Bill McGrath: A pioneer in making electricity from a pellet boiler


Bill McGrath

In 2007, Bill McGrath built a thermoelectric pellet boiler that heated his home for almost 10 years. The story, however, starts in 1998, when Bill and a group of other students at Vermont Technical College entered the “American Tour de Sol” Solar Challenge, a solar car competition sponsored by DOE, not unlike the Wood Stove Design Challenge. The competition taught him about solid state technologies and the important role DOE competitions can play in promoting innovation. 


Building on his own experience and Shuji Nakamura’s discovery of commercially viable LED lighting, Bill helped start LEDdynamics in 2000, an LED circuit and lighting manufacturer. However, in the back of his mind he was also thinking about how thermoelectric generators (TEGs–pronounced T-E-G, like L-E-D) could solve a major problem with pellet stoves and boilers: when the electricity goes out, unless you have a big battery or generator, the pellet stove stops operating.

Bill and his colleagues made the TEG powered pellet boiler from an old oil boiler, a washing machine and other various knickknacks. McGrath recalls turning the fire chamber of the old oil burner into a pellet stove, using metal cat food dishes from the dollar store as burn pans, and using an old washing machine as the hopper by shaping it into a funnel that connected to a DC auger that fed the pellets into the burn pans. The hot water coming from the boiler heated one side of the thermoelectric modules, while the cool water that circulated through the home’s radiator system cooled the other side of the modules. This temperature differential (known as the Seebeck effect) generated the electricity to power the auger, blowers and water pump for the heating system.  The thermoelectric pellet boiler produced up to 60 watts and kept him and his family warm for over 9 years, even during power outages. One goal of the Design Challenge is to improve on Bill’s TEG boiler so that a thermoelectric wood stove or boiler can produce substantially more electricity to help power lights, recharge batteries and augment solar power.
After 9 years of heating Bill’s home and
making its own electricity, the home-
made boiler came out of the basement.


In 2013, Bill and his team created a thermoelectric energy generation division at LEDdynamics called TEGpro to share their expertise with everyone from large multinational corporations to small inventors. Surprisingly, the division has found many opportunities for their thermoelectric technologies’ in the petroleum and gas industry. With miles of piping, this industry has a large demand for TEG powered pressure sensors and wireless devices that measure liquid and gaseous chemicals and fuels as they move through the pipeline.  TEGpro is working with the petroleum and gas industry as an “intermediate step” until they can fund projects that hold larger implications for growth in thermoelectric wood and pellet stoves and boilers. 

TEGpro’s customers are already demonstrating the advantages of thermoelectric technology in residential applications across the world. For example, Bill references many instances of users in Alaska and Canada transferring wood stove heat through their cabins by putting TEGs on their central boiler systems, providing them a critical source of electricity without having to use a generator. 

Bill expects TEGs’ trajectory to be like what he experienced with the rise of LEDs since his start at LEDdynamics. Today’s modern LED light was discovered by Shuji Nakamura in 1994, who received the 2014 Nobel prize in physics for his work. Like the pre-Nakamura LEDs, Bill recognizes that the cost and efficiency of thermoelectric generators remains a challenge, but he believes that thermoelectrics will become as commonplace as LEDs.  With events like the Wood Stove Design Challenge, he is optimistic for the future of TEG power generation. However, commercializing energy alternatives like LED lights and solar power needs support from government agencies like DOE to fund the university research and competitions that can make TEGs as common as LEDs.

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Adventures in masonry stove testing from 1988 to 2017

by Norbert Senf, 
Chair of the Masonry Heater Association Technical Committee

Left to right: Mark Champion (in his 
VT test lab), Boris Kukolj (Tulikivi), 
Chris Prior (MHA President), Norbert 
Senf (blog author)  and Jean Francois 
Vachon (soapstone supplier). 
Photo credit: Mark Seymour.

EPA started regulating wood burning stoves for particulate (PM) emissions in 1988. Regulation was limited to airtight heating stoves. Masonry heaters were not regulated, the stated reason being that they were likely to be clean burning.

