Low Watt Density Element

Milsey

Hello all, This is my first post in this forum but first of many iI hope. I've brewed a few beers from the can but moving on too all grain brewing. I'. going to build a HERMS style rig with RIMS chamber in it. I'm fine with pumps, electrics Keggles etc. I've done a lot of research on more American brewing forums where there seems to be some hardcore brewers,
I'm going to automate the process as much as possible and use 3 converted kegs as my HLT, MLT and Kettle. I'm looking for info on "low Watt density immersion heater". Is there a min and max watt per inch required for home brewing. How do you calculate it yourself.
If you have a standard heater at 5kw and a low watt density heater at 5kw, both same size in length and size then what is the difference in their performance or how is it achieved.
Sorry for the long post but I cant find exact answer elsewhere. If anyone has any info on low watt density elements please fill me in.
Oh yea and hi again. A bit heavy for a first post but sure there ya are!

oblivious

2.4kw elements are most common, people generality have two for a 50-60 litre boil http://www.hopandgrape.com/public/detailv1.asp?itemcode=ELE20206569



The other option is to look a immersion hear elements

Milsey

Had a look at that webpage. I don't see any mention of "low watt density". It seems like a normal element. I' m talking more about an element for the rims heater. Low watt density is suppose to give less of a chance of scorching the wort and caramelizing the wort.

oblivious

Milsey wrote: »

Had a look at that webpage. I don't see any mention of "low watt density". It seems like a normal element. I' m talking more about an element for the rims heater. Low watt density is suppose to give less of a chance of scorching the wort and caramelizing the wort.

A Heat Exchanged Recirculating Mash System is a better design and avoids the disadvantage of scorching of wort

Milsey

Hi Oblivious, thanks for the interest. At the moment I'm undecided which type I'll go with. Im still at the research and design stage. Heat are the advantages and disadvantages of the herms over rims in yor opinion. Would you recomend going all electric or gas or both. At the moment Id be thinking gas for the hlt. Would imagine it might get up to temp quicker. I could be wrong though. Also on a running cost thing which would be cheaper to run, gas or electric. I intend to build a prety decent rig and going to take my time building it so want to make sure I go in the right direction to start with. I Thais it your using here yourself so. Cheers for the replys.

oblivious

HERME's you can modify your Hot liquor tank so less additional parts to build. As you are passing the Wort through the heated water there is much less likely or scorching the wort/ enzyme inactivation. Also it would allow for greater control over the mash temp

Electricity should be cheap an most importantly safer to deal with and you brew in doors

Mashtun

I think the type of element ur looking for is one like this

Basically an equivalent regular element rated for the same power output has a smaller surface area and therefore its surface temp has to be higher to output the same heat. This is where your possibilities for scorch come from with regular elements

I've found them on amazon but i'm not sure what the shipping situation. Alternatively you can use the one in the link below which is what i have, poxy cheap, pi** easy to put into a keggle and works fine for me.

http://cgi.ebay.co.uk/CAMCO-02293-Screw-Element-Hot-Water-Heater-3800W-USA-/360342168235?pt=LH_DefaultDomain_0&hash=item53e61122ab

+1 for the herms approach!

Mashtun

Found one, delivered to ireland for $30-ish. It's 4.5kW which is huge but being low density you should be ok.

http://www.amazon.com/Low-Watt-Density-Screw--Element/dp/B0006JLVC6/ref=sr_1_14?ie=UTF8&qid=1308302152&sr=8-14

Milsey

I'm after writing a big reply with questions lads and lost it but busy at work at moment but will reply again later tonight and would appreciate yer knowlege and opinions. Thanks

Mashtun wrote: »

Found one, delivered to ireland for $30-ish. It's 4.5kW which is huge but being low density you should be ok.

http://www.amazon.com/Low-Watt-Density-Screw--Element/dp/B0006JLVC6/ref=sr_1_14?ie=UTF8&qid=1308302152&sr=8-14

Milsey

Mashtun wrote: »

I think the type of element ur looking for is one like this

Basically an equivalent regular element rated for the same power output has a smaller surface area and therefore its surface temp has to be higher to output the same heat. This is where your possibilities for scorch come from with regular elements

I've found them on amazon but i'm not sure what the shipping situation. Alternatively you can use the one in the link below which is what i have, poxy cheap, pi** easy to put into a keggle and works fine for me.

http://cgi.ebay.co.uk/CAMCO-02293-Screw-Element-Hot-Water-Heater-3800W-USA-/360342168235?ldpt=LH_DefaultDomain_0&hash=item53e61122ab

+1 for the herms approach!

I can see what you mean about the low watt density element. It's what I thought. In the photo you show you can see where the element is folded once and doubled over giving it 4 times the surface area or twice at a minimum than a standard element.
On the HERMS thing, if you want to raise the temp of the mash by a few degress do you not need to raise the temp in the hlt before you raise the temp in the mash tun. Would this not be slow. Would the Rims not be more responsive and closer controlled with the wort being heated direct on a low watt element. Please dont take from this that I am pro RIMS, well I am at the moment but only because of the reading I have been doing and can be persuaded either way with pros and cons.
The other thing is do you use gas or Elements only. How long will it take an elemnt to heat a keggle as a m lt and do you use it in your boil kettle also. Cheers.

Mashtun

Milsey wrote: »

On the HERMS thing, if you want to raise the temp of the mash by a few degress do you not need to raise the temp in the hlt before you raise the temp in the mash tun.

