Lost heat - what a waste!

Doesn't sound normal. Where my vent goes through the wall you can easily put your hand on it at all times. What does your stove use as a heat exchanger?

tjnamtiw said:

I was up on my chimney putting Crown Coat on the top and was really disappointed to see how hot the vent cap was on my liner coming from my Castile insert. Looks like I use a lot of my pellets to keep that 17 feet of 3" flex pipe nice and warm. At 75% efficiency, we use 500 pounds of pellets out of every ton just to heat the great outdoors. What a waste! When you look at the path that the hot air takes through the stove you can see why the efficiency is so poor. It sure isn't well thought out. One pass across nice, smooth pipes (laminar flow) and out the exhaust. If my stoves weren't new, I'd get in there on the off season and weld some fins on the pipes where the scrapers don't go to break up the flow and make it tumble as well as present more surface area to absorb heat. Those pipes really should be corrugated or finned and there should be a lot more smaller ones for more surface area. Piss poor design IMHO.
Has anyone done anything to address this situation?

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Efforts to improve net efficiency with a vented space heater has got to be a hard nut to crack.
We all know some heat exchangers are better than others but the difference between them isn`t great.
It might very well be that the Dell Point pellet stove is the very best at addressing net efficiecy but it comes at a price and with some trade offs.
To read about the Dell Point burn technology and their use of low percentage of air mixture resulting in less heat exiting the vent is impressive but I haven`t been able to find much praise or definitive proof outside of their brochures. I`d like to believe that their stove technology is the future but I can find no valid proof to substantiate the claims that it performs significantly superior or that it uses significantly less fuel that other top end stoves.

tjnamtiw said:

I was up on my chimney putting Crown Coat on the top and was really disappointed to see how hot the vent cap was on my liner coming from my Castile insert. Looks like I use a lot of my pellets to keep that 17 feet of 3" flex pipe nice and warm. At 75% efficiency, we use 500 pounds of pellets out of every ton just to heat the great outdoors. What a waste! When you look at the path that the hot air takes through the stove you can see why the efficiency is so poor. It sure isn't well thought out. One pass across nice, smooth pipes (laminar flow) and out the exhaust. If my stoves weren't new, I'd get in there on the off season and weld some fins on the pipes where the scrapers don't go to break up the flow and make it tumble as well as present more surface area to absorb heat. Those pipes really should be corrugated or finned and there should be a lot more smaller ones for more surface area. Piss poor design IMHO.
Has anyone done anything to address this situation?

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Did ya ever hear of the Magic Heat?????

Regarding pellet stove efficiencies, I`d like to present a somewhat related analogy:
An oil burner mechanic aquaintence told me that I ought to consider changing out my *Beckett* oil burner to a *Riello* (made in Italy).
The Riello is by his opinion the best and requires the least repairs over the years not to mention it`s unique quiet air flow design. I asked if it would burn less fuel and he couldn`t say so I tried to find out from different sources and was unable.
From all information available to me that I could find the Beckett is rated very high also. Mines not needed service (other than cleaning every two years) since it was installed new in 1996. Thats 14 yrs and it appears that little to none advancements have been made in oil burner technology since.
Oh and let me add this, all local oil burner techs are schooled and experienced to service the Beckett but few are to service the Riello.
Pellet stoves have been around for maybe 25 yrs + and it looks like even less new technology has been made other than auto start , thermostats, and ash pans.

Gio said:

Regarding pellet stove efficiencies, I`d like to present a somewhat related analogy:
An oil burner mechanic aquaintence told me that I ought to consider changing out my *Beckett* oil burner to a *Riello* (made in Italy).
The Riello is by his opinion the best and requires the least repairs over the years not to mention it`s unique quiet air flow design. I asked if it would burn less fuel and he couldn`t say so I tried to find out from different sources and was unable.
From all information available to me that I could find the Beckett is rated very high also. Mines not needed service (other than cleaning every two years) since it was installed new in 1996. Thats 14 yrs and it appears that little to none advancements have been made in oil burner technology since.
Pellet stoves have been around for maybe 25 yrs + and it looks like even less new technology has been made other than auto start , thermostats, and ash pans.

