Extra Long Plate Chiller?

[dutchoven]

So I've been looking into plate chillers and see the maximum length on most "homebrew" chillers is around 12 inches. Does anyone know of a manufacturer that makes longer chillers for homebrew applications? I know Duda sells their 32, 52, and 95 series chillers; brazetek has similar ... little too big ...

My ideal chiller would be 18+ inches long, 2-3 inches wide, and would have fewer than 20 plates (maybe even less than 10). I know this would require higher pressure to feed. Anyone see one out there?

Now, I'm sure the Therminator folks will chime in on why they feel their chillers are so great. And the "I have a 10,000-plate chiller and it rocks" crowd will be involved as well. More plates does not equal faster chilling. I want length over plates ... ... get your brains out of the gutter ...

 

[Nateo]

Why would having fewer, but longer plates increase the heat transfer coefficient?

The big advantages of a plate chiller in the first place are the high surface area, compact design, and low-pressure flow. I'm not sure what you're going for here.

 

[Demon]

Why would having fewer, but longer plates increase the heat transfer coefficient?

The big advantages of a plate chiller in the first place are the high surface area, compact design, and low-pressure flow. I'm not sure what you're going for here.

Length is better than amount of plates because of amount of time the wort spends in contact with cold water. A 12" 30 plate is more efficient than a 7" 40 plate. I'd imagine going with 18" you could get away with 8-10 plates.

 

[Nateo]

With how thin the plates are, how long does it actually take for the temps to equalize? You'll never get the wort colder than the cold-side liquid, so wouldn't it be much more efficient to change your delta T?

 

[oakbarn]

It is a question of surface area

If the plates were the same width, say six inches

12 x 6 x 30 = 2160 Square Inches

7 x 6 x 40 = 1680 Square Inches

But a 60 Plate

7 x 6 x 60 = 2520 Square Inches


Additional the temp of the cooling water greatly effects the "power" of the plate chiller. I do have a Therminator and in the winter in Dallas, I can cool Wort to 65 degrees as fast as I can pump with tap water as the coolant. In the summer, I use a utilty pump and iced water but have to go slow. I am thinking of getting a 60 plate chiller from Keg Cowboy to use in the summer.

 

[oakbarn]

Just in case you did not get it from the above post, There are 5 factors that effect the cooling in my mind.

1. Surface Area
2. Coolant Temperature
3. Wort Temperature
4. Coolant Flow Rate
5. Wort Flow Rate

I would list 1 and 2 as the greater factors.

 

[Nateo]

1. Surface Area
2. Coolant Temperature
3. Wort Temperature
4. Coolant Flow Rate
5. Wort Flow Rate

With regards to 1: why would 12 x 12" plates be better than 24 x 6" plates?

 

[dutchoven]

Length is better than amount of plates because of amount of time the wort spends in contact with cold water. A 12" 30 plate is more efficient than a 7" 40 plate. I'd imagine going with 18" you could get away with 8-10 plates.

Agreed.

A longer chiller allows for a better heat transfer. More plates allows for increased flow.

Compare to tube-in-tube CFCs ... one 30-foot CFC is more efficient than three 10-foot CFCs, even though the surface area is the same. The length of the 30-foot CFC gives the wort more contact time with the cooling water. With the three 10-foot CFCs, however, you could push wort roughly three times faster. A plate chiller works the same way, just replace the tubes with plates.

 

[Nateo]

How are you defining and evaluating "efficiency?" Why does a longer chiller allow better heat transfer? Are there any numbers to back that up, or is that just conjecture? Do you have any examples with real measurements?

I don't really buy that a 30ft chiller is "more efficient" than 3 x 10' chillers. If the wort equalizes temp with the water within 5 feet, it doesn't matter if the chiller is 5' long or 100' long. It can't get any colder than the cold-side liquid.

 

[dutchoven]

I would define efficiency in this instance as the greatest amount of heat removed from the wort using the least amount of cooling water in the shortest amount of time. Here are some numbers: http://www.dudadiesel.com/files/beerwortchart.pdf.

In that chart, at 5 gpm chiller water, the longer B3-23A 20 plate chiller chills faster (6.67 vs. 10.00 minutes) and uses less water (33 vs. 50 gallons) than the shorter B3-12A 40 plate chiller, even though the surface area is nearly identical (0.46 vs. 0.48 m²).

Keep in mind that in most homebrew plate chillers the entire volume of wort does not contact the entire surface area of the chiller ... if that were the case, it wouldn't matter what shape the chiller was. The wort does not snake its way back and forth through the entire chiller. Instead, the wort enters the chiller and is divided across a certain number of channels (# plates/2); it then flows through those channels in parallel from one end of the chiller to the other as it is chilled.

In terms of efficiency, the surface area per plate is more is more important than the overall surface area of the chiller. A longer chiller has more surface area per plate than a shorter chiller with the same overall surface area.

 

[oakbarn]

I went to that site as well and according to them size does matter. 12 inches is better than 7.5. Who knew? Women Brewers?