In Europe, only carbon monoxide (CO) emissions were regulated. CO is easy to measure, however PM can be very tricky. Wood smoke includes  compounds that will only be captured by a filter if you cool them down and condense them. This is done in the laboratory by mixing them with air in a dilution tunnel, and this is thought to simulate what happens in the ambient air in the real world.
State and county air quality authorities soon started to address wood smoke, and would often pass a generic local regulation that banned all appliances except those that were EPA certified. We, the fledgling Masonry Heater Association (MHA), decided to seek EPA certification.
Although we “knew” that masonry heaters were cleaner even than EPA stoves, nobody had ever measured the PM on one with the dilution tunnel method. With funding help from the Wood Heating Alliance (now HPBA), we were able to participate in a $ 100,000.00 test method development project for masonry fireplaces and masonry heaters. The project took place at Virginia Polytechnic Institute (VPI) in 1989 and was headed by Dr. Dennis Jaasma.
The results were interesting, with some surprises. EPA did not accept the proposed test method. We immediately realized that we needed do a lot more testing,  and that we would need to develop the capability to do it ourselves.
We were fortunate in being able to arrange for training with OMNI-Test, one of the leading EPA-accredited certification testing laboratories, then and now. OMNI developed a training session for us that took place in September 1996. It included presentations by regulators, an emission chemistry expert (Dr. Jim Houck),  and laboratory testing personnel. Dr. Stockton (Skip) Barnett showed us the low cost portable dilution tunnel that he invented, known as the Condar. He developed it while working for the Condar Company. It was widely used at the time by the major stove manufacturers for in-house testing to develop their certified  stoves.

The attached Powerpoint, Repeatability of Cordwood Combustion Particulate Measurements,  presents a summary of the work we have done at the Masonry Heater Association to calibrate the Condar against the EPA Method 5G laboratory dilution tunnel. It includes a close look at the PM testing repeatability issues,  a major discussion point over the years. We have recently completed 2 cordwood studies, using very carefully matched loads in a masonry heater. Repeatability was within plus or minus 15% – 25%, depending on the ignition method. With crib fueling, we were able to get within 10% repeatability on PM, and within 1.5% repeatability on CO.

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20 Stunning Wood Fired Hot Tubs from Around the World

Wood fired baths are an ancient tradition, dating back at least to Roman times when baths called hypocausts were built by running hot flue gases under a stone tub.  Those Roman tubs were also off the grid, as are these.  Some are quirky, some romantic, some practical and some just downright hedonistic.  Which is your favorite?
See our other photo essays: Wood Stoves from Around the World, and and Firewood Collection and Stacking from around the world. 

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20 Beautiful Wood Fired Hot Tubs from All around the Planet

Wood fired baths are an historic tradition, relationship again at minimum to Roman instances when baths known as hypocausts had been built by working sizzling flue gases below a stone tub. &nbspThose Roman tubs have been also off the grid, as are these. &nbspSome are quirky, some passionate, some sensible and some just downright hedonistic. &nbspWhich is your favored?
See our other picture essays: Wooden Stoves from Close to the Globe, and and Firewood Assortment and Stacking from about the entire world.&nbsp

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Last Report on Wood Stove Decathlon from Brookhaven Lab

Reproduced underneath are the absract and introduction of a seventeen-website page paper that provides an excellent overview of the specialized aspects of screening stoves on the Nationwide Mall for the Wood Stove Decathlon, held in November 2013. &nbspTo go through the whole report, click on listed here.

