Meet the Teams: Canada’s largest stove company looks to the future in automated stoves

This post is the third in a series introducing the 12 teams participating in the 2018 Wood Stove Design Challenge in November.

By John Ackerly and Shoshana Rybeck, Alliance for Green Heat 

The SBI team 

Stove Builder International (SBI) built the innovative Osburn Volta pellet stove in 2012 and made important strides in understanding how sensors can control combustion. The Volta is unique in that it runs on direct current (DC) when all other pellet stoves run on the normal household AC current. The Volta has its own battery pack and can be easily integrated with solar power.

After seeing the announcement for the first Wood Stove Design Challenge, SBI knew that it could convert skills and lessons from the Volta to an automated cord wood stove. Their prototype was not ready for that competition, but lead engineer Nicolas Gagnon attended the 2013 event and was excited by what he saw.

Guillaume Thibodeau-Fortin, an SBI mechanical engineer, believes that wood stove automation is likely to be one of the main trends in stove manufacturing in the future. But finding the time and resources for the R&D was tricky. Guillaume started working at SBI in 2013 and knows that stove buyers are price conscious and they need to see far more value in an innovative stove than its ability to burn clean.

SBI’s location in Quebec, the French speaking part of Canada, gives them more insight and interaction with the European stove market where small, vertical stoves are more popular and where more companies are experimenting with automation. SBI’s headquarters is also not far from Montreal, North America’s largest urban area experiencing severe wood smoke issues. If there is any major North American city that needs a cord wood stove that can run reliably clean in the hands of consumers, it's Montreal.

“So we designed this for multiple reasons—not just to build a stove that operates cleanly in our customer's home. Automation also serves to improve safety, efficiency and ease of use,” Guillaume said.

The Technology

The stove is built on two radically new ideas. The first is that the stove automatically finds the optimum combustion conditions. That is a core goal of all modern combustion, whether it’s in a car, a power plant, or now, a wood stove. The second is connecting that stove to the operator to engage, inform and educate the operator to better perform his or her roles.

Final model of the stove

A key problem with appliances that need periodic operating adjustments is educating the owner. Printed owner's manuals are often not good education tools, even when they are read and reread by the operator. The SBI stove is connected via Wi-Fi to a smart phone, and Guillaume’s vision is to transfer the old fashioned owner’s manual into a far more appealing, usable and effective interface on the phone. The stove can alert the operator when it’s time to reload for example, and instructions will appear that can include a link to a video about how to tell if your wood is dry.

To automate the stove, the first step was attaching a temperature sensor, but the key was to correlate data from the thermocouple with a static pressure sensor. Utilizing an oxygen sensor could have been better but the pressure of keeping down costs steered the team away from that strategy. The team then turned to computational fluid dynamics to track and predict gas activity in the firebox. 

Efficiency and particulate matter emissions are focal points of progress for wood stove design. With better efficiency, PM is usually reduced as combustion is more complete and therefore cleaner by nature. However, the opposite condition is not necessarily true, as emissions can be reduced by adding oxygen which ultimately penalizes efficiency. SBI is paying closer attention to efficiency, which many stove manufacturers did not do in the past, but ultimately, it’s the PM level that determines if a stove can go to market.  

Electronic board in the stove

SBI’s model for increased efficiency relies on sophisticated control of the primary air inlet and a digital user interface that is connected through Wi-Fi on the user’s mobile device. The stove includes three burn rates, low, medium, and high, and is set to each level via a mobile application. To achieve the user-set burn rate, the automatic stove then takes over, using temperature and static pressure sensors to open and close the air inlets and run a motor that adds primary air in or blocks it out depending on how high combustion is and what level the user would like. While the user has control over the desired heat output, the user does not actually have the ability to change the stove's air flow to raise or lower the burn rate mechanically. The inlet for the primary air cannot be opened or closed by the operator, unless the stove is running cleanly, and if so, the stove will respond in real time to the operator’s changes. If the stove is not burning cleanly, it will first get to a cleaner burn before getting to the desired heat output set by the operator.

