How to calcualte refrigerating capacity at given temperature ?

[ijazali]

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]

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]

thank you brother....but can u explain it...what is D1,TD C2 ??

[nike123]

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 0°C = 30K x Specific heat of water x mass of water, which is total sensible heat of water

You have temperature difference of ice from 0°C to -5°C = 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 0°C to ice of 0°C 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 30°C to 0°C, freeze it and cool ice further to -5°C.

[ijazali]

sorry about the D1 ( its miss typing) ,
thank you so much brother, for the explanation.it helped me alot

[Magoo]

Hi ijazali
what type of ice machine are you working with, tube ice, sheet ice, block ice, etc..

[semoo112]

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]

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]

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 ..