Check my calcs! How quick will electricity pay for itself?

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I agree with you, but I cannot easily convert my pots to electric and compare directly.

I can calculate how long it takes me to heat water and how many lbs of propane I use, but the comparison to electric would not be a fair one unless the efficiency number also had vessel loss in it, which 100% obviously does not.

I see your point. That throws another wrench into it. What are you boiling in? Stainless compared to other metals is relatively non-conductive...Another reason direct fired vessels may be less effecient.

I have heated water in my uninsulated (covered) HLT to 125, left it at about 50 degree ambient temps for over 12 hours and come back to 85 degree water. So, if we are talking similar vessels, the heat loss from the vessel itself should be negligible at least for our purposes.

Also, we agree that electric cannot be assumed at 100% There are losses between the meter and element. If we figure electric at 95% we can at least get some comparison.
 
Honestly, I have never looked up specs for propane burners. We had one when we started brewing and just went with it. I tend to trust your observations much more than manufacturer claims. Have you ever checked your actual fuel useage (gallons or pounds) against your time calcuation?

I never knew that figure for raising air temp. A little goes a long way there.

I never looked them up either until this thread came up. Price per pint is not exactly why I brew beer. And I calculate the cost of each batch more on the ingredients then anything else. The burner I purchased as a Turkey Fryer at a local HEB. I live in Texas and a Turkey Fryer is about as common as dirt.

And since I fill my own tank off my 250 gallon tank I am pretty sure that I use more then 20# to fill a 20# tank. My numbers were not really to be exact but more about how I view the cost of propane vs electricity. I tend to think of it as electricity is twice as expensive.

Then again I spend allot of my time out at our ranch which is off grid. Meaning if I wanted to put in a 30A 120V circuit I would have to have a pretty hefty bank of batteries, an inverter and some way to recharge it (solar/wind). It is about 20 miles from the closest electrical pole and I am not paying to get the poles installed. I find propane much easier to use and sort of enjoy brewing outdoors anyway. But if you lived in an apartment I can fully appreciate the need to use electricity over gas.
 
I am using 18 or 20ga SS pots.

I agree with you that at 125deg the effect is probably fairly minimal, but that would grow as you get higher and higher in temp.

I can measure from as cold as possible (probably around 60) to about 125 to minimize this effect. I will also have it covered. Ambient temp tonight should be higher than normal, around 50, so it's a good day to try.
 
:D
I never looked them up either until this thread came up. Price per pint is not exactly why I brew beer. And I calculate the cost of each batch more on the ingredients then anything else. The burner I purchased as a Turkey Fryer at a local HEB. I live in Texas and a Turkey Fryer is about as common as dirt.

And since I fill my own tank off my 250 gallon tank I am pretty sure that I use more then 20# to fill a 20# tank. My numbers were not really to be exact but more about how I view the cost of propane vs electricity. I tend to think of it as electricity is twice as expensive.

Then again I spend allot of my time out at our ranch which is off grid. Meaning if I wanted to put in a 30A 120V circuit I would have to have a pretty hefty bank of batteries, an inverter and some way to recharge it (solar/wind). It is about 20 miles from the closest electrical pole and I am not paying to get the poles installed. I find propane much easier to use and sort of enjoy brewing outdoors anyway. But if you lived in an apartment I can fully appreciate the need to use electricity over gas.

I believe electric would be much more expensive for you in your situation. I dont see you converting. Hank Hill would be proud:D

:mug:
 
I never looked them up either until this thread came up. Price per pint is not exactly why I brew beer. And I calculate the cost of each batch more on the ingredients then anything else. The burner I purchased as a Turkey Fryer at a local HEB. I live in Texas and a Turkey Fryer is about as common as dirt.

And since I fill my own tank off my 250 gallon tank I am pretty sure that I use more then 20# to fill a 20# tank. My numbers were not really to be exact but more about how I view the cost of propane vs electricity. I tend to think of it as electricity is twice as expensive.

Then again I spend allot of my time out at our ranch which is off grid. Meaning if I wanted to put in a 30A 120V circuit I would have to have a pretty hefty bank of batteries, an inverter and some way to recharge it (solar/wind). It is about 20 miles from the closest electrical pole and I am not paying to get the poles installed. I find propane much easier to use and sort of enjoy brewing outdoors anyway. But if you lived in an apartment I can fully appreciate the need to use electricity over gas.

Solar powered brewing would put us all to shame. :mug:
 
I am using 18 or 20ga SS pots.

I agree with you that at 125deg the effect is probably fairly minimal, but that would grow as you get higher and higher in temp.

I can measure from as cold as possible (probably around 60) to about 125 to minimize this effect. I will also have it covered. Ambient temp tonight should be higher than normal, around 50, so it's a good day to try.