Progressive good particulate measurement systems for the Wood Stove Design Problem&nbsp
R. Trojanowski1, T. Butcher1, C. Brown1, G. Wei1, Y. Ahn2 , and J. Wong2&nbsp
one. Vitality Conversion Team, Brookhaven National Laboratory, Upton, New York, United states of america&nbsp
two. Chemical and Molecular Engineering Office, Stony Brook College, Stony Brook, New York, United states of america&nbsp
Summary&nbsp
The increasing price of fossil assets has contributed to the enhance in the amount of wooden-fired household heating appliances. Wood stoves are typically neglected by the community as a cleanse and renewable source owing to worries about particulate (PM) emissions. In purchase to achieve acceptance in the market the Alliance for Eco-friendly Heat and
Popular Mechanics magazine initiated a Wooden Stove Style Challenge (WSDC). The selected groups created stoves that included the greatest methods in style and procedure to maximize performance and reduce PM and carbon monoxide (CO) emissions given that most frequently high emissions are noticed as a result of incomplete combustion. Additional, a screening protocol for the obstacle was produced exclusively to measure the emissions in a non-laboratory environment. Normal screening procedures may possibly not be agent of in-use fuel and operational techniques and, thanks to the opposition location and timetable contstraints, could not be utilised for the WSDC. New transportable PM sampling technology introduced in the European market place recently was adopted for the competitors and evaluated to present U.S. PM measurement approaches to construct a correlation.&nbsp
INTRODUCTION

Tom Butcher makes use of the Wohler transportable
particulate sampler to test a stove.
&nbspAs the value of heating oil has improved, much more people in the northeastern location of the United States have returned to heating with wooden. Most present wooden stoves date from ahead of the Environmental Security Agency (EPA) carried out emission certification demands for these products. These much less effective wooden stoves often cause higher amounts of smoke, yielding particulates identified to set off coughs, throat and mucosal irritation, acute respiratory bacterial infections, occurrence of asthma and other conditions over extended exposure. A evaluation from Bølling et al. described residential wood combustion has also been reported to contribute substantially to raised stages of air air pollution regionally, each with respect to enhanced stages of fine particles (particulate make a difference with an equal aerodynamic diameter &lt 2.5 μm PM2.five), the natural and organic particle portion, particle sure polycyclic fragrant hydrocarbons (PAH) and volatile organic compounds. Even people wooden stoves that do meet up with EPA’s Section II requirements might have unacceptably large emissions once in use. This is thanks to many factors like the style of the equipment,&nbspweather designs and location, combustion exercise, wood species and good quality, and operator habits. Whilst the EPA is establishing new laws, the take a look at strategy used for certification is not representative of in-use fueling and operational procedures.&nbsp
Types that enhance combustion and emission functionality, thermal effectiveness, and operational &nbsp
The Decathlon tent on the Nationwide
Shopping mall, in between the Capitol and
the Washington monument

variability are required in the U.S. heating marketplace. Modern wooden stoves have revealed diminished described emission aspects in contrast to typical wooden stoves, 34-330 mg/MJ from 50-2100 mg/MJ, respectively. Nevertheless, if the modern stoves are not operated appropriately the combustion overall performance can be compromised yielding increased emissions.

This function showcased superior systems that could help tackle the dilemma of enhanced particulate emissions and empower the continued use of wood as a renewable gasoline. The groups chosen arrived from various backgrounds, ranging from set up wooden stove companies to independent inventors and engineering pupil groups. Some of the stoves chosen for the WSDC were controlled by microprocessors and connected to smartphones whilst other folks were extremely-successful stoves primarily based on seventeenth century Scandinavian styles. A number of condition-of-the-art hybrid stoves that are previously on the industry ended up also included4. 6 of the twelve finalists have been from Europe.&nbsp
Groups had been judged on their innovation, emission and effectiveness overall performance, affordability and buyer relieve. In November 2013 on the National Mall in Washington D.C., ten judges (produced up of top experts from Popular Mechanics, the New York State Energy and Research Advancement Authority (NYSERDA), the U.S. Forest Support, Washington Point out Section of Ecology, DOE’s Brookhaven National Laboratory (BNL), The Biomass Thermal Strength Council (BTEC), the Osprey Basis, the Masonry Heater Association and UC Berkeley) examined and assessed the 12 stove finalists and announced an all round winner as properly as winners in certain classes.&nbsp
A essential challenge in this opposition was measuring the particulate emissions accurately in a discipline atmosphere. This task sought to create an energy effectiveness and emissions testing protocol for the WSDC which decreases the variability due to gas and functions. The present normal examination strategy (EPA Strategy 28) entails testing stoves utilizing a dilution tunnel. Given that the WSDC was held&nbspat the mall in Washington D.C., this take a look at strategy would not suit and so there was the&nbspchallenge of measuring the emissions in a repeatable actual-time way, in a non-laboratory atmosphere. Just lately, new moveable particulate measurement programs have been launched in Europe for area inspection of biomass heating systems. Two particular products were chosen for use in this project the Testo 380 and Wöhler SM 500. Equally analyzers are a low price selection and supply the advantage of relieve and portability.&nbsp
To establish the precision, precision, instrument variety, and applicability for use in the WSDC for thermal performance and emissions of these transportable immediate evaluate analyzers, an analysis was executed even though at the same time adhering to the regular methods for deciding the emissions. &nbspFrom laboratory screening, BNL created a screening protocol implementing the analyzers for the competition.

