1400 KW DX Plant for Offshore Platform
1400 KW DX Plant for Offshore Platform
(OP)
Friends
This for an offshore drilling rig application. Brief specifics are as follows
1. Application : Offshore Drilling Rig
2. Location: Tropical
3. System : AHU’s with DX coil serving mechanical areas and Living quarters (approx 15 AHU’s)
4. Ambient : 35 deg C, 80% RH
5. Total Cooling Load : App 3000 KW
My question is
Client want to use central DX plant in 3 x 50% (Basically assembly of compressors and water cooled condensers) configuration located centrally on the project. The length of pipes to the AHU's could be as long as 50m and may be much more depending on the pipe layout.
Please advice:
1. Is this a practical system.
2. We have proposed chilled water systems as we feel this it as a more reliable and simple system but owner want to go for DX.
3. Any idea how much refrigerant charge would be required.
4. Is there any limit on the maximum cooling capacity available for water Cooled DX plants.
5. Is pressure drop and heat gain in tubes could be an issue.
6.Is VRV a possible soilution for such an application.
7. Any other issue with DX system for such application
It would be great if someone can advice on merits and demerits on these systems.
Thanks
This for an offshore drilling rig application. Brief specifics are as follows
1. Application : Offshore Drilling Rig
2. Location: Tropical
3. System : AHU’s with DX coil serving mechanical areas and Living quarters (approx 15 AHU’s)
4. Ambient : 35 deg C, 80% RH
5. Total Cooling Load : App 3000 KW
My question is
Client want to use central DX plant in 3 x 50% (Basically assembly of compressors and water cooled condensers) configuration located centrally on the project. The length of pipes to the AHU's could be as long as 50m and may be much more depending on the pipe layout.
Please advice:
1. Is this a practical system.
2. We have proposed chilled water systems as we feel this it as a more reliable and simple system but owner want to go for DX.
3. Any idea how much refrigerant charge would be required.
4. Is there any limit on the maximum cooling capacity available for water Cooled DX plants.
5. Is pressure drop and heat gain in tubes could be an issue.
6.Is VRV a possible soilution for such an application.
7. Any other issue with DX system for such application
It would be great if someone can advice on merits and demerits on these systems.
Thanks





RE: 1400 KW DX Plant for Offshore Platform
RE: 1400 KW DX Plant for Offshore Platform
Refrigerant Charge: A LOT
Limitations for water cooled DX systems: i'm afraid i never see a limit in it, but don't have enough experience in this subject.
Chilled water system : Definitely
RE: 1400 KW DX Plant for Offshore Platform
2 - I agree that going for a chilled water system would be much simpler with off the shelf components and much less change of operational issues.
3 - A lot of refrigerant is required! Need to piping schematic and do a take-off, similar to calculating water volume in a chilled water system.
4 - Water cooler chilled are water cooled DX plant, but talk to someone like Bitzer who can give guidance on compressors (and system design) http://www.bitzer.de/home/index.php
5 - Pressure drop, heat gain etc are all fundamental issues and hence require an experienced designer.
6 - Doubt VRV (ie Daikin style) is applicable. You can get large VSD controlled compressors which may be applicable or use unloading on reciprocating style compressors.
RE: 1400 KW DX Plant for Offshore Platform
RE: 1400 KW DX Plant for Offshore Platform
I think damage to environment should be the biggest concern. We talked to some of our suppliers for the quantity of refrigerant. It is huge (5~6 Tonnes???). We are not sure if this is correct. Is there any rule of thumb to calculate approximate quantity of refrigerant charge?
Imagine how much damage this system can cause to environment if there is a small undetected leak in the system and if we multiply this with the life time of rig (25 years)...
RE: 1400 KW DX Plant for Offshore Platform
RE: 1400 KW DX Plant for Offshore Platform
Think of the maintenance of the DX system in those conditions - it would end up being full time. Also, no flexibility.
How much is a rig worth? $ 500 million? 1 billion? What's the chilled water system worth relative to that and the daily production costs?