Setting the heat level from the comfort of your couch via their mobile device should appeal to many customers. Knowing that you don’t have to periodically check to see whether you have given the stove too much or too little air should give everyone in the house more peace of mind. If the main person who operates the stove is out, the person who adjusts the stove doesn’t have to worry about over firing, making stove smolder, or putting out the fire. The internal temperature and static pressure sensors will bring the stove to the desired heat level in the safest and cleanest manner. 

When we spoke to the President of SBI, Marc-Antoine Cantin, about the development of an automated stove at the HPBA Expo in Nashville, we were struck with how hands off he was with the R&D process on the automated stove. He gave Guillaume and his team the autonomy and support to go through the multi-year process of developing a stove that the company can stand behind. To us, this indicated a company that is big enough to support engineers working on tangential, forward looking projects and an engineering team that has built the trust of management.  

While introducing an efficient, and user-friendly automated wood stove to the market is important, SBI understands that people are first and foremost looking for an affordable and reliable form of renewable heat. When designing and creating their model, the concept of affordability was always key. One of the three head engineers on the project said, “keeping it simple is best for efficiency and the bank.” For them, the 2018 Wood Stove Challenge is giving them the platform to challenge their engineering skills in order to prepare for a cleaner wood burning future.

Contact the team

Guillaume Thibodeau-Fortin
gthibodeaufortin@sbi-international.com

Maxime Legros
mlegros@sbi-international.com

Nicolas Gagnon
ngagnon@sbi-international.com

A Brief Analysis of Stoves at the Wood Stove Decathlon

The danger of naming a winner at a competition like this is that the many achievements of the non-winners receive little focus. Here we list the top 6 stoves in each category: Overall Performance, Innovation, Affordability, Particulate Matter Emissions, Efficiency, Market Appeal and Carbon Monoxide Emissions. We try to note the trends between stove classes and the stand out performances of stoves that did not win prizes.

The scoring was done by nine judges. Three of the areas -- PM emissions, efficiency and CO emissions -- were scored only by the testing equipment, meaning the judges had no discretion to change the grade of the stoves for those three areas. Each stove was tested at least two times. For more on scoring see: http://forgreenheat.blogspot.com/2013/11/how-stoves-are-scored.html

OVERALL

1) Woodstock Soapstone
2) Travis
2) Wittus
4) Intercontinental
4) Ecolabel Tile Stove
4) Hwam

Woodstock Soapstone

The Grand prize went to a finely tuned, naturally drafting catalytic wood stove without any electronic controls. In fact, the winning Woodstock Soapstone hybrid is very similar to the design of one of the second place stoves, the Cape Cod by Travis.  Wittus is also a naturally drafting steel stove that has a unique downdraft burn into a lower chamber. Technically, this is a non-cat stove, but its design has little in common with the traditional non-cat stoves on the market today.

The fourth and fifth top overall stoves were masonry stoves, and while they did not take home any prizes (due to their high pricetags and perceived lack of innovation, as the underlying designs and principles are so old), it is clear that they performed extremely well overall.  Two of the top 6 stoves overall had electronic sensors and computers.

INNOVATION

HWAM

1) HWAM
2) Wittus
3) IntensiFire
4) Woodstock Soapstone
5) Mulciber
6) Travis

The two top innovation scores went to a Danish stove and a German stove.  First place went to the Hwam Autopilot stove with its onboard computer and oxygen sensor. If testing lasted many hours, not just 15 minutes, these features would have likely helped the stove receive higher overall points. The stove also alerts the homeowner to the optimum time to reload and how much wood to reload. There is no control on the stove for users to adjust; they can simply load it and leave, knowing that the stove will do the rest.

