Bulk storage for pellet stoves

[Deering]

I'm sure this has been discussed here at length before, but I searched the threads and couldn't find much, so apologies if I'm beating a dead horse...

Up here in SE Alaska we have a lot of hydropower which has yielded pretty low electricity rates in the past. Many houses were built with electric resistance baseboard as their sole source of heat. But over time as the population grew, the electric demand outstripped the supply and rates began to rise. At the same time the price of oil decreased so thousands of houses installed Monitor or Toyo stoves - small free-standing, direct-vented oil stoves. We don't have natural gas up here, and propane is prohibitively expensive, so oil was the only option.

Seemed like a great solution until the price of heating oil skyrocketed over the past 20 years. Now both electric and oil heat are expensive. Lots of people use wood stoves, but we all know that cordwood isn't a solution for everyone for a number of reasons. Pellets, at around $350/ton up here (half the cost is in barging) still offer big savings over oil or electric. And if the demand grows enough, we'll see local pellet mills spring up and then the cost will drop substantially.

Pellet stoves are pretty much a drop-in replacement to Monitor stoves - they're a similar size, can be direct vented, and function pretty much the same way. But there's only one problem - a Monitor is connected to a 250 gallon oil tank, it can run for months before refueling. A pellet stove needs fuel added every day or two. If there was a pellet stove that featured an exterior bulk silo connected to it, with automatic fuel transfer (auger or pneumatic), then the pellet stove could truly replace the Monitor stove.

So why aren't there any? I've surveyed the stove market and haven't found any manufacturers that offer this option. Harman comes close - they have a 1,500 lbs bulk hopper for their PB-105 boiler and the literature states that it's also compatible with some of their stoves, but the sheet metal hopper isn't something you're going to want in your living room, and it isn't suitable for outdoor siting. Anyone out there have one of these connected to their pellet stove? What does the connection detail look like?

This just seems like a huge gap in the market. Pellet stoves are relatively cheap compared to boilers or furnaces. They have lots of flexibility where they can be installed. The newer ones are efficient and relatively low maintenance. They're a great heating solution that are within reach of a lot of people. If they only connected to bulk storage, they'd be a complete solution. I could see hundreds of them being sold up here, and we're just a small market - surely we're not unique. So why hasn't this gap been filled? What am I missing?

 

[vinny11950]

I'll give it a try.

The cost of something like that like that would make those stove much more expensive. Also you are adding another system/motor to deliver the pellets from the bulk storage so it would be another set of parts to maintain and replace. Pellet stoves already have enough moving parts that make them hard to maintain for the average user.

Though Europeans have something like that with some of their systems. If you search for threads about European pellets you will see it discussed.

Plus, bulk storage would require getting a bulk storage container put in somewhere near the stove which would then limit exactly where to put it.

Easier and cheaper to do it by bag.

Happy Holidays and stay warm.

 

[Bioburner]

AK still doesn't have that big of population. Kernal burner could use a external holding bin and used flex flight auger system. Flex flight augers are the same that are used in feeding pig and chicken operations. Ive seen feed system adapted for stoves and is fairly simple timer and switch to control.

 

[Deering]

Vinny, you're right on all counts, but...feeding by the individual bag fails when you have to go out of town for a week or end up in the hospital. Or maybe you're too old or otherwise unable to physically hump bags of pellets. Your same arguments could also be applied to Monitor stoves to some degree - that big external tank is expensive, requires pumps and piping and filters and valves and switches, it's expensive and represents a spill risk - it would just be easier and cheaper to fill the day tank on the stove with gallon jugs of kerosene. But no one does it.

Bioburner, that's along the same lines I had in mind. Maybe a small hopper mounted on the outside wall adjacent to, and above the stove with a gravity feed of some sort filling the stove's onboard hopper. A sensor would signal the hopper when the stove was getting low. The hopper would be filled by a pneumatic unit, similar to a CornVac maybe http://www.cornvac.com/SecondaryTank.html, which could pull pellets from a bulk bin or silo some distance away. That bin could hold several tons of pellets, enough for a single refueling per year. This kind of arrangement would allow maximum flexibility in placement of the stove.

What would this cost? Well, the CornVac hopper unit is $250, add in a strong vacuum (maybe a whole-house vac system), hose, connections, some kind interface to the stove, with appropriate fire safety elements, controls...$1,000? Maybe $1,500 installed? Then add a bin or a small silo for maybe another $2,000 depending on the size. So you've doubled the cost of a high-end pellet stove at around $6,000. And if this system was manufactured in quantity, I could see some of those prices come down.

Even at our sky-high pellet prices up here, a pellet stove can knock 1/3 off of a home's annual heating bill. So if a house spends $3,000 here (a lot higher in the more remote communities where heating oil can approach $6 per gallon), the payback could be in 6 years. Not an unreasonable proposition, it seems to me.

 

[Enigma869]

heating oil can approach $6 per gallon.

Pardon my ignorance if I'm wrong about this, but I thought Alaska produced most of the oil in this country? I admittedly don't know much about Alaska, but always thought it was a very oil rich region. I assumed (apparently, wrongly) that oil prices might be less expensive, if that were the case.

 

[iceguy4]

What does the connection detail look like

It requires you to cut an oval hole aprox 2. 1/4 "X4 1/2" in the side of your existing hopper. I'll post a picture if necessary

 

[DneprDave]

Pardon my ignorance if I'm wrong about this, but I thought Alaska produced most of the oil in this country? I admittedly don't know much about Alaska, but always thought it was a very oil rich region. I assumed (apparently, wrongly) that oil prices might be less expensive, if that were the case.

They don't have any refineries in Alaska. All the refined oil products are shipped in.

