Question about firebox and flue gasses and particulates

[habanero]

Sounds like a heat pump with a wood stove for the coldest nights is a good compromise. The heat pump will be inexpensive to operate and provide AC in the summer.

The 2b Classic is a modern EPA approved solid fuel heater with an air wash over the glass. It actually has a flap inside the door that actually does most of the work keeping the smoke from coming in. If I'm foolish on a reload smoke will roll out and I've had the draft momentarily reverse on rare occasions when lighting a cold stove during a fall windstorm. This stove is actually extremely easy to operate and live with.

Thanks for the heat pump/wood heat combo suggestion. I was able to put the friends mentioned in the OP in touch with some other friends who installed an all-electric mini-split system about 18 months ago. The friends with the mini-split system also has a small Jotul in one of their rooms. Might be a viable solution.

Also thanks for the feedback on the 2b Classic.

 

[habanero]

There is no constant firebox tending with most bobcat stoves. Yes cat stoves will burn longer. But if you read through many of the cat stove threads here and elsewhere smoke or creosote smell is a common complaint with them.

Thanks for the tip regarding smoke and creosote smells being a common complaint with cat. stoves.

 

[peakbagger]

As part of my current job I review a lot of energy efficient heating and coolings systems being installed in Massachusetts. The building owners that install them get heating credits similar to solar SRECs for 10 years. They do not get credit for cooling but the COPs are higher than air source so its smart idea. I am seeing a lot of small to medium size (6 story) buildings getting geothermal installed with no backup heat source. A lot of them are variable refrigerant flow systems that pump refrigerant around the building instead of hot air. Ultimately there are air handlers at each floor. ASHRAE requires a certain level of outdoor air in every occupied space so that is managed with separate ducting. Mass is too cold for air source units but if the winter time temps above 10 F then air source units are a lot cheaper to install. They are 2 to 4 times more efficient then straight electric heat. These systems use glycol to move the heat around to radiant emitters or air handlers. In low humidity areas with some care they also can be swapped to radiant cooling instead of air handlers. There still is a need for air makeup using an ERV, but as discussed a combination of HEPA filters and a carbon bed scrubber will take out just about any air contaminant. Outdoor air is going to get in house somehow, the key is intentionally introduce it from a treated source and slightly pressurize the house so unfiltered sources do not sneak in. Ideally there is double door arrangement at primary entrance door so that someone entering the space has to close the outside door before opening the door to the interior. A lot of New England homes have mudrooms that serve the same purpose of keeping out cold drafts from outdoors. I have one and it works remarkably well.

 

[maple1]

I don't think I would want to introduce wood burning into the situation that has been explained here.

Not that wood burning is bad, it can be very good. If done right, with proper installation, operation and other practices. But one little slip up or forgetful moment can spill some smoke.

 

[Socratic Monologue]

I think the combustion byproducts can be brought into the home quite easily in a drafty house. Usually these direct vent appliances exhaust at adult human chest or head level if on the ground floor.

That's a good point. I don't know the venting requirements of the OP's furnace, but this could likely be easily, cheaply, and effectively remedied by a longer venting run, or venting out the roof.

 

[SpaceBus]

I don't think I would want to introduce wood burning into the situation that has been explained here.

Not that wood burning is bad, it can be very good. If done right, with proper installation, operation and other practices. But one little slip up or forgetful moment can spill some smoke.

I think as a backup for sub 10df nights (rare even in N Cal) something like a Jotul 602 or similar would work well. It would only be lit a few times of year and this family is reportedly ok with wood as primary heat. As peakbagger mentioned better air sealing and improving make up air quality is also going to be a big part of this.

 

[habanero]

As part of my current job I review a lot of energy efficient heating and coolings systems being installed in Massachusetts. The building owners that install them get heating credits similar to solar SRECs for 10 years. They do not get credit for cooling but the COPs are higher than air source so its smart idea. I am seeing a lot of small to medium size (6 story) buildings getting geothermal installed with no backup heat source. A lot of them are variable refrigerant flow systems that pump refrigerant around the building instead of hot air. Ultimately there are air handlers at each floor. ASHRAE requires a certain level of outdoor air in every occupied space so that is managed with separate ducting. Mass is too cold for air source units but if the winter time temps above 10 F then air source units are a lot cheaper to install. They are 2 to 4 times more efficient then straight electric heat. These systems use glycol to move the heat around to radiant emitters or air handlers. In low humidity areas with some care they also can be swapped to radiant cooling instead of air handlers. There still is a need for air makeup using an ERV, but as discussed a combination of HEPA filters and a carbon bed scrubber will take out just about any air contaminant. Outdoor air is going to get in house somehow, the key is intentionally introduce it from a treated source and slightly pressurize the house so unfiltered sources do not sneak in. Ideally there is double door arrangement at primary entrance door so that someone entering the space has to close the outside door before opening the door to the interior. A lot of New England homes have mudrooms that serve the same purpose of keeping out cold drafts from outdoors. I have one and it works remarkably well.