The IntensiFire claimed the number 3 spot because it is a relatively simple, elegant solution for old, uncertified stoves. And Mulciber, the University of Maryland stove, took 5th place with a pressurized, fan driven combustion chamber and co-axial stack.

AFFORDABILITY


1) Woodstock Soapstone
2) Walker Stoves
2) IntensiFire
4) SmartStove
5) Travis
6) Intercontinental

Tom Morrissey’s hybrid Ideal Steel from Woodstock Soapstone is clearly a great value given its size, BTU output and performance. The company has committed to retail it for $2,000 and hopefully that doesn’t mean it’s a loss leader for the company. The Walker stove, a hybrid rocket stove that can be made with more thermal mass, also impressed the judges and has lots of potential to get on the market for less than $2,000.

This is the one area that the SmartStove appears in the top 6 rankings for its control system that can automate virtually any non-catalytic stove, significantly reducing its overall emissions for about $200 on top of the stove price.

PARTICULATE MATTER EMISSIONS

Mulciber

1) Mulciber
2) Intercontinental
3) Woodstock Soapstone
4) Wittus
5) Ecolabel Tile Stove
6) Travis

In the emissions category, seen by many experts as the key goal of high performing stoves, the underdog team from the University of Maryland took a surprising first place with a least one run where the PM 2.5 particulates were so low they were barely measurable. The students used a home-made catalyst and a unique self-cleaning particulate trap to achieve these results.

Again, the masonry stoves did very well along with the other catalytic stoves. The Travis Cape Cod has the lowest PM measurement of any certified wood stove at .45 grams an hour, one tenth of the more stringent Washington State limit, when tested with dimensional lumber.

EFFICIENCY

1) Wittus
2) Tulikivi
3) Ecolabel Tile Stove
4) Mulciber
5) Intercontinental
6) IntensiFire

Wittus

All the masonry stoves performed extremely well in the efficiency category, even though the top spot went to the downdrafting German Wittus stove that has a relatively small firebox. Since efficiency is measured using a stack heat loss method, the masonry stoves could lose most of their heat to the masonry mass before exiting the chimney. The University of Maryland’s Mulciber stove often had stack temperatures around 200 degrees, half that of some of the other stoves.

What is surprising here is that neither the Woodstock Soapstone nor the Travis placed in the top 6, even though they have 3rd party efficiency testing that rates them around 82% in the EPA wood stove list. This could mean that these other stoves could hit efficiencies even higher, around 84 or 85% using the EPA’s B415.1 test, or it may simply mean that the efficiency testing and methodology at the Decathlon favored masonry stoves or was not good enough to measure very minor differences between very efficient stoves.

Travis

MARKET APPEAL

1) Travis
2) Wittus
3) Woodstock Soapstone
4) Ecolabel Tile Stove
5) Hwam
6) Tulikivi

The more polished stoves that were already in production won out here, with the catalytic and masonry stoves vying again for top spots. The judges appeared to vote based on what they thought was likely to appeal to the average consumer based on aesthetics, without regard to price.

CARBON MONOXIDE EMISSIONS

1) Travis
2) Woodstock Soapstone
3) Tulikivi
4) Tile Stove
5) Intercontinental
6) IntensiFire

Again, this category was a battle between the catalytic stoves and the masonry stoves, with the catalytic stoves taking the top spots. The University of Maryland team also used a catalyst but insufficient air on at least one run hurt their CO levels. It is noteworthy that the IntensiFire made it into the top 6, given that it used a very simple, affordable change to an old, uncertified stove.

Consumer Reports Rates Chain Saws

Heavy-Duty Gas

Think it’s hard to decide between industry leaders Stihl and Husqvarna? Well, so does Consumer Reports magazine. But in the October 2013 issue, Stihl edged out Husqvarna on performance and price, garnering a “CR Best Buy”. The Stihl MS 180 C-BE (or the 181 C-BE) got CR’s top rating, and cost only $230.

