DOE request input about wood heater R&D needs

The Bioenergy Technologies Office of the US Department of Energy has begun to provide R&D funding

to the wood heater manufacturing community.  To date, it has had two rounds of funding, with $10 million available.  The DOE provides R&D funding to many different renewable energy technologies to "enable sustainable ... energy security, reliability and resilience while creating economic opportunities across the country."  The Bioenergy Technologies Office "selects research and development projects through open and competitive procurements called Funding Opportunity Announcements (FOA) and encourages collaborative partnerships among:

• Industry
• Universities
• National laboratories
• Federal, state, and local governments, and
• Non-government agencies.

Now, the DOE is asking for input from the extended wood heater community about what the community needs to build cleaner and more efficient stoves.  This likely indicates that they may change the focus of their funding next year.  In the past, they provided funding for 

• Novel and innovative residential wood heater designs to improve combustion chamber geometry, combustion air flow distribution, mixing of combustion air with gasification products, stove baffling designs, etc. 
• Improvements in automation of stoves to optimize combustion control. 
• Wood heater power generation via thermoelectric module integration 
• Improvements in catalyst technologies for emissions reduction

Input should be sent to FY21MultiTopic@ee.doe.gov and is due by 5:00 PM September 21, 2020.  We have reproduced the details of the Request for Information below (except we omitted language about a parallel ROI on biofuels). For the full text, click here.

FY 2021 Bioenergy Technologies Office Multi-Topic RFI (DE-FOA-0002386)

DATE:           August 20, 2020 

SUBJECT:     Request for Information (RFI) 

Description 

The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) Bioenergy Technologies Office (BETO) is requesting information on research opportunities related to residential wood heater technology advancement 

Purpose 

The purpose of this RFI is to solicit feedback from industry, academia, research laboratories, government agencies, and other stakeholders on issues related to overcoming the technical barriers and challenges in the design of clean, efficient residential scale wood heaters. EERE is specifically interested in information on identifying the critical technology gaps and resources required to significantly reduce emissions and improve efficiency of residential wood heaters. Gaps of interest include but are not limited to the stove design, automation, catalyst development, retrofit technologies for older wood heaters, sensor technology, and stove performance testing methods. 

This is solely a request for information and not a Funding Opportunity Announcement (FOA). EERE is not accepting applications. 

Category 1: Residential Wood Heater Technology Advancement 

Technological Barriers 

1. What are the critical technical hurdles for improving performance of stoves for new installations (e.g. combustion chamber design, combustion air management, controls, mixing, sensors, etc.)? 

2. What are the critical technical hurdles for improving performance of stoves already installed in homes (e.g. combustion chamber design, combustion air management, controls, mixing, sensors, etc.)? 

3. What practical and new techniques are used to significantly reduce transient emissions (startup, shutdown, load changes)? 

4. What practical and new techniques are used to measure transient emissions that could be implemented in laboratory or field testing? 

5. How can new exhaust emission control technologies be developed and practically deployed? 

6. How could integrated hybrid systems, in which biomass heaters are combined with other technologies such as heat pumps, solar, and high efficiency gas and liquid-fired appliances, be a route to reduced emissions? What are the technology barriers to this approach? 

7. How could field measurement methods be improved to ensure that biomass-appliances do not create local air quality issues in long-term use? 

8. What stove features commonly encourage end-users to purchase new or replace a wood heater? Or, what stove features are commonly attractive to the end-user? 

9. What advantages or disadvantages would continuous field performance data provide for advancing stove designs? 

Tools and Capabilities

1. How are trial-and-error test methods used to improved stove performance and advance stove design (i.e. development by implementation of incremental change and testing)? 

2. Is access to performance testing facilities a barrier to development? 

3. What in-house test methods are relied upon to validate and facilitate wood heater development? 

4. How much could rapid performance measurement methods shorten R&D test cycles? 

5. What specific test methods would be of interest to your enterprise? 

6. How are modeling and simulation tools being applied to improve wood heater designs? 

7. How could modeling and simulation tools be improved to meet your needs? 

8. What are the fundamental modeling gaps to enable broader use of modeling and simulation such as Computational Fluid Dynamics (CFD) to improve wood heater design? 

9. How are current measurement methods meeting your needs for evaluating performance and emissions from wood heaters? What could be done better? 

10. What performance/emissions measurements are most challenging to obtain? What makes obtaining these measurements challenging? 