Well, post up the results. Just thinking and wondering what the difference would be for a sustained a boil for an hour. I think the conductivity of the kettle would really come into play here.
 
Well, post up the results. Just thinking and wondering what the difference would be for a sustained a boil for an hour. I think the conductivity of the kettle would really come into play here.

It would on both accounts, the heat getting in through the bottom and the cold getting in through the sides and top. My personal opinion is that this would muddy the results, since it depends more on the pot, ambient air temp, wind speed, etc than the actual burner.
 
It would on both accounts, the heat getting in through the bottom and the cold getting in through the sides and top. My personal opinion is that this would muddy the results, since it depends more on the pot, ambient air temp, wind speed, etc than the actual burner.

I think electric would really shine with a sustained boil. The heat with electric is applied directly to the liquid inside the vessel and only has resistance getting out. A direct flame has to get past the resistance of the vessel to get the heat to the liquid in the first place. The more thinking I do on it, I believe this is what will make the most difference.

But, yes this would muddy things. Lets see what it would take to get to a boil first:mug:
 
I think electric would really shine with a sustained boil. The heat with electric is applied directly to the liquid inside the vessel and only has resistance getting out. A direct flame has to get past the resistance of the vessel to get the heat to the liquid in the first place. The more thinking I do on it, I believe this is what will make the most difference.

But, yes this would muddy things. Lets see what it would take to get to a boil first:mug:

I feel like sustaining the boil hardly takes much energy at all. Sure, it is on for a long while and is probably a good portion of the energy use, but I barely even have the burner on during that phase, and you electric guys turn your PID's down pretty far too.

I feel the opposite (though neither of us really knows), that the way up and the boil itself will be exactly the same efficiency for both. This is, unless one vessel is more well insulated than the other, in which case it would shine at the boil levels, but that's not really a fair comparison anyway.

You could make the argument that an electric vessel is easier to insulate though, THEN electric would shine at a sustained boil.
 
It would on both accounts, the heat getting in through the bottom and the cold getting in through the sides and top. My personal opinion is that this would muddy the results, since it depends more on the pot, ambient air temp, wind speed, etc than the actual burner.

Well as long as we are getting picky you would have to know the recipe and the SG as well. The higher the gravity the more it will take to heat it. Loss due to surface cooling would probably be much higher (evaporation vs convection). So maybe use a lid to negate pot dimensions.

Also you may want to take into effect the fact that electricity, at least in the US, is quite dirty. That is to say it is seldom exactly 120V@60Hz. Anyone with a power correcting UPS can tell you about that. And I do not know how much that would effect the efficiency of an electric element.

Hank Hill is not exactly my hero but if I did not hear that burner while I was brewing something would not feel right. I think I am pretty much at peace with "it is somewhere about 2x the cost" then anything else. Although I would be interested in the results.
 
Well as long as we are getting picky you would have to know the recipe and the SG as well. The higher the gravity the more it will take to heat it. Loss due to surface cooling would probably be much higher (evaporation vs convection). So maybe use a lid to negate pot dimensions.

SG of 1.000, since we are using water to test. ;)

Our results are going to be anything but exact, but that wasn't exactly the point of this post either. :mug:
 
I think electric would really shine with a sustained boil. The heat with electric is applied directly to the liquid inside the vessel and only has resistance getting out. A direct flame has to get past the resistance of the vessel to get the heat to the liquid in the first place. The more thinking I do on it, I believe this is what will make the most difference.

But, yes this would muddy things. Lets see what it would take to get to a boil first:mug:

Actually the numbers I looked up assume it is over and hour use. Joules are in KWh and a BTU is 1 degree over and hour. So they both have an hour boil built into the calculation. Still I would like to see someone else numbers.
 
Actually the numbers I looked up assume it is over and hour use. Joules are in KWh and a BTU is 1 degree over and hour. So they both have an hour boil built into the calculation. Still I would like to see someone else numbers.

I would also need to calculate exact boil off in that case as well...plus I am at 4000ft+ elevation...that must have some effect on boil.

I think for now I will stick to straight "How much and how long does it take to heat 10gal of water from 60F to 125F with my burner?" We can get complicated from there, I need to leak test my mash tun tonight anyway.
 
Solar powered brewing would put us all to shame. :mug:

I am hoping to do just that. Right now the federal government is giving huge tax rebates for solar and wind. I have a ton of both here in colorado. They are also giving even larger incentives to businesses that convert to systems that connect to the grid. We are in the process of starting a taproom. We will eventually offset our power use. (electric brewery) with solar and or wind.

Right now though. I am spending much less per brew using electric then i was with propane. I could do about 3 brews from a blue rhino exchange. The cost of that was about $23 (everything is more expensive in Vail). So lets say $7 per 10 gallon batch. Well with a 5500 watt element and a PWM circuit to control how often the element "fires" I am spending about $3 per brew during peak hours. I am not sure why this thread is getting so complicated with efficiency and material types of kettles. It is a pretty easy breakdown. Electric is much cheaper if you are not buying your propane is bulk.
 
