Designing a Condenser

[skhan855]

Hi

I have been running cold storage in Pakistan since last 10 years and technology is outdated. I am planning to change from local compressor to KIRLOSKAR 6 cylinder compressor which will give me refrigeration capacity of 320 KW at 750 RPM. This capacity is good for me.

Now, I am stuck with condenser, as we make everything in Pakistan therefore we will make condenser also in Pakistan. We have done this before also.

I have discussed matter with one of my Chinese friend engineer who suggest me 2700 meter length of coil 19 MM inner diameter and 2.8 MM carbon steel thickness, without any fins to be cooled by combination of water and air.


I have changed his design to a a flab bad type condenser which is normal design of air cool but I will use both water and air to cool it down. (Pictures attached)

My desired room temperature is +3.0 Degree C, with ambient temperature between +6.00 - 25 degree C, to store fresh fruits.

My question is that:

Is pipe specifications are ok?
Is length calculated ok?
Should I installed fins also?

Problem in Pakistan is that electricity is world's most expensive therefore initial investment gets faster returns.

Regards
Salman Khan

[chemi-cool]

hello Salman,
Condenser capacity is not measured by meters but by capacity,
Q [heat you want to reject] = compressor cooling capacity + compressor current draw [+ 10% to 15%]
Thats in KW.

Now you can find the condenser size.

[skhan855]

Is compressor current draw in Amperes?
My compressor is 320 KW refrigerant capacity and it will draw 125-130 amperes.

[chemi-cool]

Is compressor current draw in Amperes?
My compressor is 320 KW refrigerant capacity and it will draw 125-130 amperes.

All parameters should be in KW.

[D.D.KORANNE]

Hi Salman,

I might be able to suggest on condenser capacity . But I need the following info:

1) Evaporation temp :

2) condensing TEMP :

3) Comp capacity : 320 kw

4) Kirloskar comp model : Please confirm Model : KC-6 ?? @750 RPM

5) Refrigerant : AMMONIA

6) You will need evaporative condenser .....

Rgds ,

D D KORANNE

[haris]

Dear Salman,

You need to calculate the total heat of rejection to know exactly what will be your condenser load.

Total heat of rejection can be calculated as total refrigeration load (In KW) + motor power (of compressors in KW if load is in KW) and a correction factor depending on your difference in Dry & Wet bulb.

Then you can use the formula of surface heat transfer i.e: heat transfer coefficient X surface area X log.mean of temperature difference.

Here the temperature difference would be discharge temperature - condensing temperature.

I believe this cold storage is in Lahore (Kasur) I think I have seen this one already :)

Anybody here give some suggestions to refine this, improve this please..