Gas Vs Electric

[Andyd]

Guys,

I'm doing s**t load of work around the house at the moment, part of which is having to relocate the electrical lead-in from the street. SO ... I figured if I need to do that I might as well bring 3-phase into the house to deal with the amount of power I'm using when I run the HLT and heat exchange.

I currently brew on LPG burners like most, and at the same time I'm having our gas line extended for a BBQ. So I thought I could run it into the garage to run burners on Nat Gas.

But should I bother? Im seeing a lot of people going over to all electric systems at the moment, but I just can't convince myself that you get as good a boil off an electric set-up (at least, the kind of kettle I can run at home, which is a 75L SS pot).

Any opinions? If anyone's absolutely passionate about electric, what sort of elements should I be considering for that size kettle?

Regards,

Andy

 

[razz]

Morning Andyd. I think if your going to the expense of 3 phase power then you can run a larger (3600 watt element) kettle. Or am I getting confused with 10amp v's 15amp ?

 

[Andyd]

The main reason for bringing in additional phases (for me) was to make sure that if I'm running all these heating elements (2 for the HLT, and probably 2 for the kettle), I've got enough juice so that the house doesn't trip out if SWMBO is also runnig a dryer or the AirCon, and the fridges kick in etc...

I think (from memory) most line fuses trip at 60A total draw from the house, so the whole 10A vs 15A issue is really about whether you've got wiring that is up to carrying that load, rather than the ability of a single phase to provide eough juice.

The other neat advantage of having 3 phase in is that if I ever get around to buying a decent milling machine I'll be able to run it's 3 phase motor Bring on the toys...

Andy

 

[chovain]

Morning Andyd. I think if your going to the expense of 3 phase power then you can run a larger (3600 watt element) kettle. Or am I getting confused with 10amp v's 15amp ?

There are two ways of getting bigger elements. One is to go for higher current (thicker wiring, and slightly different power points where you want to access the 15 or 20A): That gives you up to 3600W for 15A, or 4800W for 20A.

Three phase power gives you the ability to run one or more points at higher voltage. It needs all 4 wires on the telegraph poles to be connected to your house instead of just 2. The power points are quite weird, being much larger, and having 5 contacts (three lives, a neutral and an earth) instead of 3, and give you an effective 415V. Running at 10A, you can get 4.1kW. 15A gives you 6.2kW, and so on. You need a slightly different kind of element to run 415V (it needs 4 contacts instead of 2).

Of course if you have 3 phase to your house, your ordinary single phase outlets don't need to change. You just drop 2 of the phases at the distribution box.

 

[troydo]

i personally like the idea of electric HLT and a gas kettle,

My rational is you dont have to clean sticky solution off a hot element...

 

[quadbox]

Bear in mind that you cant just plumb an LPG burner up to natural gas town gas, at the very least the jets will need changing, and it's possible it'll require a different regulator as well. Methane's a very different creature to propane

EDIT - Any gas-fitter should be able to help you out there though

 

[Andyd]

Of course if you have 3 phase to your house, your ordinary single phase outlets don't need to change. You just drop 2 of the phases at the distribution box.

My current plan was to run a seperate phase down to the workshop and out to the brewery to prevent the brewing load interacting with the household supply.

Speaking to a heating element supplier, it seems that more power in a single element is not desirable if I want to minimise the impact of surface contact with the wort. His recommendation was to go with two 2400 inductrial elements that have a lower sheath loading. His recommendation was an element with 77 kW/m2, as opposed to 120kW/m2 you get with a hot water system element. Their next lower element (also 2400W) has a sheath loading of 31 kW/m2, but the shortest one of those is 500mm - too long for my kettle.

Andy

 

[Ducatiboy stu]

You may not be able to get 3 Phase to your property, and it is because the electricity mob will only generally run 3Phase to industrial premises, plus they like to keep the phases balanced as they go down the street. You will probably find that the houses in your street are on different phases.Of course I may be wrong... <_<

The idea of extending the gas line would be my choice, and just get the burner re-jetted. Its easy to do.