I am hoping to do just that. Right now the federal government is giving huge tax rebates for solar and wind. I have a ton of both here in colorado. They are also giving even larger incentives to businesses that convert to systems that connect to the grid. We are in the process of starting a taproom. We will eventually offset our power use. (electric brewery) with solar and or wind.

Right now though. I am spending much less per brew using electric then i was with propane. I could do about 3 brews from a blue rhino exchange. The cost of that was about $23 (everything is more expensive in Vail). So lets say $7 per 10 gallon batch. Well with a 5500 watt element and a PWM circuit to control how often the element "fires" I am spending about $3 per brew during peak hours. I am not sure why this thread is getting so complicated with efficiency and material types of kettles. It is a pretty easy breakdown. Electric is much cheaper if you are not buying your propane is bulk.

Solar gets crazy credits here too, around $3/watt from Oregon alone, but even if I covered my entire south facing roof with panels, I couldn't even cover my household's normal electric usage, much less brewing. I will probably do so later in the year, but it is mostly irrelevant to the current conversation.

So, in your case you save $4 a batch, which is cool. Not sure how much just one element and a PWM cost you, but since you aren't doing any automation, it was probably a bit cheaper than what I am talking about. Either way, even with your insane costs, it would take me about 275 brews to break even on electric.

The reason the thread is getting complicated is because we answered my question, and Torq's too, but we are trying to find out now a real comparison between electric and propane, not just locales.
 
:off:

If you can connect your panels to the grid you will be suprised how much you will get out of it. You will be sending power to the grid when you are not using it. I bet a 6Kw system would (which is what the government cutoff for rebates caps at) would have you paying very little in electricity bills per year.

:off:

My system cost about $1500 so yeah it would take about 375 brews to pay that with the difference in what I am saving. This is my first rig though. So my only loss was the price of the turkey fryer i was using. In my case I was looking at what I would save between building my first system to use propane or electric. I was starting from scratch.
 
:off:

If you can connect your panels to the grid you will be suprised how much you will get out of it. You will be sending power to the grid when you are not using it. I bet a 6Kw system would (which is what the government cutoff for rebates caps at) would have you paying very little in electricity bills per year.

6Kw would more than cover my household and brewing.. I live in one of those uber-efficient houses though so the roof is small. I could maybe fit 3Kw up there. Oregon's residential cutoff is at 2Kw anyway for their tax credit.

:off:

My system cost about $1500 so yeah it would take about 375 brews to pay that with the difference in what I am saving. This is my first rig though. So my only loss was the price of the turkey fryer i was using. In my case I was looking at what I would save between building my first system to use propane or electric. I was starting from scratch.

Starting from scratch makes a bit of a difference, cause you can subtract the cost of what a propane system would cost, and 375 brews is probably doable either way, though on the upper end of the scale of what I would call feasible. Mine was more like 500-700 though.
 
Realized my scale wasn't very accurate, but oh well.

.5lbs of propane used.
Starting temp 67F
Ambient Temp: 65F
8gal of water

4:00 - 80F
7:00 - 93F
10:00 - 104F
13:00 - 116F
15:47 - 125F
 
3712 BTU needed (8lbs/gal * 8 gal * 58deg)
11000 BTU used (about)

34% efficiency.

Well, that is fairly close to your original estimate. The 75% manufacturer ratings obvioulsy do not reflect delivered efficiency. Is a burner really only 75% efficient itself?

Do you by chance have an aluminum pot to compare? Thermal conductivity of Aluminum is 237. 304 stainless is only 16.3. I think this would have to make quite a difference. I think with some pots they sandwich a layer of aluminum between stainless on the bottom for this purpose.
 
Well, that is fairly close to your original estimate. The 75% manufacturer ratings obvioulsy do not reflect delivered efficiency. Is a burner really only 75% efficient itself?

Do you by chance have an aluminum pot to compare? Thermal conductivity of Aluminum is 237. 304 stainless is only 16.3. I think this would have to make quite a difference. I think with some pots they sandwich a layer of aluminum between stainless on the bottom for this purpose.

Lol, I have a crazy thin aluminum pot but I think the diameter is too small to fit on my stand, it would fall into the hole.

When I used to use it to make beer, the heating was crazy fast, but it also lost heat like crazy. Not bad for a boil/cool, but I wouldn't want it as a MLT/HLT.

The "Tri-Clad" or whatever you want to call them is made for even heat distribution over the bottom, not increased conductivity. The layer of aluminum spreads the heat over the whole source which then is transmitted slowly through the top layer of stainless. It is for scorching reasons, but mostly unnecessary for beer. Love it in my cooking pots though, though the middle layer is copper, not aluminum.
 
lschiavo, what units are your thermal conductivities listed in? Those look close to what I know for those materials in W/m/*K, though I think your aluminum is a bit high and your stainless value is a bit low. Not by much, though, and you're certainly in the right order of magnitude.
 