These two top performers both weighed 11 pounds and had 16 inch chains. The Husqvarna 435 440E came in second at $270. Third and fourth place went to Echo, and a Poulan Pro came in 5^th at $180.

Light-Duty Gas

Among the light duty saws, the Craftsman 34190 (made by Poulan Pro) came in top, at $150 and the Homelite UTI0589A second at $160. The light duty saws were no lighter in weight, and sometimes were heavier than the heavy-duty saws. Their chain length was also the same, either 16 or 18 inch.

Corded Electric

The top ranked corded electric saws performed as well as the light-duty gas saws. The best, the Worx WG303.1 cost only $100 and weighs 11 pounds. It sawed as quickly as some light duty models and spared you the hassle of refueling, pull starting and tune-ups.

Consumer Reports did not provide any information on repair history. For the complete CR story you may have to be a CR subscriber: http://www.consumerreports.org/cro/chain-saws.htm?loginMethod=auto

Now for advice from the Alliance for Green Heat: Even if your wood stove can take an 18 or even a 20 inch log, considering cutting lots into lengths of about 14 to 16 inches, especially if you're planning to burn it in the next few months (less than 6 months). Shorter, split pieces of wood will dry faster, and give you more usable BTUs from each log. And remember, you need to split the wood as soon as possible to really start the drying process. Un-split wood does not dry well and can double the time it takes to season the wood. The EPA's Burn Wise program's Best Burn Practices notes, "Wood burns best when the moisture content is less than 20 percent. You can purchase a wood moisture meter to test the moisture content of your wood before you burn it."

Do Electric Rates Impact Wood Heat?

Electric heat is clean in the home,
but not when its made and line
losses are significant.

When the price of oil goes up, it goes up for everyone.  But electricity rates vary widely by state with residents of some states paying double what they pay they other states.  New York and Connecticut saddled with the highest electricity rates in the country, which may have contributed to the rapid rise of wood heating in those states.  Conversely, in the south where electricity rates are the cheapest, the use of wood heat decreased in most states between 2000 and 2010. 

Electric heating has surged in recent years – though not as fast as wood heat – in part because of more efficient heat pumps.  Residential geothermal heat is slowing gaining traction but requires a lot of electricity to pump the heat from the earth through the home, leading some experts to regard it simply as very efficient electric heat, not as a renewable. (Electricity for geothermal heat costs an average of $10.43 per million Btus compared to $12.63 per million Btus if you purchase cordwood.)

The economic disadvantages of fuel oil and propane as heating fuels are often discussed, but electricity is a more complex story.  More than a third of American homes use electricity as the primary source of heat (US Census) and another 24% use it as a secondary heat source (EIA).  Granted many of them are in the south, where the heating load is smaller but more northern states can have surprisingly high rates of electric heating.  For example, 15% of homes in Connecticut, where electricity is second in price only to Hawaii, primarily use this form of heating (US Census).  

An electric boiler costs an estimated $35.05 per million Btu, according to EIA, and an electric space heater, a common appliance used for secondary heating, costs an estimated $34.32 per million Btu.  An EPA certified wood stove running at 72% efficiency, in contrast, is estimated to cost only $12.63 per million Btu.       

These EIA calculations assume that electricity costs only 11 cents per kWh.  However, half of the U.S. averages more than that amount.  In northeastern states such as New York and Connecticut where electricity costs over 17 cents, the cost of using an electric heater can be as high as $56.42 per million Btu.  This may make consumers think twice before buying an electrical space heater instead of a wood stove as a secondary space heater. 

Map of average U.S. electricity prices by the Alliance for Green Heat. Click to enlarge.

Consumer rates in Alaska, California, Maryland, New Jersey and Washington DC are on the high side, ranging from 14 - 17 cents per kWh (an average of $41 - $50 per Btu for electric heating).  The majority of homeowners in the south, west and midwest pay 9 - 13 cents per kWh for their electricity, which works out to about $26 - $38 per Btu.  That is a much cheaper rate than some states, but still twice the cost of heating with wood.

