How the Liars in California helped Ban our Lister CS Clone

Posted on October 9, 2010 by George B.

No doubt the diesel is one of the most efficient prime movers on the planet, if it were not so, the railroads and the maritime industry who lives or dies on the cost of fuel would use something else! If it were not for the manipulated data, we’d likely still have our beloved slow speed stationary diesels.  

 http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/10/07/BAOF1FDMRV.DTL#ixzz11iqEfuN9

In the real world, emissions have everything to do with the amount of fuel we burn to get the job done. There are exceptions, Hydro being one, but as we know, the environmentalists want all the dams removed, sure they’ll be the first to bitch about the higher costs of food, loss of millions of jobs, but that won’t stop them, as they have no clue what they do. Here in Washington State, millions of acres of farm land depend on hydro for irrigation out of the Columbia, and the amount of food grown and jobs provided  here is mind boggling!

Here’s an example of why you shouldn’t trust State Government, especially corrupt California. They create the numbers to match the direction they want to take the economy, they know CARB is so powerful that Industry must comply or die.

Of course when you have people like Senator Patty Murrary representing you, don’t expect a lot of logic to be applied to decision making.   Here’s a person that doesn’t know the difference between an IOU and a BTU, and the peope of Washington state might choose to keep her in power this november! There’s a reason she is known as the ‘Dumbest Senator’. Patty doesn’t read or study anything she signs, and there’s all too many that operate in the same mode that represent us.

http://www.norcalblogs.com/post_scripts/2010/10/our-dumbest-senator-in-wa.html?utm_source=twitterfeed&utm_medium=twitter

Posted in Small Diesels | Tagged , , | Leave a comment

Jack Belk, a Three AM Encounter

Posted on September 30, 2010 by George B.

Many who visit the utterpower pages know of Jack Belk, and if you don’t know of him, a google search using words ‘utterpower jack belk’ will find you more.  Few people know more about living off grid or being self sufficient.  Jack shares a three AM encounter he had this morning, you might recall a similar experience….. an increase in your heart rate, the thief in the night.

I was up to pee at three this morning and while groggily waiting for gravity to do it’s thing, was suddenly flashed by the turn signal on my dump truck suddenly coming on down at the ‘Orchard’ project about 150 yards away. Of course it *had* to be some thief prowling around so I grabbed pants and shoes, camo pullover and a pistol to go with the spotlight and planned my stalk in very bright moonlight. Keeping a bushy Russian Olive between me and the truck would gain 50 yards, but the going was rough in deep grass and rocks. Once to the tree I stopped and watched and planned the next move. The next stage was just crouching down and run down a fence line keeping in the shadows until I’d be within 30 feet of where the truck and backhoe were parked. I just knew I could see whoever it was messing around in the moonlight, but I stared until my eyes were wet and could see nothing. I snuck up to the truck to check for tracks in the dust and the damn blinker came on right in my face as an owl flew out of the window. Talk about exciting!!!

Thanks for the story Jack!

      

Posted in Utterpower's Friends | 1 Comment

Wood Gas Generators

Posted on September 28, 2010 by George B.

10-19- 2010 update.  News flash! Berkley Gasifier Developments covered by Huffington Post’s ?Science Editor?  Kelpie Wilson. 

Background:

Up to now, I’ve found it difficult to find any hard figures on recent DIYer Gasifer power output done with any certainty. We have seen people promote products in the past that weren’t ready for prime time, some sell gasifier parts branded as “experimenter’s parts” and make no claim as to their ability to provide some kind of return on investment, I respect their efforts to be honest about that.

I do receive updates from some of the folks who work on gasifier development, and of  course I try and supply parts or ideas passed along from others in our DIYer group that might be helpful. Younger people think adding processor control can quickly turn an old unworkable idea into something magic. In reality, as per the understanding of these gases, their BTU value and how best to put them to work, I can find little that wasn’t done by the end of WWII.  If we review methods of control prior to the microprocessor, there were elegant solutions available, albeit more expensive. During WWII there were gasoline engines likely more efficient than most in production now. Of course the engines I reference were built as part of the war effort and cost was not part of the engineering exercise. The point? I need help in understanding what’s new since WWII, and why every large furniture factory with tons of low moisture content wood fiber (a most desirable fuel for a gasifier) isn’t running their factories off Wood Gasifiers? I believe this question is part of critical thinking, and it’s a trade mark of seasoned DIYers.

About: Kelpie Wilson

 Here’s an article I found that she wrote in the Huffington Post:

http://www.huffingtonpost.com/kelpie-wilson/tea-party-20—tax-the-ri_b_473405.html

Now let’s look at her coverage of the recent Berkeley Gasifier Meet:

http://www.huffingtonpost.com/kelpie-wilson/post_1050_b_760217.html

Nice work Kelpie, it’s exactly what kind of coverage we expect from a young liberal.  A lot of us just want to know if there’s a return on investment. Let’s take this report and compare it to a report on a toaster. Would Kelpie ever get around to whether it made toast or not?

For many that frequent pages here, (likely older people than Kelpie). We’d love to see someone slap a ‘power analyser’ with a name we recognize on the generator attached to the “10KW power pallet” and tell us the sustained power output. We know it will light a light bulb or two, but we get these reports that engineers are involved.  One Author references Liberals in Academics attending. My question at the end of the day.. Isn’t there at least one Engineer in this group that’s not a little embarassed by the fact that they keep meeting and never seem to get around to deliver the basic facts? Am I expecting too much?

I have a therory about AE, much of what is presented as a solution will never provide a return on investment….. but… the way it’s reported on makes it seem we’re ready to abandon other forms of energy “if only we would do so”  Soon we have the delusional and uninformed voting in favor of the impossible based on Kelpie style reporting.

One last Question, “Liberals in Academics” It just dawned on me.. I’ve made an assumption that these folks had backgrounds in mechanical engineering or electrical engineering and had little excuse for not borrowing some test equipment. Now that I think it through, these folks could be from the political science department, and it’s likely no one would trust them with a decent power analyzer.

GB…

Previous comment below… 

I’ve opened this page to discuss this technology here.  Many of us understand that the gas plants in cities hundreds of years ago light the town square, and the town crier often lighted the lamps at night and extinguished them in the morning as part of his routine. He served in other capacities as night watchman and more.

 We also know that there’s been little discovered regarding the operation of these units since WWII, and a lot of the current efforts are attempts to make them function as well as they once did.

What I need your help with is finding information regarding ‘power out’ figures, we all know that watching an engine idle, or watching a vehicle move forward in it’s lowest compound gear does not impress the engineer or the seasoned DIYer. Neither does mowing a lawn that doesn’t need mowing.  Many of us in the DIYer community want to know the facts. In one demonstration  I saw a wood gas powered generator referred to as a 10KW generator for no apparent reason other than the gen head was capable of delivering 10KW.

The more seasoned DIYer realizes there are easy ways to figure the theoretical maximums in generator output, and we start with the known basics.  What is the bore and stroke, what is the operating RPM? Are we using a supercharged engine, or are we stuck with a normally aspirated engine?