Thanks again for the helpful information.

In our area residential geothermal is pretty uncommon, as far as I know. I suspect the cost would be out of our friends' budget.

Thanks for pointing out that a mudroom can function as a sort of double door/air lock, and for the idea of maintaining a slight positive pressure as a means of keeping unfiltered air sources from sneaking in.

 

[habanero]

That's a good point. I don't know the venting requirements of the OP's furnace, but this could likely be easily, cheaply, and effectively remedied by a longer venting run, or venting out the roof.

The HVAC unit is on the exterior of the home, and vents out the side of the unit, at about 18 inches above grade. During the last servicing, our friend asked the HVAC tech if it would be possible to install a vent/duct to release the exhaust above the house rather than at ground level. The tech said there would be problems with the weight of the air in the duct restricting the flow of the exhaust, and doubted that the temperature of the exhaust would be high enough to create adequate convection flow/draft. The tech said it could be done but would require custom engineering and fabrication. I think that's as far as the idea went.

 

[habanero]

Looks like such conditions are accepted as real, but it also looks as if the causes are unknown:

The Chemical Sensitivity Foundation - Heating Systems and Gas Stoves

I'm skeptical -- simply based on the fact (I take this to be uncontested) that the combustion in a condensing gas furnace may as well be taking place on Mars since it is 100% insulated from the indoor air of the space it is heating -- that 'combustion byproducts' are the issue. Sounds as if it could be anything.

The OP is convinced that the problem manifests in spaces with gas forced air heat, and not in spaces heated by wood. Whatever the cause, wood heat is apparently a solution.

Thanks for taking the time to do some research on the phenomenon of inexplicable reactions to gas heat, and for the link.

Wood heat still produces combustion byproducts which are a known problem, though I've been told the symptoms are not as severe as with gas combustion byproducts. The reason I specifically asked, in my original post, for objective data on firebox and flue gases is that one of the doctors (a "real" doctor... Dr. of Internal Medicine, 30+ years in practice) requested the data so as to compare known triggers with potential triggers.

There's quite a bit of credible data online about outdoor toxins infiltrating interior air spaces in even the most advanced, energy-efficient new buildings. This is a possible explanation as to why even properly functioning gas-fired heaters/furnaces are a problem. I'm fairly certain there's quite a bit more to the issue than this.

 

[maple1]

Seems to me that stuff in the stove/firebox that could get into the house would be the stuff of smoke spillage, e.g. from opening the door at the wrong time at the wrong conditions. Which for all intents & purposes could be regarded as simple wood smoke. Which there should be composition info for somewhere online?

 

[habanero]

I think we need to step back and look at the problem we’re trying solve. These people have some ultra sensitivity to an unknown thing in the air. We’re never going to solve this problem. A freaking hospital is too unclean for them. Since both of them have this problem I’m hoping that some mental evaluations have been made.

Then, if the drugs don’t work, we would start with environment like removing all carpet, pets, cooking, cleaning chemicals, furniture with cloth, etc. to make a clean house. Especially bedding can be horrible.

This home almost requires ductwork heating for the plethora of filtration and conditioning for the air. Electric elements in that ducting or a heat exchanger fed by heated water or refrigerant is the only way to go.

No solid fuel burning heating system in the home will be sanitary enough. Going down this road is just a waste of time and money.

I agree with most everything you've said in this post except the questioning of our friends' mental health. Their condition has been diagnosed by "real" doctors (MDs, PhDs. One is a doctor of internal medicine with 30 years of experience.) The reality of the condition has been established by competent medical professionals beyond a reasonable doubt. Our friends have gone to great lengths to follow the recommendations made by medical and other professionals which include virtually all of the common-sense steps mentioned in this discussion thread to date, plus many which go beyond anything suggested here. I'd rather not go in to further detail on these points.

I'm making a general request (which in no way is intended to single Highbeam out) that speculations regarding the medical/psychological side of the issue be dropped. This is, after all, "hearth.com", not "medicalAdvice.com" or "psychology.com". The reason I'm doing this research and not the people with the actual condition is that they, after decades of fighting these rare/odd health issues, are weary of the frequent questioning of their intelligence, integrity and mental health.

The reason I specifically asked, in my original post, for objective data on firebox and flue gases is that one of the doctors (Dr. of Internal Medicine) requested the data so as to compare known triggers with potential triggers.

Does anyone have industry contacts (perhaps a member of hearth.com) who may be able to provide the specific objective data mentioned in my original post? Does anyone know of any online resources which provide this specific data? Does anyone have access to or know of university research or private air quality research? Is there by chance a member on hearth.com who is part of the BEESL lab at Syracuse University, or something similar?

