Final Report on Wood Stove Decathlon from Brookhaven Lab

Reproduced below are the absract and introduction of a 17-page paper that gives an excellent overview of the technical aspects of testing stoves on the National Mall for the Wood Stove Decathlon, held in November 2013.  To read the entire report, click here.

Innovative fine particulate measurement systems for the Wood Stove Design Challenge 

R. Trojanowski1, T. Butcher1, C. Brown1, G. Wei1, Y. Ahn2 , and J. Wong2 

1. Energy Conversion Group, Brookhaven National Laboratory, Upton, New York, USA 

2. Chemical and Molecular Engineering Department, Stony Brook University, Stony Brook, New York, USA 

ABSTRACT 

The rising price of fossil resources has contributed to the increase in the amount of wood-fired residential heating appliances. Wood stoves are often overlooked by the public as a clean and renewable source due to concerns about particulate (PM) emissions. In order to gain acceptance in the market the Alliance for Green Heat and

Popular Mechanics magazine initiated a Wood Stove Design Challenge (WSDC). The selected teams designed stoves that incorporated the best practices in design and operation to maximize efficiency and minimize PM and carbon monoxide (CO) emissions since most often high emissions are seen as a result of incomplete combustion. Further, a testing protocol for the challenge was developed specifically to measure the emissions in a non-laboratory setting. Standard testing procedures may not be representative of in-use fuel and operational practices and, due to the competition venue and schedule contstraints, could not be used for the WSDC. New portable PM sampling technology released in the European market recently was adopted for the competition and evaluated to current U.S. PM measurement methods to build a correlation. 

INTRODUCTION

Tom Butcher uses the Wohler portable
particulate sampler to test a stove.

 As the price of heating oil has increased, more residents in the northeastern region of the United States have returned to heating with wood. Most existing wood stoves date from before the Environmental Protection Agency (EPA) implemented emission certification requirements for these devices. These less efficient wood stoves often cause high amounts of smoke, yielding particulates known to trigger coughs, throat and mucosal irritation, acute respiratory infections, occurrence of asthma and other diseases over prolonged exposure. A review from Bølling et al. reported residential wood combustion has also been reported to contribute significantly to raised levels of air pollution locally, both with respect to increased levels of fine particles (particulate matter with an equivalent aerodynamic diameter < 2.5 μm; PM2.5), the organic particle fraction, particle bound polycyclic aromatic hydrocarbons (PAH) and volatile organic compounds. Even those wood stoves that do meet EPA’s Phase II requirements may have unacceptably high emissions once in use. This is due to several factors including the design of the appliance, weather patterns and location, combustion activity, wood species and quality, and operator habits. While the EPA is developing new regulations, the test method used for certification is not representative of in-use fueling and operational practices. 

Designs that improve combustion and emission performance, thermal efficiency, and operational  

The Decathlon tent on the National
Mall, in between the Capitol and
the Washington monument

variability are needed in the U.S. heating market. Modern wood stoves have shown reduced reported emission factors compared to conventional wood stoves, 34-330 mg/MJ from 50-2100 mg/MJ, respectively. However, if the modern stoves are not operated correctly the combustion performance can be compromised yielding higher emissions.

This event showcased advanced technologies that could help address the problem of increased particulate emissions and enable the continued use of wood as a renewable fuel. The teams selected came from various backgrounds, ranging from established wood stove companies to independent inventors and engineering student teams. Some of the stoves selected for the WSDC were controlled by microprocessors and connected to smartphones while others were ultra-efficient stoves based on 17th century Scandinavian designs. Several state-of-the-art hybrid stoves that are already on the market were also included4. Six of the 12 finalists were from Europe. 

Teams were judged on their innovation, emission and efficiency performance, affordability and consumer ease. In November 2013 on the National Mall in Washington D.C., ten judges (made up of leading experts from Popular Mechanics, the New York State Energy and Research Development Authority (NYSERDA), the U.S. Forest Service, Washington State Department of Ecology, DOE’s Brookhaven National Laboratory (BNL), The Biomass Thermal Energy Council (BTEC), the Osprey Foundation, the Masonry Heater Association and UC Berkeley) tested and assessed the 12 stove finalists and announced an overall winner as well as winners in specific categories. 

