Results 51 to 66 of 66
Thread: Flooded Ammonia Refrigeration
-
07-03-2006, 11:59 PM #51
Re: Flooded Ammonia Refrigeration
Hi Josip,
The way I have always considered side loads is based on screw compressors. The main suction load flows into the compressor suction flange. Any load operating at a higher pressure (greater than the main suction pressure), and connected to the side port is what I would call a side load.
I think the side loads Andy was describing are similar. If you have a high temperature load (using an evaporator pressure regulator) that is connected to a lower main suction pressure, the high temperature load could be called a side load to the main suction line.
Originally Posted by Josip
Originally Posted by Josip
How large are the systems you work on?
-
08-03-2006, 01:24 AM #52
Re: Flooded Ammonia Refrigeration
Hi, US Iceman
Yes, I can see that we are speaking about same thing. Sometime language can make a big mass.
I agree with you about exact problem to get warm or cold water. It is sometime unbeliveable what they can put on paper...
Sorry, becuse I forgot to put quotation marks to "warm water" to make it more clear. In my country we use this ironical expression for "bright" designers. What are you using for?
Those days, I saw one new design where young designer is going to use glycol water, PHE and pumps for oil cooling instead to use ammonia thermosyphon oil coolers. He has not too much expirence with thermosyphon oil coolers and he is going to make it on old fashioned way.
I'm working mostly with ammonia from 1MW up
Industrial plants like: slaughter houses, cold stores, breweries, food process plants - ice cream, milk, petrochemical industry. Very few with *****s mostly with ammonia. I'm ammonia guy like you
-
08-03-2006, 03:24 AM #53
Re: Flooded Ammonia Refrigeration
In my country we use this ironical expression for "bright" designers
On the thermosyphon oil cooler subject... If the young person has never designed one of these systems he should have someone to show him how to design it.
If he has designed a gravity flooded system for evaporators, he has a good chance of success for a thermosyphon system, don't you think?
You are working on some good sized systems. I have a fun one to look at next week. About 12 MW total for a slaughter house. Nice little system...
-
08-03-2006, 10:28 AM #54
Re: Flooded Ammonia Refrigeration
Originally Posted by US Iceman
On the thermosyphon oil cooler subject... If the young person has never designed one of these systems he should have someone to show him how to design it.
If he has designed a gravity flooded system for evaporators, he has a good chance of success for a thermosyphon system, don't you think?
You are working on some good sized systems.
I have a fun one to look at next week. About 12 MW total for a slaughter house. Nice little system...
-
08-03-2006, 01:35 PM #55
Re: Flooded Ammonia Refrigeration
The system is an old one. The building is probably over 100 years old. It is the original facility. Most of the original equipment has been replaced by now.
Some of the system is liquid overfeed. Some of it is using a controlled pressure receiver for liquid feed.
Other areas use what we call pumper drums (liquid draining by gravity into a small vessel. When the vessel fills up with liquid, high pressure gas is used to displace or "pump" the liquid out to the system).
There about 26 screw compressors of various sizes connected to about 4 suction pressure systems. Two stage compression.
-
08-03-2006, 03:43 PM #56
Re: Flooded Ammonia Refrigeration
Originally Posted by US Iceman
Some of the system is liquid overfeed. Some of it is using a controlled pressure receiver for liquid feed.
There about 26 screw compressors of various sizes connected to about 4 suction pressure systems. Two stage compression.
Other areas use what we call pumper drums (liquid draining by gravity into a small vessel. When the vessel fills up with liquid, high pressure gas is used to displace or "pump" the liquid out to the system).
-
08-03-2006, 06:38 PM #57
Re: Flooded Ammonia Refrigeration
This facility has always been used for pork.
The areas where the controlled pressure liquid is used is difficult to sort out right now. I have been in the facility twice before.
The liquid at some controlled pressure is used to feed the liquid level control valves and some evaporators. When the controlled pressure liquid is used, a hand expansion valve is used to meter the refrigerant into the coil. Some coils may have a distributor, some may have orifices. The new coils being installed with controlled pressure liquid normally use refrigerant distributor, otherwise you have to many problems with the flash gas.