Kershner

This may be a tad off topic but thought I'd throw this out there. If you're wanting to save money on propane I may have a solution depending on your setup.

I use a turkey fryer with the original stand and brew 5 gal batches. I noticed that a bunch of heat was pouring out of the sides and bottom of my stand. I bought some roof flashing and all-thread to make a heat shield. I bolted the all thread to my stand's legs (for the flashing to rest on) and made a cylinder out of the flashing that is tall eneough that my kettles are entirely enclosed (up to the handles). The flashing extends below the factory wind guard. I now use ~2-3 lbs of gas per brew session now and I'm starting with 50F water. The $8 I spent on flashing and all-thread paid for itslef in about two brew sessions.

Don't know if this will be of use for your setup, but it made my brewery a hell of lot more cost effective.

Cheers
 
Ichthy, a wind screen is a cost effective way to get more heat to the pot, no doubt. I already have a pretty ideal setup as far as wind screening and heat direction is concerned, about 5 1/2" but for a turkey fryer it is truly a great idea.

Thank you for helping though, but the idea is not how to make my propane setup better, but more to explore other opportunities. If anyone has any ideas on how to improve the setup like ichthy did, I am always open though.

So you have an idea:
2010-05-07_17_22_51.jpg
 
lschiavo, what units are your thermal conductivities listed in? Those look close to what I know for those materials in W/m/*K, though I think your aluminum is a bit high and your stainless value is a bit low. Not by much, though, and you're certainly in the right order of magnitude.

I just did a quick google to compare. I cant find the site again but I believe those were the units.
 
I always assumed nat gas is cheaper than electric (I know most of the comments refer to propane) but I was really struck by the observation that in a HEx setup all the heat has to go through the liquid before it can be "wasted" while it is is obvious that my gas burners are heating more than just the liquid - How much more is the 64 kwh question. I don't know how to measure it but I did the basic cost calcs. Gas heat wastage has to be enormous the justify the cost difference! Here's what I found in Northern NJ:

Electric cost: $0.1703/kwh
Gas cost: $1.2389/therm
1 therm = 29.31 kwh

So 1 therm of electricity costs about $5.00! Zoiks! That's a 4x cost advantage for gas.
Does that seem right?

I can piss away 3 units of gas for every one that goes into my brew before electricity is competitive. With that fact it doesn't seem like I have to get too crazy measuring thermal efficiencies of my system. It would not change the result.

I need to figure out how to power my TV with gas.
 
I always assumed nat gas is cheaper than electric (I know most of the comments refer to propane) but I was really struck by the observation that in a HEx setup all the heat has to go through the liquid before it can be "wasted" while it is is obvious that my gas burners are heating more than just the liquid - How much more is the 64 kwh question. I don't know how to measure it but I did the basic cost calcs. Gas heat wastage has to be enormous the justify the cost difference! Here's what I found in Northern NJ:

Electric cost: $0.1703/kwh
Gas cost: $1.2389/therm
1 therm = 29.31 kwh

So 1 therm of electricity costs about $5.00! Zoiks! That's a 4x cost advantage for gas.
Does that seem right?

I can piss away 3 units of gas for every one that goes into my brew before electricity is competitive. With that fact it doesn't seem like I have to get too crazy measuring thermal efficiencies of my system. It would not change the result.

I need to figure out how to power my TV with gas.

Your calcs seem correct. Your electric rate is about 25% higher than mine so that makes quite a difference to start
 
U
I always assumed nat gas is cheaper than electric (I know most of the comments refer to propane) but I was really struck by the observation that in a HEx setup all the heat has to go through the liquid before it can be "wasted" while it is is obvious that my gas burners are heating more than just the liquid - How much more is the 64 kwh question. I don't know how to measure it but I did the basic cost calcs. Gas heat wastage has to be enormous the justify the cost difference! Here's what I found in Northern NJ:

Electric cost: $0.1703/kwh
Gas cost: $1.2389/therm
1 therm = 29.31 kwh

So 1 therm of electricity costs about $5.00! Zoiks! That's a 4x cost advantage for gas.
Does that seem right?

I can piss away 3 units of gas for every one that goes into my brew before electricity is competitive. With that fact it doesn't seem like I have to get too crazy measuring thermal efficiencies of my system. It would not change the result.

I need to figure out how to power my TV with gas.

Your calcs seem correct. Your electric rate is about 25% higher than mine so that makes quite a difference to start with.

You likely aRe "pissing" away up to 75% of the gas you are burning. That would depend on your system of course. If that were the case gas and electric would be about equal for you. No motivation to change.
 
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