A key challenge in this competition was measuring the particulate emissions accurately in a field environment. This project sought to develop an energy efficiency and emissions testing protocol for the WSDC which reduces the variability due to fuel and operations. The current standard test method (EPA Method 28) involves testing stoves using a dilution tunnel. Since the WSDC was held at the mall in Washington D.C., this test method would not suit and so there was the challenge of measuring the emissions in a repeatable real-time way, in a non-laboratory environment. Recently, new portable particulate measurement systems have been introduced in Europe for field inspection of biomass heating systems. Two specific products were selected for use in this project the Testo 380 and Wöhler SM 500. Both analyzers are a low cost option and offer the advantage of ease and portability. 

To determine the accuracy, precision, instrument range, and applicability for use in the WSDC for thermal efficiency and emissions of these portable direct measure analyzers, an evaluation was conducted while simultaneously following the standard methods for determining the emissions.  From laboratory testing, BNL developed a testing protocol implementing the analyzers for the competition.

To read the entire PDF report, click here.

For more information about the 2013 Decathlon, click here.

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

Woodstock Soapstone, Travis and Wittus Win the Wood Stove Decathlon

FOR IMMEDIATE RELEASE: November 20, 2013

Woodstock Soapstone, Travis and Wittus    Win the Wood Stove Decathlon

Catalytic, Masonry and Electronically Controlled Stoves Show High Results in Testing

Washington D.C. – In an international competition to significantly reduce pollution from wood stoves on the National Mall, one finalist, Woodstock Soapstone of New Hampshire, won first prize of $25,000. Two other teams, Travis of Washington State and Wittus of New York, were awarded $5,000 each. The teams were recognized for all around performance in efficiency and emissions, affordability, consumer appeal and innovation. Members of Congress Dan Benishek (R-MI), Chris Van Hollen (D-MD), Jared Huffman (D-CA), Paul Tonko (D-NY) took part in the awards ceremony.

The Woodstock Soapstone Team

In accepting the first prize of $25,000, Woodstock Soapstone owner Tom Morrissey announced that he was giving part of the prize money to two other teams - Walker Stove and Intensi-Fire - who had come to the Decathlon on a shoestring and needed funds for their work. Travis donated their $5,000 to the Alliance for Green Heat to help pay for the expenses of the Decathlon.

“These award-winning technologies are part of the solution for millions of Americans to reduce their reliance on fossil heating fuels,” said John Ackerly Founder and President of the Alliance for Green Heat, which organized the Wood Stove Decathlon. "We'd like to thank all the teams for participating and contributing to an ongoing educational effort to help the US government appreciate the potential of cleaner and more efficient wood heating," Ackerly added.

Competitors represented a wide range of wood stove technologies. Two of the top three winners were catalytic hybrid stoves. While the three masonry stoves did not take home prizes, they had some of the highest scores in efficiency and cleanliness.  

The Wittus Twin Fire, that was tied for second prize overall, scored highest in the efficiency category. Travis’s Cape Cod Hybrid, which also tied for second overall, scored highest in consumer appeal and for low carbon monoxide. The Hwam 3630 IHS scored highest in innovation, with its oxygen sensor and control device that alerted the consumer when and how much wood to reload. The Woodstock Soapstone, which won the Grand Prize, also won in the affordability category. And the University of Maryland’s stove, the Mulciber, won in the lowest particulate matter category. 

The overall ranking of stoves was:

WOODSTOCK SOAPSTONE		1
TRAVIS		2
WITTUS		2
INTER-CONTINENTAL		3
TILE STOVE		3
HWAM		3
TULIKIVI		4
INTENSI-FIRE		5
MULCIBER		5
WALKER STOVES		6
SMART STOVE		7
KIMBERLY		8

The competition differed from EPA tests of wood stoves in several key respects to more closely resemble how consumers use stoves. First, the stoves in the competition were tested using cordwood instead of 2x4s and 4x4s. Second, technicians loaded stoves with 12 pounds of wood per cubic foot of firebox space for the first round of testing, whereas EPA only uses 7 pounds of wood per cubic foot.

Two of the stoves made small amounts of electricity and four had electronic control systems. More detailed analysis will be forthcoming. The primary funders of the Wood Stove Decathlon are NYSERDA, the Osprey Foundation, the District of Columbia Urban Forestry Administration, the US Forest Service, the West Penn Power Sustainable Energy Fund and the Arbolito Foundation. 