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The efficiencies in oil burners hasn't changed much but if you use a boiler for hot water baseboards, the furnaces themselves have changed a lot. I installed a Viessmann Vitorond 100 (German) boiler several years ago (before I even thought of a pellet stove). This boiler is called a triple pass boiler because the water in the heat exchanger passes thru the combustion chamber three times before leaving the boiler. I managed to drop my oil usage from around a 1,000 gallons a winter to less than 600 gallons heating the same space to the same temps. The tradeoff is that this boiler is quite a bit larger than my previous one but what the hey, it's in the basement. Now with the pellet stove I am using less than 150 gallons a winter and that is only to heat the bedrooms at night or to keep the house from freezing when we are away for the weekend.

Marbleguy said:

Gio said:

Regarding pellet stove efficiencies, I`d like to present a somewhat related analogy:
An oil burner mechanic aquaintence told me that I ought to consider changing out my *Beckett* oil burner to a *Riello* (made in Italy).
The Riello is by his opinion the best and requires the least repairs over the years not to mention it`s unique quiet air flow design. I asked if it would burn less fuel and he couldn`t say so I tried to find out from different sources and was unable.
From all information available to me that I could find the Beckett is rated very high also. Mines not needed service (other than cleaning every two years) since it was installed new in 1996. Thats 14 yrs and it appears that little to none advancements have been made in oil burner technology since.
Pellet stoves have been around for maybe 25 yrs + and it looks like even less new technology has been made other than auto start , thermostats, and ash pans.

Click to expand...

The efficiencies in oil burners hasn't changed much but if you use a boiler for hot water baseboards, the furnaces themselves have changed a lot. I installed a Viessmann Vitorond 100 (German) boiler several years ago (before I even thought of a pellet stove). This boiler is called a triple pass boiler because the water in the heat exchanger passes thru the combustion chamber three times before leaving the boiler. I managed to drop my oil usage from around a 1,000 gallons a winter to less than 600 gallons heating the same space to the same temps. The tradeoff is that this boiler is quite a bit larger than my previous one but what the hey, it's in the basement. Now with the pellet stove I am using less than 150 gallons a winter and that is only to heat the bedrooms at night or to keep the house from freezing when we are away for the weekend.

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Thanks Marbleguy, I was talking about the burners themselves but your reply is quite relovent and definitely related..
I`m familiar with the German Buderus boilers too. They are super efficient too with regards to net efficiency.
All this this kinda re-enforces / relates to my favorite topic (pet groan)on with pellet stoves , that being the design of the heat exchanger itself being where the most improvements are to be made.

tjnamtiw said:

Gio said:

All this this kinda re-enforces / relates to my favorite topic (pet groan)on with pellet stoves , that being the design of the heat exchanger itself being where the most improvements are to be made.

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Glad to hear it's your pet groan too. Let's form a groan society............... Hmmmm, that didn't come out right. %-P

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Don't you think that there are way to many of them around already. Seems to me that there is at least one in most households.

Regarding the oil boiler comments:

We replaced our 39 year old American Standard boilerBeckett burner with a Buderus triple pass boiler with a Riello burner this last December and the difference is amazing. (Right, it should be with 39 years difference in age.) The Riello burner operates VERY differently than the legacy Beckett ( which never gave us any trouble, just different technology).

The Buderus is a zero start and we have the Buderus super insulated hot water tank as compaired to a domestic hot water coil inside the old boiler.

The wood boiler is in parallel with the new oil boiler and connected so that, when in use, the wood boiler will heat the house as well as the domestic hot water.

I told the oil guy to take us off automatic delivery. I guess he doesn't listen well as for the January unwanted and unasked for automatic delivery fill , they could only stuff 16.7 gallons into the oil tank. I chuckled about that for a few days!!

Still, I love the pellet stove and enjoy having multiple options for heating. I HATE to be cold! I am a certified HEAT HOG.