As you can imagine, after decades of living with these issues, this family has amassed quite a bit of valid data and spent, by now, countless hours researching the matter. Please assume these people are diligent, intelligent and well informed because, quite frankly, they are.

Sorry to be so blunt. And, again, thank you all for your input.

 

[Socratic Monologue]

So, this may be an insultingly simple suggestion, but: have you dug around on Google Scholar?

I searched for 'wood stove emissions' there, picked a nearly random hit on the first page, and found this abstract:

"The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NOx, organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJfuel, while OGC varied from 210 to 3300 mg/MJfuel. Dominating VOCs were methane, followed by ethene, acetylene, and benzene. Methane varied from 9 to 1600 mg/MJfuel. The nonmethane volatile organic compound (NMVOC) emissions were in the range of 20−2300 mg/MJfuel. The PAHtot emissions varied from 1.3 to 220 mg/MJfuel, in most cases dominated by phenantrene, fluoranthene, and pyrene. PMtot were in all cases dominated by fine particles and varied in the range 38−350 mg/MJfuel. The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200−320 and 220−330 nm, respectively, and number concentrations in the range of 1−4 × 1013 particles/MJfuel. Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of condition is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies report considerably higher emissions especially for diluted particle sampling." (https://pubs.acs.org/doi/abs/10.1021/ef1007787)

This one seems interesting since you seem to be looking for measurements of specific chemicals, which this study investigates.

Not all articles you find there (https://scholar.google.com/) are accessible by the public, but some are, and others may be worth paying for, and you may be able to find someone on your end with university credentials who will take you to their library for a couple hours and get you access. You could also contact the authors of studies -- likely you'll mostly get ignored, but you might find someone willing to give you some leads.

 

[habanero]

So, this may be an insultingly simple suggestion, but: have you dug around on Google Scholar?

Not insulting at all. I stopped using Google products 10+ years ago and had forgotten about Google Scholar. Thanks for the suggestion and the links.

You could also contact the authors of studies -- likely you'll mostly get ignored, but you might find someone willing to give you some leads.

I'd considered doing that a few years ago when researching another subject, but, like you, assumed I'd get no response. Thanks for the suggestion. Now might be the time to give it a try.

Virtually all of the research I've come across has studied emissions, not firebox gases and particulates. My guess is there's funding available for studying emissions since this is what the EPA and other agencies are focused on. It's also possible that there are no practical means of measuring firebox gases. I'm also guessing that what is exhausted from a wood stove is actually cleaner than what's in the firebox.

 

[Socratic Monologue]

I'd considered doing that a few years ago when researching another subject, but, like you, assumed I'd get no response. Thanks for the suggestion. Now might be the time to give it a try.

A suggestion for getting a response, based on my time in academia: the primary author (first listed, typically) likely isn't interested in too much low-level correspondence. Contributing authors might be more interested, especially if they are graduate students (who are often still excited about their subject area). If you have the time and inclination, digging around in the online presence of the contributing authors may reveal one or two who seem more willing to help you out (mid-program grad students [the new ones don't know anything, and dissertation candidates have their hands full], someone whose academic website gives the impression of being honestly interested in their studies, one who seems to give more news outlet sorts of interviews, an so on).

 

[maple1]

Not insulting at all. I stopped using Google products 10+ years ago and had forgotten about Google Scholar. Thanks for the suggestion and the links.


I'd considered doing that a few years ago when researching another subject, but, like you, assumed I'd get no response. Thanks for the suggestion. Now might be the time to give it a try.

Virtually all of the research I've come across has studied emissions, not firebox gases and particulates. My guess is there's funding available for studying emissions since this is what the EPA and other agencies are focused on. It's also possible that there are no practical means of measuring firebox gases. I'm also guessing that what is exhausted from a wood stove is actually cleaner than what's in the firebox.

It would seem to me to be very obvious that the exhaust will be cleaner than the firebox.

I would also guess that any lack of data on firebox gas composition vs. exhaust emissions is simply because what comes out of the exhaust is what is important, when it comes right down to it, and it doesn't really matter what is in the box. Exhaust is what regs are tied to, and what manufacturers have to deal with - poison in the box is kind of irrelevant if it gets dealt with and made to disappear before exhausted. So to speak. I have never looked, but there must be data out there on what is in simple wood smoke? That would seem to be the starting point, or a good assumption of what is in the box.

Also not sure about the funding aspect. Manufacturers have to pony up big bucks - of their own - for R&D, and testing, before they can sell. Which has put some out of business, they were looking at so much $$ they felt it wasn't worth trying.

