Additive for wood boiler?

[bwolfgti]

Did some searching but didn't find anything. Is there an additive i can use in my Rite-way indoor wood boiler to keep the water hotter, longer? Maybe a dumb question but thought i would ask. thanks in advance.

 

[DenaliChuck]

More wood.

(sorry, couldn't resist)

 

[bwolfgti]

More wood.

(sorry, couldn't resist)

yea thats what i kind of figured. Not that im unhappy with how the boiler is working but if there is a better way i figured i might as well give it a shot.

 

[Fred61]

I ran across an additive at Autozone that claims to enhance heat transfer in automobile cooling systems. I assume it is a surfactant (like soap) that essentially makes water wetter. I would think that this material would help the heat transfer in a flat plate heat exchanger or dip tube system as it would thin the boundry layer.

The stuff wasn't cheap. Several $$ for about 6 oz. But I would think that If someone did some searching for a non foaming wetting agent (surfactant) on line, they should be able to find something that is more reasonably priced. As yet, I haven't had the time to do it. I think it would help in a non-pressurized storage system.

 

[ManiacPD]

I don't remember anything from the heat transfer equations for heat exchangers in Thermodynamics class that factors in how wet the water is. You best bet is more wood or more water IMO.

Paul

 

[stee6043]

There are chemicals availble that can "enhance" a waters ability to tranfer heat. Typically this is used for the exact opposite of what you are looking for. I picked up a gallon of "Engine Ice" for my motorcycle and I can tell you that it works. I can run a consistent 10-15 degrees cooler.

I think a materials ability to retain heat is going to be tightly related to it's density and/or viscosity, among other things....

 

[Fred61]

You may be assuming that "Engine ice" only keeps your engine cool because it is marketed and used for running your engine cool. Perhaps it has no cooling qualities whatsoever but does exactly what I assume these materials do, which provide for better heat transfer. Should work in both directions. This may answer the age old question: How does my thermos bottle know whether to keep my coffee cold or warm?

 

[pybyr]

Did some searching but didn't find anything. Is there an additive i can use in my Rite-way indoor wood boiler to keep the water hotter, longer? Maybe a dumb question but thought i would ask. thanks in advance.

water is better than virtually any other non-ultra-exotic material in terms of how many BTUs it will store per unit of volume. to get better than that you have to get into some really exotic stuff like phase change materials- which won't be an easy thing to integrate in/ with your existing system

 

[Dave T]

Nofossil had some interesting things to say when I mentioned oil filled EKO,search oil filled EKO? Dave

 

[Nofossil]

Nofossil had some interesting things to say when I mentioned oil filled EKO,search oil filled EKO? Dave

..As opposed to the rest of the time? ;-)

I probably made some smart-alec comment along these lines:

If water were an exotic material developed by NASA that cost $10 per gallon and was only available for local pickup in Nevada, we'd be clamoring for it and figuring out how to put together group buys. It's only because it's so commonplace that we don't give it the credit it deserves. As mentioned in a previous post, there is essentially no other fluid known to man that does a better job than water of storing and transporting heat. It has an enormously high heat capacity and a low viscosity. The boiling and freezing points are easy to work around, and in the bargain, it's non-toxic, non-flammable, and reasonably non-corrosive.

Ammonia is the ONLY fluid I'm aware of that has a higher specific heat. Most other fluids store half as much heat as water. or less. I don't know of any solid that stores as much heat per pound, and most don't store as much per cubic foot, either.

 

[pybyr]

Nofossil had some interesting things to say when I mentioned oil filled EKO,search oil filled EKO? Dave

..As opposed to the rest of the time? ;-)

I probably made some smart-alec comment along these lines:

If water were an exotic material developed by NASA that cost $10 per gallon and was only available for local pickup in Nevada, we'd be clamoring for it and figuring out how to put together group buys. It's only because it's so commonplace that we don't give it the credit it deserves. As mentioned in a previous post, there is essentially no other fluid known to man that does a better job than water of storing and transporting heat. It has an enormously high heat capacity and a low viscosity. The boiling and freezing points are easy to work around, and in the bargain, it's non-toxic, non-flammable, and reasonably non-corrosive.