The screw compressors are: Howden, Sullair, Mycom, and Dunham-Bush. Most of these are at least 20 years old, and all run very well.
The one thing I do not like about the pumper drums is that you have to maintain a minimum gas pressure for pumping the liquid. Otherwise they are very simple to understand. You are exactly right about the NRV's.
This thread is getting very long. Perhaps we should start a new one??
-
08-03-2006, 06:40 PM #58
Re: Flooded Ammonia Refrigeration
I forgot to answer on of your questions. I am not sure about the purger. I think I remember seeing an old manual refrigerated purger mounted in a corner somewhere.
-
08-03-2006, 07:30 PM #59
Re: Flooded Ammonia Refrigeration
Hi US ICEMAN, What make of air purger ?? We use 4Armstrong H370 on the 3 plants that we have on this site. We have set them up to work on auto with Danfoss EVRA 3 valves and on a timer unit, Two of them working on 4 condensers with two take off points on each condenser. They work well and keep the head pressure down to about 160 Psi on a 17 ton charge ammonia plant. What type do you like to fit on your systems.
all the best Arthur.
-
08-03-2006, 08:06 PM #60
Re: Flooded Ammonia Refrigeration
The one I remember seeing looked like the old Armstrong single point purger. I do not know how it was connected to the system, or if this is the only purger.
When I was last at this plant we were looking for other issues and I just happened to notice the old purger attached to a wall (in the shadows).
I suspect that whatever they have, it is probably too small. This system has over 300,000 pounds of ammonia in it.
The purgers I have used in the past are the Hansen multiple point purgers. They seem to do a very good job of removing the noncondensable gas.
-
08-03-2006, 09:37 PM #61
Re: Flooded Ammonia Refrigeration
hi thanks for the info will have to look up Hansen and see how they work.
-
08-03-2006, 10:43 PM #62
Re: Flooded Ammonia Refrigeration
Hello guys,
hansen multiple point purger is good. Have some expirience with, more or less positive. With proper maintenance can work for long time. On another hand possibility to purge couple of points is very important for big plants. Power reduce cost is significant becuse here we have almost always very big el. motors with high power consumption. I think that is a must device for such a plant.
aawood1 please check this link for Hansen purgers:
http://www.hantech.com/products/purge.asp
hope you can find something there
I agree to start a new thread becuse this one has a long beard
-
11-03-2006, 08:50 PM #63
Re: Flooded Ammonia Refrigeration
Hi Josip, Had a look at the site will have to see if the man will spend some of the companey pounds. Have not worked out what we save on the main plant system, But did on a small ammonia system and we reduced the power cost by £ 1,180 last year. Reduced the working head pressure down from 180 psi (12.5 bar) to 150 psi
(10.5 bar) on two Grasso RC11 9 cylinder units with a 4.5 Ton charge in the system working at -38oC. Must change the pressure gauges and stop useing psi.
-
17-03-2006, 01:58 AM #64
Re: Flooded Ammonia Refrigeration
Originally Posted by Andy
-
17-03-2006, 02:01 AM #65
Re: Flooded Ammonia Refrigeration
Originally Posted by Peter_1
-
17-03-2006, 03:33 AM #66
Re: Flooded Ammonia Refrigeration
Originally Posted by latent heat
The more liquid drawn from a low pressure vessel also requires additional higher pressure liquid flowing into the vessel to maintain a constant level. This adds load to the compressor.
It is not free.
Similar Threads
-
advanced refrigeration technology
By Lc_shi in forum FundamentalsReplies: 10Last Post: 16-02-2011, 05:22 PM -
ammonia refrigeration system
By Lc_shi in forum FundamentalsReplies: 48Last Post: 25-06-2010, 10:03 AM -
Flooded Ammonia Part Two
By Josip in forum NH3Replies: 28Last Post: 05-02-2009, 03:45 PM -
Ammonia Based Combustion/Electric Refrigeration Principles
By GeeeAus in forum FundamentalsReplies: 4Last Post: 28-01-2006, 05:30 PM -
ammonia refrigeration
By deepakrbhat in forum RefrigerantsReplies: 77Last Post: 23-04-2004, 12:07 AM