What is the efficiency of 53 versus 250 dry kiln

[rjwoelk]

So if one drys 1000 bft with the 53.
Then you dry 4000 bft with 250.

What is the difference in cost.
If any on a bft bases. 
Does the 250 use 2x or 3x the energy to do 4000?  Is there a direct correlation between 1000 bft cost ?
4000 bft cost ?
What about drying say 1000 bft in a 250?
Hope I am making my self understood.

[Southside]

@K-Guy would be the best one to provide you with the answers you need. 

[rjwoelk]

Thanks Southside. Will call him tomorrow.
Just out of interest. Do you always fill your kiln to max capacity for the type of wood your drying?
What was the deciding factor to go with the larger kiln?

[Southside]

No I don't always fill it, but what I do involves a lot of just in time production and it's always odd dimensions. 

My decision was easy, 4 times the capacity for twice the money, and when I do need to fill it I am done in less than half the time I would be otherwise. 

I would guess there is not a significant operation cost difference between the two when comparing # of water removed from X volume of wood, at least not enough to factor into which system makes more sense if you need the larger capacity in a time sensitive manner, if even on occasion. Does that make sense? 

[rjwoelk]

Yes. Do you have to do anything special to the system when shut down and don't have anything drying.

[Southside]

No, just make sure your wet bulb reservoir is empty or otherwise protected from freezing. 

[WDH]

The L53 uses standard 110 volt power.  The L200 (I believe this is the same) uses 220 volt power. 

[GeneWengert-WoodDoc]

Dying time will only vary if you have different temperatures, humidities and air flow.  The 250 gets hotter, I believe.

Electricity is a big cost, and both systems will use about the same kWh per 1000 BF IN A WELL INSULATED kiln.  As you use less insulation in the kiln, the larger unit will be more efficient, which probably could be as much as 10%, but in most cases will be closer to 5%.  This savings is $2.50 per 1000 bf...not much.

Labor will be less per BF in a larger unit.  Depreciation will be less as the larger building costs less per BF.

In many cases you will need 4 times more lumber at the same MC, species, and thickness.  Running a kiln 75% full increases costs per BF and reduces profit.  On the other hand, if your profit is $50 per 1000 bf, you will make 4x the profit.

[rjwoelk]

Gene.
So if it took 4 weeks to dry 1000 bft in the 53. This would translate into 4 months for 4000.bft
The l200 could do the 4000 bft in one month.
Would the electrical use be the same in both cases?
Or would it be less.
 4 weeks of use opposed to 16 weeks of running fans and kiln

[doc henderson]

rj, The bigger kiln dehumidifier has more power and can dry more wood in the same time.  L200 is bigger than the L53.  if you go to the Nyle website (link at the left) and look at the manuals, they show kiln sizing and loads.  click on resources then manuals.  so depends on you plans.  If you are cranking out the wood, go big.

[YellowHammer]

They are virtual scale models of each other, both in terms of capacity and electricity.

The Nyle L53 as a 1/2 hp compressor and rated to dry 1,500 bdft of hardwood, but I have had my best success with max loads of 1,000 bdft.  The Nyle 200, has a 2 hp compressor, which is the same as the WM 250, so 4 time the compressor power and dries 4 times the load.  Both mine run 24/7. Electricity bill on my L53 is about $100 per month and the bills on my L200 is about $400 per month, so the electricity usage is pretty liner and comparable.  

The L53 has 1 kW heat, the L200 4kW.  Both have the same operating parameters, as far as temperature limits, and are virtually scaled up models.  Both seem to be bulletproof, or at least train proof. :D

If you dry max or near max loads, then the BTUs per wood bdft dried will be about the same.  However, if you do short loads, or over loads, then other factors come in to play.  Setting pitch and otherwise running the heat strips will have an effect on the electricity draw.  

These unit ratings are for hardwood, but for green softwood, the ratings drop because of the rate at which softwood can give off water.  So the L53 drops to about 300 bdft, and the L200 drops to 1500 bdft max load, green wood.  If the softwood is air dried, then full loads can be put in.

If the either unit has a short load, the compressor will cycle off until the wet bulb comes up to your set schedule.  So it operates like a HVAC unit on your house with a thermostat.  If the unit's compressor is idling, then the expense is based on the fan consumption in the kiln and the fan baffle.  The kiln fans never tun off, even if the compressor is off.

Bob,
What size loads are you planing to dry?

[rjwoelk]

 

  queen size bed.
I am looking at doing more of this kind of work. Got the equipment except for the kiln.
So far they are doing fine, this is third one made and so far no checking. The problem is it takes a lot of time  for air drying and then worry about problems down the road with movement. For ourselves I am ok it can be fixed, different if you do for others.
I am looking at getting off the road or at least cutting back on months. The other item would be tables.  Will see how it all works out. Can sell birch lumber for other home projects, and kiln drying is needed.
It takes a 14 inch x16 ft log to make one bed.  Aprox 70bft to make one bed.

[K-Guy]

 rjwoelk

The efficiency is about the same but the capacity is different. We estimate 1 inch pine to need 250 kwh/ 1000 bf. So if your power is 12 cents per kwh this is the math.

250 x .10 ÷ 1000 = 0.03

or 3 cents per board foot. The drying time and board foot cost is about the same for both units but the number of board feet dried is different.

[Tom the Sawyer]

Stan,

Wasn't that supposed to be    250 x .12 / 1000 = .03 

Is that figure for drying from green, per day, etc.?

[rjwoelk]

Thanks for all the info.

[K-Guy]

Tom the Sawyer

Yes that is drying from green. 

[rjwoelk]

What would be the kwh to dry 2x birch. And time like weeks. let's use 30% mc and 1000bft charge.. I am thinking cut my birch all 2 inch and then laminate the legs for beds and tables after drying.
Would that 250 for green 1 inch mean
500kwh for 2 inch green.