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ijazali
30-10-2014, 08:33 AM
i have been given a problem ..
An ammonia ice plant operates b/w condenser temperature of 35c and an evaporator temperature of -15c.it produces 10tons of ice per day from water at 30c to ice at -5c .assume simple saturation cycle
calculate Cpacity of refrigeration plant ??

how to find this ? plz help me..

Magoo
30-10-2014, 08:49 PM
54.52 Kws evaporator duty.

Q= ( C1 x TD ) + Latent + ( C2 x TD ) = 470kj/kg
10,000 kg /24 hours = 0.116 Kg/ second.
Evap duty = 470kj/kg x 0.116 Kgs/ sec = 54.52 Kws

ijazali
31-10-2014, 11:41 AM
thank you brother....but can u explain it...what is D1,TD C2 ??

nike123
02-11-2014, 09:30 AM
Where do you see D1?

C is specific heat of matter
TD is temperature diference

C1 is specific heat of water
C2 is specific heat of ice

You have temperature difference of water from 30 to 0C = 30K x Specific heat of water x mass of water, which is total sensible heat of water

You have temperature difference of ice from 0C to -5C = 5K x Specific heat of ice x mass of ice, which is total sensible heat of ice

And you have specific latent heat of changing water of 0C to ice of 0C x mass of water/ice which is total latent heat of frezzing of water to ice

Adding that together you get your heat needed to remove in order to cool water from 30C to 0C, freeze it and cool ice further to -5C.

ijazali
02-11-2014, 08:13 PM
sorry about the D1 ( its miss typing) ,
thank you so much brother, for the explanation.it helped me alot

Magoo
03-11-2014, 11:05 PM
Hi ijazali
what type of ice machine are you working with, tube ice, sheet ice, block ice, etc..

semoo112
06-11-2014, 11:12 AM
54.52 Kws evaporator duty.

Q= ( C1 x TD ) + Latent + ( C2 x TD ) = 470kj/kg
10,000 kg /24 hours = 0.116 Kg/ second.
Evap duty = 470kj/kg x 0.116 Kgs/ sec = 54.52 Kws



can u explain this in more details with numbers ??
Q= ( C1 x TD ) + Latent + ( C2 x TD ) = 470kj/kg ????????/

thank you very much

fathy

Josip
06-11-2014, 07:07 PM
Hi, semoo112 :)


can u explain this in more details with numbers ??
Q= ( C1 x TD ) + Latent + ( C2 x TD ) = 470kj/kg ????????/

thank you very much

fathy

my advice .... you need to read the thread from beginning to follow calculation procedure ... within nike123 post you have definitions ... what is what ...

and then you will catch the numbers .... numbers are irrelevant ...


and then you can change them as you like or as you need ... quite simple ...




another way is to search RE forums for cooling capacity calculation ...

something you can find on the WEB ....

something about Ice in fisheries ... good to read ...
http://www.fao.org/docrep/t0713e/T0713E00.htm#Contents

some calculation
http://www.fao.org/docrep/t0713e/T0713E03.htm#3. Quantity of ice required

about water and ice ...
http://www.fao.org/docrep/t0713e/T0713E0c.htm#12. Some useful facts about water and ice


Hope this will be of some help to you ...

Best regards, Josip :)

ijazali
07-11-2014, 08:48 AM
Hi ijazali
what type of ice machine are you working with, tube ice, sheet ice, block ice, etc..

its actually a problem in my book, iam still studying ..