The DIYer might identify the particular engine the wood gas experimenters are using, identify it’s typical fuel and the power output at rated RPM. Knowing the BTU value of they typical fuel, we might compare it to the wood gas fuel and it’s BTU value and arrive at a theoretical maximum power output at any given rpm. We realize that the maximum horse power has everything to do with the BTU value of the fuel, and we know we have an optimum fuel air mixture to work around.  We all understand that wood gas is very low in BTUs compared to SVO, and most other fuels for that matter.  It leads us to believe that we’ll need a lot of additional cubic inches or a supercharger to get enough energy into the combustion chamber to make equivalent power to the normally reccomended fuel.  When you see a 24 horse power NA engine attached to a 10KW generator head and the Experimenters touting it as a 10KW gasifier, alarms might go off in your head. It’s not such a disappointment if they’re all ultra green thinkers who have never stepped foot out of the class room, but if they’re boys from the ranch or farm with practical experience, or professional engineers, you wonder if the intent is to sell something not quite ready for service?  Just how much effort would it take to put a resistive load across the output of  the generator and measure the power output with a clamp on and decent volt meter? I’d also love to see a gasifier power an engine for an hour or so. If you can help educate me, please do,consider this page a potential advertisement for your favorite gasifier..  

So here it is, my page to discuss this further, I have a lot of questions, I’m hoping you have the answers, and you’ll offer some comments to this post.  

All the best, and thanks in advance.

George B.

Posted in Off Grid Power | Tagged , , , , | 3 Comments

Five Gallon Bucket Washing Machine

Posted on September 27, 2010 by George B.

Seth wrote in and said he couldn’t find the utterpower 5 gallon bucket washer, so I put it back on you tube. Here you go Seth…

I made this to wash shop rags, and I also found it handy up at off grid Easton when I was crawling around in the dirt getting really dirty building the pump house, you can see the finished project on YouTube as well.  I dropped a few items in the bucket while I was taking a shower.. Presto! they were at least man clean in no time:-)  I made this from a Honda wiper motor assembly as I found it incredibly easy to extract from junk autos VS other makes.

Sure beats washing rags by hand in your shop too, and you know your wife will want to kill you if you toss those rags in her washer and leave a grease ring in it, ask me how I know? It was 30 years ago, but I still remember it was kinda a one-sided conversation…

Cut one of the stock wiper arms rods to proper length, use a sleeve to join them. Build a turn table and spindle. The bell crank drives the table. Good idea is to size turn table so it just fits inside the lip of the bucket, that way it stays put.  The bell-crank drives a knuckle located on the underside of the turntable, knuckle borrowed from the wiper assembly.

This unit runs very well directly off a small solar panel.  On the smaller solar systems, something like this could be part of a ‘dump load’ in otherwords, schedule the work to be done when your batteries are in float, and the sun is doing the work directly.  If you are running a ‘make do’ system, covering the corner of a solar panel with a tee shirt can control the speed of the washer.

As with most anything you build, I have simplified and improved this washer about 5 times. It seems you must do it a number of time to study what can be improved, and made more simple, easier to build and less costly.

If you think this is worth more construction detail, consider leaving a comment.

Thanks

GB

George B.

Posted in DIYer Skills, How Tos, Projects, Survival Skills, Things I like | Tagged , , , | 5 Comments

Another Off Gridder belts up the PMG

Posted on September 26, 2010 by George B.

Thanks to Bill Rogers, the Utterpower PMG was designed with certain voltage characteristics that has made it ideal to charge batteries utilizing the build in chargers in the better and more serious inverters like the Outbacks. We believe this is one of the primary missions for a generator in off grid living, and the unit also does a better job running a wire feed welder and other chores because we didn’t get whimpy on the voltage at 60hz.  I didn’t realize just how long some of these generators run to charge batteries, but some of my customers who run long hours off grid repported that they were actually burning less fuel and getting the charging done a >lot< quicker with their PMGs VS Honda and other makes of generators. They knew this because they had been running battery plants for years to charge batteries, and at some of these sites high in the mountains when the cloud cover rolls in, there’s a lot of generator time and off gridders get real familiar with the same ole routine, when something changes, they usually recognize it in a hurry.

Some generators have such a low peak voltage that certain inverters don’t even recognize them! You can hook them up, the voltage can be present at the input of the built in charger, and noting happens!  Some of the on line stores that support folks with solar power installs understand this problem well, and they sell a transformer that will jack up the voltage five percent or so, this does allow the inverter charger to work at a far more favorable voltage, but as we know that transformer is now just an additional and permanent loss in the chain of machinery that allows us to convert a BTU of energy into stored energy in those batteries.  As we have discussed elsewhere, it’s really all about the cost of a KWH of energy over time, engineering in extra losses isn’t the better design. The PMG operates at the top end of the ANSI standard for voltage, and this allows this very routine task to be done with more efficiency and quicker. If you are using the far more efficient diesel engine as your prime mover, you have a great opportunity to save money as you get this job done.  

It’s always interesting to read accounts from people who have years of off grid experience. Some who run PMG have little to compare to, the more experienced are somewhat amazed at how different battery charging works, and how different their equipment seems to run and sound.

Here’s one from Montana Mac I received tonight, few people have more experience running bio fuels in the Lister Types, and Mac has powered his place with Solar and bio fuels for years, following is his short email.

(MAC) Normally when I started the engine, got it up to speed and turned on the main breaker … it was obvious that there was a load on the gen head as you could hear the engine coming under load. With the PMG … the engine still responds but to a much less degree … much smoother.

The next test I ran was to turn on a florescent light in a small room which always “flickered” a bunch with the ST head and was pretty well useless unless running on batteries and inverter. With the PMG running … NO FLICKER! Needless to say … I was surprised and impressed.

I am running an Outback inverter hooked to a fair size battery bank for daily home and shop use. The Outback has a battery charging circuit that has always done a fairly good job of battery charging. However, with the PMG running the battery charging appears to be much better and appears to be putting out full current while I have always suspected that the ST head was delivering less than ideal power to the inverter resulting in less than advertised charging current. As an added benefit the engine room noise is less and the whole system “sounds” smoother.

So far … I am well pleased and excited to try some heavier loads in the shop to see how the PMG handles some wire feed welding, air compressor, etc.

I will send some pictures of my setup soon.

Thanks for another quality product, good service and your friendship

Mac

Posted in PMG | Tagged , , , | Leave a comment

A DIYer’s Observation, Induction Motors

Posted on September 26, 2010 by George B.

Rich Barber writes about a curious situation he describes below. I figure this is a learning situation for many of us, and there might be some fun applications as well. I tag on a very expensive lesson I learned, and it was a rarity, as I learned it at a friend’s expense VS my own. 

Subject: Observation

 Message: Hello George, Interesting experience last week. 5KW Onan repeatedly tripped 15 A breaker when trying to start 1.5 HP drill press. So…I turned on my 8″ bench grinder which takes several seconds to reach full speed. With the grinder running the drill press stated without a problem. I am thinking must be either a capacitance issue or grinder inertia is helping generator.

…………………………..

Now of course there’s a lot of questions to ask here, some that come to mind is the spindle speed of the drill press, is it set up to run at 6000 RPMs, did this cause current to remain high for a longer period at start up, is this an older drill press with considerable mass attached to the spindle, is there something wrong with the start winding circuit.. on and on..

But at the end of the questions, Rich notes, the drill press starts when the grinder is on and idling.

I shared this email with Bill Rogers, his input helped me focus on the more probable explanation.  We don’t know why a five KW Onan didn’t start the drill press, but we can guess why the grinder aided and prevented the circuit breaker from blowing durign the start up. Bill, like most Engineers would collect more data before forming any conclusions. 

Here’s the theory:

The Onan generator  is stable in RPM, same with the induction motor grinder, Rich then adds the drill press which is a good sized load, and we can’t assume the 5kw generator is wired for 120VAC only, we don’t know if this unit is using the entire stator winding or one side, thus, we have less idea as to how much voltage droop we might see during this start, exactly how well the governor is functioning is yet another unknown.

