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gas costs per firing

updated fri 22 feb 08

 

Hank Murrow on wed 20 feb 08


On Feb 20, 2008, at 2:45 PM, Mike Gordon wrote:

> Hank wrote......Well, I went to the Gas Co. for rate
> information, and asking again how many cu.ft. of gas is in a therm,
> etc. I even read the meter during one firing to corroborate the
> figures from my firing logs. I was consuming an average volume of gas
> for each firing including the soak in oxidation of around 3300 cu.ft.
> At the rate we pay here in Eugene($1.12/1000 cu.ft.) that firing cost
> $3.70! I was astonished, and quickly drove over to the Gas Co. to
> have them check my logs, and check my billings, etc.
>
> Mike answered;

> Hank, I tried to do the same thing here in Walnut Creek, Ca.- Pacific
> Gas & Electric Co. They told me that cost per therm changes all the
> time, although my bill has an average taken over the billing
> period. My
> other problem is all the pilots in my house remain lit during my
> firings. It's not much, I guess, but still not accurate. I'll try it
> again next firing and take it to them..... we'll see. Mike Gordon

After doing this exercise with the Gas Co, I decided that the house
pilots were insignificant, as there are 16 bigger pilots on my kiln.
Sort of swamps whatever the house pilots are doing. I calculated the
volume of gas passing a single 7/32" orifice each hour at the
different pressures in water column that I recorded. Multiply the
hours times the cu.ft. from the Eclipse chart(Bulletin L-100 lists
orifii sizes vs. wc pressure), and add up the sums for each gas
setting throughout the firing and you have the total cu.ft. of gas
used in that fire. My kiln(with the soak in oxidation during cooling)
consumes between 2900 and 4000 cu.ft. of natural gas. You are correct
that therm prices vary if you sign up for the 'averaged' billing
basis. Here it varies between $1.07 and $1.15 per therm. I used $1.12/
therm and a therm is 1000 cu. ft.

I had the Gas Co go over all my figures to be sure before posting.

I look forward to more reporting on this,

Hank

Mike Gordon on wed 20 feb 08


Hank wrote......Well, I went to the Gas Co. for rate
information, and asking again how many cu.ft. of gas is in a therm,
etc. I even read the meter during one firing to corroborate the
figures from my firing logs. I was consuming an average volume of gas
for each firing including the soak in oxidation of around 3300 cu.ft.
At the rate we pay here in Eugene($1.12/1000 cu.ft.) that firing cost
$3.70! I was astonished, and quickly drove over to the Gas Co. to
have them check my logs, and check my billings, etc.

Hank, I tried to do the same thing here in Walnut Creek, Ca.- Pacific
Gas & Electric Co. They told me that cost per therm changes all the
time, although my bill has an average taken over the billing period. My
other problem is all the pilots in my house remain lit during my
firings. It's not much, I guess, but still not accurate. I'll try it
again next firing and take it to them..... we'll see. Mike Gordon