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The Alliance for Green Heat is an independent non-profit that promotes high-efficiency wood heating as a low-carbon, sustainable and affordable heating solution. The Alliance seeks to make wood heat a cleaner and more efficient renewable energy option, particularly for those who cannot afford fossil fuel heat.

Meet the Contestants; The Wittus Twinfire

With the first Wood Stove Decathlon only a few months away, we are profiling each of the teams. Learn more about how they hope to win the competition!

Wittus – Fire by Design has entered into the Decathlon their EPA certified Twinfire stove. The stove was originally designed by two German engineers to create an efficient burning method and offset air pollution in developing countries. It uses a patented double combustion chamber to maximize its efficiency through gasification, a process that superheats wood gas to reach a claimed 93% efficient wood burning capacity. The upper chamber is the main firebox used to build and tend the fire. The lower chamber is the exterminator that burns any remaining ash down to bits.

The Twinfire stands in a long line of Wittus products that are dedicated to high efficiency, low emissions, and an attractive design. The Twinfire has won several prestigious European awards including the German Land of Ideas award in 2012. Founder Niels Wittus values the quality of these stoves and strives to create smart stove designs to maintain a healthy environment. Perhaps his background and passion for cooking has brought the health and detail oriented mindset to selecting the best ingredients to making a top quality wood stove.

In Denmark, Wittus was set to apprentice at a high-scale restaurant, but after a trip to the US, he decided to stay. Over 30 years later, Wittus is keeping the Danish brændeovn or wood stove tradition alive, combining it with the modern style and state-of-the-art technology of an American businessman.

Even with the busy schedule, hard work, and resulting success, Wittus still holds on to his passion for cooking. At business gatherings and dinners, he treats his team members, Bodo Specht, Alyce Wittus, Sandra Lena, Patti Boker Elkon, and Gail Jankus to some wood fire grilling.

We are looking forward to seeing the Wittus Twinfire in action at the Wood Stove Decathlon November 16-19, 2013. Vote for your favorite stove at Popular Mechanics.

Here is a link to a video of the Twinfire in action.

Sources include the Lewisboro Daily Voice

Meet the Contestants; Woodstock Soapstone

With the first Wood Stove Decathlon only a few months away, we are doing a weekly blog to showcase the Decathlon competitors. Take this opportunity to learn more about the design teams and their stove’s innovative features.

“When we started, stoves were basically six-sided boxes, and you put a fire in it. Now we’re making equipment, with a lot of moving parts. The technology is much better and increasing rapidly,” said Tom Morrissey, owner of Woodstock Soapstone Co. in West Lebanon, New Hampshire, which has been building cordwood-burning stoves for 35 years. For the Decathlon Woodstock Soapstone has entered their Union Hybrid stove.

Design Team (clockwise from lower left); Jason Guimaraes, Lorin Day, Harold Garabedian, Larry Young, Tom Morrissey, Ken Blum, Lewis Thibodeau, missing: Dan Batchelder & Kristie Haupt

The stove includes many technological aspects that make it a strong competitor in this year’s Decathlon. It uses an advanced hybrid combustion design incorporating both catalyst and secondary combustion. It has variable and self-regulating air/fuel ratio in order to maximize combustion efficiency and minimize emissions at all burn rates. Also, the soapstone body helps radiate heat for high heat transfer efficiency.

“We are essentially making a gasification stove,” he said, “If you look at this thing when it’s burning, the fire does not look like what you would think of as a wood fire. The whole top of firebox is like an inverted gas burner; there are 120 holes with a tube of flame coming out of each one.”

In development at Woodstock Soapstone are two beta-test modules: a Thermoelectric Module and a remote Woodstove Monitor. The module powers a small fan that assists with heat transfer. The power produced may also be used to charge a cell phone or LED light.

User responsibility and effectiveness are key to an efficient and low emission wood stove. Computers have largely cut out the need for a human operator in many technological fields, but Woodstock Soapstone hopes to avoid the added expense of computer controls. Instead, they will employ a remote Woodstove Monitor. It will provide real-time feedback on burn rate, BTU output, efficiency, emissions, and stove temperatures.