We do know that the grinder is running at some slip speed WHEN the generator and grinder are stable and no other loads are popping in our out, wiht this stable situation we dump this larger motor across the line, and alternator sees what looks close to a short for an instant or longer with the rotor at rest.  The generator lost RPM, and the idling grinder now finds itself running well above slip speed, in fact it’s now become a generator and is converting the energy stored in the rotating mass into electrical energy and back into the line where the Drill Press is able to make use of it. With E held higher, I stays low enough to keep the breaker from tripping and  and the drill press motor builds enough RPM to produce the CEMF necessary to shut off that big current draw seen durign start up.  We might place a good ‘clamp on’ amp meter to the line feeding the grinder and actually measure it’s contribution to starting the drill press.

I have a seven horse power 37xx RPM single phase motor, I also have a 50 pound flywheel I’ve been wanting to fit to this motor and use it as an accumulator of sort to play with. The desire comes from a bonafide observation I made in a glass blowing shop 10 or more years ago in Cindy Miller’s, ‘Hot Shop’ south  of Seattle near Lake sawyer. she’s a glass blower.

Cindy worked with a sales type who eventually sold her an 8KW natural gas generac auto start generator. The high priority load was the furnace blower, and a few overhead fluorescent fixtures. It was assumed (by the generator salesmen) the 8KW Generac was plenty enough to start this motor.

Here’s something to remember whether you’re an electrical engineer or hobbyist.  The person who designed this masterpiece of a blower used a high RPM motor, they also used poured cast iron to create a very nice looking blower with considerable mass. Of course it was likely designed by a glass blower and on commercial power with less distribution losses, all was well.  To listen to this motor start up was memorable, a slow spool up, sounded a little like a cream separator winding up. 

Hot shops are an interesting environment, once the furnace is up to temp, the blower may run a year or more. With that understanding this glass shop was losing blower motors.. They’d shut off the furnace, and the motor would not restart! After a lot of screwing around it was determined that the 8KW Generac could start this specialized blower motor once, AND since the start was so marginal, it would burnout the start winding with the start. the problem is the unit might run happily for a year and it took some time to realize that the all too small Generac generator OR the poorly designed blower was at fault.

And older man with some experience in perspective knows how the argument goes.. the salesmen knows it was the designer of the blower at fault.  The person designing the blower might expect any backup generator would be just as capable as hoover dam in starting his appliance.

I share this experience because I have more than once ignored what is on that motor shaft, and just looked at the electric motor manufacturer’s literature. If the glass shop would have had someone like Bill Rogers on site to watch that slow spool up, there would have been concern from the beginning as to how long that start winding was in the circuit and just how toasty it was getting. The majority of us look for these things more closely AFTER we have opened our wallets and bought an expensive replacement motor.          

OK, food for thought, there’s soft starters out there, would they help, and under what conditions? Some of use might think a voltage regulator or the lack of same was at fault, but I thing the Generator ran out of grunt, that little extra stored energy in the grinder likely powered the drill press through the start.

All the best, and than you Rich for sharing your observation!

GB

Posted in Generator Realities | Tagged , , | 3 Comments

Effect of Moisture on Wood Burning Efficiency, Revised – Installment 3

Posted on September 25, 2010 by George B.

By John E. Laswell, Mechanical Engineer – Aug 2008

    Disclosure Statement – the information in this article is mainly the opinion of the author except where websites are shown.  There may be errors in the information and errors in any calculations.  So, the ideas presented herein should not be used to design a heating system for any home or building.  Application of any engineering formulas and principles may be in error.  This article is stickily for the reading enjoyment of the curiously minded individual!!

     Forward, Hello fellow DIYers.  My name is John L. and I live in the hills of scenic, southern Indiana.  I have burnt a wood furnace in my basement for 22 years.  The wood came from my 38 acre farm, mainly from dead or non-timber grade trees.  My wood was cut with a chain saw and hand split for the first nineteen years.  I now have a 27 ton hydraulic log splitter.  I mainly burn oak, hickory, ash, hard maple and dogwood.   For the last three years I have I have been heating one half of my home with a King, 1107J, Blaze King stove.  It is wonderful.  I have installed it in my dining room.  In my opinion this is the best wood stove.  If there is any interest, I would write an article about my experience with buying, installing, operating and the pure enjoyment of heating with the “king”. 

     I am so tired of products that have been “value-engineered” to the point of planned-failure-in-design.  How many times have you been asked when you purchase a fairly simple product if you wanted to buy an extended warranty plan?  Here is some of the modern philosophy: use it up, burn it up or throw it out when it stops working.  I recently bought a pair of trousers where it cost almost as much to alter the length as the cost of the trousers!  Something is wrong!  I know what it is? Products made in China and cost of labor in USA.

     This article comes in three installments:

     First – Introduction, Wood Stove Efficiency and Results

     Second – Determining The Percent Of Moisture In A Wood Sample, Conclusions,                               Energy to Cook-off Moisture, Operating the Wood Stove

     Third – What Is The Value of Burning Wood?, Creosote and Soot – Formation and                            Need for Removal, Chimney Fires, Combustion of Wood

What Is The Value of Burning Wood?

The answer to this question is, it depends on several factors.  In general it is cost effective to burn wood for heating purposes.  That said let us get into the details.  The value of burning wood should be determined by the cost of other forms of heating such as electricity, fuel oil, LP, natural gas, heat pump, geothermal heat pump, coal, corn, wood pellets, fireplaces, etc. I will only consider electricity, corn & LP for a comparison.

First factor is the cost of wood to you.  Second is your facilities for burning wood.  Third is your present facilities for heating.  Fourth is the design of the structure to be heated.  Fifth is the cost of other forms of fuel to you.  Six is your situation for seasoning / storing wood.  Let us now consider some basic engineering conversion factors.  Assume that dry wood contains 7,000 BTUs per pound.  One kilowatt-hour is equivalent to 3410 BTUs.  LP has about 91,000 BTUs per gallon.  And dry corn has 8,000 BTUs per pound.  A cord of wood is128 cubic feet of wood.  A rick (face cord) of wood is about one third of a cord of wood.  A cubic foot of seasoned oak weighs 45 pound.  Therefore, one board foot of seasoned oak weighs 3.75 pounds. Fifteen percent moisture corn weighs about 56 pounds per bushel.

The thermal efficiencies of the heating appliance must be considered.  Electric heat is almost 100 % effective in transferring electric energy to heat energy.  Efficiencies of wood stoves  range from 20 to over 80 percent depending on the design of the stove, the type of wood and the method of operation of the stove.  Modern LP heating furnaces are 75 – 85 percent efficient in extracting heat from the LP, but central air conditioning systems are not all that efficient.  In the days of “cheap” energy, central air conditioning was considered desirable, just heat the whole house!!!  But now, space heating, zoning, “tight” construction & well insulated houses must be considered.  Just a few years ago, outside wood boilers were considered “the way for wood heating”, but the stories that I have heard is they are expensive, very inefficient and very smokey, beware.  If you have lots and lots of cheap wood, no problem.

