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Thread: NH3 external chiller
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24-05-2006, 03:02 PM #1
NH3 external chiller
Dear all,
I write you from France, a country very late concerning NH3 development.
I am employed by STEF-TFE and I am in charge to retrofit a lot of industrials installations (R22 pumped technologies).
Add to this refrigerant problem, we would want to reduce cooling tower due to water consumption and water hygiene.
The goal is to change installations for news concept in accordance with Kyoto protocol.
I think the best solution is to use NH3 for primary refrigerant and a secondary refrigerant.
The secondary refrigerant should be Glycol for +2°C(35°F) air cold room temperature and must be CO2 for –25°C(-13°F) air cold room temperature.
To use NH3 is a good solution concerning energy saving but this fluid is dangerous when the charge is big.
Today, CIAT, MYCOM are able to deliver NH3 chillers, but all of there are supplied with a water condensor.
So, my question is, do you know a manufacturer of external chiller (like RTAC from TRANE) for cooling capacities from 150 to 800 kW (40 to 230 tons) with shell and tube evaporator and air condensor.
Thank you in advance.
David
nota : Excuse me for my french english !
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24-05-2006, 04:17 PM #2
Re: NH3 external chiller
Hi David
J&E Hall are developing air cooled ammonia chillers with plate heat exchanger evaporators you can contact them through
jehall.co.uk
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24-05-2006, 05:55 PM #3
Re: NH3 external chiller
Hi, David LIOPE
Welcome to RE forum
Originally Posted by David LIOPE
"THERE CAN NEVER BE A PLANT THAT IS TOO SAFE.
SAFETY SHOULD BE A WAY OF LIFE"
Concerning energy savings you are going to install energy saving plant but at the end of story you need a fan to throw all saved energy into wind
Here in Europe the best energy saving solution is evaporative condenser or shell&tube with cooling tower due to climate conditions.
For example before 30 years company Samifi from Italy used to install air condensers at many ammonia plants in Saudi Arabia. There they do not have water at all, but today they reinstall evaporative condensers with desalinated see water (they have so many oil to produce electrical energy) what do you mean, why?
Production of desalinated water is cheaper then to run air condensers, because you can use water for defrosting and then reuse that cold water for condensation and then again.....
You can use both PHE for evaporator and for condenser having very small amount of ammonia in your system (you can keep it in your bedroom )
For low temperature rooms at -25C is ok to use CO2/ammonia cascade.
If I am you David, I will take another look around trying to find some realy better solution.
Originally Posted by David LIOPE
Guys, come here and help with your comments, please.
Best regards,
Josip
It's impossible to make anything foolproof because fools are so ingenious...
Don't ever underestimate the power of stupid people when they are in large groups.
Please, don't teach me how to be stupid....
No job is as important as to jeopardize the safety of you or those that you work with.
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24-05-2006, 06:34 PM #4
Re: NH3 external chiller
Hi David,
Nice to hear from you again. Most of the comments I was going to post would be similar to Josip's.
but this fluid is dangerous when the charge is big.
ALL REFRIGERANTS ARE DANGEROUS. Ammonia just happens to have a distinctive smell that scares people. The liquid is very dangerous due to the high latent heat, moisture absorption ability, and pH.
You can get ammonia burns, instant freezing of skin (or body parts), and panic from the smell always gets someone hurt. However, the other refrigerants (not counting water and hydrocarbons) are silent but deadly. Since they have no distinctive odor a person could work in an area where these have been released (not recommended). Of course if you wake up in the hospital you are lucky.
To use NH3 is a good solution concerning energy saving
Using glycol requires another heat transfer step, which lowers the refrigerant evaporating temperature. Using pumped ammonia directly in the evaporators is best for efficiency. The glycol pumps can have high power requirements since the TD on the glycol will be low to provide good cooling (higher mass flow).
You also have to develop some sort of defrost cycle for the low temperature coils. Water will work, but this adds additional cost to the project. Or, you can use warm glycol, but this adds a layer of complexity to the system.
Using air cooled condensers on ammonia refrigeration systems will present several problems. Some affect energy use, others affect the system design.