“Burning wood without this information is like driving a car without a speedometer and gas gauge,” said Morrissey. Knowing this information will help stove owners use their stoves more responsibly and effectively.

“Ten years ago, you could never imagine having a little computer on the stove. If you were in a small industry like ours, you couldn’t dream of having a graphic-user- interface, but now it’s available and affordable,” Morrissey said. The Union Hybrid stove, with its 21^st century technology and efficiency and emissions capabilities, is certainly a far cry from a six-sided box with a fire in it.

We are looking forward to seeing Woodstock Soapstone’s Intercontinental in action at the Wood Stove Decathlon November 16-19, 2013. Vote for your favorite stove at Popular Mechanics.

Source: Hearth.com http://www.hearth.com/talk/threads/is-woodstock-going-to-automated-computer-controls.111252/

Cast Your Vote for the Wood Stove Design Challenge!

NEW YORK - Popular Mechanics magazine has launched an online ballot that allows people to choose which Wood Stove Design Challenge finalist they think is most innovative.

The Wood Stove Design Challenge was launched by the Alliance for Green Heat to bring more innovation to a popular, widely used renewable energy device. The winners of the competition will be selected by judges after a series of rigorous tests in Washington DC this November. The People's Choice award is intended to encourage public engagement and education in wood stove technology.

"Wood stoves have been held back by the perception that they can't be clean enough," said John Ackerly, President of the Alliance for Green Heat. "We think they can be and recent innovations show that some wood stoves can be nearly as clean as pellet stoves."

The People's Choice Award will also shed light on what the public perceives as the most innovative wood stove features.

"If next-generation wood stoves lack compelling benefits, then the innovation won't make much of an impact on the market," said Jim Meigs, judge and Editor-in-Chief of Popular Mechanics. Maybe the public will value user-­-friendliness most-or perhaps functionality, practicality, cost, automation or connectivity. Here's a chance for the public to help shape the next generation wood stove."

Click here to cast your vote!

Each website visitor will be allowed one online confirmed by IP address. Visitors to the Wood Stove Decathlon will also have the chance to cast a paper ballot.

The finalist who receives the most votes will be named the People's Choice winner during the Wood Stove Decathlon, which will be held at the National Mall in Washington, DC this November.

During the Wood Stove Decathlon, a team of stove, air quality, and combustion experts will select an official Grand Prize winner and several second-place winners, based on five criteria: emissions, efficiency, affordability, innovation and ease of use.

For more information, visit:
http://www.forgreenheat.org/stovedesign/vote.html

Forty Teams to Compete for Spots in Wood Stove Decathlon

October 31, 2012 - With only one day left before the registration deadline, more than 40 teams have registered for the Next Generation Wood Stove Design Challenge.

“We are thrilled by the amount of interest we received and are pleased that the judges will have a diverse pool from which to select finalists,” said Melissa Bollman, Program Manager for the Design Challenge. In January, the judges will convene at the Brookhaven National Laboratory to select up to 16 finalists to be tested and judged at the Wood Stove Decathlon in November 2013. Finalists will be announced on January 31, 2013.

The 40 registered teams come from 14 countries, representing all continents except Antarctica. Most are based in the U.S., Canada, and Europe, but several are from less-developed countries like Mexico, Columbia, India and the Philippines. The five student teams include the University of Alaska Fairbanks, Purdue University and University of Maryland, winner of the 2011 Department of Energy Solar Decathlon.

The Wood Stove Design Challenge pits well-known American stove brands with garage inventors and college students for the $25,000 prize and title of best next generation wood stove. Finalists will be tested next November by EPA accredited labs onsite at the National Mall in DC. A panel of recognized wood stove experts serving as judges will select the finalists, oversee testing and choose the winners.

Competitors represent a range of wood stove technologies

The competition is designed to be as inclusive as possible, giving all cordwood stove developers the chance to demonstrate why their particular technology is the cleanest and most efficient in the world. Although teams are not required to disclose technical details at this early stage, it appears that several will be using oxygen sensors to regulate combustion, 4 are masonry heaters, 2 are catalytic hybrids, 5 use high-tech European technology, and 8 are smaller, less high-tech designs for use in smaller homes or in the developing world.

