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| Diagram of stove field testing unit. |
We also urge stakeholders to reinforce points made by AGH in your submission to the DOE. Please feel free to copy any of the points we make below, put them in your own words and/or develop them further. If you feel any of our points are off-base and should be changed or expanded, please email John Ackerly at jackerly@forgreenheat.org. For more background, click here.
Dear DOE,
Thank you for requesting input through this Request for Information (RFI). We are especially thankful that BETO has embraced this relatively small effort to distribute $5 million to support developing and testing new wood heaters. We are also mindful that the effort required to run a $5 million grant program may be similar to the effort required to run a $50 million program.
The wood heating manufacturing community has not had this kind of support from a government agency in the past several decades. However, it came at a time when the manufacturing community was in the final stage of testing to meet the stricter 2020 EPA emission standards. Much of the community does not have experience applying for federal grants, which can be challenging for smaller firms.
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| R&D labs could apply to test stoves after certification to help assess effectiveness of designs on emission performance. |
We are encouraged that some of the questions posed in this RFI may indicate BETO is open to expanding the focus of future grant cycles. Questions on the performance of stoves already installed in homes and field testing are important as they embrace the life cycle of heaters. Congressional language has urged BETO to “support development and testing of new domestic manufactured low-emission, high efficiency residential wood heaters.” Testing of new heaters can also occur once they are installed in the field. Testing can include various iterations of round robin testing before or after certification. And, the development of new heaters can include the development of component parts, software applications, and other essential stages in the development process, not just the final act of assembling a finished stove for certification.In short, we fully support BETO to follow the Congressional language and not add additional restrictions or preconceptions about the traditional stove certification process.
We think that the barriers to developing and testing new stoves are not the only barriers stove manufacturers face. Thus, we are unsure if the list of technical questions you ask will solicit robust feedback on many key issues pertaining to the development of heaters. The engineering expertise and solutions to these questions can be built up. Many academics, non-profits and jurisdictions are eager to engage in more field testing of new stoves, and to do additional types of testing before deployment.
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| Norbert Senf, AGH's board chair, introducing the SBI team at the 4th Stove Design Challenge. SBI later won one of the DOE grants with their US partner. |
Renewable energy technology development often happens quickly when there is significant government subsidies and expanding consumer demand. The DOE’s programs supporting solar PV, paired with Congressional support for significant tax breaks, is a good example.
BETO’s program can help on the technical side of this equation by promoting the development and testing of heaters that meet the requirements of modern renewable energy incentive programs. These programs often need to better understand field performance characteristics of the technology in question.
Unlike some European counties, U.S. federal and state agencies have barely ventured into the realm of aggressively promoting the cleanest heaters, which first requires the development and testing of classes of heaters that are appropriate for greater deployment. State policy frameworks are beginning to shift from decarbonizing electricity solely to also include decarbonizing heat, and it is likely that the federal government will do so as well in coming years. BETO can play a vital role in preparing for this by focusing on technical issues related to heater development and testing.
We are providing answers to those questions where we have the most expertise and where we think BETO can be most influential.
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.)?
A. We applaud BETO’s focus on supporting efforts to develop automated heater controls, as these are one of the most effective ways to improve performance over the lifetime of the heater.
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.)?
A. Some technical solutions, such as adding an ESP, exist; however, these quickly can become more expensive than a stove replacement. The most cost-effective changes relate to the fuel used, and significant change in this area may require new local and state firewood regulation. For BETO’s mandate to support not just the development of heaters but also testing, there is much work to be done on testing new heaters that have just been installed in homes to better understand how performance can be improved.
3. What practical and new techniques are used to significantly reduce transient emissions (startup, shutdown, load changes)?
A. Automation of stoves is one of the most promising ways to improve transient emissions. Changes in test methods are also vital, and test methods depend on developing data about transient emissions and making that data transparent to the public.
4. What practical and new techniques are used to measure transient emissions that could be implemented in laboratory or field testing?
A. There is an increasing variety of technologies to measure not just transient emissions, but all emissions, both in the lab and in the field. The problem is that there is little funding or mandates for them.
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?