I am not a herms expert but my understanding is, and i stand to be corrected, is that to heat the mash the liquid part of the mash is recirculated through an immersion heater which as far as I know this is a coil of copper tubing immersed in hot water. Put simply a smaller HLT with tubing immersed in it

Milsey wrote: »

Would this not be slow. Would the Rims not be more responsive and closer controlled with the wort being heated direct on a low watt element.

Heat exchangers are pretty fast and efficient as far as I know but dont take my word for it, ask on the hardcore american brewing website that you were talking about, more specifically the electric brewing forum on said site.

Milsey wrote: »

The other thing is do you use gas or Elements only. How long will it take an elemnt to heat a keggle as a m lt and do you use it in your boil kettle also. Cheers.

Elements have been used in MLT's but i'm not sure to what level of sucess. The recirculation approach seems to be the norm but half the fun in this kind of thing is doing what you like. Yup i use an elctric element in a keggle to do my boils it works great

Oh on the electric gas thing, if your going electric to any degree bin the gas, from what i've read nobody ever looks back

steinone

Milsey wrote: »

How long will it take an elemnt to heat a keggle as a m lt and do you use it in your boil kettle also. Cheers.

For an element its not too hard to get a rough guide on how long it would take.
Stop me if I get too technical.
The formula would be: amount of energy taken= mass of the liquid X specific heat capacity X change in temp(ie 100C-15C)
1L of water=1kg
Specific heat capacity of water is 4180Jkg-1K-1

Sooo time taken= energy supplied divided by energy per second(1kW=1000J per second) and the time will be in seconds.

Its rough but it should take not too much more time than that.

rubadub

Mashtun wrote: »

Found one, delivered to ireland for $30-ish. It's 4.5kW which is huge but being low density you should be ok.

http://www.amazon.com/Low-Watt-Density-Screw--Element/dp/B0006JLVC6/ref=sr_1_14?ie=UTF8&qid=1308302152&sr=8-14

2.99kW is the max power you can have on a standard plugtop here, which is 13A at 230V.

That element is also 4500W, 240V, which means when it is plugged in at 230V it will be lower power, about 4.1kW.

A low watt density element might be pricey, you can hook up elements in series which raises their resistance, which decreases their power -and so lowers the watt density.

e.g. if you have 2x 2kW elements in your container then if they are wired in series you now have 0.5kW from both, so 1kW in total.

The other advantage of dual elements is that you can use them on their own too, e.g. heat up just water with 4kW (best having 2 separate wirings to both elements, connected to 2 completely different sockets). then you can wire differently to lower your power

The formula would be: amount of energy taken= mass of the liquid X specific heat capacity X change in temp(ie 100C-15C)
1L of water=1kg

you will boil roughly 10litres per kW per hour. So 5L would take 30mins with 1kW, or 10mins with 3kW.

Mashtun

rubadub wrote: »

2.99kW is the max power you can have on a standard plugtop here, which is 13A at 230V.

Standard guage cable used for a socket ring is 2.5mm 3 core which has a max current rating of 25amps, although the trip switch is usually 20amps. To take advantage of this you just have to use 2.5mm on the other side of the socket and make sure the fuse in the plug is up to the job.

Another way to control power without buying a second element would be to use a PWM circuit that drives an SSR. Might sound complicated but i think off the shelf stuff can be bought very cheaply and it's quite accurate. Here's a circuit diagram of how one would go together if anybody feels like it!

Dont think it matters anyway looks like the OP has gone to the pub and forgotten about it

Milsey

Mashtun wrote: »

Standard guage cable used for a socket ring is 2.5mm 3 core which has a max current rating of 25amps, although the trip switch is usually 20amps. To take advantage of this you just have to use 2.5mm on the other side of the socket and make sure the fuse in the plug is up to the job.

Another way to control power without buying a second element would be to use a PWM circuit that drives an SSR. Might sound complicated but i think off the shelf stuff can be bought very cheaply and it's quite accurate. Here's a circuit diagram of how one would go together if anybody feels like it!

Dont think it matters anyway looks like the OP has gone to the pub and forgotten about it

"It always matters Mashtun"

Milsey

rubadub wrote: »

2.99kW is the max power you can have on a standard plugtop here, which is 13A at 230V.

That element is also 4500W, 240V, which means when it is plugged in at 230V it will be lower power, about 4.1kW.

A low watt density element might be pricey, you can hook up elements in series which raises their resistance, which decreases their power -and so lowers the watt density.

e.g. if you have 2x 2kW elements in your container then if they are wired in series you now have 0.5kW from both, so 1kW in total.

The other advantage of dual elements is that you can use them on their own too, e.g. heat up just water with 4kW (best having 2 separate wirings to both elements, connected to 2 completely different sockets). then you can wire differently to lower your power

you will boil roughly 10litres per kW per hour. So 5L would take 30mins with 1kW, or 10mins with 3kW.

Hi Rubadub. I see what you mean. If Im go Electric which is the way i'm swaying right now then I wouldn't be wiring the elements to a plugtop. I would wire them to a panel which would be connected to a 32 amp breaker with a 32amp industrial plugtop. which would mean i could use the 4.5 kw low watt density element.
Also if i used the 2 elemts in series then I wouldn't have enough wattage to boil the water. Although I could split them as you say.
I'm thinking of using an elemnt like the one in photo above controlled by a pid controller in the HLT to maintain temperature using a thermocouple and then use PID controller in manual mode to controll the boil kettle element using a percentage scale on the Pid.

Mashtun

Milsey wrote: »

"It always matters Mashtun"

haha!:P