Dave

 

[briansol]

Maine has a bulk system in place at a dealer...
(broken link removed to http://www.maineenergysystems.com/Bulk_Pellet_Purchases.htm)

Maybe something like this will end up in AK eventually. Maybe it's a biz op.



IMO, unless I physically couldn't do it, if I had trees available on my property, i'd be a wood stove user. Pellets are easy because I don't have any wood. My requirements were running a full 12+ hour day without me doing anything while I was gone at work. A wood stove would be risky/unreliable for that, so there's always things to take into consideration.

 

[Bioburner]

They don't have any refineries in Alaska. All the refined oil products are shipped in.

Dave

I believe they have 6 refineries, according to last government reports.

 

[krooser]

I doubt there is a source for bulk pellet delivery in your area… maybe I'm wrong.

 

[Deering]

I believe they have 6 refineries, according to last government reports.

There are a few, doubt if it's six, but they mainly make jet fuel for the trans-national air freight hubs in Anchorage. Not for heating oil or gasoline. All of that gets barged up from WA & CA. Kind of ironic, huh?

I admittedly don't know much about Alaska, but always thought it was a very oil rich region. I assumed (apparently, wrongly) that oil prices might be less expensive, if that were the case.

Lots of disparities here. Some are quite rich, but when you get into the more remote areas people are living in conditions that are not much better than third world. In those areas small amounts of oil have to be barged, or even air freighted in some cases, and there's only one supplier who has a monopoly on the community. Heating oil can consume a large portion of household income.

krooser, we do have some sources of bulk pellets depending on the community. Some pellets are being shipped up from the Lower 48 in bulk in shipping containers too. We have a couple mills in the state that you can get bulk in, or in 1-ton super-sacks. Even a 1-ton bin connected to a stove, that had to be filled by 40 lbs bags, would solve some problems. Have pallet-loads delivered near the bin. Hire the neighbor kid to cut open and dump bags if you aren't able to. We're hoping to grow the demand for bulk pellets so suppliers can invest in mills and storage and delivery trucks.

 

[Deering]

It requires you to cut an oval hole aprox 2. 1/4 "X4 1/2" in the side of your existing hopper. I'll post a picture if necessary

Yes! Would you please? Thank you.

 

[sante fe]

I think if I lived there I would be prepared to live off the grid and have a good wood-stove with a good supply of wood. And electric baseboard for back up.

 

[Madcodger]

I think another problem would be maintenance, or more appropriately the fact that many people just wouldn't do it, with a bulk system. I'm doing my monthly cleaning on two stoves today, which takes me 20-30 minutes each. One stove needs a weekly ash removal and the other requires it every other day or so (2-5 minutes each). And then there's the annual tear down...

In contrast, I have friends who go all year without even changing their furnace filter, and know some who don't have their heat pump or dino burners serviced until they break. Some don't even have a programmable thermostat! They just want to turn the heat up, and wait for spring, and maybe complain about the cost.

While I absolutely like this idea of bulk delivery (the bags are probably my least favorite part of being a pellet user) I think a bulk system might be a problem because of people failing to do maintenance as much as anything else.

I think if I "went bulk", I might just convert to a whole house pellet furnace instead.

 

[PassionForFire&Water]

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[iceguy4]

I think if I "went bulk", I might just convert to a whole house pellet furnace instead

A wise move ...central pellet heat...best of both worlds My problem is no one in my area delivers bulk...any one know of one?

 

[lbcynya]

Unless space is an issue, why replace one with the other? I use cord wood, pellets and propane... Pellet stove runs 24/7 downstairs, wood stove runs nights and weekends and propane fills in the gaps. As you know, committing to a single heat source has it's advantages and disadvantages. I'd keep the monitor and add a pellet stove. Next year, when heating oil dips, maybe it's less that year to burn oil. 3 years from now, maybe electric is the way to go... Give yourself more options and you can flex to the heat source that is most competitive at the time. Easier said than done, but something to consider.

PS - The goal was to greatly reduce pro-pain usage. I went from 400 gallons every 6 weeks to 600 gallons for the entire year. Adding a bag or two per day isn't that bad. Pellet stoves work best then they aren't forgotten about....

 

[iceguy4]

Pellet stoves work best then they aren't forgotten about....

no truer words....

Unless space is an issue, why replace one with the other

What are you referring to?

One consideration no one has addressed. any bulk storage system must also maintain the air tight seal.... on not only the burner it is feeding but its self too. Harman's bulk storage does this.

 

[iceguy4]

Yes! Would you please? Thank you.

Pictures...

 

[iceguy4]

Any more requests? Pictured is attachment to boiler. green device (light is on because it was filling at time of pic) is a 'proximity" switch wired to a relay. 1500 lb hopper???I can only get 12 or 13 hundred into it (pellet size)

 

[Deering]

Pictures

Thanks! What's the green plug below the tube? A level sensor?

 

[iceguy4]

Thanks! What's the green plug below the tube? A level sensor?

read above

 

[lbcynya]

What are you referring to?

Sorry, I was referring to space inside...for another stove...

 

[Deering]

read above

Sorry - posted my question before your second pic arrived. Perfect.

any bulk storage system must also maintain the air tight seal.... on not only the burner it is feeding but its self too

Can you elaborate? Airtight in what respect? So water doesn't intrude? For fire safety?

 

[iceguy4]

If you notice the sensor is like 9+ inches down from top of hopper. the pellets stop filling when they reach the bottom of sensor. this causes a pile near the sensor that goes over to the bottom of the hopper just covering the outlet with a few inches of pellets. If the bulk hopper failed my boiler would be without pellets in less then a day. I would estimate the hopper on boiler runs less then 50 lbs.