PDA

View Full Version : Two stage ammonia system







Samarjit Sen
24-04-2008, 08:48 AM
We are expecting a project for Ice Cream The system has to be with NH3. The total heat load has been assessed by us is 15 TR at -38 oC Te and 40 oC Tc.

We are planning to use one Vilter-Frick India reciprocating open type 2 stage compressor. There shall be 2 nos of Evaporators inside the room, each of 50% of the totl load. The Condenser shall be of the Evaporative Type.

I am not much aware of NH3 plants and whatever I have learnt is from this forum. Now prior to the finalisation of the project, I would like to prepare myself. What I have learnt from the RE, that for such application, Liquid Overfeed is very effective. How do I assess the capacity of the Liquid pump ? I presume One pump shall be suffecient to for the 2 Evaporators.

Since importing the vessels would be very expensive, I would also like to know the details of the vessels required so that accordingly i may get it constructed here. The Evaporator shall be imported.

There will be more questions, and your patience and reply shall be highly appreciated.

bruceboldy
25-04-2008, 09:34 PM
The system design is not very difficult, but I have found that i need a min of 3 evaorators at low temp to make enough defrost gas for the defrosting of a evaporator. I can send a few vessel details that you can use for a typical recirculator with a pump. Send me an email address and I will forward a few details from our Recirculator vessel designs.

Best to you

Bruce

Samarjit Sen
27-04-2008, 05:44 AM
Dear Bruce,

We propose to use two Evaporators and have electric defrost system.

You may send the details to me via a PM

I shall be keenly awaiting your reply.

Thank you.

Samarjit Sen
27-04-2008, 04:07 PM
Hi Bruce,

I have sent a PM to you. Rearding the Defrost, we propose to use electrcic defrost.

Hope to hear from you soon.

Samarjit Sen
27-04-2008, 04:11 PM
Hello Chillin Out,

I am sorry to have put my e mail id as I know very well that the same should not be put. But then I would like to point out that there are a large number of posts where the e mail ids have been put for getting the relevant informations.

Maybe due to oversight they were not removed.

kelvin_27_84
15-05-2008, 05:37 PM
maybe i can help too, but i think instead of using electric defrosting, why not just use hot gas defrosting, so much easier. design a 3 line system. i can send you a rough design, PM me ok

hendry
18-05-2008, 05:51 AM
Hi samarjit,

so you are using liquid overfeed with pump. ...

i've experienced ice cream plants in DX design.

would you consider that?

yeah, vessel is pretty expensive these days every where. better to do it locally. good choice!

but you must know the design. some suppliers may give you non Ammonia design. so be careful.

how about your intercooler? open flash type you use?

anyway, i know you are capable to solve the problems. hope my questions induce further evaluation.

Hendry, on wesak day holiday.

Josip
18-05-2008, 09:42 AM
Hi, :)


maybe i can help too, but i think instead of using electric defrosting, why not just use hot gas defrosting, so much easier. design a 3 line system. i can send you a rough design, PM me ok


Hi samarjit,
so you are using liquid overfeed with pump. ...
i've experienced ice cream plants in DX design.
would you consider that?
yeah, vessel is pretty expensive these days every where. better to do it locally. good choice!
but you must know the design. some suppliers may give you non Ammonia design. so be careful.
how about your intercooler? open flash type you use?
anyway, i know you are capable to solve the problems. hope my questions induce further evaluation.
Hendry, on wesak day holiday.

please, check this

http://www.refrigeration-engineer.com/forums/showthread.php?t=12866

Best regards, Josip :)

mazbut
31-05-2008, 11:51 PM
I may suggest that you refer to some technical literature by ASHRAE or atleast have a look at books authored by Steve Elonka
I learnt much from his books when I came across industrial refrigeration!
all the best

ajish
16-01-2010, 10:27 AM
We are expecting a project for Ice Cream The system has to be with NH3. The total heat load has been assessed by us is 15 TR at -38 oC Te and 40 oC Tc.

We are planning to use one Vilter-Frick India reciprocating open type 2 stage compressor. There shall be 2 nos of Evaporators inside the room, each of 50% of the totl load. The Condenser shall be of the Evaporative Type.

I am not much aware of NH3 plants and whatever I have learnt is from this forum. Now prior to the finalisation of the project, I would like to prepare myself. What I have learnt from the RE, that for such application, Liquid Overfeed is very effective. How do I assess the capacity of the Liquid pump ? I presume One pump shall be suffecient to for the 2 Evaporators.

Since importing the vessels would be very expensive, I would also like to know the details of the vessels required so that accordingly i may get it constructed here. The Evaporator shall be imported.

There will be more questions, and your patience and reply shall be highly appreciated.

charlie n
16-01-2010, 04:08 PM
For such a small system, a Flooded design would be much more economical than pump recirculated. Hot Gas defrost will require at least 3 evaporators so you're probably best served by electric defrost. DO NOT USE DX. IT WILL NOT WORK WELL AT THESE TEMPERATURES.

jaysephus
16-01-2010, 09:06 PM
personal stuff sorry

ajish
19-01-2010, 05:32 AM
Hi Dears
I Have a question:
1.how can i calculate separator&receiver(or some tank like accumulator ,intercooler,..) volume in double stage ammonia system?
thanks for your kindly attention

Ambrish_bajpai
20-01-2010, 11:47 AM
Please give a brief description of your system. what type of separator are you using ?? is it a oil seperator ??