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Thread: MBP Hydrocarbon refrigeration
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22-09-2007, 03:07 AM #1
MBP Hydrocarbon refrigeration
Hello all,
I have a project for a medium pressure refrigeration system that requires a cooling capacity up to 15kW.
The customer is paramount on the use of hydrocarbons.
At the moment i am looking into changing all the electical components to make it safe but not sure if the compressor would be suitable. I have looked into the oil and that is ok although i am adding a crank case heater.
Does anyone know of any compressors that would do the job. Evap at 7°C condense 50°C probally R290 (propane) as the compressor manufacturer at the moment does not offer any solution.
Its a friday night and i am googles up to the eye balls.
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30-09-2007, 09:07 AM #2
Re: MBP Hydrocarbon refrigeration
Good luck, I know bitzer are hesitant to warrant use on r290. Have seen small danfoss comps - under 1 kw on r290 at sydney olympics - none since though.
...and she said "give it to me you big fridgie"
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30-09-2007, 02:21 PM #3
Re: MBP Hydrocarbon refrigeration
The comp needs to be intrinsicly safe.
All conections need to be sealed and no sparks possible.
The comp internals will be ok as long as it is compatible with the oil.
Pure refrigerant in the system is safe, as long as there is no Oxygen in there with it. Even if there is oxygen in the system, the pressures involved almost negate any chance that you will achieve the correct partial pressure to cause a problem. The risk is almost negligable.
Cheers taz.Last edited by taz24; 30-09-2007 at 02:25 PM.
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30-09-2007, 02:30 PM #4
Re: MBP Hydrocarbon refrigeration
Yorkie
the only difference between Hydrocarbon compressors and normal is that the internal protection is elecrtronic not Klixon typre as you do not want any sparks internally. I know Danfoss/Manuerop do HC comps. The question as to changing the electrics is a difficult one as on most systems I have worked on normal electrics are used as the refrigerant is inside the system so why protect against it and to be honest with the quantities used and the dillution factor in normal areas where the plant is installed you would never get to an explosive concentration anyway. If it is AC why not use a HC water chiller outside and just pump glycol into the area to be cooled. Looking at the loading this may not be feasable on this occasion. If you keep the runs short you should not have a problem.
Ian
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30-09-2007, 11:33 PM #5
Re: MBP Hydrocarbon refrigeration
It can also depend on the size of the charge to go in the system as to whether you can use HCs or not.
Have a read here, on page 7, for starters.
http://www.bbc-consultancy.com/Hydro...Guidelines.pdfBrian - Newton Abbot, Devon, UK
Retired March 2015
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01-10-2007, 12:02 AM #6
Re: MBP Hydrocarbon refrigeration
Brian
the regs look similar to ammonia and we all know how dangerous that is. Realistically taking that you usually need only 60 to 70 percent of an equivilant HFC charge for a given cooling capacity with HC's a 15kw duty aslong as the pipe run is short or you use two systems there should not be a problem.
Ian
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01-10-2007, 01:16 AM #7
Re: MBP Hydrocarbon refrigeration
Originally Posted by Pooh
How dangerous are other refrigerants?If all else fails, ask for help.
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01-10-2007, 01:32 AM #8
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01-10-2007, 01:28 PM #9
Re: MBP Hydrocarbon refrigeration
Guys
as an ammonia engineer I was being sarcastic in my comment. The big problem with ammonia and HC is the perceived danger not the actual danger.
Ian
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03-10-2007, 01:12 PM #10
Re: MBP Hydrocarbon refrigeration
...and she said "give it to me you big fridgie"
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07-11-2007, 08:43 PM #11
Re: MBP Hydrocarbon refrigeration
Thank you all for the comments to date and sorry for the long reply
The system is going to be on the primary side (on roof)(2 circuits) with a secondary refrigerant supplying some AHU's via a Heat Exchanger.
Its a fully ventilated system with an external control panel located about 2m away.
I know to increased the viscocity of the oil as well due to miscibility of the refrigerant/ oil.
I need to get the job done asap.
Customer getting a bit twitchy.
Not sure to say sorry and go back to a system with R410A.
My old boss used it many years ago and i think he would be proud for me to use it again but safer than the really old stuff.
?
Yorkie
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