Ranger

Independent efficiency testing on the Castile (according to Quad) has been in the low 80s...not too bad, a well tuned conventional oil boiler gets in the mid 80s...anything much higher than that and you run into condensing issues in the exhaust stream (Creosote)..the lennox condensing gas furnaces are in the low 90s but condensing oil furnaces...well I not sure I've ever seen one......these are limitations of combustion,,,sure you can easily make a heat exchanger to take all the heat out of the exhaust stream but there would be trade offs to deal with!!

I think the Dell Point are different because of their 2 stage burn, the first stage is slow low temp burn to drive the combustion gasses out of the fuel (gassification) , followed by the 2nd stage which is a very clean hotter burn of the gasses extracted in stage one....I looked into the Dell-Point and spoke with Claude Lapointe, but decided against it only because at the time there was no local dealer network.....love the concept though!!

peirhead said:

Independent efficiency testing on the Castile (according to Quad) has been in the low 80s...not too bad, a well tuned conventional oil boiler gets in the mid 80s...anything much higher than that and you run into condensing issues in the exhaust stream (Creosote)..the lennox condensing gas furnaces are in the low 90s but condensing oil furnaces...well I not sure I've ever seen one......these are limitations of combustion,,,sure you can easily make a heat exchanger to take all the heat out of the exhaust stream but there would be trade offs to deal with!!

I think the Dell Point are different because of their 2 stage burn, the first stage is slow low temp burn to drive the combustion gasses out of the fuel (gassification) , followed by the 2nd stage which is a very clean hotter burn of the gasses extracted in stage one....I looked into the Dell-Point and spoke with Claude Lapointe, but decided against it only because at the time there was no local dealer network.....love the concept though!!

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If the Dell Point could actually save a user 25% or a ton of pellets each year the payback might be worth it. But as you stated the dealer network , service , parts availability have to be considered especially for a 5K investment.
Then again, if this technology is so good we should have expected others to follow it by now as it isn`t rocket science either. I`d have to believe the large pellet stove companies could refine the design , reduce cost , making it more competitively priced. But you just don`t see this happening.

Sometimes, with advances in technology, and old idea finally actually becomes viable...perhaps the age of gasification is upon us!!..here is a link to an interesting article. http://www.gasificationaustralia.com/index.php?option=com_content&task=view&id=15&Itemid=31

tjnamtiw said:

I was up on my chimney putting Crown Coat on the top and was really disappointed to see how hot the vent cap was on my liner coming from my Castile insert. Looks like I use a lot of my pellets to keep that 17 feet of 3" flex pipe nice and warm. At 75% efficiency, we use 500 pounds of pellets out of every ton just to heat the great outdoors. What a waste! When you look at the path that the hot air takes through the stove you can see why the efficiency is so poor. It sure isn't well thought out. One pass across nice, smooth pipes (laminar flow) and out the exhaust. If my stoves weren't new, I'd get in there on the off season and weld some fins on the pipes where the scrapers don't go to break up the flow and make it tumble as well as present more surface area to absorb heat. Those pipes really should be corrugated or finned and there should be a lot more smaller ones for more surface area. Piss poor design IMHO.
Has anyone done anything to address this situation?

Click to expand...

I solve that by using a 94.9% LHV stove in our showroom. Only waste 100 pounds per ton. Considering we burn a lot in here even in the warmer months as demonstrators, a stove that burns 30-40% less pellets pays off. I just wish they would hurry up and make a fireplace insert.

Guys,

Just some quick comments on heat exchangers no matter the heat source (wood coal, oil or natural gas). I spent a little time last night running some thermodynamic calculations. I will not bore you with the math.

My general theory and premise was that it should be possible to design a better heat exchanger that will provude more heat to our controlled environmant (home) vs "up the Chimney"

I used my pellet stove as a base line (harmon accentra insert)

I thought that by changing the material in the baffles I should improve the heat transfer. Currently I used cold rolled steel as the base line and ran the calculations for Alluminum and copper (both 7 to 10 times better at transmitting heat) and coudl only get an increase of 1 and 1.23% respectively.

