Who's on First.

[WoodyIsGoody]

When I purchased my Chinook 30 the local Blaze King dealer said they include a free BK moisture meter with the sale of every BK stove. I picked up the stove at their off site warehouse (which was actually a dilapidated but picturesque wooden barn). Since I forgot to swing by their showroom for the MM, I swung by today.

I'll be comparing it head to head with the measurements from my current setup (a Fluke Multimeter and conversion tables published by the USFS). How are you burners who entered the 2016 Blaze King Pet Photo Contest liking your BK moisture meters? Has anyone broken a probe yet? I'm wondering how aggressive I can be with it in harder woods to get the recommended 6mm measuring depth without breaking a probe?

Anyone know what other brand names this moisture meter is sold under?

 

[Highbeam]

When I purchased my Chinook 30 the local Blaze King dealer said they include a free BK moisture meter with the sale of every BK stove. I picked up the stove at their off site warehouse (which was actually a dilapidated but picturesque wooden barn). Since I forgot to swing by their showroom for the MM, I swung by today.

I'll be comparing it head to head with the measurements from my current setup (a Fluke Multimeter and conversion tables published by the USFS). How are you burners who entered the 2016 Blaze King Pet Photo Contest liking your BK moisture meters? Has anyone broken a probe yet? I'm wondering how aggressive I can be with it in harder woods to get the recommended 6mm measuring depth without breaking a probe?

Anyone know what other brand names this moisture meter is sold under?

I use my BK meter and like it better than the HF meter I also have. Results are similar between the two. I realize that these things are not and don't need to be highly precise instruments but neither has broken physically or internally. I also think that we worry a bit too much about this. Whether it's 15% or 20% is probably not that important.

 

[blades]

Lot of difference in the heat output between 20/15%

 

[Highbeam]

Lot of difference in the heat output between 20/15%

I disagree. Fuel with either MC will satisfy the thermostat and/or overheat the stove. Perhaps you mean a lot less energy will be wasted boiling water by using drier wood? That's true.

 

[WoodyIsGoody]

I disagree. Fuel with either MC will satisfy the thermostat and/or overheat the stove. Perhaps you mean a lot less energy will be wasted boiling water by using drier wood? That's true.

Maybe I'm missing your point but doesn't "a lot less energy wasted" = "a lot of difference in heat output"?

 

[Highbeam]

Maybe I'm missing your point but doesn't "a lot less energy wasted" = "a lot of difference in heat output"?

Absolutely not. Even a very inefficient stove can glow red. You need to disconnect efficiency from output capability.

 

[WoodyIsGoody]

Absolutely not. Even a very inefficient stove can glow red. You need to disconnect efficiency from output capability.

Oh. It sounded like you were disagreeing with Blades statement that there is a "Lot of difference in the heat output between 20/15%" (moisture content).

I guess I would find it useful to know whether my wood was 15% or 20% MC because there would be a considerable difference in heat output (due to the fact that a lot less energy would be wasted in boiling the excess water off).

 

[Highbeam]

Oh. It sounded like you were disagreeing with Blades statement that there is a "Lot of difference in the heat output between 20/15%" (moisture content).

I guess I would find it useful to know whether my wood was 15% or 20% MC because there would be a considerable difference in heat output (due to the fact that a lot less energy would be wasted in boiling the excess water off).

I am. A stove has the same output abilities whether burning wet wood or dry wood. Haven't you ever burned wet wood? You can still overfire the stove which is max output whether burning dry wood or wet wood. What happens is that your burn time will go down because you are wasting a lot of energy to boil water off, using a higher draft setting, less efficient.

I think your problem is that you are mistaking output for total heat delivered to the home per load. Output is an instantaneous measure.

Yes, dry your wood. It is more efficient and you will get more energy per load delivered to your home per load with dry wood. We agree on that. The real question is to what extent a few little % matters one way or the other.

 

[WoodyIsGoody]

Yes, dry your wood. It is more efficient and you will get more energy per load delivered to your home per load with dry wood. We agree on that. The real question is to what extent a few little % matters one way or the other.

I suppose what is still confusing me is that you initially characterized the difference in energy wasted (with 20% MC vs. 15%) as "a lot" and now you are wondering to what extent a "few little % matters one way or the other". Because, by definition, "a lot" is a very significant amount.

 

[Highbeam]

I suppose what is still confusing me is that you initially characterized the difference in energy wasted (with 20% MC vs. 15%) as "a lot" and now you are wondering to what extent a "few little % matters one way or the other". Because, by definition, "a lot" is a very significant amount.

I see what you're confused about. A lot of energy is wasted by inefficiency and boiling water but that has nothing to do with available output. Each log contains a certain amount of energy and many people waste a lot of it by boiling water out of the wood. That energy used for boiling water does not heat the home. You just have to burn more wood to make up for the lost energy.

I was reading the kuuma furnace manual. Highly efficient and clean burning. They specify between 18-28% MC for the fuel wood. 28% is quite high I thought.

 

[WoodyIsGoody]

A lot of energy is wasted by inefficiency and boiling water but that has nothing to do with available output.

I see what confused you. When Blades referred to "heat output" he was speaking of the amount of useable heat from a given load of wood. But you mistakenly thought he was talking about a stoves maximum heat output which isn't really related to the discussion.

You just have to burn more wood to make up for the lost energy.

Understood, hence the interest in knowing the moisture content of our firewood.

However, there are processes at play here that are much more significant than the heat of vaporization and many people don't realize just how significant these losses can be. Let me briefly explain.

Over 99% of wood is flammable (excluding the water). These flammable components consist of complex compounds that form resins, lignin and cellulose. Wood will spontaneously ignite between 600F-700F which causes these complex compounds to break down into simpler compounds such as methane, hydrogen and carbon monoxide. Yes, even carbon monoxide will burn and give off heat (but only if it reaches 1100 degrees). The methane driven from the wood requires 1200 degrees to ignite and even the hydrogen requires 1000 degrees. If they escape without encountering those temperatures, not only do they pollute, they rob you of their Btu's.

The heat of vaporization absorbs heat from the combustion process and thus lowers the temperature where combustion is occurring. This also lowers the temperature of the entire firebox. Because of the lower temperatures, a higher percentage of the compounds released from burning wood will escape up your chimney without igniting.

That is why higher moisture content wood produces much less heat than a simple calculation of the heat of vaporization of the water would indicate. In other words, the difference in heat output is much greater than most people assume.

note: I am not speaking of a stoves maximum heat output but the efficiency of the burn which is directly related to useable heat produced. At maximum burn rates firebox temperatures will likely be high enough that few gasses will escape un-burned but, in the real world, people do turn their stoves down which is when you will really notice the loss of heat output between truly dry wood and wood that is almost dry.

 

[Highbeam]

Now you're getting it...

 

[WoodyIsGoody]

Now you're getting it...

Yeah, but who's on first?