To go through the entire PDF report, click right here.

For far more information about the 2013 Decathlon, click here.

For details about the 2014 Collaborative Stove Design Workshop, click here.

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Summary of NSPS Remarks from the Alliance for Environmentally friendly Warmth

The Alliance for Inexperienced Warmth is sharing its draft summary responses with all stakeholders to advertise transparency and dialogue and to solicit input on how we can enhance our feedback. &nbspWe also urge stakeholders to consider incorporating the points that you concur with, into your feedback. &nbspPlease truly feel cost-free to leave input or suggestions for the Alliance on this site or if you want them to continue to be personal, ship to john@forgreenheat.org. &nbspComments have to be despatched to the EPA by Monday, Might five.

-draft –

Alliance for Environmentally friendly Warmth

Responses on
EPA’s Proposed Requirements of Overall performance for New Household Wood Heaters, New Household Hydronic Heaters and Pressured-Air Furnaces, and New Residential Masonry Heaters
Docket ID No. EPA-HQ-OAR-2009-0734
April 30, 2014&nbsp

SUMMARY OF Remarks

The Alliance for Inexperienced Heat (Alliance), appreciates the possibility to remark on EPA’s proposed New Source Efficiency Standards (NSPS) for wooden heating devices.[1] &nbspThe Alliance is an unbiased non-income business that operates with environmental and forestry corporations, air quality experts, the wood and pellet stove market, and other individuals in the wood burning community to market substantial-efficiency wood combustion as a low-carbon, sustainable, nearby and cost-effective heating resolution.&nbsp The Clear Air Act demands EPA to overview and revise, if suitable, the NSPS at least every 8 several years.&nbsp The Alliance strongly supports EPA’s decision to update the standards for wooden stoves and to require a number of formerly unregulated wood heating devices to reduce their emissions.&nbsp We also imagine that the new requirements, which replicate important advancements in wood heating technological innovation, are the two acceptable and extended-overdue.&nbsp

We have numerous suggestions for bettering the proposed NSPS, which we outline below.
In our responses on the NSPS, we make the pursuing points:
·&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp
&nbsp &nbsp &nbspVery first, it is important to understand that wood heating is renewable heating and should be acknowledged as this kind of by EPA.

·&nbsp&nbsp&nbsp&nbsp&nbsp 2nd, the Alliance strongly supports EPA’s decision to problem revised overall performance requirements for wooden stoves and other wood and pellet heating appliances.
o&nbsp&nbsp The Alliance supports EPA’s determination to shut existing loopholes and to include all main types of wooden-fired heating gadgets in the new performance expectations. &nbspBeforehand exempted gadgets and units earlier mentioned Action One particular emission restrictions should not be “grandfathered.”&nbsp&nbsp
o&nbsp&nbsp The Alliance supports a nine-month promote by way of for qualified stoves that emit greater than Step 1 emission expectations and a two-calendar year market by means of for boilers or furnaces that are EN303-5 accredited or EPA competent.
o&nbsp&nbsp In the following NSPS, the Alliance urges the EPA to control uncertified, pre-1988 stoves as new resources if they are installed in a new spot.&nbsp Performing so will help to hasten the removal of the oldest, most polluting stoves from our airsheds.
o&nbsp&nbsp In the up coming NSPS, the Alliance also urges EPA to control fireplaces.

