant tubing in the concrete floor slabs, and will also dump heat into a 120-gallon solar storage tank in the house. We are adding temperature sensors and flow meters to each system to monitor how much heat is used.
Also, the homes have skin (for the most part), i.e. metal siding. Two green, one blue, and one gray with patches of other colors and salvaged dredge pipe. They look cheerful and also at home in the spruce forest.
It’s easy to get lost in the jargon when shopping for a boiler or other home heating appliance. This article covers some of the common terms you may encounter when shopping for a combustion boiler. If you have questions about what type of boiler is best for you, be sure to talk with a heating professional.
Most oil boilers are mechanical draft boilers, which use a fan to draw in combustion air. There are two main methods of mechanical draft that are common in residential models.
–Induced draft uses a fan to remove flue gases from the furnace and force exhaust gas up the stack (and usually operate at a slightly negative pressure).
–Forced draft uses a fan and ductwork to force air into the furnace, and usually operates at a slight positive pressure.
In mechanical draft boilers, the fan also creates turbulence in the combustion chamber, allowing for a more complete burn. These are typically more efficient than natural draft boilers.
Natural draft boilers rely on the buoyancy of hot combustion exhaust. The exhaust is hot, so it rises passively out of the flue. As the hot exhaust gases exit upwards, the draft causes fresh air to enter the combustion chamber. Because natural draft boilers consume a large amount of air in this process, they are less efficient than mechanical draft boilers. If the air pressure inside the house is less than the air pressure outside, a natural draft boiler can backdraft and poisonous gases such as carbon monoxide could potentially enter the home.
Examples of natural draft heaters are propane water heaters and drip-oil stove heaters.
Sealed combustion boilers use a duct to bring in outside air directly to the combustion unit and not from inside the house. The combustion chamber (where burning occurs) is sealed off from the inside of the home. These boilers are safest, because they are unlikely to backdraft poisonous exhaust gases such as carbon monoxide (CO) into the home.
Condensing boilers are more efficient than standard combustion boilers. A condensing boiler is able to reclaim additional heat from the exhaust gas by cooling it to a point where water vapor from combustion condenses out. The condensation releases the latent heat from the gas, and this heat is captured by a second heat exchanger. The condensate water is acidic (it has the same acidity as some vinegars), so corrosion-resistant materials like stainless steel or PVC pipe must be used for the heat exchanger and pipes. Condensing boilers must have a drain that allows the water to enter the wastewater plumbing system. In older homes with pipes that could corrode, a neutralizing filter can be added to the drain line. These boilers also have a fan to blow the cooler exhaust gas, which is not buoyant enough to exit the flue on its own, outside the building.
Non-condensing boilers are less efficient because they have to operate at higher temperatures to prevent condensation. However, they do not require a drain and can be made of materials such as iron, steel or copper that would eventually corrode in a condensing boiler.
High mass boilers are very heavy, as the name implies. The mass comes from a large heat exchanger, which contains heavy metal, often cast iron, and large diameter pipes that contain a high water volume. The high mass design helps the boilers maintain steady state efficiency. These boilers take longer to heat up when they are started, so they should not be short-cycled, or turned on and off frequently, as this will lower their efficiency.
Low mass boilers have a smaller heat exchanger that does not contain a large mass of metal or iron. While short-cycling a boiler (or turning it on and off frequently) is never ideal, a low-mass boiler will generally respond better than a higher mass design, as it takes less time to heat up. These boilers also have less standby loss when they cool down, because they do not have the mass to retain a lot of heat while firing.
During Week 12, we insulated walls of the second house with six inches of fiberglass batting on the inside and 8 inches of foam board on the outside. We also blew two feet of cellulose insulation into the roof of the first two homes. Cellulose is made from recycled material like newspaper and cardboard.
We also began installing windows in the homes. All windows are triple-pane, low-e argon filled, designed to minimize heat loss and avoid condensation in an extreme climate.
Each home will be sided with a different color combo, with a mix of metal siding and recycled steel pipe.
Do you seek a different style of on-campus life? Do you want to know how to grow your own food? Are you excited about monitoring and reducing your energy consumption? Are you aware of your personal carbon footprint? If you answered yes to these questions, consider applying for residency for the 2012-2013 academic year at the UAF Sustainable Village!
By Cornerstone on June 15, 2012
The UAF Office of Sustainability is now accepting student applications for residency for the 2012-2013 academic year at the new UAF Sustainable Village. This opportunity is for students seeking a different style of on-campus life, wanting to know how to grow your own food and monitoring and reducing energy consumption.
The UAF Sustainable Village, UAF’s newest student housing, is a student-led and -driven initiative. Students have been integral to all stages of the process: from concept to design to construction. It is a demonstration of environmentally sustainable technologies in a residential setting and will provide hands-on experiential learning opportunities. Students will collect and disseminate information about sustainable building and living best practices, and encourage others to live in a more sustainable way.
The Sustainable Village is open to UAF students, sophomores through graduate. Students interested in living in the UAF Sustainable Village for the 2012-13 academic year need to complete this form and attach a signed UAF Sustainable Village Social Contract /Agreement. Selection is based on application and an interview with the Sustainable Village Committee.
Students interested in being part of the innovative, nationally recognized Sustainable Village and feel personally committed to sustainability, are encouraged to sign up. For more information visit the Sustainability Village website for more information or contact sustainability director Michele Hebert at email@example.com or 907-388-6085.
