Industrial Chiller Books or Classes

[StoneCold]

My company has two 60 ton chillers with screw compressors. We purchased them used and are having quite a few problems with them. (No surprise.) What I need is a good book on the design and operation of industrial chillers. I get the basics but I am wondering if we are missing some ancillary equipment that would help us monitor the units better and help us know when they are not working. We currently have no way of telling what the load is on the chiller or what the inlet and outlet temperature of the process fluid.

Anyone have a good book on this or a good class they went to?

Thanks
StoneCold

 

[imok2]

Here is agreat web site:

http://tristate.apogee.net/cool/home.asp

 

[friartuck]

What problems??


Friar Tuck of Sherwood

 

[micjk]

I'm with friartuck what sort of problems ie vibration, surge, low flow, poor energy transfer, etc.

Roy Gariepy
Maintenance and Reliability Dept.
Dorlastan Fibers LLC.
Goose Creek, South Carolina USA

 

[StoneCold]

FriarTuck, micjk
Sorry it took so long for me to reply. I have been out of the office. The problem with the chillers is that there are times when they can not adequately cool the processes in the plant. Right now the only temperature reading I have is for material returning from the plant. That does me very little good when I am trying to trouble shoot the unit. I have no way of knowing if it is a flow problem (to the chillers or out to the plant as they are separate loops) or if it is a chiller cooling problem. Maybe the load is just to large for the chiller to keep up. I don't know. I need to add some thermocouples and a flow meter to each loop I think. I want to use a plc and constantly calculate the head load from the plant and the cooling rate of the chiller. This would allow me to know where the problem is, so I can get a handle on it.

Any suggestions?

Thanks
StoneCold

 

[Cooky]

Hi Stonecold,

You're on the right track with a plan to monitor the flow and temperatures for each process loop, make sure you also monitor the chiller in the same way.

If it's a new system, can you talk to the guy who designed the system?.

Also, was the chilled water system properly balanced during the commissioning process?

Cooky

 

[davefitz]

The problem could also be at the cooling tower side of the cycle.

It would seem useful to monitor the cooling water flow and temperature to/from the cooling tower, and use those values as the basis of the total heat dumped to the environment. That must equal the chiller duty plus the chiller power input. Check the COP based on this data ( COP= chiller duty/ power input). If you know the total power input plus the cooling water to tower heat load, you can tehn determine the chiller duty by difference.

The original performance curves should be consulted to determine what the expected COP would be for the tested chiller duty and temperature difference DT (DT= chiller return fluid temp - cooling water in temp). If the tested COP is close to design , then the problem is not the chiller, but may be either the cooling tower sizing or the chiller sizing is not adequate for the current chiller load.

 

[ClydeMule]

For the small chillers we build, when the chillers cool sometimes, but not others, 9 times out of 10 the chiller is too small.

Of course this assumes the chiller is working properly. If something is screwed up, it may be able to keep up at a parial load but not at a higher load, which should still be within the capacity of the chiller.

Try looking at your process first; exactly what happens in your plant or process when they stop keeping up with the load? Is it always at the same time or process? Is it always at the same time of day?

Was any data taken originally to determine that 2 x 60 ton chillers were adequate? Try getting a hold of that. If there is NO data used to size the chillers, I would be suspcious that they are just too small. Could have been the boss knew that a some chillers were needed and HEY here is a smokin' deal on a couple of used machines. I only point at this because it has happened on our equipment so often. We sell 1/2 through 30 tons in a plastics catalog. 1/2 and 1 tons are the most returned units we have, 99% of them have no problems. They just happened to be the cheapest units we have. We have had people who have needed 15 tons but buy the 1/2 ton because it is so cheap.

On the classes; I am alwaus a proponent of getting more education, but I would recommend that you not have the notion that you will take class and be able to fix the problem. They area also kind of pricey. If I was your
boss, I would invest in the tools required for you to find out as much info as possible to monitor the process (temp, flow, etc.) and have some experienced service technicians to check out the chillers. Make sure you are around when the techs are. Try to ask questions without being annoying. If YOU are the expert on your process and they are the experts on the equipment, you will be able to discover and fix the problem quickly and efficently.

Good luck. Let us know what went on so we can all keep learning.

Regards,

Clyde