Simple calculations will show that one gallon of LP is equivalent to 13 pounds of wood.  One gallon of LP is equivalent to about 11.38 pounds of corn.  And that about 2 kilowatt-hours equals one pound of wood or 2.35 kilowatt-hours is equivalent to one pound of corn.  Now specifically, wood is fairly cheap in southern Indiana at about $35-40 per good rick which is about 1300 pounds for seasoned, well split oak.  My last LP cost me $1.79 per gallon for summer fill.  So, now it is about $2.20 per gallon.  A rough calculation is 1300 pounds of oak is equivalent to 1300 divided by 13 or 100 gallons of LP which would cost you $220.  At first glance the price of wood looks like a real winner.  But, appliance efficiencies must be considered.   How many effective BTUs of heating am I getting in each of the following examples: LP – 100 gal times 91,000 BUTs per gallon times 75 % efficiency equals 6.83 million BTUs which is $32.21 per one million BTUs.  Now, for wood consider this matrix of variables:

Table 2

               % moisture,  great stove,    good stove,    old stove

                                  15            .68%              .59%               .51%

Million BTUs                           6.19               5.37                 4.64

Cost per million BTUs           $6.64             $7.45               $8.62

—————————————————————————————–   

                                  30            .53%              .46%               .32%

Million BTUs                          4.82                4.19                 2.91

Cost per million BTUs          $8.30              $9.55             $13.75

As you can see wood that costs $40 per rick clearly has the cost advantage over LP, even the old, inefficient stove while using 30 percent moisture wood.  But, $80 per rick wood would not have near the cost advantage as $40 per rick wood, but by burning well season wood, all three stoves still have a good advantage over LP costing $2.20 per gallon.

Now what about electric heaters?  The calculations are similar.  I  pay about 16 cents per kilowatt-hour, wow.  Two KWHs per pound of wood times 1300 pounds per rick equals 2600 plus KWHs per rick of wood.  Then 2600 KWHs times $0.16 equals $416 of electricity and is equivalent to one good rick of oak wood.  The equivalent number of 2600 KWH to BTUs is about 9 million BTUs or a cost of $46.22 per million BTUs at 100 % efficient heating.  Table 2 still applies to the electric heat situation, so you can see that heating with electric heaters can be much more costly than LP.  Wood can be 6-7 times more cost effective than electric heaters.

Calculations for corn heaters are similar to LP and electric heating.  One good rick of oak is equivalent to1135.5 pounds of corn (20.3 bushels) or a cost of $101.56 for $5 per bushel corn.  Thus the cost for one million BTUs for corn heating with an efficiency of 60% would be 101.56 divided by 9 million times 60 percent equals $18.81 per million BTUs.  Again comparing to the wood cost in Table 2, the wood stoves with well seasoned wood have a significant cost advantage over corn heat.  Remember this comparison is based on $40 per rick wood and $5 per bushel corn.  Two dollar corn would have been very competitive to $40 per rick wood but back when wood could be bought in southern Indiana for $30 per rick.

One final aspect of the value of wood for burning is the amount a timberman will offer to pay for standing timber?  Lets assume that there is a nice, red oak tree that has 40 feet of logs and is 20 inches at the butt.  The tree has a taper of the diameter that decreases two inches ever ten feet.  So, the timberman is planning to cut four, ten foot logs that are 1) 20 in dia & 18 in dia, 2) 18 in dia & 16 in dia, 3) 16 in dia & 14 in dia, 4) 14 in dia & 12 in dia.  The timberman will pay you for board feet based on the small end of the log, but the total weight (wood to be burned) of the logs is almost twice the weight of the lumber that is sawed out! 

The calculations show that the four logs will saw-out about 383 total board feet of lumber and a weight of 1,437.5 pounds; however, the total weight of the logs that were sawed would be 2,562 pounds or 17.94 million BTUs which is equivalent to 199.3 gallons of LP or $438.46.  Thus, the logs of the sawed-out board feet of lumber would be worth $438.46 of LP divided by 383 board feet which equals to $1.14 of LP!!  The timberman might offer you one half of the$1.14 per board foot but more likely, one third.   

Creosote and Soot – Formation and Need for Removal (www.supervent.com)

Wood-burning stoves may require a great deal of chimney maintenance.  How you burn wood in your stove directly affects the formation of creosote.  Smaller, hotter fires are better than large, smoldering ones.  Fast, effective start-ups are important, as is the moisture content of the wood being burned.  Ideally, you should use seasoned wood with a moisture content of 15 % or less.  If your wood is not completely seasoned, use more dry kindling and paper first to warm up the chimney system to a temperature of 350 to 500 degrees F.  A good investment in assisting you in monitoring your heating system is a surface thermometer for single wall stove pipe or a probe thermometer for double wall stove pipe.

When wood is burned slowly, it produces tar and organic vapors as smoke, which combine with expelled moisture to form creosote.  The creosote vapors condense in a relatively cool chimney of a slow-burning fire.  As a result, creosote residue accumulates on the flue lining.  When ignited, the creosote makes an extremely hot fire.

With a new chimney and stove installation, the chimney should be inspected every couple of weeks to determine the rate of creosote buildup.  When familiar with the stove and chimney, it should be checked every 2 months during the heating season.  If creosote is building up, it must be removed to prevent the risk of a chimney fire. 

Chimney Fires (www.supervent.com)

 Chimneys are not designed to be used as combustion chambers.  It is very easy to over-fire your stove with kindling, scrap lumber, or any fast burning fuel, with the result that flames and high temperatures are produced all the way up the chimney and the result may be chimney damage.  If you see the stove pipe glowing red, then you are risking chimney damage or a fire.  The creosote in the chimney may be on fire.  Flames may be coming out of the top of the chimney.   If you suspect a chimney fire, first, immediately close all draft doors / dampers.  Second, alert all occupants of the danger of an overheated flue.  Third, inspect your stove and chimney surroundings for damage and if in doubt call your fire department.  Fourth, do not use the stove or chimney until a thorough inspection of the total installation is made.  Fifth, after a chimney fire, when it is safe to do so, check the internal locations such as attic and under the roof and keep watching for a few hours for delayed, smoldering and any subsequent ignition, even if the fire inside the chimney has been controlled.   

Combustion of Wood (http://www.rise.org/au/res/wood/index.html )

Wood is grown by the process of photosynthesis of carbon dioxide, water and trace minerals.  Such that,  CO(2) + 2H(2)O = ([CH(2)O + H(2)]) + O(2)   which is a reversible process with sunlight required for the left side of the equation and energy (heat) is released on the right side of the equation.  CH(2)O is a carbohydrate.  Less than one percent of the Sun’s energy is converted into biomass (grass, trees, shrubs, etc.).  Wood is composed of hemi-cellulose and lignin.  It also contains water, sulphur, nitrogen and some inorganic compounds that remain as ash after combustion is complete.  For dry wood the stoichiometric equation for the combustion of wood was found to be:

C(4.17) H(6.5) O(2.71) + 4.44 O(2)  = 4.17 CO(2) + 3.25 H(2) O

From the above equation, one pound of dry wood requires1.42 pounds of oxygen ( about 11 cu ft or 6.13 pounds of dry air which is about 56 cu ft measured at Standard Temperature and Pressure (STP) of  32 deg F and 14.7 psi).  And the combustion products are 1.83 pounds of CO(2) (10 cu ft) and 0.59 pounds of water vapor (8 cu ft) at STP.  About 0.5 % of the combustion products of the original weight of the wood are ash.

 You might ask, “Where is the creosote?”  The creosote comes from the incomplete combustion of wood!  The stoichiometric equation above represents experimental combustion with the different elements and compounds being controlled and measured.  The smoke you see from the chimney is the condensed, unburnt volatiles.  If there were complete combustion of gases coming from the chimney, then you normally would see nothing or in colder weather you would see a white, stream of water vapor that is condensing.

From the above equation and associated calculations you can understand one reason for the inherent inefficiencies of the wood stove.  For each pound of wood burnt, the “perfect” stove requires 6.13 pounds of air that is taken into the stove at about 70 deg F and exhausted up the flue at 250 to 400 deg F.  In actual use, the EPA Phase II stove probably uses two times that amount, which would be over 12 pounds of air for each pound of dry wood.  In colder weather you might be using 5-6 pounds of wood per hour, which translates into 60-70 pounds of air per hour.  Other inefficiencies of the wood stove come from having to keeping the flue hot and the flue’s associated heat losses.  The stove must be heated and kept at operating temperature.  The ash absorbs energy which is lost when it is cooled and removed from the stove.  The ash itself (0.5 % of charge) is part of the stove’s inefficiency because it can not be burned. 

