Calculating Firing Costs With External Digital Controller

[neilestrick]

Here's something I just figured out today. Seems obvious now that I realize it, but had never thought of it before:

 

I'm firing my little 1 cubic foot manual test kiln with some fusion buttons for my glaze formulation students. I just recently hooked it up an external Orton digital controller I got from a customer. For those of you who haven't used one, the way external controllers work is the kiln plugs into the controller unit via its regular power cord, and the controller sends power through the cord as needed to heat up the kiln. It cycles the kiln on and off like any digital controller, to control the rate of climb.

 

The kiln itself has a Sitter on it with a timer. You have to put a cone in the sitter that's higher than the projected firing (or just jam a piece of kiln shelf in it), push the power button, and turn all the knobs on high. Because power is only going through the sitter intermittently, as the relays in the digital control unit cycle the power on and off, the timer on the sitter only moves when there is power to the kiln. So at the end of a firing I can tell exactly how long the kiln was 'on', and calculate the cost of the firing by way of the wattage of the kiln. Awesome!

[Marcia Selsor]

That is awesome. I had one of those external controllers in our co-op in Montana. I just read the electric meter when I started and again when I finished.

Marcia

[Guest JBaymore]

You can get digital timers that can be wired onto the same circuit as the relay control voltage line. The timer will only "count" the nthe relay is in the "on" state. This trick has been standard for years. But it does require some knowledge of electrical circuits. It is quite simple really.

 

Yours certainly works well if there is a sitter on the kiln.

 

best,

 

.................john

[Chilly]

I use two different kilns, both controllers tell me the Kw used at the end of a firing.  I think it is only approximate, and I had to tell the controller what Kw the kiln is when I set it up.  My controller remembers the usage until I start a new firing, the one at the centre remembers it until the power goes off, which is less convenient.  But at least I get an idea of the power used and therefore cost of firing.  It's easier than guessing how long the kiln was running at quarter/third/half/full power and then working it out.  The controller at the centre was new about 4 years ago, and it's predecessor didn't have this feature.

[neilestrick]

I use two different kilns, both controllers tell me the Kw used at the end of a firing.  I think it is only approximate, and I had to tell the controller what Kw the kiln is when I set it up.  My controller remembers the usage until I start a new firing, the one at the centre remembers it until the power goes off, which is less convenient.  But at least I get an idea of the power used and therefore cost of firing.  It's easier than guessing how long the kiln was running at quarter/third/half/full power and then working it out.  The controller at the centre was new about 4 years ago, and it's predecessor didn't have this feature.

The Orton controller I'm using has that feature, but I haven't had time to set it up yet. I'll do that some day, but for now I was happy to figure out the sitter timer method! I wish Bartlett would put that feature into their controllers.

[Guest JBaymore]

So long as the timer doesn't draw much current away from the relays it would be fairly straight ahead to add a timer to the 12 volt circuit on each relay.

 

 

Yup....... it is pretty much a nothing.

 

But the internal monitoring of the "on" cycle by the controller itself is a real sales feature, I'd say.

 

best,

 

..................john

[Mart]

o_O  Why not just install the electricity meter and know EXACTLY how much juice was used.
Modern electricity meters are really small too, no spinning wheels etc.  and work with multiple rate (day/night) too.

[Norm Stuart]

I sent Bartlett this thread, but this is the best answer Steve Issacson of Tech Support can provide currently.  The link to Paragon kilns is essentially the sort of detailed information I received from Cress kilns for each firing speed and Cone in order to calculate out firing costs.

 

 

Norm,

The V6-CF controller can not determine the cost off firing.

Check out the link below and this will help you understand how to calculate the cost of firing.

http://www.artclayworld.com/Tips-TechSheets/KilnFiringCosts.pdf

Steve
 

[Guest JBaymore]

o_O Why not just install the electricity meter and know EXACTLY how much juice was used.

Modern electricity meters are really small too, no spinning wheels etc. and work with multiple rate (day/night) too.

 

Bacause this requires a meter on the separate kiln circuit, and (at least here) that is a very expensive installation that for most people must be done by a licensed electrician.

 

best,

 

...............john

[neilestrick]

Remember that when you are looking up the KwH price from your electric company, it's not just that price that you're being charged. You're also being billed for the delivery charge, other services and taxes. So while my KwH price is just under 5 cents, my actual cost when I take my total monthly bill divided by my KwH usage comes out to 14 cents per KwH.

[neilestrick]

My baby kiln just cost me about $2.50 for a relatively fast firing to cone 6 with a controlled cooling from peak temp down to 1400F (what I would need to do to simulate a firing in my big kiln). Total on the sitter timer was about 10 hours.

[Guest JBaymore]

My studio rate here in New Hampshire is a flat $0.15.556 per KwH, plus a monthly flat fee of $12.44. Day, nite, peak demand period, low demand period.... always 24/7/365.

 

best,

 

...................john