I did have some calculations based on boiling 28 Ltrs in a reasonable time and it was in the order of 3300wats or about 14Amps, so If you are looking at 50-60 ltr batches you are probably looking at 30 amps, plus a bit more to take into account losses....You are talking some serious power....and some serious wirring..


the choice is yours....but I would go the gas route...

 

[Andyd]

Hmmm. The sparkie has ben booked, and he's not raised any issue with getting 3-phase in. I've got a couple of mates with 3 phase mills who have managed it in the past.

I do like the safety aspects of using a few elements, and the wiring has been designed to run 60A continuous, so there shouldn't be a problem there, except for the fact that that is a serious amount of juice!

Andy

 

[chovain]

Speaking to a heating element supplier, it seems that more power in a single element is not desirable if I want to minimise the impact of surface contact with the wort. His recommendation was to go with two 2400 inductrial elements that have a lower sheath loading. His recommendation was an element with 77 kW/m2, as opposed to 120kW/m2 you get with a hot water system element. Their next lower element (also 2400W) has a sheath loading of 31 kW/m2, but the shortest one of those is 500mm - too long for my kettle.

Yep - In one of the other threads going on at the moment, I'm asking a related question: What's the highest power density you can have that won't scorch the wort? There's very little actual information out there on what you can get away with.

You may be able to ask one of the local manufacturers to further bend an element that is too long for you. I expect it should be possible to bend the element in half again. You might end up with about a 300mm element, that is perhaps 100mm wide. I've seen sites in the US that recommend bending your element into an "S" shape, but I don't think I'd want to be doing that myself.

 

[Ducatiboy stu]

Hmmm. The sparkie has ben booked, and he's not raised any issue with getting 3-phase in. I've got a couple of mates with 3 phase mills who have managed it in the past.

I do like the safety aspects of using a few elements, and the wiring has been designed to run 60A continuous, so there shouldn't be a problem there, except for the fact that that is a serious amount of juice!

Andy

You may be one of the lucky ones to be able to get 3 phase...

30 Amps will probably be required to get it up to boil, then you can turn off a few elements to keep the boil going.....


Now ..someone is going to say..."yeah But I get a boil with a single 2400w element.....blah...blah..blah ", you will, but how long does it take, and how good a boil is it

 

[Andyd]

You may be one of the lucky ones to be able to get 3 phase...

30 Amps will probably be required to get it up to boil, then you can turn off a few elements to keep the boil going.....


Now ..someone is going to say..."yeah But I get a boil with a single 2400w element.....blah...blah..blah ", you will, but how long does it take, and how good a boil is it

Yep, and then I get to play with a PC controlled triac to establish the level of boil

Andy

 

[Peter Wadey]

Hmmm. The sparkie has ben booked, and he's not raised any issue with getting 3-phase in. I've got a couple of mates with 3 phase mills who have managed it in the past.

I do like the safety aspects of using a few elements, and the wiring has been designed to run 60A continuous, so there shouldn't be a problem there, except for the fact that that is a serious amount of juice!

Andy

Andy,
Are you getting a new meter installed along with the upgrade to the dist. box?
Does your local authority have Time Of Use tariffs?
If so, are you likely to heat during their peak periods?

I am currently paying 115% more (ie 27.61 c/kWh instead of 12.87 c/kWh between 2pm-8pm working weekdays) for my electricity because a new meter was installed when the power was upgraded to the house. I didn't know I was getting a new meter & was not informed of the possible implications of this change. According to my local provider (Energy Australia) all new meters being installed have this capability.

Look out!

Pete

 

[chovain]

Now ..someone is going to say..."yeah But I get a boil with a single 2400w element.....blah...blah..blah ", you will, but how long does it take, and how good a boil is it

Yeah, you're going to need decent power to bring 75L to the boil. How big is your actual boil?