The state of Alaska invested an estimated $110 million from 2008 to 2011 on extra insulation, new boilers, air sealing, and other retrofits for roughly 16,500 homeowners—about 10 percent of all homeowners in Alaska.
The Home Energy Rebate Program provides funding to help homeowners make their houses more energy efficient. CCHRC recently worked with the Institute of Social and Economic Research to look at the economic impacts of the program. The study, funded by the Alaska Housing Finance Corporation, showed homeowner investment, fuel savings, payback periods, job creation and more. Here are some highlights:
· Total spending for energy efficiency improvements was about $185 million, with state rebates covering 60 percent and homeowners 40 percent. Homeowners should recoup their investment in roughly 3.5 years. State and private spending will be returned in homeowner savings in less than 9 years.
· Annual fuel use dropped an estimated 33 percent for households who participated. The average homeowner will save an estimated $1,300 a year on fuel (or 26 percent).
· Every $1 million in state spending generated 12 Alaska jobs—7 direct retrofitting jobs and 5 indirect jobs—amounting to about 1,330 jobs.
· Overall, participants are saving an estimated $22 million annually. If they spend those savings locally, every $1 million in new household spending generates 11 jobs throughout the state economy—an annual average of about 240 jobs.
· The biggest money savers were more efficient boilers or furnaces (constituting 50 percent of energy savings). Adding extra insulation to walls, doors, and ceilings made up 25 percent of savings; sealing air leaks accounted for nearly 15 percent of savings; replacing windows and water heaters comprised 10 percent of savings.
· Anchorage homes made up 49 percent of retrofits; other Southcentral communities 27 percent; Fairbanks 14 percent; and Juneau 6 percent.
The full snapshot is available here.
*Changes in fuel costs and savings are estimates from AHFC’s energy-rating software as actual household heating bills aren’t currently available.
Workers began adding exterior foam to the homes, which will all have some version of a REMOTE wall-meaning the majority of insulation goes outside the vapor barrier and sheathing (learn more about the wall system here). Three homes will be insulated with 8 inches of EPS foam board and one will be filled with cellulose, for an R-value of 60 apiece. We also sprayed a foot of polyurethane foam insulation under one of the raised pile foundations, for an R-60 floor.
We trenched the communications lines and electric, and finally turned off the generator! Next up is spray foaming the rim joists, finalizing plumbing and electric, and hanging Sheetrock, which will probably begin later this week.
Many people focus on the building envelope – the amount of insulation in the roof, the R-value of the walls, how many panes the windows have. Others think first of appliances – is the refrigerator certified as an ENERGY STAR appliance? What is the efficiency of the boiler? Does the hot water heater have a high energy factor? Are the lights incandescent bulbs, LEDs or CFLs?
Certainly all of these things have a role in making buildings energy efficient. However, there is an even more important factor that is often overlooked–the behavior of occupants. An oft-repeated saying in the building industry is “There is no such thing as a zero-energy home, just zero-energy homeowners.” Efficient buildings can’t reach their full potential if residents have energy-intensive habits. On the other hand, inefficient buildings can see large performance improvements just by changes in residents’ habits.
There are two main parts to energy efficient behavior: the types of appliances you buy and the way you use them. For example, do you own a large-screen plasma TV or a modest one? Both your consumer decisions and pattern of use play into your personal energy efficiency. For example, if you buy a 15-watt CFL floodlight and keep it on all the time, you may still actually use less than a 75-watt lamp that you turn off when not in use.
When it comes to your habits, remember what your mom and teachers probably used to tell you: Turn off lights when leaving a room; don’t leave the faucet running when you brush your teeth; take shorter showers; and put on a sweater instead of turning up the thermostat.
Changing habits can be difficult or uncomfortable, however, so there are also other options.
Many behavior elements can be addressed with technology:
· If you constantly forget to turn out the lights, or find yourself leaving on an outdoor light for hours while waiting for a spouse to come home at night, consider installing lighting controls. Motion sensors that can turn on and off lights are available for as little as $30 at home improvement stores.
· Programmable thermostats can be used to turn down the set temperature automatically while residents are away at work or asleep, and turn up the set temperature when residents are at home and awake. They can be programmed in 5 minutes – and offer savings on heating bills throughout the winter with no extra work.
· Do you have a number of devices plugged into the wall (phone chargers, TV, computer, etc.)? These devices draw a small baseline amount of current, called a phantom electrical load, as long as they are plugged in – even when they are turned off. Remembering to unplug everything can be difficult, but there are solutions. Plugging everything into a power strip means you only need to turn off one switch. Also, a smart power strip will shut off the current to peripheral devices such as a monitor and speakers when a central device, like a computer, is turned off.
· Do you have an electronic calendar on your phone or attached to your email? Use it to add automatic reminders for maintenance tasks, such as the yearly check-up on your heating appliance, or changing filters on a forced air distribution system. Remembering basic maintenance tasks improves the efficiency of equipment and prevents breakdowns.
· If you need to replace an appliance anyway, consider purchasing an Energy Star-rated one.
How else can you make your home more energy efficient? Go to www.cchrc.org or the website or Golden Valley Electric Association (http://www.gvea.com/resources/save) for more ideas.