- Air cooled condensers will require a very large area for their location
- Air cooled condenser have high fan motor power requirements
- Air cooled condensers (especially for ammonia) will require higher design pressures for the system
- Using air cooled condensers will increase the discharge pressure and temperatures, while also reducing the COP
- Air cooled ammonia condensers can be relatively expensive
- These can be difficult to keep clean
- This is a short list of things that come to mind right now.
...water consumption and water hygiene
A good chemical water treatment person can take care of this for you.
One thing you might want to investigate is using a slightly lower condensing temperature on the evaporative condensers, say 90F (32.2C). The lower condensing temperature also helps to provide a lower water temperature in the sump.
Edit: The lower condensing temperature also helps to imrove the COP and reduce the energy input required by the compressor at a higher discharge pressure.
This helps to slow the scale formation rate and also helps to keep the scale softer. Most of the time, the soft scale will pop off of the condenser coils during cooler weather.
I would also recommend a VFD on the condenser fans, and one other item... Don't cycle the water circulating pump for the condensers. This will help to scale a condenser almost as fast as hard water.Last edited by US Iceman; 25-05-2006 at 12:23 AM.
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26-05-2006, 10:12 AM #5
Re: NH3 external chiller
Thank you very much for your replies. I just answer now, because yesterday, it was a day of in France.
In first, I say "thanks" to colinmcmanus
for Hall address. I will contact them because I know, they work hard with CIAT in 1990 to develop NH3 in direct expansion.
Now, I just want to give my opinion .
I agree with Josip and US Icemanwhen you write NH3 is dangerous with big quantity. STEF-TFE have 30 big cold storage with NH3 refrigeration installation. The major of these installations have more than 10 000 kg of NH3. So, to manage this kind of installation we have our owner maintenance team.
The design of these installation is with pump recirculation, NH3 direct in evaporator and the condensation is made with cooling tower, and a large part of them are equipped with a fan speed controller .
That to say we have experience of "the best refrigeration installation" concerning energy saving.
But, now, in France we have a lot of problem with this kind of installation due to the regulation.
- Under 150 kg of NH3, it is easy to build an installation and concerning the safety, it is not so bad.
- From 150 to 500 kg it is necessary to declare you want to made it and you need to write a big file and you have a lot of constraints.
- Up to 500 kg, you must have authorization from government, it is a long and difficult phase with many constraints.
This microbe like hot water (from +30°C (+85°F) to +35°C (+95°F)) and we often find it cooling tower.
That the reasons, my colleges have installed a lot of chiller with R134A for refrigerant with air condensers.
So, today, I am convince it is not the right way to develop this kind of technologies and I think, it is better to conserve R22 system instead to do that but in 2015……………..R22 supply will stop in Europe.
For STEF-TFE, the positive and the negative are two distinct job. For negative cold storage, it is current to have a maintenance team and it will be possible to use a cooling tower. It is just necessary to be sure, the water consumption it is not higher than the energy saving.
Concerning the security, it is easy to use a secondary refrigerant like CO2 in order to reduce by 10 the nh3 quantity.
Concerning Positive cold storage, it’s not so simple. There is often only one guy for technical survey.
There is not an industrial culture.
This last point drive me to try solution, a kind of mix between safety, energy saving and Kyoto.
I understand there is not A solution, but my feeling is we have a lot of regulation in France against NH3 and 50% are du to lobbing from commercial refrigeration.
Solution with R134a, R404A,…..are temporize solutions.
Now, I a working for a user and it is important for me to think for the future.
I am convince if we can extend solution combine NH3 and security, we have a technical solution for a long time.
I hope you understand our problematic
http://www.stef-tfe.fr
Thank you again for your replies
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26-05-2006, 10:12 AM #6
Re: NH3 external chiller
Thank you very much for your replies. I just answer now, because yesterday, it was a day of in France.
In first, I say "thanks" to colinmcmanus
for Hall address. I will contact them because I know, they work hard with CIAT in 1990 to develop NH3 in direct expansion.
Now, I just want to give my opinion .
