Will My Current Baseboard Emitters Work Well With Gasifier and Storage?

provided your boiler is sized properly for demand and storage size then yes. reason being baseboard performs poorly with water temps less than 160 deg.. i struggle with mine and it makes me crazy in cold temps trying to keep up. once i scrub the 165 deg water out of my tank and it starts coming down the struggle is on, lol.

velvetfoot said:

Before I actually order the boiler, I am wondering if the current baseboard emitters, which are of the standard variety, will work well with the new gasifier and storage? Do people successfully do this? I'd like to think low temp. baseboard or even radiant might also be in my future, but I am thinking boiler/storage first.

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You raise a really important question. Almost all fin tube baseboard installations were originally sized for 180 dg supply water. At 160 the output drops by approx 25% . At 140 degrees the output is a little over half of that at 180 and at 120 dgs a little under a third. Now...that said, many (if not most), original installations over-sized both the fin tube footage and the boiler (pretty much always the boiler). So..many homes heat fine on the coldest days with 160 degree water and on more moderate days with 140 dg supply water. BUT ..if you have a room that is struggling on cold days you'll surely need to add more radiation there to heat with lower water temperatures.

The cost of adding some additional or higher output fin tube in an under performing room is pretty low compared to your investment in the materials and labor for a gasifier and storage. If you are heating with a fossil fuel boiler now you may want to try resetting the boiler aquastat to 160 on some cold day to see how your system performs.

In the future.. low temp baseboard, properly sized panel radiators, old cast iron radiators or radiant floors will only make life better

velvetfoot said:

Are you saying your boiler is a tad under-sized? I'm shooting for 1000 gallons and a 40 kW boiler. I figure 40 kW should be big enough to charge the storage. So, if I can charge the tank to what, 180, or 190, the lowest I can drift down to is 160? On the cold days, anyway? I guess I have to figure out how long that storage will last for the 20-30 degree delta.

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I have only Slant Fin baseboard. This winter, when home during the day, I have taken to fully depleting my storage, and not making a fire on until I feel the house is losing heat (i.e. the house temps start to drop). Usually, when I get feeling that, my storage is down to 130/115. Or so. Depends on the day of course.

Like the post above alludes to, it comes down to how well engineered the distribution system was when it was put in and how closely matched it is to heat load. I didn't get any of the paper work for that from when the heating guys did their thing when we built (or at least, I can't find it anywhere) - but from how this winter has gone, I think more Slant Fin went in back then than was necessary. Which I am quite grateful for now.

If you wanted to try to get an idea now, you could do a heat loss calc on your house, then see how the results of that compare with what your system is capable of by measuring all your baseboards & adding up what they should be capable of. But the simple bottom line is - if you want more heat from baseboard from lower temp water, just add more baseboard. It's rather cheap, relatively speaking - and I did do just that a few years ago in a couple of odd spots on a couple of my zones. But it still won't be quite as capable down low as say in-floor radiant.

the portion of my house that has baseboard performed with no issues with 160-180 degree water even prior to the wood boiler install. now with 140-150 degree water and say 10 deg. outside temp and lower, the baseboard cant maintain the target temp of the thermostat. it is old baseboard and not enough of it if it were to be calculated with lower water temps. i have decided to utilize lower temp emitters rather than upgrade my baseboard for next year. but again, i am undersized and trying to accomodate until my budget permits me to upgrade. as frustrating as it is for me to work with, i hope the issues i have run into can help others.

maple1 said:

Usually, when I get feeling that, my storage is down to 130/115. Or so. Depends on the day of course.

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i typically am looking at these same temps in the a.m. and then again in the evening when i get home if that helps? baseboard is starting to get pretty cranky with no solar gain, cold outside temps and cooler water temps.