Ammonia is the ONLY fluid I'm aware of that has a higher specific heat. Most other fluids store half as much heat as water. or less. I don't know of any solid that stores as much heat per pound, and most don't store as much per cubic foot, either.

190 degree F ammonia is such a bummer when it gets loose in your house, too... has this nasty habit of killing things

but, beware the hidden hazards of water, too:
http://www.dhmo.org

 

[Nofossil]

190 degree F ammonia is such a bummer when it gets loose in your house, too... has this nasty habit of killing things

Makes it a lot easier to find leaks, tho......

 

[Fred61]

You guys are all correct in stating that water has the highest specific heat of any material with the exception of phase change materials and I had been hoping that NOFOSSIL would chime in since he has proven to me in passed discussions to have an analytical mind. However the discussions have migrated to the ability of a medium to store heat.

I was looking forward to more discussion on heat transfer from the contributors to this site that have impressed me with their logic.

When I was applying nickel-cobalt plating to hard drive media, a wetting agent (surfactant) was needed to in order to allow the plating bath to make better contact with the base material. When I spied the bottle of heat transfer fluid in the auto store it jogged my memory and my imagination and it made sense in my mind that the thinner you can make the boundry layer, the better heat transfer is possible i.e. the reference in the post above to "Engine Ice".

 

[leaddog]

I think the thread started with the question if there was anything that could be added to make the boiler hold heat longer. well-----btu's in btu's out. there isn't any way to get more btu's if you don't put more btu's in. I don't care how wet you make the water. If you don't take out the btu's in the boiler will hold heat longer but that don't heat the house well and if you take them out you better put them back or the house gets cold.
Now if someone would come up with something that you could add to the water that would make water hot without putting more btu's in they would be a very very rich man. Thats cause the oil co's would buy him out like they did that carb that make cars run while making gas to go back into the pump. They did that to save the envioment cause there would have been to much gas and soon it would have overrun the planet. See the oil co's arent all that bad.
leaddog

 

[Nofossil]

The whole surfectant thing has to do with boundary flow and can make some difference at low velocities in the transition from laminar to turbilent flow. Since virtually all flow in hydronic heating systems is turbulent, I'd be really surprised if you could make a significant difference in heat transfer.

However, as always, I'm a data junkie. Show me real numbers and I'm willing to learn new things.

 

[Fred61]

I think the thread started with the question if there was anything that could be added to make the boiler hold heat longer. well-----btu's in btu's out. there isn't any way to get more btu's if you don't put more btu's in. I don't care how wet you make the water. If you don't take out the btu's in the boiler will hold heat longer but that don't heat the house well and if you take them out you better put them back or the house gets cold.
Now if someone would come up with something that you could add to the water that would make water hot without putting more btu's in they would be a very very rich man. Thats cause the oil co's would buy him out like they did that carb that make cars run while making gas to go back into the pump. They did that to save the envioment cause there would have been to much gas and soon it would have overrun the planet. See the oil co's arent all that bad.
leaddog

Sorry leadog, I should have raised this question of conductivity on a new thread. I haven't been asleep for the last 60 years and all of a sudden woke up thinking I could make water hold more heat.

 

[leaddog]

just trying to inject a little humor. There might be some merit to the wettability of water but I don't think it would make much difference in the use we put it to. now maybe in some of the seton style it might make a difference as the surface area is less there.
leaddog

 

[steam man]

I've operated boilers for years and tested boiler water thousands of times. If there was a chemical that increased heat transfer I never heard of it. But then, boiler water chemistry is maintained to keep scale/deposits from forming on the tubes (among other things) to maintain heat transfer efficiency. Scale can lead to tube failure by creating a "hot spot" where heat transfer is restricted. Keep in mind the higher the pressure and temp the more critical maintaining chemistry is. It really isn't much of a problem in an average boiler unless you have water quality problems. Maintaining boiler chemistry ulimately will result in forming of a "non-adhering" sludge that can be eventually blow down if the total disolved solids level gets too high. Boiler chemistry 101.

Mike

 

[Fred61]

Thanks for your input. Pleased with the responses.

I was mostly thinking about the application in the unpressurized storage tank which would involve one side of the flat plate HX and the dip tubes. The copper coils are my biggest concern since they are just sitting in the bath with essentially no water movement around them.