ammonia (NH3) condensers selection

[joaocruz]

Hi all! I am a student from Portugal i am currently frequenting a masters in refrigeration climatization and energy. In on of the subjects i have this semester (refrigeration) we have to project a warehouse for fish conservation this warehouse is formed by 3 principal rooms a fast frizzing room a preparation room and a frozen fish conservation room.

All the loads calculations are made (thermal balance)
the fluids are:
Ammonia (NH3) and glycol

Is there any software that could help me selecting the ammonia condensing units?

[Josip]

Hi, joaocruz :)

Welcome to RE forums....

we also have one forum: New to RE for first post to introduce yourself;)



All the loads calculations are made (thermal balance)
the fluids are:
Ammonia (NH3) and glycol

Is there any software that could help me selecting the ammonia condensing units?

Anyhow, please try those links:

Handbook
http://www.baltimoreaircoil.com/english/info_center/handbook/index.php

Software
http://www.baltimoreaircoil.com/english/info_center/pss/ec/index.php

You can search Evapco site for another software....

One more excellent software CoolPack: need registration but it is free;)

http://www.et.web.mek.dtu.dk/Coolpack/UK/reg-download.html

....hope this will be of some help to you:p

one more thing...searching RE forums you can find a lot of links to different info...books, software, etc...just try

Best regards, Josip :)

[nike123]

Hi, joaocruz :)


One more excellent software CoolPack: need registration but it is free;)

http://www.et.web.mek.dtu.dk/Coolpack/UK/reg-download.html



For those who are terrified of registration of any kind, there is link for direct download of CoolPack great and free software: http://tinyurl.com/3yt3w3 ;)

[US Iceman]

I am a student from Portugal i am currently frequenting a masters in refrigeration climatization and energy.


:confused::confused::confused:

Are you going to school to learn how to use software or to learn how to do engineering?:rolleyes:

Almost all ammonia systems are custom engineered to the specific operating conditions and capacity requirements. If you know your cooling loads and operating conditions we might be able to assist you (a little bit, after all you are the one trying to learn this;)).

Shortcuts using any software should only be used by experienced engineers, not by someone trying to learn. I say this because you will not have any feeling for answers generated by the software.

Unfortunately, the only way to develop this understanding is to do the math yourself.

[nike123]

Shortcuts using any software should only be used by experienced engineers, not by someone trying to learn. I say this because you will not have any feeling for answers generated by the software.

Unfortunately, the only way to develop this understanding is to do the math yourself.

To add to that, any software is just a tool. If you don't know how to use it and what to do with it, than it can not help you much. But if you know what are you want and do, than time and effort saving is huge.:cool:

[US Iceman]

Just as you would not use a screw driver when you need a chisel.:D

[Josip]

Hi, US Iceman:)


Just as you would not use a screw driver when you need a chisel.:D

I will not bet on this....you must know what Einstein said about endless things....


"There are only two endless things in the world: the universe and the human stupidity... but I'm not sure in the first one"

Coming back to original post....


All the loads calculations are made (thermal balance)
the fluids are:
Ammonia (NH3) and glycol

Is there any software that could help me selecting the ammonia condensing units?

No one word about help.....but never to late for original poster to come back and ask;)

Best regards, Josip :)

[joaocruz]

for the conservation (freeze fish) room the conditions are:

Dimensions 20*60*7.5 m
outside conditions: t=35ºC and HR (relative humidity 50%)

Temperature -25ºc

entering product temperature : -15ºc

Relative humidity 50%

daily product entry 8% of the volume

density of occupation 350 kg/m3

compressors work 18H day

load to remove (evaporators) : 140.7 Kw affected by 20% coefficient regarding the heat produced by the motors actuating the fans of the evaporators

I am considering the installation of 5 evaporators

[US Iceman]

If the heat load is 140.7 kW then you have to add the 20% (of the fan motor heat) to the cooling load. The evaporators have to cool the heat load plus the fan motor heat.

Then you will have defrosts. A rough rule-of-thumb is if you have 4 defrosts per 24 hours, then the cooling time (24-4=20) available to meet total heat load increases the minimum required capacity of the evaporators. This assumes the total defrost cycle is no greater than 1 hour.

What you will end up with is something like this:

(140kW *1.20) / (20/24) / 5 evaporators = 40.3 kW per coil.

Therefore, when one coil is in defrost the other coils can still provide sufficient capacity to meet the cooling load.

Now, if your room temperature is -25C, then this means your evaporating temperature has to be colder for the evaporator to work.

Room temperature - evaporating temperature = degrees of temperature difference to select evaporator.

Since you will have pressure loss through the suciton line (from the evaporator to the compressor suction) you have to account for the pressure loss.

Did the professor address any of the above?:confused: