Ammonia Vs ***** for potato storage

[apgurgaon]

Dear Friends,

Already I am building a 5000 m Ton potato cold storage with ***** systems.

What are pros and cons i have to be ready to face ,

Please suggest.

regards,
Apgurgaon

[gregd1401]

What refrigerant are you using and what temperature are storing at?

[apgurgaon]

R22, 3~6 deg C, 95% Rh

[priti]

Go for ammonia cold storage.

It will be having low operating expenses than *****.

Rgds.

Priti

[gregd1401]

Are you planning on using direct expansion or liquid recirculation? To use R22 on liquid recirculation would prove to be very expensive.

[apgurgaon]

Yes I am using Direct Expansion .Air cooled 3Tr Emerson compressors.Hermatically sealed.
Thank you

[apgurgaon]

How much low/high operating cost.Please give some numbers,
regds,

[D.D.KORANNE]

what is the refrigeration load , kw / tr ?

[D.D.KORANNE]

In cold stores , it is better to avoid sealed unit compressors since initial pull down period is longer & compressors could be subjected to high pressures initially. It will be a good idea to have semi or open drive units . Sealed units can be a problem in rural areas where power situation is a question , particularly in india .

Ammonia is best suited for potato cold storage applications. But system design mainly ends up in a plant whereby it needs to be attended by operators .Ammonia nneds a smaller size displacement compressors v/s ***** but system is bulky . ***** systems are compact . Vesus ***** systems can be automated whereby a minimum operator depedence is warranted .

Ammonia leak in public place poses safety problem whereas ***** can be relatively safer.

NH3 is cheap v/s ***** . NH3 piping design is simpler .

you may send a PM to me on ddk0123@gmail.com

[lowtempman]

First place to start is to determine the refrigeration load in KW, TR or BTU per hour, whatever you are comfortable with. If you give the kilos, pounds of potatoes I can help you with this; or give the size of the storage room with some info about insulation thickness, how many and how big are the doors, what is outside the door[s], for instance another room at ambient, or a dock or the general outdoors. Only after you have the refrigeration load can you then think about the type of system whetehr it will be ammonia, halocarbon, and type of compressor, hermetic, open, semi, screw , recip, scroll, etc.

[charlie n]

You'll have more success with gravity flooded or pump recirculated ammonia. These systems can have a much closer approach temperature so over dehumidification will be less of a problem. Use large surface area coils with very few rows in the path of the air. Properly designed ammonia systems are not bulky or dangerous. R-22 will soon be cut back and banned even in India.

[priti]

5000mt potato cold storage will be having around 100tr refrigeration load in peak loading period.

Using of ammonia flooded refrigeration system will only be the right option.

Priti

[lowtempman]

Some random comments:
1.Prtit reports load is 100 TR. If correct, your 3 TR R-22 DX units add up to at least 33 units which is a high number to have to maintain and will involve rather high installation costs.

2.

[lowtempman]

Some random comments:
1.

[CHilly1]

HANDS DOWN AMMONIA!, your operating cost are way lower. There are more regs with how the system is set up and more precautions and safety gear nessassary but if the company has a maintenance department this is easy, a little training as some good saftey equipment. I would use a Cooling tower and either Vilter,frick or other screw compressors, For capacity control both have means for varying the capacity and software for seamless integration, But yourk (Frick) has a much better software package for minimizing energy usage.

[CHilly1]

The frick and vilter screw will also work on R507/404, 134A etc. IF the customer is planing for future expansion this is better, You can also go to a company like Deltaheat Transferr and get an engineered Rack system with multiple 10,20,30 ton Screw compressors in a single condenser configuration, Ultimitly you need to look at effeciency, total system cost plus energy usage and cost savings to help you customer make the best decision.

[lowtempman]

Chilly1 has a good point with his comment about a rack system.
1.Multiple compressors provide backup capacity and also improve efficiency compared to one or two compressors since controls can be set up so that only fully loaded compressors run and screw compressors peak efficiency is at full load.
2. Rack systems usually operate with air cooled condensers as opposed to water cooled condensers with cooling tower or evaporative condensers. Air cooled eliminates water requirements and associated costs with maintenance, water disposal and cost, water pumps, filters, water treatment but of course at the added cost of electric power for the greater compressor HP.