“We are excited to see some of the new R&D from the international cook stove movement being applied to heating stoves,” said John Ackerly, President of the Alliance. “One of our goals is simply to bring together innovators, manufacturers, regulators, testers and funders to learn from each other and see what innovation works the best in different applications.”

Earlier this month, the Alliance decided to remove one of its minimum eligibility criteria that barred stoves with less than 1.5 cubic foot fireboxes from entering. “We hoped that dropping the minimum firebox size would open the competition to more teams from colder regions of the developing world who need very affordable heaters,” explained Ackerly. The Global Alliance for Clean Cookstoves, a public-private partnership that focuses on the universal adoption of clean cookstoves and fuels, is a partner of the competition. Other partners include Popular Mechanics, the New York State Energy Research and Development Authority and the Washington State Department of Ecology.

Sponsorship opportunities are available to help underwrite the competition, contact Melissa Bollman (melissa@forgreenheat.org) to learn more.

Technology Competition Seeks Cleaner Wood Stove

For Immediate Release                                                    
 February 28, 2012 

Contact: John Ackerly
Melissa Bollman
301-841-7755
cell 202-365-4765

Technology Competition Seeks Cleaner Wood Stove

Innovation may help re-invent the classic wood stove

Today the Alliance for Green Heat announced the public launch of a Next Generation Wood Stove Design Challenge that seeks to promote innovation in wood stoves.

The Challenge will culminate in a Wood Stove Decathlon, modeled after the Solar Decathlon, which will take place on the National Mall in Washington DC in November 2013. Eminent stove, technology, air quality and combustion experts will judge this public exhibition of next generation wood stove designs. Stoves will be judged on emissions, efficiency, affordability, innovation and ease of use.

The Design Challenge grew from discussions between the Alliance for Green Heat and editors at Popular Mechanics magazine who believe innovation can overcome some of the problems inherent in the wood stove and that a “smart” wood stove may be on the horizon.

Modern wood stoves can burn relatively cleanly, but they can be smoky and inefficient when not used properly. “Wood stoves are a lifeline for millions of mostly rural low and middle-income families, but they are too easy to misuse by operators,” said John Ackerly, President of the Alliance for Green Heat, the independent non-profit organization sponsoring the Design Challenge.

According to the U.S. Department of Energy, wood stoves produce 80% of residential renewable energy in America, while solar and geothermal combined produce 20%. The U.S. government funnels hundreds of millions of dollars into R&D and incentives for solar, biofuels and other technologies, yet the renewable energy device used by most Americans has been neglected.

“The wood stove is a vital part of our nation’s technological legacy, and we think it can be a vital part of our future,” said James Meigs, Editor-in-Chief of Popular Mechanics magazine. “We are excited to see what sort of innovation engineers, inventors and university teams can bring to the table to make the wood stove cleaner, and possibly re-invent its consumer image,” he continued.

Federal standards for wood stove emissions will be somewhat stricter by 2014, but will do little to impact how consumers use and misuse stoves. The two biggest problems with wood stoves happen when operators use unseasoned wood or do not give the stoves enough air, which leads to incomplete combustion. “We expect the Design Challenge to produce stoves that integrate electronics that are ubiquitous in today’s appliances and can include novel features that consumers want,” Ackerly said. “A smart wood stove may motivate people to trade in their older polluting stove and replace it with an higher efficiency, higher tech model,” Ackerly said.

A powerful and growing array of partner organizations that are helping with the Challenge include Popular Mechanics, the State of Washington Department of Ecology, the New York State Energy Research & Development Authority (NYSERDA) and the Global Alliance for Clean Cookstoves. The Design Challenge will also bring together engineers working on developing clean cookstoves in the developing world with those working on heat stoves in the developed world on the common goal of increasing efficiency and reducing emissions.

The deadline for initial applications is December 20 and the finalists will bring their stoves to Washington for the Decathlon in November 2013. The winning design will receive $25,000 and coverage in Popular Mechanics magazine. Second prizes will share a $10,000 award. For rules and more information about the Wood Stove Design Challenge, go to www.forgreenheat.org/stovedesign.

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The Alliance for Green Heat promotes wood and pellet heat as a low-carbon, sustainable and affordable energy solution. The Alliance works to advance cleaner and more efficient wood heating appliances, particularly for low and middle-income families.  The Alliance is a 510c3 non-profit organization based in Maryland.