Vegetable Dryer... Pls Help~

[krazatchu]

Hi all...

New member here... and very new to the science of refrigeration etc...

Well... I'm looking for someone to point me in the right direction...

So, like the title says, here is what I'm trying to do...

1) I would like to "dry" vegetable matter (roughly 80% water)... 50 kg in a few hours time (2 to 6 hours).

2) There is no concern of the final nutrient quality, or the appearance so I don't think I need freeze drying. (powder is ok!)

3) I'm trying for something cheap and reletively compact. And most importantly, energy efficient.

So far.... What I have determined with my very limited knowledge... and a bit of excel...

I have figured I will need a heat pump of about 20,000 Btu to remove the 40 kg of water (80% of 50kg) in roughly 4 hours time...

I'm thinking an r134a system would work... I looked at MVC systems but the compressors for r718 are much too expensive... (roots blowers) ...

I see some strong simularities between what Im trying to do and some of the recent heat pump clothing dryers by LG and Panasonic...

So, please correct any mistakes... and perhaps someone could point me in the direction of what I should be learning to accomplish this...

Thanks...
Michael

[Samarjit Sen]

Please give more details as to the application and why you want to dry the vegetable without maintaining its nutritional values and color. Going through your post, it appears the cheapest way out is to fry it.

[krazatchu]

Frying will put too much heat and moisture into the surounding area, in this situation there is no possibility of venting it.

Energy efficiency is also a concern, frying would use alot more energy than a heat pump.

thanks

[Samarjit Sen]

What is the quantity per batch and the type of vegetables you propose to dry. Are they fresh vegetables or cooked ones.

[krazatchu]

Hi,

The quantity per batch is about 50 kg.

There are a few different vegetables, mostly the starchy kind... Most specifcally cooked cabage.

Thanks

[TONY LONGTHORNE]

Hi Krazatchu.
You need to vacuum dry these veg,s useing a purpose made vacuum dryer, go on the web and lookup vacuum driers.
Regards Tony L.

[krazatchu]

Yes, that's the idea...

I want a purpose made dryer...

Purpose made by me ....

Hence my web searching brought me here...

So far, I have devised a very simple system but I don't know what math or practical knowledge I should be using to arrive at a conclusive shopping list of parts....

I have figured so far... I will need around 20,000 Btu to do this within 4hrs...

I think it will be an R134a system as it seems suitable. (right?)

I'm going to have to figure out what size of tubing it needs... (suggestions?)

Also need to figure on the size of the evaporator and condensor, seems bigger is better... and space isnt so much a concern... (suggestions?)

I dont know whats needed to control the super heat... (suggestions?)

I also dont know whats required for the valve/regulator... (suggestions?)

Ya... thats alot to ask....
But I would like to do this myself ... jsut for the sake of learning ...

Thanks,
Michael

[krazatchu]

Perhaps someone could suggest a book or website I should read...

Something with examples would be great..

And the more technical the better...

Thanks

[Samarjit Sen]

Hi Krazatchu, I was going to suggest you what has been stated by Tony. I will try and find out the details and let you know. It may take sometime.

[krazatchu]

Thanks!

That would be great~~

[Samarjit Sen]

Hello Krazatchu.

Try the following links.

www.aaronequipment.com

www.arnoldeqp.com

www.niroinc.com

www.cuddon.co.nz

www.madehow.com ( go to volume 2 and then click Freeze Dried Food )

I hope the above will help you. If you go to google, you will get a lot of information on Vacuum Drying of Vegetables.

[krazatchu]

Hi~

Thanks for the links...

I have previously taken a look at similiar systems and came to the conclusion that most were too large and unsuitable for my requirements...

So, I would really like to put together my own system... for a couple of reasons...

a) I'm sure I could build it for less $$ than for what I could buy....

b) I have a CNC Mill and CNC lathe (not hobby size), and would like to get some use out of them...

c) The project may get up sized if it works well enough...

Thanks,

Michael

[Samarjit Sen]

Hi Michael,

When you get it together, please do let me know as to how is it operating. There may be some one who would be interested in the same.

[krazatchu]

Sure, will do...

Actually, my father is also interested in a dehumidifier for wood since he does alot of woodworking and cuts his own lumber....

I suppose it wouldn't be much different and once I figure out the heat pump loop I can suggest something for him...

Well... I hope someone could suggest a standard heat pump loop for a 20k btu system...

Thanks

[krazatchu]

Hi agian...

So far, this is what I have figured out. I hope someone can correct my mistakes or offer better suggestions...

Compressor:
R22 hermetic type.
Running R134a.
Rated for 20,000 Btu(h).

Evaporator:
Stainless steel or coated.
Size: unsure.

Condensor:
Coil of tube, 1/2 inch.
Submerged in vegetables or wrapped around pot.
Coated or stainless.

Superheat control:
??? i dont know...

Air system:
Blower: Regenative.
Volume: 200 cfm.
Pressure: have to check, its something i already have from another project.
Cyclone to seperate and reduce dust.
Return air will provide aeration to vege's.

Well, that's all I have so far...
I'm drawing up some parts in solidworks... and have to do more research...

Please let me know if I'm on the right track here...

Thanks,
Michael.