Archive for the ‘Small boiler experiment’ Category

Moving the dial

Friday, October 12th, 2012

Dutch Dresser

When you work on introducing a new technology to a population and region, you discover lots of intriguing impediments to that introduction that you’d never have imagined. Yesterday (October 11, 2012) the Maine Fuel Board voted to allow Maine Energy Systems to engage in an “Emerging Technologies” project with them that might lead to elimination of one of those impediments for the pellet central heating industry in the State of Maine.

Maine is unique in its licensure of technicians for “solid fuels.” In Maine a person installing a boiler must have “solid fuel” authority on his license to legally install a “solid fuel” boiler in someone else’s building. (It’s a bit more complicated than that, but let’s avoid the levels of license detail.) The need for this rule apparently arose from three potential hazards associated with “solid fuel” boilers: the possibility for a thermal run-away during a power outage as combustion continues on a load of fuel while circulation fails due to lack of power, high chimney temperatures, and high boiler surface temperatures.

As highly sophisticated automatic pellet boilers made their way into the American market, they were defined in Maine as “solid fuel” appliances because pellets are solid. While that seems innocent and logical enough, the categorization has one substantial flaw and it creates one significant impediment to product growth in the marketplace.

The Flaw

State-of-the-art pellet boilers display none of the attributes that led to the perceived need for “solid fuel” rules in Maine. The rules were devised for cordwood boilers and coal stoker boilers that can hold a significant charge of fuel at any given time. The combustion of that fuel is relatively uncontrolled. Pellet boilers burn a very small quantity of fuel at any given time, and the combustion of that fuel is highly controlled. Combustion stops almost immediately if the power goes out, hence, no excessive heat can be produced during a power outage.

Cordwood boilers and coal stoker boilers can produce very high stack temperatures. The exhaust gas temperatures from state-of-the-art pellet boilers are very much like those of modern oil boilers. In fact these boilers are so efficient, the stack gas temperature is often quite cool, 250F, or so, but it never exceeds 400F. Therefore, high chimney temperatures never occur.

Old cordwood and coal stoker boilers could develop high surface temperatures making installed distance from combustible surfaces important. The surface temperature of these state-of-the-art pellet boilers is the same as the temperature of the room. The heat exchangers are extremely well insulated to achieve the desired efficiencies. So, the worry about proximity of flammable materials due to high boiler surface temperatures is not justified with these boilers.

The Impediment

Because these highly sophisticated boilers are lumped in the same category as cordwood boilers and coal stoker boilers, “solid fuel” license holders must install them in Maine. There are many fewer “solid fuel” license holders than ordinary oil license holders, so scheduling boiler installations in this rapidly growing segment is very challenging in the busy times of the year. Other busy technicians find it hard to justify studying for a test that focuses generally on boilers they’ll never see, so they’re not inclined to prepare for the “solid fuel” test to install pellet boilers as they’re just beginning to make a mark on the marketplace.

The Emerging Technologies Project

On October 11, 2012, the Maine Fuel Board approved a request made by Maine Energy Systems for a year long project intended to confirm the company’s assertion that their boilers, and those similar to them, can be installed by oil boiler license holders who have been suitably trained in the differences between pellet boilers and oil boilers.

This is great news for the pellet industry in Maine as the State’s boiler inspectors will inspect some, or all, of these installations and, thereby, become much more familiar with these sorts of systems. If the project leads to the anticipated conclusion, the request to re-categorize the boilers for licensure requirement purposes should be reasonably received. We have little doubt that the Project will reach successful conclusion as these very same boilers are installed throughout the Northeast by the same technicians who install oil boilers and who have been trained at Maine Energy Systems in fuel handling and burner adjustment.

In the meantime, Maine Energy Systems will be training oil boiler technicians in the installation of their equipment to ensure that all who choose to install the MESys AutoPellet boiler can do it this heating season on a schedule that works for them.

Dutch Dresser is the Managing Director of Maine Energy Systems in Bethel, Maine.

Summer Pellets/Storage Emptying

Thursday, June 30th, 2011

My large, New England farmhouse-style home has served as a lab of sorts for our heating products and practices since we began installing wood pellet central heating systems more than two years ago.  Because I have received more than two years’ worth of pneumatic deliveries of pellets of various types into the chromatiq pellet storage bag in my typically damp Maine basement, I recently decided to empty my storage bag to see what two years of deliveries and several seasons of high humidity had left for residue in the bottom of the bag.  Dust does not move as quickly down a storage unit as pellets do, so it can accumulate over time.  To my delight, the bag emptied fully, including whatever dust may have been in the bottom through my auger system.  Everything burned leaving no residue for cleaning.

My boiler is now in “summer mode.”  In this mode, the burner starts only when my domestic hot water tank demands heat.  The pellet boiler runs once, or twice, a day depending upon water usage in the house.  My summer pellet consumption will be very small, indeed.

Following the bag emptying, I filled the storage unit with pellets for my summer and fall use.  I received 2.5 tons for $587.50 ($235/ton).  That quantity of pellets has the energy of 300 gallons of #2 heating oil for which I would have paid $1,170.00 on the market here in Maine today ($3.899/gallon).  This load of pellets will last me deep into the fall when I will top off for the serious heating months.  I will use about 10 tons of pellets during the coming calendar year.