A. Many of these systems exist as prototypes or are on the market, especially in Europe. There are few technology barriers to this approach. When policies mandate increasing residential renewable heating, hybrid systems will emerge to make use of the strengths of different technologies and the seasonal costs and availability of electricity, solar, biomass and stored energy. BETO could play an important role by focusing future FOAs on hybrid systems and making R&D funding available for the integration of wood heaters with heat pumps. Funding could be routed through heat pump companies, wood heater companies or even software companies to achieve this. Integrating solar thermal with biomass thermal also holds tremendous potential.
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| Annual emission testing using handheld devices like the Testo 380 is vital to understand impacts of wear and tear on emissions. |
7. How could field measurement methods be improved to ensure that biomass-appliances do not create local air quality issues in long-term use?
A. Testing new heaters in real world settings is vital before and after the certification process. Manufacturers need equipment to enhance their beta testing in homes during the winter(s) before they finalize and certify products. Academics and non-profits can use existing or newly developed equipment to test emissions of newly certified heaters once they are installed in homes. In terms of ambient air quality, a variety of sensors, including the Purple Air sensor network, exist or could be developed to help understand impacts of stove groupings. States that have enforcement capacity and use opacity criteria in the field, such as Washington State, have experience with identifying and understanding why certain stoves may be particularly problematic. Sensors or sensor networks could also calculate the benefits of deploying the cleanest heaters, instead of perpetually trying to monitor, enforce and manage emissions of traditional certified wood stoves that can burn unseasoned wood at low air settings at any time.
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?
A. Price is a top consideration. Clean glass is another. Aesthetics are always a driving factor. The actual or perceived ease of use can be very important. Heating capacity, log size and burn time are key for many consumers. There are also different considerations for wood versus pellet stove customers, and for those looking for a primary versus a periodic or secondary heater. Fuel management is also a big issue, with some operators switching to pellets to avoid the enormous work of wood stoves, and others giving up pellet stoves because they can’t lift 40-pound bags. For pellet stoves, durability, reliability and access to professional service should be higher priorities than they are currently. BETO could play a very productive role in developing durable pellet stoves that use interchangeable, easily sourced replacement parts, for example.9. What advantages or disadvantages would continuous field performance data provide for advancing stove designs?
A. This sort of data is extremely valuable, and funding programs to collect it would help develop and test new wood heaters. This data is also helpful in developing new test protocols, which in turn would lead to changes in stove design. Depending on the metrics produced and how they are communicated, data could help consumers operate stoves better. It could also help stove R&D departments, especially if the data came from the stove manufacturer's own stoves. If this data is only available in summary form via a regulatory agency, it would have diminished applications. There is tremendous potential and a wide range of opportunities to gather certain types of field performance for different stakeholders: users, neighbors, retailers, manufacturers, air quality agencies, academics, etc. Continuous field performance data is currently collected by solar PV installers, internet providers and auto makers, for example, for a wide variety of purposes. One of the most obvious is to help with remote trouble shooting, which in turn leads to the R&D of software and hardware that avoids those issues.
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?
A. Most mid-sized and larger manufacturers have their own in-house labs for testing. Increasingly, the definition of a testing facility or testing lab is broadening, as more affordable and handheld equipment comes on the market, enabling anyone to enhance their in-house testing capacity. The third-party labs used for certification have the capacity to handle testing but the time and cost involved is a barrier. If the time and cost involved were less, companies may engage in more R&D and update their stove designs more often. Currently, when a stove model gets certified, it can remain unchanged on the market for 10 or 20 years, or until required by the EPA to test again to meet a new NSPS.
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?
A. A variety of test methods and practices are of great interest to AGH, starting with cord wood testing using test methods involving multiple labs, or being used on new stoves after installation in the field.
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Stove testing is often considered as exciting as
watching paint dry. Here, AGH researcher Gabriel McConnel assists in
DOE's Brookhaven lab in advance of a Stove Design Challenge. |
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?
A. Current methods usually do not evaluate heater performance apart from the narrow conditions under which they were tested. There is much potential in affordable measurement methods. The more complex part is whether manufacturers will have the motivation to use them.
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?
A. 1. Funding. AGH could engage in extensive activities to advance stove development and testing with more funding.
2. Lack of a more robust community of academics, non-profits, agencies and private sector companies involved in innovative stove designs and testing.
3. Lack of policy frameworks that focus on decarbonizing residential heating and a lack of incentives for the very cleanest and most efficient heaters.
Sincerely,
John Ackerly,
President
Alliance for Green Heat