 

[peakbagger]

I have a wood gas handbook somewhere in the house. Its about 2" thick and has far more information than most would want to wade through on wood stoichiometry. There are all sorts of intermediate reactions. that are going on. They are all contained in the firebox so few worry about it except for the folks who are trying to extract precursers from the intermediate reactions.

 

[EbS-P]

nice finds. If you need access to articles I’m happy retrieve them and post for you (if my library has access)

evan

So, this may be an insultingly simple suggestion, but: have you dug around on Google Scholar?

I searched for 'wood stove emissions' there, picked a nearly random hit on the first page, and found this abstract:

"The characteristics and quantities of a large number of gaseous and particulate emission components during combustion in a residential wood log stove with variations in fuel, appliance and operational conditions were determined experimentally. The measurement campaign included CO, NOx, organic gaseous carbon (OGC), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), total particulate matter (PMtot) as well as particle mass and number concentrations, size distributions, and inorganic composition. CO varied in the range of 1100 to 7200 mg/MJfuel, while OGC varied from 210 to 3300 mg/MJfuel. Dominating VOCs were methane, followed by ethene, acetylene, and benzene. Methane varied from 9 to 1600 mg/MJfuel. The nonmethane volatile organic compound (NMVOC) emissions were in the range of 20−2300 mg/MJfuel. The PAHtot emissions varied from 1.3 to 220 mg/MJfuel, in most cases dominated by phenantrene, fluoranthene, and pyrene. PMtot were in all cases dominated by fine particles and varied in the range 38−350 mg/MJfuel. The mass median particle diameters and the peak mobility diameters of the fine particles varied in the range 200−320 and 220−330 nm, respectively, and number concentrations in the range of 1−4 × 1013 particles/MJfuel. Air starved conditions, at high firing intensity, gave the highest emissions, especially for hydrocarbons. This type of condition is seldom considered, though it may occur occasionally. The emissions from Swedish wood stoves, comparing a Swedish field study, are covered fairly well with the applied methodology, but other field studies report considerably higher emissions especially for diluted particle sampling." (https://pubs.acs.org/doi/abs/10.1021/ef1007787)

This one seems interesting since you seem to be looking for measurements of specific chemicals, which this study investigates.

Not all articles you find there (https://scholar.google.com/) are accessible by the public, but some are, and others may be worth paying for, and you may be able to find someone on your end with university credentials who will take you to their library for a couple hours and get you access. You could also contact the authors of studies -- likely you'll mostly get ignored, but you might find someone willing to give you some leads.

 

[Mech e]

Clean rooms are very common in the medical device and integrated circuit (e.g. Intel) industries. These rooms can be much larger than your typical home. Perhaps contacting a mechanical contractor that specializes in clean rooms and applying some of their practices to your friend's home could be an option.

I would still start with a heat pump and then go from there.

 

[maple1]

Also seems like that furnace situation - hung and vented low on the outside of the house - would give potential for flue gasses creeping back in through the envelope somehow.

 

[habanero]

A suggestion for getting a response, based on my time in academia: the primary author (first listed, typically) likely isn't interested in too much low-level correspondence. Contributing authors might be more interested, especially if they are graduate students (who are often still excited about their subject area). If you have the time and inclination, digging around in the online presence of the contributing authors may reveal one or two who seem more willing to help you out (mid-program grad students [the new ones don't know anything, and dissertation candidates have their hands full], someone whose academic website gives the impression of being honestly interested in their studies, one who seems to give more news outlet sorts of interviews, an so on).

Thanks. Those are excellent suggestions.

 

[habanero]

nice finds. If you need access to articles I’m happy retrieve them and post for you (if my library has access)

evan

Thanks, Evan. Very thoughtful offer.

 

[habanero]

Clean rooms are very common in the medical device and integrated circuit (e.g. Intel) industries. These rooms can be much larger than your typical home. Perhaps contacting a mechanical contractor that specializes in clean rooms and applying some of their practices to your friend's home could be an option.

I would still start with a heat pump and then go from there.

Thanks for the suggestions. About 10 years ago our friends spoke with an air quality specialist who designed/built clean rooms for tech and medical clients. The cost of applying the technologies to a residence which would yield results over and above what our friends already have in place were cost prohibitive.

 

[habanero]

Also seems like that furnace situation - hung and vented low on the outside of the house - would give potential for flue gasses creeping back in through the envelope somehow.

Thanks for the suggestion. They'd already considered that and spoke with an HVAC tech about venting the exhaust above the roofline. It's mentioned in this post: https://www.hearth.com/talk/threads...e-gasses-and-particulates.178620/post-2400681

 

[maple1]

Thanks for the suggestion. They'd already considered that and spoke with an HVAC tech about venting the exhaust above the roofline. It's mentioned in this post: https://www.hearth.com/talk/threads...e-gasses-and-particulates.178620/post-2400681

Yes, I saw that. I think I might try another opinion from another furnace guy.