 You can now understand the engineering-value of a catalytic combustor that is incorporated into the design of some wood stoves and is capable of burning the volatile gases and smoke particles.  These clean burning stoves are probably as clean or cleaner burning than many diesel trucks or oil fired furnaces.   Now, hear the conclusion of the matter about wood stoves and my parting advice is to season your wood folks, season your wood! Finis

   

Posted in Alternative Energy Sources | Tagged , , | 5 Comments

Our electric coffee pot, a favorite ‘off grid’ appliance

Posted on September 21, 2010 by George B.

Wake up and smell that coffee!

Mr Coffee thermos Type coffe brewer

Mr Coffee thermos Type coffe brewer

 

I’ve lost count of all the articles an opinions I’ve read about what’s best for off grid use, there are still some that insist that 12 volts is the answer! They have an investment in 12 volt appliances, less than ideal batteries in parallel, excessive distribution losses, expensive or poorly made appliances, and more.

Of course I am goring someone’s Ox when I share any opinion, but many of us, ‘if not most’ will agree that embracing well defined  standards can bring us many benefits. Whatever local commercial power delivers, that’s my first choice.  Thanks to the advances in Inverters over the years, the efficiency is quite amazing, and the idle current draw of a typical modern inverter is quite low.

In the 1970s, I bought a small inverter that was little more than a toy, the commercial rigs of the day were expensive and the ones I studied used quite a bit of energy to ‘idle’. We can thank the engineers in my home town of Kent, Washington for starting it all, one of the first really good Inverters was produced here, and the Engineers who worked for Heart spawned the other well known companies that produce Inverters today.  Hats off to these engineers and the competition they created to build world class products and the convenience off gridders now enjoy.

But… when does an electric coffee pot make sense? I’ll give you our Easton off grid location for example. I have a modest 520 watts of panels, and a 24 volt string of S530 rolls batteries. The FX2000 watt Outback inverter is also modest by some standards, but my chop saw, table saw, and small air compressor to name just a few run just like they’re plugged in on a short cord back home nearest the breaker box here at Easton.

We watch TV on the dish for a few hours most evenings,  sometimes we might just use the TV for background noise, but it’s on, so is the porch light, we use the microwave quite a bit, the small Dorm room sized fridge is always on, we use lights in the out buildings as much as we like.

Most summer mornings, I get up about 6:00 AM, I watch the sun creep towards the fixed mounted panels, it takes little time for the sun to make up the debt from the night before, and sometimes, it’s just minutes before the green light is on.  When you have energy production you can’t store, why not divert it to a dump load?  Or.. one better, this amazing little Coffee pot. What we like is it’s the right size for two people, the coffee pot doubles as a thermos, and there’s no energy used to keep it warm. I’ve come into the cabin at noon and found the coffee still hot.  Pouring a cup, and sitting on the porch and inhaling the country side along with a sip of  coffee is a favorite thing to do.  Hats off to the people who designed this coffee pot, it’s five star and two thumbs up… Just the opposite of the night mare coffee pot I wrote about on a recent post.

9/23/2010 AM… I decided to tag on this email snippet ‘conversation’ below, this may be helful for younger men, and slower learners. If you are gay, there’s less reason to keep reading, as you’ll have a natural tendency to understand what the average man overlooks.

Daniel writes:

“My thoughts on the DC charging is this, if your inverter did quit and your standby battery charger quit, you would still have capability to charge your batteries to run lights, DC refrigeration as well as a DC water pump for water!”

George Answers:

We get into opinions here,  read the latest article up at utterpower.com ‘new site’ regarding the coffee pot dump load.

You receive rather significant dividends WHEN you embrace standards. As you study off grid power, as your personal experience grows, you learn how profoundly wise KISS principles are; and part of KISS is to adopt local standards or use the most available products as they always prove to offer the best return on investment over time.

We know there are several Websites dedicated to 12 volts DC and the appliances they ‘SELL’. We expect them to disagree, and of course they might accuse me of “goring their ox”. We expect people to be critical of our opinions WHEN ours are contray to their right?

With the current crop of really good and dependable inverters with high efficiency and priced from near  ‘give away’ to fairly significant investments for the larger and more capable units, most of us are covered.

WHEN you consider all the inexpensive appliances you can run directly off the inverter OR the PMG generator WHEN you embrace the commercial power standard.  I’d hate to show up at a debate and try and defend the use of low voltage DC, it gets into a lot of things… lower the voltage in the distribution system by half, and double your losses, but that’s only the beginning of the discussion.

In one off grid site we experiment at, we feed power to buildings several hundred feet apart,  easy to do when the voltages are higher.  Yes there are people who start out small and know they’ll never need or want more than a Wall Mart economy deep cycle battery and a few auto tail light bulbs to light the way to the outhouse and maybe one over the cooler so they can find a cold beverage after dark, BUT the typical off girder desires more convenience and comfort as he grows older or wiser.

Here’s a good rule of thumb, if you are a hunter or camper, and you are building a camp…. your  buddies will suffer along with you no matter how sparse the amenities you offer. There is generally whiskey for entertainment, and you can sit around a Smokey fire and tell lies for entertainment. No matter how uncomfortable your camp, if you drank enough whiskey before bed, you might ignore the snoring, the fact that you bed is a foot too short, and other short comings of your man built camp.

Now, I share the golden rule of engineering design, IF you are going to invite a woman into your camp, especially a wife, then you best rethink your entire plan!  Yes, there are young men who think they are the master of the house, the dumbest of them will attempt to design the kitchen for their wives without her input.  Fact is, 99% of Off Gridders who share space with a female companion know how important standards are, and they expect to add amenities along the way.

My wife has taught me a good deal over the years, she has followed me up mountainsides so steep that we cross paths with other men headed down saying the climb was too long or too hard. She will break ice to bath in cold water. Washing her hair near daily is a ritual hard to deny her.  Her hair dryer followers her everywhere, and being able to plug it in generally means my breakfast is more to my liking.  I might get my favorite sausage, eggs, and toast when the lights are the correct color and the hair dryer works, or I might find a pot of boiling water, and instant oatmeal for breakfast. Yes, you can be the boss, but there are so many ways a wife can make her appreciation of your effort known 🙂 Only young men and dumb men ignore a woman’s input and comfort.

More mature men take inventory of a woman’s appliances, hair dryer, electric lip balm applicator? Whatever it is, plan for it or you will pay in ways you never anticipated.

Now as far as space planning, only foolish men will build a living space without the advice of a woman. Few men will think to place the kitchen window giving the best view, or the view of the drive way so she can see who is coming to the door. Few men will know the size of standard furniture and what will fit in a room. They are often clueless where the lights need to be located, and the better place to put wall plugs. If you have an ounce of sense, you will consult a women BEFORE you build…….”unless you’re Gay.”

Danile writes:

“Please let me know what you think!”

Now Daniel, don’t you regret this invitation?

Thank you again!

Daniel

You are welcome Daniel….

George B.

Posted in Products | Tagged , , | 2 Comments

Wood Burning, 2nd installment

Posted on September 18, 2010 by George B.

Effect of Moisture on Wood Burning Efficiency, Revised – Installment 2         

By John E. Laswell, Mechanical Engineer – Aug 2008

      Disclosure Statement – the information in this article is mainly the opinion of the author except where websites are shown.  There may be errors in the information and errors in any calculations.  So, the ideas presented herein should not be used to design a heating system for any home or building.  Application of any engineering formulas and principles may be in error.  This article is stickily for the reading enjoyment of the curiously minded individual!!

