1500w hotplate w/ CM column questions

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jsanders420
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1500w hotplate w/ CM column questions

Post by jsanders420 »

I've been running 10 gal batches on propane for the past few years and had no problems but winter is coming so I want to run in the garage. I got a 1500w hotplate yesterday for 5 gal. runs. I'll use the BH flat bottomed milk can and bypass the thermostat and with it being CM reflux I've never had trouble over heating. Here are the questions.

Does it really take 3 hrs for heat up in 40 to 60* weather? Is there a way I can speed up heat up with my current gear? With it being CM, can I run properly without a power controller? I have read this section extensively and seen different answers and know a lot of the answers depend on the gear so I hope The is too repetitive, I just want confirmation that I understand it all.

That's it. Thanks. Invaluable site and info. More info than anyone could ever hope for! :D
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der wo
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Re: 1500w hotplate w/ CM column questions

Post by der wo »

1500W is not much for a 5gal reflux run. Is it a 2" column?

You can speed it up much with insulation. Insulate the boiler, the lid and the column, everything except the bottom and perhaps the lowest 5cm of the boiler.

Is it not possible to get a more powerful hotplate?
What is the diameter of the 10gal boiler? Perhaps you can stand it on 3 small hotplates each 1000W perhaps.
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure. - Rosa Luxemburg
jsanders420
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Re: 1500w hotplate w/ CM column questions

Post by jsanders420 »

Yeah, there are some 1800w hotplates, I'm just going with what I got for now to learn electric with. It's a 3" column. I'm all insulated up. I'm going to stick with small batches for now.
jsanders420
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Re: 1500w hotplate w/ CM column questions

Post by jsanders420 »

Oh yeah! Didn't I see a calculator that was for wattage and heat? I looked on the main site and didn't see it. and I searched here.
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der wo
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Re: 1500w hotplate w/ CM column questions

Post by der wo »

For 3" you definetely need much more wattage AND you should insulate everything. 3-5kW. Either install internal elements or combine hotplates.

Edit: And generally hotplates are effective only, if the bottom of the boiler is absolutely plain when heated. If the thin metal of the milk can forms a bowl when heated, forget the idea using a hotplate.
In this way, imperialism brings catastrophe as a mode of existence back from the periphery of capitalist development to its point of departure. - Rosa Luxemburg
jsanders420
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Re: 1500w hotplate w/ CM column questions

Post by jsanders420 »

OK. I guess it's not doable. I have everything insulated, it is a flat bottomed container and I can bypass the thermostat. From what I have read here up to this point made it sound like some people have used this method. I guess I'll just stick to propane.
jsanders420
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Re: 1500w hotplate w/ CM column questions

Post by jsanders420 »

According to this and heating at 95% efficiency it will take 63 min for 5 gal water to reach boiling point. How does the 3" column factor in to keep it from working? I'm pretty science savvy but don't understand this part.
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der wo
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Re: 1500w hotplate w/ CM column questions

Post by der wo »

You need a balance between diameter and wattage. Because vapor and reflux speed must be in balance.
Diameter and wattage determines the vapor speed. But you cannot control much the reflux speed. It is gravity and a bit packing tightness.
With 1.5kW and 3" the reflux drops too fast down compared to the vapor speed.
So 1.5kW and 3" will give you less pureness than 2" with the same reflux ratio (speed). 3" is more expensive, heavier and a waste of time at 1.5kW.

But of course 3" has run with a reasonable wattage much advantages. For 5gal batches IMO 2" is enough, for 10gal better go 3".
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rad14701
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Re: 1500w hotplate w/ CM column questions

Post by rad14701 »

jsanders420 wrote:
According to this and heating at 95% efficiency it will take 63 min for 5 gal water to reach boiling point. How does the 3" column factor in to keep it from working? I'm pretty science savvy but don't understand this part.
You can only use 95% efficiency for an internal element... For a hot plate you should shoot for an efficiency closer to 65%, give or take, unfortunately...
jsanders420
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Re: 1500w hotplate w/ CM column questions

Post by jsanders420 »

OK, thanks Der and Rad. I get it. I will stick with propane until I'm ready to cut a hole in my keg and install an element. Right now I just can't bring myself to cut it.
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