With Maine Energy Systems pellet prices guaranteed (for new boiler customers) at not more than $239/ton through June of 2014, customers like me can be assured of savings of 50%, or more, over #2 heating oil in Maine over the next three years.  For me that will represent a savings of approximately $7,050 over the next three calendar years, assuming oil does not exceed its current retail price.

Add to this the fact that virtually all of the $2,350/year I spend to heat my house and hot water will remain in the regional economy, and I’m feeling quite good about the heating solution I have chosen and the one I help make available to the Northeastern United States.

Needing more heat

Thursday, January 7th, 2010

As I’ve reported in earlier blogs, my large, old farm-style house in Bethel, Maine, was heated experimentally last winter with a four-section pellet boiler. The Janfire-fired system is rated at 23 kilowatts, about 51,000BTU/hour. The system heated the house to our satisfaction pretty well last winter with the exception of a few “design days” when outside temperatures dropped below zero. On those days, we were faced with a house at, or below, 60 degrees F, or burning a bit of oil to support the pellet boiler.

During this past Christmas seasons, my 86 year old mother joined us for two weeks. Our standards for suitable heating (67F, or so) didn’t work for her, so we needed to try to keep the house at 70F at a minimum. The little boiler fired at capacity much of the season to meet the demand and was generally successful. However, on days when single digit to sub-zero temperatures struck, there was no way. The boiler is just too small to fill that demand largely due to heating time lost to the ashscraping cycle of the top-fed burner. To meet the need, I set the oil boiler to fire when water temperatures dropped to 160F. All worked well; the boiler fired occasionally, generally following an ashscrape cycle when water temps would drop below the target level. My mother was warm and little supplemental oil was burned. During the past heating season, I used a total of 40 gallons of supplemental oil.

It is my assumption that a small boiler of the same capacity of an underfed pellet burner design that did not require lost time to ashscraping would meet my demand without support from the oil boiler. It would be fun to test the assumption.

Because I’ve been able to use an extended ashscrape cycle due to the improvements in pellet quality, I haven’t been cleaning my boiler as often as I did last year. That’s been a mistake. In this particular Bosch/Janfire system there is ample opportunity in the cast iron boiler for ash to reduce boiler efficiency. I’ve returned to a two week cleaning cycle for this boiler to keep efficiency up and pellet consumption down.

In the interest of full disclosure, Dutch Dresser is the Managing Director of Maine Energy Systems which sells both the Bosch/Janfire system referenced here and the more advanced AutoPellet systems made under license from OkoFEN of Niederkappel, Austria.

Domestic hot water from summer pellet burning

Monday, September 14th, 2009

In the interest of full disclosure the author is a Director of Maine Energy Systems.

I am often asked what I do about domestic hot water in the summer since my house is heated with a MESys pellet boiler system. The answer is, “I burn some pellets” just as I have burned some oil to create hot water for decades.

The follow-on question is always, “how many wood pellets does it take?” In a single case sample, my own, I have found an answer. Three adults live in my house full-time, one a college-aged son who loves long showers. We have frequent overnight company, including the families of four of our older son and our daughter. We use a washing machine and dishwasher as anyone does, and we’ve made no particular water reduction modifications to our house so our hot water consumption is probably typical for Americans like us.

My system contains an indirect hot water tank, which I keep adjusted to 180F during the heating months. During the non-heating months, I’ve reduced that setting to 120F, so the boiler fires at low level or in “keep alive” mode most of the time.

This summer, since the end of the heating season, I have averaged 20 pounds of pellets/day for the heating of water using my MESys 4000/Janfire system. At $270/ton that places my average daily hot water costs at $2.70, or the cost of a bit more than a gallon of #2 heating oil.

Ideally, I would have solar panels on my barn roof to further reduce combustion of any sort for the production of domestic hot water, but that will have to wait a bit.

Dutch Dresser

There is a limit…

Friday, January 16th, 2009

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Last night the weatherman on television was delighted to be able to report that we would see low temperatures like we haven’t seen for years.  In some ways, this was good news to me; I’d get to see how the little pellet boiler would do in our big, old house in very cold weather.  Not wanting to risk any frozen pipes, I adjusted the AquaStat on the oil boiler to kick in if the water in the system dropped below 150F.

Today's temp

Today's temp

At 6:00 a.m. today, my thermometer said -30F.  The house was at the temperatures we customarily keep, and the kitchen was cool, as it generally is during hard cold snaps.  There is insufficient fin tube in the kitchen to heat it effectively in very cold weather and it faces northwest.

I heard the oil burner kick on and run for about five minutes indicating that water temperatures in the system had dropped below 150F.  When I go up, I checked the systems, and the MESys 4000 had a boiler temperature of 172F despite the fact that all five zones in the house were calling.

Showers, morning dishwashing, and keeping up with the house dropped the water temperature below 150F once more giving the oil burner another four or five minutes of catch up.  For the balance of the day, no oil burner time was required, and the house stayed at its usual temperatures.

I gained confidence that the little boiler would have kept the house from freezing on those conditions, but layered clothing would also have been a good idea.

Dutch Dresser