I then thought I coudl design a better baffle to absorb the heat into the airstream. Well I could and get about 15% more heat out. The only problem is I couldn't figure out how to clean the Damn thing.

I ran some numbers based on clean and dirty. Guys We need to clean our systems of flyash at theast every week. I took a measurement of the fly ash on ine after 5 days of burning. Heat transmission drops by 17.2% on about 1/16th of an inch of fly ash. (clean is important)

OK I checked to make sure we have turbulent flow in the home air source and found that as long as the distribution fan is on even at the lowest setting we have turbulent flow. (increaseing fan speed will distribute the heat throughout the house better but will not improve the heat exchanger performance.

About the only method I found that will improve the efficinecy of the system is to install a second heat exchanger in the exhaust pipe. This could be done as an after market part and with a small squirl cage fan. You are looing at getting another 10 to 12% (depending on your delta T) increase in efficiency but this will also creat back pressure on the combustion chamber and without a significant study and possible modification to the combustion fan I can not invision OEM approval on that.

tjnamtiw said:

At 75% efficiency, we use 500 pounds of pellets out of every ton just to heat the great outdoors.

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I think it's worse than that. I read somewhere's that the exhuast on my stove is limited to 400* I always run on max and the most heat i get out the front is 150* This stove is rated for 85 percent efficiency, I'm not good with math, but that would be something like 900 lbs per ton wasted or 40 percent efficiency.



I've been thinking about putting a pipe in the flame to heat the baseboard.

That isn't how efficince is rated it isn't output temp vs exhaust temp...

It is BTUs obtained in the heated space/ BTUs available in the pellets.

You calculate BTUs based on volume of heated medium (air or water etc) times a constant for the medim * the change in temperature.

85% means that the absolute best the manufacturer was able to do in a laboratory with perfect conditions was to tranfer about 6800 BTUs into the air (room) per pound of pellets.

To give an example. this time of year I need 20,000 BTUs per hour to hold the temperature at 70* in my house.

so I need to burn 3 pounds of pellets.

Trickyrick, right or wrong I bow down before your great geekdom... thank you

Maybe someone will come out with a 90-95 % condensing pellet stove. Stainless steel second chamber with water drain line, PVC vent pipe. Probably cost only a few grand more.
I think I will stick with my Quad, lots of heat on medium, blower moves lots of air.

slls said:

Maybe someone will come out with a 90-95 % condensing pellet stove. Stainless steel second chamber with water drain line, PVC vent pipe. Probably cost only a few grand more.
I think I will stick with my Quad, lots of heat on medium, blower moves lots of air.

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94.9% on the Europa. Already done. Retails for $4500 currently. Multi fuel, battery backup and a no drama ash managment system. Heats 1500 square feet here in CNY on 2 lbs per hour most days of the year.

The 99% eff. on the Europa is an interesting number, it means...
"99% Fuel Efficiency
99% of the corn, wheat or wood pellets fed into your Europa pellet burning stove are used for combustion - leaving only 1% of waste." Quoted from dealer web sight

This is the same as every other pellet stove using premium pellets... 1% or less ash... 1% of waste.

The other eff rating quoted is "amazing 86% heat transfer efficiency" Similar to other stoves

So where do you get the 94.9% you are talking about?

Franks said:

slls said:

Maybe someone will come out with a 90-95 % condensing pellet stove. Stainless steel second chamber with water drain line, PVC vent pipe. Probably cost only a few grand more.
I think I will stick with my Quad, lots of heat on medium, blower moves lots of air.

Click to expand...

94.9% on the Europa. Already done. Retails for $4500 currently. Multi fuel, battery backup and a no drama ash managment system. Heats 1500 square feet here in CNY on 2 lbs per hour most days of the year.

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The Europa is a very good stove no doubt, but they are rated at 86% overal efficiency according to their website. Very similar to most certified pellet stoves. I think 94.9% refers to combustion efficency.