Pacific northwestern states with a strong hydro-electric presence and Appalachian states with an abundance of coal typically average electricity costs below 9 cents per kWh.  Idaho has the cheapest average electricity rate of any state at 7.99 cents per kWh, thanks to low demand and a large number of dams on the Snake River.    

To compare heating fuel costs in your home, download the EIA’s comparison calculator here: www.eia.gov/neic/experts/heatcalc.xls  

Case Study Finds Wood Costs Least of Alternative Energy Sources

 The Cumberland times ran an article yesterday titled "Don't Knock Wood as an Energy Source" discussing how Derrick Bender, University of Maryland Extension educator, is in the middle of a case study comparing the cost of using wood, wind and solar as alternative energy sources. The laboratory? A house in Cumberland, MD that has solar panels on one side, two wind turbines on the other and a wood-burning furnace in the garage.  

"According to numbers crunched thus far by Bender, a homeowner who self-installs a furnace and cuts his or her own wood will pay a little more than 4 cents per kilowatt hour. Having the furnace installed, but cutting own wood increase the cost to almost 6 cents per kWh. Having the furnace installed and buying wood jumps it again, this time to almost 13 cents per kwh.

On the other two hands, the cost for wind is almost 29 cents and the tab for solar almost 33 cents."

Bender will present a free workshop on Feb. 7, from 7 to 9 p.m., titled “More Heat, Less Firewood.” You can read the full article here.

New Zealand Study Finds Wood Pellet Heating Improves Health for Low-income Families (excerpts)

Last week in New Zealand, the Productivity Commission released a Housing Affordability Report.  The report included a review of a housing, insulation and health study involving 1,400 households from seven regions. It showed dramatic health improvements brought about by interventions such as replacing inefficient electric heaters and unflued gas heaters with heat pumps, wood pellet burners and flued gas heaters. These positive effects were more marked for low-income families. 

In New Zealand, excess moisture is a major problem leading to mold and ill-health effects and the dry heat produced by pellet stoves was an excellent remedy.

One of New Zealand's leading researchers on inequality in health and housing, Philippa Howden-Chapman, pointed out that the lowest income families spend about 13 percent of their income on heating, while the wealthiest only about 2 percent. Around 1600 extra people die in winter than in summer due to poor housing and a lack of heating.

Lack of affordable housing and heating is not a new phenomenon.  Two thousand years ago a pregnant woman and her carpenter husband could not find adequate or affordable lodging, and the woman had to give birth in a manger. 

For the full story:

http://www.stuff.co.nz/nelson-mail/opinion/columnists/teresa-o-connor/6173976/Stressmas-rams-home-key-themes

Top Four Reasons to Use a Wood Stove

So why are we so crazy about wood burning?

4. The technology is not what your grandpa remembers! Modern stoves emit less particulate matter pollution than fireplaces, and pellet stoves emit next to nothing. Sometimes there's a stigma attached to wood burning, but that's only because back in the day stoves simply weren't as advanced as they are now.

3. It's part of a diversified energy efficient future! Any expert will tell you that we cannot rely on any single energy source for our nation. Every area and every energy usage has a different set of needs and suitable sources. Unlike solar and wind power, direct wood combustion is the most efficient use of wood energy.

2. It's clean and renewable! When sustainably harvested, wood and wood byproduct heating fuel is carbon-neutral, and can easily reduce your carbon footprint by 2 to 4 tons per year. Plus, it only takes a few decades to grow a tree compare to a few millennium to make fossil fuel.

1. It's affordable and stable! With ever fluctuating high fuel prices, traditional fossil fuel heating systems drive up energy expenditures substantially. Wood and pellet prices don't fluctuate as much, and are always cheaper. Plus, the upfront cost of installation is significantly less than wind, solar, or geothermal.