New York and Canadian companies win technology challenge to automate the wood Stove

Jonathan Male, director of the DOE's Bioenergy
Technology Office, announces the winners.
Photo: Sam Kittner for Brookhaven National Lab.

(Washington, D.C.) – Two companies with years of experience in electronics and stove design won coveted first and second prizes in the 2018 Wood Stove Design Challenge, held in Washington DC from November 9 – 13. 

Manually operated wood stoves are extremely common throughout the northern US, Canada and Europe but no one has yet popularized a solution to prevent them from emitting excessive smoke in the hands of operators.

Wittus, a company based in Pound Ridge New York, teamed up with German engineers and won first prize for both the automated and thermoelectric categories with a living room unit that also heated water for space heating

The Wittus team who won first place in both
the automated and thermoelectric categories.
Photo: Kittner for BNL.

and generated an average of 161 watts and a maximum of 268 watts over the 2.5-hour test period. Total power output over the test period, net of parasitic losses, e.g., pumps and fans, was 276 watt-hours of electricity. The use of thermocouple sensors and fans facilitated clean and efficient combustion.

Stove testers from Brookhaven National Lab and
New York Department of Health.
Photo: Kittner for BNL.

Second prize went to Stove Builders International (SBI) a Quebec based company that designed a simple, affordable stove that allowed the operator to select high or low heat output and used a low-cost control board and thermocouple sensors to ensure that the stove burned cleanly.

Second prize in the thermoelectric category went to California based Vulcan Energy, who

SBI, a prominent Canadian stove manufacturer
spent years developing automated features.
Photo: Kittner for BNL.

developed a thermoelectric generator for the gravity fed Wiseway pellet stove that generated an average of 123 watts, and a maximum of 139 watts, during the 2.5-hour test period. Total power output over the test period, net of parasitic losses, was 235 watt-hours.

The People’s Choice award, based on votes from the general public, went to 509 Fabrications, for their unique gravity fed pressed log stove.

Key partners in the Challenge included Olympia
Chimney, and CSIA, and NFI installers from
Winstons Chimney and  Sugarloaf Chimney.
Photo Kittner for Brookhaven National Lab.

The goal of the Woodstove Design Challenge is to demonstrate how improved designs including sensors and computer controls can make wood stoves cleaner and more efficient. The technology boom of the past few decades has largely missed the wood stove industry, yet innovation still holds great promise. 

Researchers including Brookhaven National Lab, with support from the New York State

Fred Leavitt won 2d prize in thermoelectric
with Jonathan Male, DOE, Ramesh Koripella,
Sandia National Lab and John Ackerly, AGH.
Photo: Kittner for BNL

Energy Research and Development Authority (NYSERDA), have been developing new methods for the next generation of assessment protocols for wood heating appliances. Currently, most stoves in America are tested for EPA certification with standardized fuel pieces and spacing. Research has focused on in-home use operational practices, user fueling patterns, and new real-time measurement method techniques with random loading patterns and variability in piece size to better replicate real-life conditions.   

Automated stoves that are designed and tested with this new robust cordwood test method can help improve woodstove designs and in-use performance leading to higher efficiency and lower emissions.

Les Otten of Maine Energy Systems with Julie
Tucker of the USDA Forest Service.
Photo: Kittner for Brookhaven National Lab.

A team from Stony Brook University also competed in the event with a prototype that featured a unique wood drying and preheating chamber. The stove did not win a prize but offered students a rich opportunity to engage with national stove design and testing experts. A full list of the competing teams can be found here. 

Partners for the Design Challenge include NYSERDA, the Department of Energy’s Bioenergy Technology Office, the U.S. Forest Service, the Osprey Foundation and Olympia Chimney. The automated stoves were tested by Brookhaven National Lab. A complete list of partners and sponsors can be found here.

Meet the teams: Fighting global warming with a gravity fed, thermoelectric pellet stove

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

By Ken Adler, and Shoshana Rybeck, Alliance for Green Heat 

Jill Elsner (CEO) and Fred Leavitt (VP) 
using a modified version of their
Greenway Power Stove to power a light bulb.

Fred Leavitt has been working in thermoelectrics since he graduated from college in 1982. He learned the technology from the team that developed the SNAP-27 thermoelectric generator left on the moon by the Apollo missions, as well as the team that developed the thermoelectric generators for the Voyager spacecraft. Now, as Vice President of Hi-Z Technology, he wants to bring that technology to your living room. 

Fred developed a thermoelectric pellet stove twenty years ago, but the thermoelectric modules were too expensive and the market wasn’t ready. With dramatically lower module costs, Fred is looking to do more than just “power lights.” Hi-Z, in collaboration with Northwestern’s Department of Material and Engineering Science, will be adding a custom made thermoelectric generator (TEG) to a WiseWay pellet stove for the 2018 Wood Stove Design Challenge.   

Hi-Z Technology is a powerhouse of thermoelectric expertise. Founded in 1988, it is a California R&D business of engineers and technicians who design, develop and manufacturer bulk thermoelectric modules and generator systems. Hi-Z, along with ASAT, another team in the Wood Stove Design Challenge, also received a $300,000 grant from the EPA to work on thermoelectric cook stoves.

Fred’s goal for the WiseWay is to produce about 100W of power, enough to recharge a home battery, supplement photovoltaics, power lights and small appliances, and provide potable hot water. 

Wiseway stove prior to modification

The WiseWay, invented by Gary Wisener, was certified by the EPA in 2012 and later bought by US Stove. It was the first and remains the only gravity-fed pellet stove on the US market that does not need electricity. The stove is thus an ideal candidate to produce electricity as it's often used off-grid in homes that need more reliable electricity, particularly in the winter. 

Fred is adding a water-cooled TEG near the combustion chamber, technology that Fred says “is simple, but works.” He likes pellet stoves because the combustion chamber has less temperature fluctuations compared to cordwood stoves, which improves TEG power output and longevity. Fred plans to cool the water with a hydronic radiator, which would allow the WiseWay to heat more than one room in a home and provide hot water for cooking and cleaning. 

Come November, Hi-Z plans to bring their new and improved stove complete with a water-cooled electric generator to the challenge. Fred and his team are also working to eliminate the need for manually igniting the stove with a propane torch by adding a battery-powered heating element. They are also exploring the addition of a DC-powered exhaust fan to improve combustion.  

The Hi-Z team recharging a cell phone
from one of their cook stove designs.

The development of the thermoelectric WiseWay has had minimal technical struggles. However, Fred notes that the team has faced considerable challenges making the model “cheap enough to make it a commercially viable product.” The team is determined to showcase a thermoelectric pellet stove that is easier to operate, can reliably produce electricity, heat and hot water, and is affordable.  

Goals for the Team

Fred's career has consisted of many projects that aim to reduce human contributions to climate change and sees the Wood Stove Design Challenge as a major opportunity to help homeowners get off of fossil heating fuel. Bringing this stove to market is likely to spark the interest of homeowners looking to heat with pellets, secure a back-up or secondary electricity source and reduce their overall carbon footprint. That is why Fred and his team “firmly believe in making pellet burning stoves major players in the fight against climate change.”  

Contact the team 

Fred Leavitt

f.leavitt@hi-z.com 

Jill Elsner
j.elsner@hi-z.com