If you're boiling 60L, it'll take 251kJ/C (ignoring heat loss). If you want to be able to rise by a degree per minute, then you'll need 4.1kW of power. That means you'll need 20A single-phase, or 10A three-phase.

As for maintaining a good boil: It takes 2.26MJ to vapourise a litre of water (40.65 kJ/mol; 55.5 mol/L). Assuming a 60L boil and 10% evaporation per hour, to boil off 6L will take 13.4mJ/h, or 3.71kW (again, ignoring heat losses through the kettle's sides).

For a full 75L, you're going to need to add 25% to all those power figures.

 

[Ducatiboy stu]

Yeah, you're going to need decent power to bring 75L to the boil. How big is your actual boil?

I If you want to be able to rise by a degree per minute, then you'll need 4.1kW of power. That means you'll need 20A single-phase, or 10A three-phase.

As for maintaining a good boil: It takes 2.26MJ to vapourise a litre of water (40.65 kJ/mol; 55.5 mol/L). Assuming a 60L boil and 10% evaporation per hour, to boil off 6L will take 13.4mJ/h, or 3.71kW (again, ignoring heat losses through the kettle's sides).

For a full 75L, you're going to need to add 25% to all those power figures.

A degree a minute is fairly slow........assuming that it came out of the mash tun at 70*( which is generous ), you are looking at 1/2hr before it starts to boil...


"Yeah,but my 2400w kettle element in my Bucket O Death is all you need....blah...blah...blah..." <_<

 

[chovain]

A degree a minute is fairly slow........assuming that it came out of the mash tun at 70*( which is generous ), you are looking at 1/2hr before it starts to boil...

That's about all I get with my LP regulator on my 40L kettle. It takes me a little under an hour to get to strike temp, and half an hour to get the boil on. It's a great opportunity to relax with a homebrew while checking over your targets.

If your requirements differ, it's not that hard to calculate the element you need for your requirements. Really want to bring 60L up at 2 degrees a minute? Fine. You'll need 8.2kW, for which you'll need 20A at 415V.

I'm personally in no rush on brew day.

 

[Andyd]

Andy,
Are you getting a new meter installed along with the upgrade to the dist. box?
Does your local authority have Time Of Use tariffs?
If so, are you likely to heat during their peak periods?

I am currently paying 115% more (ie 27.61 c/kWh instead of 12.87 c/kWh between 2pm-8pm working weekdays) for my electricity because a new meter was installed when the power was upgraded to the house. I didn't know I was getting a new meter & was not informed of the possible implications of this change. According to my local provider (Energy Australia) all new meters being installed have this capability.

Look out!

Pete

Thanks for the heads up Pete - I've shot my sparkie some mail to confirm.

Andy

 

[Andyd]

So I'm only ever boiling about 60L. So many things to think about... if I get the gas line in, I can install an instant water heater for strike water, and run the burners to by hearts content. Electricity makes it easier to control anda little safer...

I think I'll mull it over in my sleep

 

[Andyd]

Andy,
Are you getting a new meter installed along with the upgrade to the dist. box?
Does your local authority have Time Of Use tariffs?
If so, are you likely to heat during their peak periods?

I am currently paying 115% more (ie 27.61 c/kWh instead of 12.87 c/kWh between 2pm-8pm working weekdays) for my electricity because a new meter was installed when the power was upgraded to the house. I didn't know I was getting a new meter & was not informed of the possible implications of this change. According to my local provider (Energy Australia) all new meters being installed have this capability.

Look out!

Pete

Thanks Peter - Just checked, and it's all good. The trick is to not ask for an off-peak meter...

Although - a seperate off-peak meter could be a real boon for weeknd boils!

Andy

 

[Ducatiboy stu]

Off-Peak meters only deliver power during off-peak times....basically in the middle of the night, sure the rate is a lot cheaper, but they dictate when you get power thru the meter..Sometimes you can hear the meter-relay pulses...