·&nbsp&nbsp&nbsp&nbsp&nbsp 3rd, the Alliance thinks that the proposed emission limitations, however affordable, could be more stringent for specific gadgets:
o&nbsp&nbsp Data from at the moment licensed stoves look to justify a a lot more technologies-forcing, lower Action 1 performance normal for wooden stoves.
o&nbsp&nbsp Pellet stoves are plainly able of conference a lower restrict for Stage One particular.&nbsp The bulk of pellet stoves accredited by EPA are currently emitting much less than 2.five grams for each hour (g/hr).
o&nbsp&nbsp Forced air furnaces could attain a Step 1 emission restrict of .forty eight pounds per million BTUs (lbs/MMBTU), as an alternative of the proposed .93 lbs/MMBTU. A .forty eight common corresponds to the lbs ./MMBTU of a typical Washington accredited wooden stove.
o&nbsp&nbsp In addition, despite the fact that we feel a .06 lbs/MMBTU Step Two standard for pellet boilers is justifiable, this limit may not be appropriate for wire wooden boilers, based on the take a look at technique.&nbsp &nbsp

·&nbsp&nbsp&nbsp&nbsp&nbsp Fourth, the Alliance strongly supports a shorter, 5-12 months implementation period of time for the NSPS. &nbspThis deadline is the two achievable and reasonable given the state of wooden heating technology these days.

·&nbsp&nbsp&nbsp&nbsp&nbsp Fifth, the Alliance believes that credible testing and enforcement are important parts of any New Resource Functionality Standard below the Clean Air Act (CAA).
o&nbsp&nbsp The Alliance supports the proposed changeover to wire wooden screening, and phone calls on EPA to increase its cord wood tests software to get further information on the overall performance of present wooden stove versions making use of cord wooden prior to promulgation of the ultimate rule.&nbsp Alternatively, we urge the EPA to dedicate to re-analyzing the achievability of the Phase Two standards for stoves that have to be accredited on wire wood just before people requirements turn into successful.
o&nbsp&nbsp The Alliance urges EPA to create a clearer route to certification for sophisticated systems like automatic stoves.&nbsp The Alliance is also inspired by ClearStak’s responses and urges EPA to consider some of the ahead-contemplating ideas put forth in those comments.
o&nbsp&nbsp The Alliance supports EPA’s proposal to delegate some oversight and enforcement authority to the states, and urges EPA to increase the capacity of the Business office of Enforcement and Compliance Assurance (OECA) to aid make sure that point out enforcement packages are successful and that companies and merchants comply with the NSPS.

·&nbsp&nbsp&nbsp&nbsp&nbsp Sixth and last but not least, the Alliance believes that mandatory effectiveness expectations are needed. Better performance is specifically import to minimal-income wooden stove customers since it can decrease their heating expenses by demanding less fuel to warmth their houses.&nbsp Even so, the Alliance supports EPA’s decision to get much more data on wood stove effectiveness, with the knowing that future NSPS would set obligatory effectiveness standards.
o&nbsp&nbsp The Alliance strongly supports a necessity to put up B415.one HHV effectiveness quantities on all wooden heating appliances on the marketplace inside of six months of the rule’s promulgation.&nbsp Versions that are EN 303-5 certified or certified by an EPA voluntary plan must be permitted to use HHV quantities till they turn into EPA accredited.
o&nbsp&nbsp The Alliance opposes the elimination of the hangtag prerequisite and urges EPA to take into account extra consumer details resources this sort of as a Inexperienced Label and state incentives for shifting out old stoves and putting in the most effective new stoves.
o&nbsp&nbsp The Alliance agrees that the two particulate subject (PM) and carbon monoxide (CO) emissions information, as properly as efficiency information, need to not be considered Confidential Business Info (CBI), and urges EPA to make emissions and effectiveness data about all four burn rates community on its site.
o&nbsp&nbsp The Alliance urges EPA to right away start requiring producers and labs to scan and electronically post all paper info submissions, even as the company works to build a much more streamlined Electronic Reporting Tool (ERT).&nbsp
o&nbsp&nbsp Lastly, to stay away from deceptive shoppers further, EPA need to also remove the “default” emission element column from its posted listing of certified wooden stoves, and demand producers and merchants to stop employing these default factors in their promoting materials.

