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RANGER1
17-06-2017, 10:45 PM
A client asked some time ago how important pipework insulation is in regards to lost plant efficiency, power savings etc.
Has anyone any recommendations or papers to justify real world savings, heat loads.
Mainly talking about 2 stage ammonia refrigeration systems, coolstores.

Thanks

Segei
18-06-2017, 04:08 PM
I don't know any paper but I read long time ago that we use 5-10% of refrigeration to keep plant cool. So any improvement of pipe insulation will save a few percent of energy but it will be costly energy savings. Actually you can determine cold storage real life energy use for keeping plant cool by compare surface of pipes+vessels insulation to insulation surface of cold rooms. This is based on assumption that heat transfer through pipe insulation and freezer insulation is the same.

RANGER1
18-06-2017, 08:47 PM
Sgei,
Client asks about power savings, all air coolers blocked with dust, pipe insulation if roof space on -33 deg C wet return block of ice dripping on ceiling, probably $1000000 roof can only tell him what I see.
If you had a 100 metre pipe in 30 degC with 100mm thick ice on it, it has to be something, but what I don't know.

Segei
18-06-2017, 10:56 PM
You can do a test. Switch off all evaporators, manually open 1 or 2 liquid solenoids to make liquid/vapor flow and run the smallest compressor to measure real load to keep plant cool.

RANGER1
19-06-2017, 08:07 AM
You can do a test. Switch off all evaporators, manually open 1 or 2 liquid solenoids to make liquid/vapor flow and run the smallest compressor to measure real load to keep plant cool.
Thanks for help & reply Segei

FaultCode
19-06-2017, 05:16 PM
A document that may help...

http://bit.ly/2rIDdPX

RANGER1
19-06-2017, 08:51 PM
A document that may help...

http://bit.ly/2rIDdPX

Thanks, because it's a broad statement although useful, no one appears to have carried out a practical test that I can find.

FaultCode
19-06-2017, 10:15 PM
Agreed, there seem to be lots of docs saying it saves 5 - 10% on energy but without any backup facts.

weagle
25-07-2017, 03:40 AM
There have been several papers written on this by RETA. You may be able to find this info there.

Tycho
08-12-2017, 09:28 PM
Thanks, because it's a broad statement although useful, no one appears to have carried out a practical test that I can find.

How about this one?
https://www.irc.wisc.edu/export.php?ID=234

:)

Tycho
08-12-2017, 09:41 PM
A client asked some time ago how important pipework insulation is in regards to lost plant efficiency, power savings etc.
Has anyone any recommendations or papers to justify real world savings, heat loads.
Mainly talking about 2 stage ammonia refrigeration systems, coolstores.

Thanks

Staying over on a ship and nothing to do but reading through old posts on RE :)

I think the proper answer to that question would be:
worst case, you are spending 5-10% of all the energy you are putting into the plant to cool down the air surrounding the pipes, instead of using that energy to cool down your product.
Damaged insulation may also cause moisture to get to the pipes and cause accelerated corrosion which can lead to unwanted breakdowns and downtime.
Ice is a very good insulator, but it is very bad for your pipes :)

RANGER1
09-12-2017, 02:02 AM
Staying over on a ship and nothing to do but reading through old posts on RE :)

I think the proper answer to that question would be:
worst case, you are spending 5-10% of all the energy you are putting into the plant to cool down the air surrounding the pipes, instead of using that energy to cool down your product.
Damaged insulation may also cause moisture to get to the pipes and cause accelerated corrosion which can lead to unwanted breakdowns and downtime.
Ice is a very good insulator, but it is very bad for your pipes :)

Tycho,
If it stays as ice it keeps it like a time capsule.
When you have sweating, ice forming & retreating that's the worst area for rust.
I think 5-10% a bit much on ammonia steel pipe, but obviously better if it has good insulation.

RANGER1
09-12-2017, 02:06 AM
How about this one?
https://www.irc.wisc.edu/export.php?ID=234

:)


Thanks Tycho will check it out.

Segei
09-12-2017, 05:51 PM
About corrosion. Following factors influence corrosion. Oxygen, moisture and temperature. Found that steel warm refrigeration pipes will rust faster at presence of moisture. Recently 20 years cold storage had hot gas line rusted through. Insulation of hot gas line was not good but the most important that in one spot this pipe was located under suction line. Outside surface of suction line freeze at night and ice melt during the day. Water dripped on the hot gas line. After 20 years hot gas line rusted through. Low temperature pipes which are always frozen have little rust because temperature factor is very low.