11. What are three primary challenges your enterprise faces for advancing stove designs?

 Request for Information Response Guidelines 

Responses to this RFI must be submitted electronically to FY21MultiTopic@ee.doe.gov no later than 5:00pm (ET) on September 21, 2020. Responses must be provided as attachments to an email. It is recommended that attachments with file sizes exceeding 25MB be compressed (i.e., zipped) to ensure message delivery. Responses must be provided as a Microsoft Word (.docx) attachment to the email, and no more than 6 pages in length, 12 point font, 1 inch margins. Only electronic responses will be accepted. 

EERE will not respond to individual submissions or publish publicly a compendium of responses. A response to this RFI will not be viewed as a binding commitment to develop or pursue the project or ideas discussed.

Please identify your answers by responding to a specific question or topic if applicable. Respondents may answer as many or as few questions as they wish. 

Respondents are requested to provide the following information at the start of their response to this RFI: 

• Company / institution name; 

• Company / institution contact; 

• Contact's address, phone number, and e-mail address.

Testing Observations at the Wood Stove Decathlon

By Norbert Senf

The Wood Stove Decathlon was a historic event. It was the first ever attempt to gather a collection of stoves in the field (literally, in this case) and test them for particulate matter (PM) emissions.

Norbert Senf, right, with Neils Wittus,
center, and John Ackerly

For something untried until now, the side-by-side field-testing can claim several firsts. 

It successfully compared stoves within a surprising range of categories including masonry heaters as well as retrofit kits. The project was a success not only as a media event but also in advancing the real world testing of wood burning stoves.

Cordwood is an extremely complicated fuel to get repeatable data with because it is so inherently variable. To add to the challenge, PM is particularly difficult to measure, even in a laboratory. While the test results from the Decathlon were not sufficient to provide PM numbers that allowed comparison with EPA numbers, they did allow a ranking of the stoves against each other. This is a substantial achievement in itself.

PM is the wood fuel pollutant of greatest interest since it causes the most public health concerns. Carbon monoxide (CO) is another pollutant.  It is created by incomplete combustion like PM, but it is much easier to measure. It is generally not considered a health hazard in low atmospheric concentrations outside of densely trafficked urban areas, and eventually oxidizes to CO2 on its own.

Due to new wood burning emissions regulations in Germany, two new portable instruments for measuring PM in the field were recently developed there. Fortunately, this happened just in time for the Decathlon to try them out. The instruments are limited to the 15-minute test cycle that is mandated in the German regulation, and therefore can only measure what happens during a portion of the burn. Measuring an entire test cycle will certainly be a goal for future Decathlons.

Common wisdom holds that low carbon monoxide (CO) emissions, which are easy to measure, will also ensure low PM, which is difficult to measure. The contest results did not bear this out. The stove with the lowest PM had the second highest CO. For the stove with the lowest CO, there were 4 stoves with lower PM. To be sure, the data set is limited. The 15-minute test window did not allow for average values to be measured over the burn of an entire fuel load.

Repeatability is one of the most important measures of data quality. Since each stove in the Decathlon received two (in theory) identical test runs, we can get a brief glimpse here, as well. Discarding obvious outliers, we see a coefficient of variation (CV) in repeat runs of 43% on PM, 40% on CO and 7% on efficiency. This compares favorably with EPA inter-laboratory repeatability studies, where the two stoves with the largest data sets both came in at 44% CV on PM. For masonry heaters, an MHA (Masonry Heater Association) laboratory study on repeatability with dimensional lumber fuel cribs yielded 10% CV on PM, 1.5% on CO, and 0.26% on efficiency.

The repeatability metric provides a useful baseline for judging data quality in future decathlons. There is an ongoing fueling protocol debate in the testing community between the repeatability achievable with fuel cribs, and the real world randomness of cordwood. EPA testing is currently done with cribs. To get a repeatable EPA cordwood number may require running a large number of (expensive) laboratory test runs and taking an average. To date, very little work has been done to provide data for either side of the debate.

All in all, the Wood Stove Decathlon was a great effort towards advancing our knowledge about how wood stove emissions compare in the real world. This was particularly valuable to see for different classes of appliances with no commonly defined EPA testing methods.

Valuable lessons and insights were had for designing a future challenge. Seeing the complex testing issues play out in real life was a unique educational opportunity for contestants, organizers, judges, regulators and the testing community itself.

Norbert Senf was one of the ten judges at the Wood Stove Decathlon. He joined early efforts to write codes and standards, and was a founding member of the Masonry Heater Association of North America (MHA). He currently chairs the MHA Technical Committee.

In Memoriam: Paul Tiegs

Paul E. Tiegs
1943 - 2012

A pioneer in wood stove testing and a man of great integrity and intellect. Paul Tiegs was president at OMNI-Test Laboratories in Portland, Oregon.