     Forward, Hello fellow DIYers.  My name is John L. and I live in the hills of scenic, southern Indiana.  I have burnt a wood furnace in my basement for 22 years.  The wood came from my 38 acre farm, mainly from dead or non-timber grade trees.  My wood was cut with a chain saw and hand split for the first nineteen years.  I now have a 27 ton hydraulic log splitter.  I mainly burn oak, hickory, ash, hard maple and dogwood.   For the last three years I have I have been heating one half of my home with a King, 1107J, Blaze King stove.  It is wonderful.  I have installed it in my dining room.  In my opinion this is the best wood stove.  If there is any interest, I would write an article about my experience with buying, installing, operating and the pure enjoyment of heating with the “king”. 

     I am so tired of products that have been “value-engineered” to the point of planned-failure-in-design.  How many times have you been asked when you purchase a fairly simple product if you wanted to buy an extended warranty plan?  Here is some of the modern philosophy: use it up, burn it up or throw it out when it stops working.  I recently bought a pair of trousers where it cost almost as much to alter the length as the cost of the trousers!  Something is wrong!  I know what it is? Products made in China and cost of labor in USA.

     This article comes in three installments:

     First – Introduction, Wood Stove Efficiency and Results

     Second – Determining The Percent Of Moisture In A Wood Sample, Conclusions,                               Energy to Cook-off Moisture, Operating the Wood Stove

     Third – What Is The Value of Burning Wood?, Creosote and Soot – Formation and                            Need for Removal, Chimney Fires, Combustion of Wood

Determining The Percent Of Moisture In A Wood Sample

Before I consider another example, I want to present a method for determining the amount of moisture in a piece of wood.  For example I had 6 pieces of white oak that weighed 20 pounds and 2 ½ ounces (20.156 lbs).  So, I decided to conduct my own experiment!  I took my sample piece of white oak and “split” it into 14 smaller pieces which could be easily dried in my oven at about 125 deg F.  The initial weight of the log was 3.625 lbs and the final weight of the 14 sticks was 2.25 lbs which was a weight loss of 1.405 lbs.  With proportion I then determined what the estimated total water loss would be for all six pieces of white oak: 20.156 / 3.625 x 1.405  = 7.812 lbs of water!!  That is almost one gallon of water!!!  Would you place 12 pounds of dry wood in your stove and then pour almost 4 quarts of water on top? No! No! No!  So, the percentage of water in my arm load of wood was 7.812 / 20.156 = 38.76 %.  Looking at Table 1 at a moisture of 40% shows a heating efficiency of 43 %  for the great EPA approved stove!

Conclusions

What is wrong with the great EPA stove?  I thought that it was rated at 82.5 percent efficiency?  Well, nothing is wrong with the EPA stove.  I am simply trying to burn “very wet wood”!!!!  Even though this white oak had blown down 2 years before, its wood still had a high moisture content because it had not been split and seasoned!!  What could I do?  By drying the wood down to 10 % moisture, you can see from Table 1 that the thermal efficiency of the great EPA stove could be increased to 73 %.  Hello!!!!  That is almost double the efficiency of burning my newly split, wet wood.  This means, practically, that I would use about one-half the weight of wood if my white oak was well seasoned.

I can tell you friend that large logs take a very long time to season down to 10 to 15 percent moisture.  That is one reason why they last so long in the overnight firebox.  The lesson to be learned even by “old timers” is that lots of heat and high efficiencies can only be obtained by using seasoned wood (one year after splitting, stacking and covering).  It is a crime not to cover dry wood or take a piece of wood covered with snow or ice and place it in a thermally efficient,  Phase II EPA approved stove, especially with a catalytic combustor!!!

Strategies for Your Wood Supply

With the coming of Spring a young man’s thoughts turns to love, but with the falling of the leaves, the wise man’s mind tells him to get in his wood supply for Winter.  There is also the inherent thought that tree wood will be more dry since the tree sap has returned to its roots.  This is somewhat faulty thinking.  The moisture in a live tree in the Fall and Winter is still too high for efficient burning and heating.  Yes, some trees like Ash can be cut “green”, split and burnt, but not efficiently and not without a lot of smoke and creosote.

         Wood will ultimately assume a moisture content level consistent with the relative humidity of its surroundings.  It will absorb or lose moisture from or to the atmosphere until the vapor pressure in the wood is equal to the partial pressure in the surrounding atmosphere.   Note, it will take 2-3 times the amount of green wood to “heat your dwelling” as well-seasoned wood!   Do you understand the last sentence that I just wrote?  Let me repeat it; “it will take 2-3 times the amount of green wood to “heat your dwelling” as well-seasoned wood!”.

 Do you like cutting, splitting, and hauling lots of wood each Fall?  Do you like to have a lazy, smoldering, smokey fire which doesn’t produce much heat unless the draft is really “cranked up”?  And you don’t worry about creosote buildup in you chimney or about having a chimney fire?  Do you just dump your wood in a pile and fetch the wood into the house as required, be it rain, shine, snow or ice?  Do you have an old, inefficient stove.  Then, you should not think about burning seasoned wood!   Otherwise, a paradigm shift in thinking is required.  Have a plan to cut some or all of next year’s wood supply this Fall and Winter.  Why procrastinate, you have to take the time to cut the wood sometime, right?  But, by cutting and seasoning the wood 6 – 12 months ahead of burning, you only have to cut half the amount, hello again!  If you have an old, inefficient stove, then think about upgrading to an EPA Phase II stove which could take your 40% moisture-wood burnt in the old stove which has an efficiency of 26% to a Phase II stove burning 15 % moisture wood which has an efficiency of 59%!  That is 2.25 times less wood!

But, what can I do to improve the quality of my wood supply this year?  Start cutting wood as soon as possible, even if it is June, July or August.  Wood cut in the Summer that is split and stacked properly will loose several percentage points of moisture by December.  The rate of moisture-loss does decrease with cooler temperatures.  Spit the wood more times than usual to increase the rate of moisture evaporation (remember how I split my white oak sample into 14 pieces and how fast it dried!).  Use the finer, split wood to help burn the larger greener wood.  Try to select the dead standing trees to harvest first.  Ring-cut any live trees early, then the drying leaves will help ‘suck’ the moisture out of the tree.  Taking wood into a warmer, dry shelter will help, but?  Yes, you say, you just take some wood in by the fire and dry it before you burn it, really.  Try checking its percent of moisture content.  A professional, dehumidifying, drying kiln takes 35 days to take green oak to 8% moisture.   A deliberate wood-seasoning program is the best, least expensive method to provide quality fuel for your stove and for your enjoyment.

Energy to Cook-off Moisture

I think it might be intuitive to think that the percentage of heat of the total charge of wood to cook-off the moisture in the wood is directly related to the percentage of the moisture in the wood.  That is the more moisture you have in the wood, then the more wood must be burnt to evaporate that moisture, makes sense!  But, what exactly is the relationship.  Here is a mathematical proof to demonstrate that intuition and to quantify the relationship.

Let Wwm = the weight of arm load of wood with moisture in pounds.

And m = the percentage of moisture in the wood.

Let Wm = weight of moisture in the wood in pounds.

Thus, Wm = (m / 100) * Wwm

Let Ww = weight of the wood fiber,

then Ww = Wwm – Wm.  This means that the weight of the wood fiber is equal to the weight of the charge minus the weight of the moisture in the charge, makes sense.

Let h = heat value for dry wood in BTUs per pound, about 7,000 BTUs per pound of wood.

