Heat Exchanger Length?

[AUHEAMIC]

Hi All

I am in the process of setting up an AG brewery. The 50ltr S/S boiler and 50ltr S/S mash tun are completed. March pump approved by the finance department (for a xmas present). I am now working on the HLT which I am going to put a 3/8 copper coil heat exchanger in.

Can anyone advise me on the length of 3/8 copper tube required?

I have done a search and have come up blank.

P.S. I have only joined as a member recently but you have all helped me with this obsession we call brewing over the last twelve months. Thank you all.

 

[razz]

G'day Peels, try typing "copper coil" you will get heaps of results.

 

[AUHEAMIC]

Cheers Razz

Looks like I have got some reading to do!!!

 

[AUHEAMIC]

After a long search I could not find a suitable answer. Plenty of info on copper coil length for immersion chillers but couldnt find info on 3/8 copper coil heat exchange length.

Can anyone help?

 

[Shunty]

After a long search I could not find a suitable answer. Plenty of info on copper coil length for immersion chillers but couldnt find info on 3/8 copper coil heat exchange length.

Can anyone help?

Deleted due to me not reading the question. Too much work, not enough beer.

 

[Gulf Brewery]

After a long search I could not find a suitable answer. Plenty of info on copper coil length for immersion chillers but couldnt find info on 3/8 copper coil heat exchange length.

Can anyone help?

Hi peels

The more length that you can have in the HLT the better, so that you get the maximum heat transfer from the HLT water into the wort. I think I used 6 or 8 metres. You only want the HLT to be a degree or 2 above the required wort temperature so that you do not denature the enzymes.

What I think you should do is work out how much you can fit in there and go for it. I wrapped mine around a keg and I think it has about 8 or 10 loops.

Cheers
Pedro

 

[Peter Wadey]

Pedro,
Did you have a stirrer in the HLT as well?

Rgds,
Another Peter

 

[AUHEAMIC]

Thanks Pedro

This is a photo of the immersion chiller I made. Is there any way I could use this as a heater and a chiller.

Also what does a stirrer in the HLT do?

 

[Ash in Perth]

If you could pump hot liquor through the coil and sit it in the mash this would heat well. It would work best if your mash tun was stirring. In a well insulated mash tun, this would be pointless. I loose about 1 Degree over an hour when im not re-circing through the HLT.

A stirrer in the HLT (something i am thinking about building) would make sure there is no temperautre gradient in the tank. if not, the water around the coil could be cooler than that around the thermostat and element.

I have a SS coil in mine, abour 6m long and it does a great job. Copper is thinnner and a better conductor so you wouldnt need anything this long. i think about 3m would be plenty (depending on how well insulated your mash tun is)

 

[kirem]

I think the length should be a compromise between heating a large enough portion of the mash to change temps of the whole mash by at least 1degC/min and that volume when removed for heating not reducing the liquor to grain ratio in the tun as to compact the grain bed.

I am looking into an ideal length at present as I want to be able to do step mashing.

Kirk

 

[AUHEAMIC]

I was actually thinking of putting the coil in the HLT and reticulate the mash through it. Then during the boil flush the coil in preparation for using it as a chiller.

I have a 5mtr length of 3/8 copper so if the above doesnt work I will build a dedicated heat exchanger to go in the HLT.

 

[Justin]

Thanks Pedro

This is a photo of the immersion chiller I made. Is there any way I could use this as a heater and a chiller.

Also what does a stirrer in the HLT do?

Absolutely. There is no reason why not as long as it fits in your both your HLT and Kettle (the hole in my HLT is smaller than my kettle so my chiller doesn't fit in my HLT).

It will cost very little in fittings to rig this up and try it to see if it suits your purpose and performs to your expectations. Plus it will save you buying another length of copper which is always a good thing. The only drawback might be trying to extract all the liquid from the tube but you can factor that in and work that out.

A stirrer in the HLT just maintains the efficiency of your herms coil by keeping all the liquid well mixed, otherwise you get lazy temp transfer because of the nature of fluids, temps and boundary layers. I'd probably go a bit longer than 3m in the coil, but that's just my thoughts and I have no direct hands on experience to back it up. But 3m doesn't equal very many coils (you'd be surprised how much length is chewed up with a few coils). depending on diameter of your coils 3M might only be 2 or 3 coils.

 

[kirem]

Ok I have done a few calculations

using 1/2 inch copper pipe I can fit a 24m coil in the HLT. With my transfer lines (3m) this equates to removing 3.5L volume from the tun for heating

using 1 inch copper I can fit 12m coil in the HLT. With my transfer lines (3m) this equates to removing a 7L volume from the tun for heating.

If I am mainly going to do 45L batches that involve approx 10-12kg of grain and 36L of water, anyone got any ideas or thoughts?

Kirk

 

[Justin]

Don't know if you've seen this site Kirem but also Peels, but it might be interesting and relevant in your situation:

http://sdcollins.home.mindspring.com/

It has a lot of HERMS related info on it and for the most part his ideas and suggestions seem to be well thought out.

Just to throw a comment or two out there about your coils and length. Once again keeping in mind I don't have a herms, but hey I like to discuss things and ideas.

24m is hell of a lot length for a HERMS coil, you could be holding a world record if you went with it . Coils usually only come in 18m lengths, and I would suspect $ for $ I think you would see deminishing returns for the extra length in the coil (plus you might also have to consider flow restriction working against the pump). Be careful with your design and coil length too because you've already got a reasonable amount of head on your pump given the height of your HLT, so you may not get really great flow rates with your march pump.

On the 1inch pipe, you'd have pretty low flow restriction but will you be able to coil it tight enough to get it inside the keg (I've never tried to bend 1" pipe-I've bend 3/4" and it likes to flatten and crease when tightly curved)? Also, smaller diameter pipe is better for heat trasfer due to surface:volume ratio, but I guess if the pipe was flattened due to the bending it might actually improve this a little bit.

Just some thoughts on a lazy Friday afternoon. It is time to head to the pub.

Cheers, Justin

 

[bugwan]

Ok I have done a few calculations

using 1/2 inch copper pipe I can fit a 24m coil in the HLT. With my transfer lines (3m) this equates to removing 3.5L volume from the tun for heating

Kirk

Probably playing the party-pooper line here, but just to let you know, 24 metres of copper will cost you around $450 at the moment... Unless you have a better supplier than Bunnings!

 

[kirem]

yeah I have a good supply of copper pipe. quite a bit better than retail at bunnings. Aren't they the mob that keeps cutting down old growth forest in WA? :angry:

 

[Gulf Brewery]

Thanks Pedro

This is a photo of the immersion chiller I made. Is there any way I could use this as a heater and a chiller.

Also what does a stirrer in the HLT do?

Absolutely. There is no reason why not as long as it fits in your both your HLT and Kettle (the hole in my HLT is smaller than my kettle so my chiller doesn't fit in my HLT).

peels

I think if you can use the coil for both functions, you are on a winner. The seals where you recirculate your wort must be air tight, otherwise you could suffer from hot side aeration with the amount of wort recirculate.

I would add the coil into the HLT as this ensures that your wort is being reciruclated (rather than just temperature controlled if the coil is in the mash). Using this method I was getting full coversion in less than 20 minutes.

Cheers
Pedro

 

[AUHEAMIC]

I just scored another 3 meters of 3/8 soft copper. That makes 8 meters in total. I am going to run with the 8 meters and make a dedicated heat exchanger in the HLT.

I will post my results when I do my first AG brew later this year (I hope by late november).