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shsr
24-08-2013, 08:53 AM
Hi, I'm buying a water cooling system for an oxyacetylen welding unit, but the provider didn't write any information about cooling capacity of the system in the catalogue :(

Can anyone help me how to calculate cooling capacity of this system? (other providers often write the cooling capacity power of the chiller)

These are mentioned in the catalogue:
ElectroMotor Rater Power: 185KW
Max Flow: 25 L/min
Flow: 10 L/min
Tank Vol: 20 L
220V/50Hz

moideen
24-08-2013, 09:07 AM
hi,shsr,welcome to re.

For calculating actual capacity of a water chiller
GPM*delta T/24 = TON
or
GPM*500* delta T= btu/hr

shsr
24-08-2013, 09:54 AM
thank you for fast response.
ok. I now the formula Q[dot] = m[dot]*c*delta T
but do u mean that cooling capacity of a water chiller is just related to its flow rate?
because some providers have systems with equal flow rate but different cooling capacities;
What's your idea about them?

chemi-cool
24-08-2013, 10:01 AM
to calculate cooling capacity, you must know the heat load you need to cool.
Could it be the 185 KW electric motor?

shsr
24-08-2013, 11:07 AM
Dear chemi-cool
are you sure heat load is needed to calculate cooling capacity? in catalogues such as the one below, the cooling capacity is calculated without having any information about the load:
http://www.polyscience.com/_pdf/_catalog/POLYSCIENCE_CATALOG_CHILLERS%20%26%20COOLERS.pdf

I think 185KW is the power rated of the fan that will cool the circulating water in the chiller.

chemi-cool
24-08-2013, 11:25 AM
Allow me to copy a line from your link: "Chiller selection guide is based on heat removal"

the heat load is the heat you need to remove = heat load.


I think 185KW is the power rated of the fan that will cool the circulating water in the chiller.

That info for a fan on a chiller is wrong. please recheck it.

moideen
24-08-2013, 12:23 PM
thank you for fast response.
ok. I now the formula Q[dot] = m[dot]*c*delta T
but do u mean that cooling capacity of a water chiller is just related to its flow rate?
because some providers have systems with equal flow rate but different cooling capacities;
What's your idea about them?

Not only related to flow rate, but capacity is varies as per the condensing temperature and evaporator temperature. thus each chiller selection chart will have mentioned the ambient temperature and leaving temperature to determined the capacity of different conditions.

shsr
24-08-2013, 01:33 PM
Allow me to copy a line from your link: "Chiller selection guide is based on heat removal"

Dear chemi-cool;
let me correct your sentence in my link : "Chiller selection guide based on heat removal"
this is the title of a table that compares different chillers to give customer a criterion to select the required chiller.
and I'm doing exactly the same. I want to buy a chiller but I need to know its cooling capacity.
and as I said, in my link u can see that different chillers with the same maximum flow gpm, have different cooling capacities @ 20 c. my question is that How to calculate this cooling capacity or the nominal cooling capacity?


That info for a fan on a chiller is wrong. please recheck it.

u are right.I correct it. I mean "185W is the power rated of the fan that will cool the circulating water in the chiller."
by the way, I need the nominal cooling capacity of this system, such as the systems in that catalogue. can anyone help me?

shsr
24-08-2013, 01:45 PM
Dear moideen,
I appreciate your try, but I also have passed the Thermodynamics course in my university years ago.
But in industrial catalogues, such as this:
http://www.polyscience.com/_pdf/_catalog/POLYSCIENCE_CATALOG_CHILLERS%20%26%20COOLERS.pdf
or other catalgoues there is no data about deltaT but also they have calculated nominal cooling capasity,
I wonder when see these, "How they calculated this??"
Is there any other factor except flow rate and delta T?
Can I caluclate this system's cooling capacity:
Rater Power of Fan: 185W
Max Flow: 25 L/min
Flow: 10 L/min
Tank Vol: 20 L
220V/50Hz

chemi-cool
24-08-2013, 05:33 PM
OK, lets start from the beginning, what do you want to cool and what is your DT temp?