Let Ch = constant value to evaporate one pound of ice in wood = 1297 BTUs per pound of water.

Then let, k  = h / Ch which is assumed to be a constant for each species of wood and is in pounds      of water per pound of wood.

Calculating , k = 5.397 pounds of water per pound of wood.

.

Let, Wwb = weight of dry wood required to evaporate the moisture, pounds.

Thus, Wwb = Wm / k or Wm / Wwb = k = 5.397

 Or , Wwb / Wm = 0.1853 or 18.53%

Let Mwb = percent of total charge of wood to evaporate the moisture.

Then the relationship of Mwb and m would be:

Mwb = Wwb / Wwm * 100 and  Wwm = 100 Wm / m from above.

Therefore, Mwb = (Wwb / (100 Wm / m)) * 100 = (Wwb * m) / Wm = (Wwb / Wm) * m

Substituting, Mwb = ((Wm / k) / Wm) * m =  m / k =  m / 5.397 which says that the moisture of the wood, m divided by the constant k = 5.397 will be equal to the percentage of the dry wood required to evaporate the moisture.  So, in our example of 20 percent moisture-wood divide by 5.397 is 3.70 percent of the total charge which will be required to cook-off the water. 

It is true that this percentage could easily have been calculated by simply taking Wwb divided by Wwm = 0.74 / 20  = 3.7 %.  However, knowing the relationship of Mwb =  m / k = 0.1853 * m or the percent of wood required to cook-off the moisture is always about 20 percent of the moisture percentage.  How easy then to calculate say, 40 percent moisture-wood would require an additional 8 percent (40 x .2) of the wood “charge” to cook-off water.  I can then quickly calculate that 48 percent (40 + 8) of the wood “charge” involves the moisture in the wood that does not contribute to heating the intended surroundings. One more example of say 15 percent moisture-wood, would only involve 18 percent (15 + 3) of the wood charge.

 In summary, it has been shown that the presences of the moisture in the wood contributes about 5 times more to inefficient burning of the wood as does the heat required to “cook-off” that moisture.  The lesson again is to use seasoned wood for fuel with as low a moisture content as is practicable.

Operating the Wood Stove

It is a fact of life that things that become habitual are enjoyed less than the occasional happenstance!  So, the wood stove was “laid aside” in late Spring.  The ashes were cleaned out, the excess wood and kindling were taken back to the wood shed and the hearth cleaned-up.  However, come October with the circus of Fall colors and cooler evenings, your attention turns to a warm jacket, gloves, sock cap, hot chocolate and the wood stove.  If you were as wise as the ants, then your wood supply has been seasoning since last Fall or Winter.  Your wood is dry and maybe all you have to do is to bring it into the “wood shed”, that is great.  Using the wood stove in early Fall or late Spring is a bit tricky because the warmth that feels so good in the morning or evening is unwanted during the warmer day light hours.  So, maybe just a little kindling or sticks picked up in the yard are used to take the chill out of the air.  A serious fire will not be started for several more days, for an Indian Summer may be just around the corner.

The sign for “the fire” may be frost on the pumpkins, having to breaking a little ice or that the house is just not comfortable even with that warm sweater.  It is time to wad-up some paper, place some kindling on top of the paper, top the kindling with some small pieces of wood, open the draft / bypass and strike the match.  Don’t let the fire get to hot before controlling the draft and when the fire has a few good coals, start adding some larger pieces of wood.  The goal is to establish a good bed of coals before the “main charge” of wood is added to the fire.  The “main charge” of wood will be dictated by the time of day, the coolness / coldness of the weather and the temperature of the home.  Charging the stove every few hours to produce a “good burn” is more efficient and desirable than “filling her up” and letting the fire smolder.   A larger charge can be used if you expect to be away for quite some time.  And of course, a larger charge will be used for the overnight heat.  As the weather becomes colder, the charges must become larger.

How much wood will you need?  It depends on a few factors.  Where do you live (part of country)?  What kind of a home are you heating?  How warm do you want to be?  How efficient is your stove?  How seasoned is your wood?  Heating engineers use a factor known as monthly degree-days which you should be able to acquire from your weather service / station.  A degree-day accrues for every degree the average outside temperature is below 65 deg F during a 24 hour period.  Degree-days are directly related to the total yearly amount of heat energy you might use if you had a thermostatically-controlled, heating system which a wood stove is not.

For example, Los Angeles – 1391; New York – 5280; Minneapolis – 7977 have these typical degree-days.  The value of knowing the degree-days for wood stove users is in predicting the percent of wood that will be used each month of the heating season.  The percentages for each month for Bloomington, Indiana (5348 degree-days) for the largest degree-days months are: Nov – 11.7%, Dec – 18.7%, Jan – 21.5 %, Feb – 17.1% &  Mar – 13.3 %.  For instance, let me say that I use 1/4 chord of wood in November.  Then I would expect to use 1/4 chord in March, 1/2 chords in January, 3/8 chords in December and February each and about 3/8 chords for the rest of the heating months for a total of almost 2&1/8 chords of wood.   These degree-days are of course averages for the time period from 1971 to 2000.  Here is a wood proverb: it is best to have too much seasoned wood than not enough!  Enjoy you wood stove heating experience.

Another application of the monthly degree-days factor is to estimate the average, daily high and low temperatures for the heating season.  First, the daily degree-days for any month can be calculated by dividing the monthly, degree-days by the number of days in a particular month.  So, the number of degrees below 65 deg F in November for Bloomington, IN is [5348 x (11.7 / 100)] / 30 = 20.9 degrees.  These degrees should be subtracted from 65 deg F which is the basis for the degree-days factor; therefore,  65 – 20.9 = 44.1 deg F which is the estimated, average temperature for any day in November.  Assuming that the difference between the high and low temperature for any one day is 20 deg F and assuming that the high temperature is half of the 20 degrees difference.  Then the estimated, high temperature would be 54.4 deg F and the estimated low temperature would be 34.4 deg F for November.  I understand that this is a rather simplistic approach for estimating the high and low temperatures, but after all it is estimating the weather!

Posted in Alternative Energy Sources | Tagged , , , | Leave a comment

Burning Wood

Posted on September 16, 2010 by George B.

There is a lot of interest in wood gas and other wood topics in our DIYer group. It’s that time of year where many of us check our stoves and wood supply for the winter.  Diyer John Laswell has been burning wood for a long time, we all know that knowledge plus ‘hands on’ is a great combination. What you learn about the fuel goes a long way in understanding what might be done with it.

I recently read a post about a wood gasifier that burned so hot that it broke down water to hydrogen and oxygen and used it for fuel 🙂  Of course, if that were true we’d look no further for energy, AND water might be considered dangerous stuff. I’m sure I’ll see or hear about someone using magnets in a wood stove sooner or later.

Without further delay, my thanks to DIYer and retired Mechanical Engineer John Laswell for sharing his article here, stay tuned for more installments of this article. George B.

Effect of Moisture on Wood Burning Efficiency, Revised – Installment 1         

By John E. Laswell, Mechanical Engineer – Aug 2008

     Disclosure Statement – the information in this article is mainly the opinion of the author except where websites are shown.  There may be errors in the information and errors in any calculations.  So, the ideas herein presented should not be used to design a heating system for any home or building.  Application of any engineering formulas and principles may be in error.  This article is strictly for the reading enjoyment of the curiously minded individual!!

     Forward, Hello fellow DIYers.  My name is John L. and I live in the hills of scenic, southern Indiana.  I have burnt a wood furnace in my basement for 22 years.  The wood came from my 38 acre farm, mainly from dead or non-timber grade trees.  My wood was cut with a chain saw and hand split for the first nineteen years.  I now have a 27 ton hydraulic log splitter.  I mainly burn oak, hickory, ash, hard maple and dogwood.   For the last three years I have I have been heating one half of my home with a King, 1107J, Blaze King stove.  It is wonderful.  I have installed it in my dining room.  In my opinion this is the best wood stove.  If there is any interest, I would write an article about my experience with buying, installing, operating and the pure enjoyment of heating with the “king”. 

     I am so tired of products that have been “value-engineered” to the point of planned-failure-in-design.  How many times have you been asked when you purchase a fairly simple product if you wanted to buy an extended warranty plan?  Here is some of the modern philosophy: use it up, burn it up or throw it out when it stops working.  I recently bought a pair of trousers where it cost almost as much to alter the length as the cost of the trousers!  Something is wrong!  I know what it is? Products made in China and cost of labor in USA.

     This article comes in three installments:

     First – Introduction, Wood Stove Efficiency and Results

     Second – Determining The Percent Of Moisture In A Wood Sample, Conclusions,                               Energy to Cook-off Moisture, Operating the Wood Stove

     Third – What Is The Value of Burning Wood?, Creosote and Soot – Formation and Need for           Removal, Chimney Fires, Combustion of Wood   

Introduction 

Wood stove experts advise that wood must be ‘well seasoned’ before burning.  Therefore, I asked the following questions.  What is the effect of different levels of moisture in wood on burning and how can the percentage of moisture in wood be practically determined?  I will answer the above questions and more!  You should know that the combustion of wood is a complex process and it occurs in three basic phases: one, the primary phase is where the wood is ignited and the moisture is evaporated.  Two, the secondary phase is where the volatile liquids and gases are expelled.  These products of combustion burn at about 1100 deg F and 50 to 60 % of heating value of wood is contained in these gaseous products.  Three, is the charcoal phase which is a very slow, hot combustion process.  Now, some engineering definitions and assumptions.  A British Thermal Unit (BTU) is the amount of heat required to raise the temperature of one pound of water for one degree Fahrenheit.  So, it would take 180 BTUs to raise one pound of water from 32 to 212 degrees F.  At 212 deg F it takes 973 BTUs to vaporize one pound of water into steam.  It also takes 144 BTUs to melt one pound of ice.  Adding these values up (180 + 973 + 144) totals1297 BTUs of heat to melt one pound of ice in wood and then vaporize that water.  That requires about 1/5 of a pound of burning dry wood fiber.

     For my calculations I assumed that the heating value of dry wood (no moisture) is 7,000 BTUs per pound.  Then, assume I have an arm load of wood at 32 deg F that weights 20 pounds.  Table 1 below shows the effect of different percentages of water in the wood and the amount of heat that is available to produce heat for your intended surroundings and the efficiency in a stove when the water is  “cooking-off”.  The efficiencies for two, new Phase II EPA approved stoves and an “old” conventional stove are also calculated in Table 1.  

Wood Stove Efficiency

When I write about “the efficiency of a wood stove”, I am referring to the stove’s capability to burn a “charge” of  wood and to transfer the wood’s heat energy to the stove’s intended surroundings.   A few factors will determine the stove’s efficiency: the stove’s inherent design, the stove’s chimney, percent of moisture in the wood, maintenance of the stove: firebrick, gaskets, catalyst, etc., the manner in which the stove is “operated” which might include the size of fuel charge, amount of draft and the maintenance of the ash “pit”.

In general the stove’s inherent design can not be changed (metaphor: can not change a car’s cylinders from 4 to 6) .  So, buy a stove with the highest efficiency that meets your specifications and pocket book.  Keep in mind that you are making a long term investment of 20-30 years (metaphor: you need to find that car that gets 40-50 miles per gallon).   The cost of fuel will keep increasing with time.

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The stove’s flue must “draw” properly.  If your house is too “tight” (this calls for an outside air kit), then the draft will be weak and the amount of oxygen reaching the fire-bed will be inadequate for proper combustion which will produce smokey, lazy fires.  If the chimney is too high,  then the draft may be too strong and hard to control. Even small air leaks in the combustion chamber will cause the fire to “burn out” prematurely.

  Assuming that stove, chimney and stove maintenance factors are adequate, then the proper wood for burning will be considered next.  The use of “seasoned” wood is the most important factor in controlling the efficiency of the stove than any other aspect of owning and operating a wood stove.  My engineering calculations are tabulated in Table 1 which quantifies the effect (efficiencies) of various levels of moisture in wood when used in three levels of efficient stoves.  Moisture in wood has three major effects on efficiency: first, the “charge” of wood fiber is diluted with water.  That is a 20 pound arm load of wood that has 20 % moisture, which is considered the maximum level of moisture to qualify as “seasoned wood” by some authorities, has 4 pounds of water (that is two quarts -a pint is a pound the world around) and 16 pounds of wood fiber. 

The second effect of the moisture is that it must be “cooked off” in the form of steam which requires about one fifth pounds of wood for each pound of water.  For our arm load of wood that would be about 0.8 pounds of wood which is equal to 4 % of 20 pounds of wood.   Thus, our 20 pounds of wood has become just 15.2 pounds of usable wood fiber.  Now, consider if I burn this wood in an old-design, wood stove that is 50 % efficient, then you are only heating your intended surroundings with about 7.6 pounds of dry wood fiber, ouch, as Table 1 indicates, 20 % row & last column an efficiency of 38%.  An article on the Principles of Combustion of Wood and three stages of combustion can be found at www.montana.edu/wwwpb/pubs/mt8405.

The third effect of the moisture is the “cooling effect” on the products of combustion as the temperature of combustion is trying to increase from 212 to 575 to1100 deg F (remember how you controlled the flames of a small brush fire with a spray of water?).   The volatile gases / vapors are escaping with the evaporated water while temperatures are below 1100 deg F.  These vapors contain 50 to 60 % of the woods heat value.  Increasing the draft to “cook off” the water, means additional amounts of nitrogen gas (inert) must be heated and lost up the flue.

Table 1

Effect of Moisture in Wood on Heating Efficiency  

% LBS LBS BTUs BTUs % 0.825 0.72 0.50
Water Water Wood Cook Heat Wood % Eff % Eff %Old
      Water Total Heat Stove Stove Stove
                 
0 0 20  0  140000  1.00  0.83  0.72  0.50
5  1  19  1297  131703  0.94  0.78  0.68  0.47
10  2  18  2594  123406  0.88  0.73  0.63  0.44
15  3  17  3891  115109  0.82  0.68  0.59  0.41
20  4  16  5188  106812  0.76  0.63  0.55  0.38
25  5  15  6485  98515  0.70  0.58  0.51  0.35
30  6  14  7782  90218  0.64  0.53  0.46  0.32
35  7  13  9079  81921  0.59  0.48  0.42  0.29
40  8  12  10376  73624  0.53  0.43  0.38  0.26
45  9  11  11673  65327  0.47  0.38  0.34  0.23
50  10  10  12970  57030  0.41  0.34  0.29  0.20
55  11  9  14267  48733  0.35  0.29  0.25  0.17
60  12  8  15564  40436  0.29  0.24  0.21  0.14

 

Results

Now assuming that we have a great Phase II EPA stove with 82.5 % efficiency in heating, then the efficiency in using wood with 20 % moisture would be about 68 %.  If I were heating with an “old” conventional wood stove with an efficiency of 50% (getting very little secondary burn), then my heating efficiency with wood containing 20 % moisture would be about 38 % which would surprise many wood-stove users that this thermal efficiency is so low!   In other words only about 1/3 of the dry weight of my wood is heating my house!

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