You need to figure out how much baseboard you have and what water temps are needed to satisfy your heat load at various temperatures. If you have just enough and need 160 degree water, storage will provide limited value. For example suppose you are are awesome and charge storage to 195, that leaves 195-160 = 35 degrees * 8.34 btu/gal * 1000?gallons = 290,000 btus stored, which could be ~ 6 hours heat at 50k/hr loss. If you have tons of baseboard all over the place, you can get away with running lower water temps and get more out of your storage.

I had the same questions and you can see some of my math here: https://www.hearth.com/talk/threads/looking-for-some-input-on-distribution.123752/

I live in a 2 story house/1800 sq/ft.

I have BB with storage. It struggles on sub zero days, but basically i do like Maple1 does.

But,our home schedule is usually the house is empty during the week days, set back T-stats go down to 62. Myself or one of the kids comes home by 2 or 3pm sometimes 4 or 5pm. Start a fire about that time. The system that was installed will prioritize the house first then storage. Which in about 45minutes of lighting boiler, I have 165f water rolling thru BB's. 15 to 20 minutes later it's pushing 180f, then will run about 190's. So the BB will heat up the house very well, pretty quickly. One fire box full of wood will take 3 to 4 hours to go out.By that time storage is up to temp, house is warm. On subzero days I may have to refill boiler, or at least partially refill. At 10pm the set back T-stat will set back to 62. Very rarely gets that cold, usually 65/66f. This routine gives us enough DHW in the morning too. IMO, the thermostatic valve that will send heat directly form boiler to house, when needed, is the way to go, for my heat load. If i had to heat storage and let storage heat the BB, it wouldn't be as convenient.

I also have staple up in my kitchen. this is mainly for foot comfort, as it's a tile floor. Someday I will get ambitious and install more staple up or low temp emitters.

I hope this makes some sense.

flyingcow said:

IMO, the thermostatic valve that will send heat directly form boiler to house, when needed, is the way to go, for my heat load. If i had to heat storage and let storage heat the BB, it wouldn't be as convenient.

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(With pressurized storage, priority goes to the loads automatically.)

ewdudley said:

(With pressurized storage, priority goes to the loads automatically.)

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Thanks for pointing that out.

velvetfoot said:

Thanks everyone. I added up the baseboard length the other day and I got 55' on the first floor and 48' on the second for a total of 103. The baseboard I have puts out 560 btu/hr/ft at 180, so that'd translate to 30,800 for the first floor and 26,880 for the second for a total of 57,680 btu/hr. With the Heating Edge convectors, I only have to heat it up to 144 to get 560.

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How many sq ft is your house and do you know what the heat demand is at your design temp?

That is probably worth estimating. You can use an online calculator like this or estimate using the average annual heating degree days in your area and the amount of oil/propane/electricity/wood you used to heat it.

Velvetfoot. How is your plumbing being installed with the existing boiler? In parallel? Series? Will your primary loop pull off of the storage only or be able to pull off of the line between boiler and storage tank?

I used the existing baseboard heaters that were installed with oil boiler when house was built. (When I first bought the house 20 years ago oil was 79 or 89 cents a gallon. )

I find standard Slant Fin can maintain my room temps with 140 water but forget about using a set back thermostat as it takes forever to get back to the desired setpoint.

the taller baseboard may fit your application better too, especially if you dont have room or want to pick certain areas of a room to place it. i believe they are double rows.

I wouldn't buy any new baseboard to add to the system. that's convection heat. Heaterman pointed this out a while ago in another post. you really want radiant floor or low temp emitters.a much much better delivery system for heat

I have all baseboard in my place but I do have a lot of it. The guy who "designed" it just covered the exterior walls. The baseboard I've added since the initial installation I used the high output variety which does deal better with cooler water.

If it's cold (sub zero) and the storage is 145 or bellow it works hard, anything above that it works with out a hitch.

It's not a big deal IMHO,we stay quite comfortable.

Oh and the house taking priority over storage has everything to do with design and nothing to do with pressurized vs. unpressurized.

K