In my opinion 100 TR is not enough load to justify an ammonia system which usually requires an engineered system with central engine room, extensive ammonia piping, engineered design, and code compliance, regs, etc. Don't get me wrong, ammonia is a great refrigerant when userd in the right application.

[K.R.Iyer]

APGurgaon,
These are good inputs from forum members for you to evaluate. I did not see you mention about the proposed location of your Cold storage. In India, use of ammonia is not allowed within city / town limits by the administrative corporation / municipality authorities. If your cold store is within city/town limits, you will not be able to use ammonia.

My view on the choice of refrigerant, compressor, single big plant or multiple small units etc. will depend on who you are - a contractor, consultant or owner for this project? The perspective of all these 3 are different.

Between a hermetic and semi-hermetic, there shall be no difference in ability to withstand the pull-down load, as the motors are designed to stand upto +12.8C evaporating temperature (90Psig for R22) in both types.

If you need any suggestion specific to India condition, you could send a mail to me(though I have no commercial interest & not handling cold storage jobs for the last few years). If you need more latest ideas and suggestions on your project, continue to discuss in the forum. we derive more that way...

[Magoo]

Suggest a chilled water gycol system, with ammonia package.
The glycol system be better able to control room Rh at high levels.

[mustafaalam]

Hey Iyer,
I was wondering if you could help me with setting up a cold storage unit in Pakistan for 25000bags? Each bag is 120 kg.
Pakistan has serious energy issues, so I will also need some sort of a generator hooked up to the storage unit. What I am wondering, and this may be a stupid question, but is it possible to use solar power in such an occasion? Southern Pakistan is an extremely hot country. Do let me know what your thoughts are.

My consultant insisted on using *****.
Also, what is a refrigerant? Isn't ***** or ammonia the refrigerant? What is the function of the ammonia/***** and say something that keeps on popping up on this site (r-22) is r-22, ammonia and ***** substitutes for each other? or they serve different functions? Sorry for all the stupidy. I am 27 years old and doing research in this field as I am bent upon setting up a cold storage unit for potatoes.

[Josip]

Hi, mustafalam

Hey Iyer,
I was wondering if you could help me with setting up a cold storage unit in Pakistan for 25000bags? Each bag is 120 kg.
Pakistan has serious energy issues, so I will also need some sort of a generator hooked up to the storage unit. What I am wondering, and this may be a stupid question, but is it possible to use solar power in such an occasion? Southern Pakistan is an extremely hot country. Do let me know what your thoughts are.

My consultant insisted on using *****.
Also, what is a refrigerant? Isn't ***** or ammonia the refrigerant? What is the function of the ammonia/***** and say something that keeps on popping up on this site (r-22) is r-22, ammonia and ***** substitutes for each other? or they serve different functions? Sorry for all the stupidy. I am 27 years old and doing research in this field as I am bent upon setting up a cold storage unit for potatoes.

Welcome to RE forums...

You are building a new potato cold store for 3000 tons .... not small and simple project and design ... can you provide some more technical info about design to be able to give you some more advices ... of course if you (your consultant) like it ...

I'll suggest you indirect cooling (ammonia-glycol chiller) with ammonia as a primary refrigerant and ethylene glycol as a secondary refrigerant.

see this...

http://www.sabroe.com/products/stand...ers-recip.html

http://www.sabroe.com/products/stand...ers-screw.html

http://www.sabroe.com/fileadmin/file...009.09_scr.pdf

http://www.sabroe.com/fileadmin/file...008.10_scr.pdf

amount of ammonia within above chillers is very small ....

With all my respect to your consultant, but seems he is without any experience with ammonia .... there is no any reason to use ***** R-22 or any other for primary refrigerant

Sun energy you can use to reheat your potato before delivery to the market .... also to have a warm/hot water all around your facility almost for free ...

Maybe you can use winter cold air (I believe sometimes you have very low temperature about or even below 0*C) for cooling your potato directly ....

Dear mustafaalam, you have many possibilities to build a good cold store, but you can miss the target too ....

Best regards, Josip