We appreciate your interest to our responses and appear ahead to operating with EPA to efficiently employ this crucial rule.&nbsp The full text of our comments is under.



[1]Standards of Efficiency for New Residential Wood Heaters, New Residential Hydronic Heaters and Compelled-Air Furnaces, and New Residential Masonry Heaters, seventy nine Fed. Reg. 6,329 (Feb. 3, 2014) [hereinafter “Proposed Rule”].

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EPA Lists Efficiencies of Qualified Out of doors Boilers from 39% to seventy eight%

On April 8, the EPA&nbspposted efficiencies for outside wooden and pellet boilers, also acknowledged as hydronic

heaters.&nbsp Efficiencies ranged from 39% to 78% as measured utilizing greater heating value.

The common certified outside wood boiler is sixty three% efficient and the typical pellet boilers is 70%.&nbsp However, of the 39 units qualified under the EPA’s voluntary program, efficiencies have been only shown for 20 models.&nbsp Nineteen of the models do not have efficiency figures offered due to the fact they ended up analyzed utilizing EPA’s earlier Strategy, which resulted in excessively high efficiency quantities.
The maximum effectiveness boiler in the EPA’s experienced system is Central Boiler’s E-Vintage 1450 at seventy eight% HHV.&nbsp The most affordable is Marway Welding’s Stage two – two hundred at 39%.&nbsp An additional boiler has 47% performance, which demonstrates how boilers can qualify for the EPA’s voluntary program emission standards without having substantial thermal efficiency.&nbsp Thermal efficiency measures heat transfer from the combustion chamber to the h2o that heats the property.
The putting up of these efficiency figures was welcomed by the Alliance for Eco-friendly Warmth who has extended advocated for shoppers getting entry to reliable efficiency data.&nbsp The listing of dependable efficiencies helps make hydronic heaters the first class of wooden heating appliances to give efficiencies to the standard public.&nbsp It may possibly just take many years for the general public to get reliable efficiencies on most wood and pellet stoves, as most manufacturers have been unwilling to share that information with the public right up until it is necessary by legislation to do so. &nbspTo day, only nine stove companies have provided 3rd party effectiveness quantities for the EPA to publicly post.&nbsp&nbsp
These boiler efficiencies display that most boilers are not increased in effectiveness than top carrying out wooden stoves.&nbsp They reveal that there is even a wider range in boiler effectiveness than wooden stoves, such as several that are quite low efficiency units.&nbsp
The saga to give customers with such knowledge has taken numerous twists and turns.&nbsp In 2011, the EPA removed efficiency figures that ended up in the ninety% range following condition regulators questioned their precision.&nbsp Scott Nichols, who sells European indoor boilers that are not part of the EPA voluntary program, is a single of handful of to create about these problems that have faced EPA and the boiler sector.&nbsp
The EPA asked for outdoor boiler makers to stop employing the discredited large efficiency quantities in their marketing, but few stopped utilizing them, major to a letter from the EPA in 2013, which strongly urged manufacturers to cease employing the performance figures.&nbsp The Alliance for Environmentally friendly Heat documented on that growth and documented several instances the place out of doors boiler companies have been participating in other misleading promoting practices.&nbsp

The EPA again sent a letter to certified boiler makers on January 31, 2014 simply because “misleading data has appeared on many spouse manufactures and retailer websites.”&nbsp This data provided language such as EPA “certified” or “approved” boilers and promises that their boilers were up to 90% productive.

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