I agree with Josip and US Icemanwhen you write NH3 is dangerous with big quantity. STEF-TFE have 30 big cold storage with NH3 refrigeration installation. The major of these installations have more than 10 000 kg of NH3. So, to manage this kind of installation we have our owner maintenance team.
The design of these installation is with pump recirculation, NH3 direct in evaporator and the condensation is made with cooling tower, and a large part of them are equipped with a fan speed controller .
That to say we have experience of "the best refrigeration installation" concerning energy saving.
But, now, in France we have a lot of problem with this kind of installation due to the regulation.
- Under 150 kg of NH3, it is easy to build an installation and concerning the safety, it is not so bad.
- From 150 to 500 kg it is necessary to declare you want to made it and you need to write a big file and you have a lot of constraints.
- Up to 500 kg, you must have authorization from government, it is a long and difficult phase with many constraints.
This microbe like hot water (from +30°C (+85°F) to +35°C (+95°F)) and we often find it cooling tower.
That the reasons, my colleges have installed a lot of chiller with R134A for refrigerant with air condensers.
So, today, I am convince it is not the right way to develop this kind of technologies and I think, it is better to conserve R22 system instead to do that but in 2015……………..R22 supply will stop in Europe.
For STEF-TFE, the positive and the negative are two distinct job. For negative cold storage, it is current to have a maintenance team and it will be possible to use a cooling tower. It is just necessary to be sure, the water consumption it is not higher than the energy saving.
Concerning the security, it is easy to use a secondary refrigerant like CO2 in order to reduce by 10 the nh3 quantity.
Concerning Positive cold storage, it’s not so simple. There is often only one guy for technical survey.
There is not an industrial culture.
This last point drive me to try solution, a kind of mix between safety, energy saving and Kyoto.
I understand there is not A solution, but my feeling is we have a lot of regulation in France against NH3 and 50% are du to lobbing from commercial refrigeration.
Solution with R134a, R404A,…..are temporize solutions.
Now, I a working for a user and it is important for me to think for the future.
I am convince if we can extend solution combine NH3 and security, we have a technical solution for a long time.
I hope you understand our problematic
http://www.stef-tfe.fr
Thank you again for your replies
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29-05-2006, 07:49 PM #7
Re: NH3 external chiller
Hi, Davis LIOPE
Originally Posted by David LIOPE
How many nuclear power plants you have in France? What about safety? I do not believe that cold store with 10 or more tons of ammonia is more dangerous then the nuclear reactor ammonia is a natural substance
Originally Posted by David LIOPE
Originally Posted by David LIOPE
Originally Posted by David LIOPE
Originally Posted by David LIOPE
Best regards,
Josip
It's impossible to make anything foolproof because fools are so ingenious...
Don't ever underestimate the power of stupid people when they are in large groups.
Please, don't teach me how to be stupid....
No job is as important as to jeopardize the safety of you or those that you work with.
-
30-05-2006, 08:49 PM #8
Re: NH3 external chiller
Originally Posted by colinmcmanus
Sabroe may well have also
www.sabroe.com
Colin you wouldn't work for JE Hall by any chance
Halls are a good company, but very traditional
The chillers you are talking about are McQuay, please correct me if I am wrong
Kind Regards. AndyIf you can't fix it leave it that no one else will:rolleyes:
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06-06-2006, 03:51 PM #9
Re: NH3 external chiller
Thank you very much Andy,
I have found information I need on the web site, the chiller with air condenser is a DX LR compact
I have contacted GRASSO France and I have ask them if they know this machine.
They answer me Yes, and when I ask them "Why did you never presente it to us ?", the guy answer me "oh, it's not for french market, but if you want I can send the advertising"
Add to that, they already install one machine DX LR in France !!!!!
Thank you again for informations.
I will give you more information if I can install one.
David
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07-06-2006, 08:51 PM #10
Re: NH3 external chiller
Originally Posted by David LIOPE
happy to assist
The grasso chillers are good, we use the FX with an evaporative condenser quite often.
The DX and air cooled wouldn't be as efficent, but would suit your market.
Let us know how you get on, if I can help in anyway let me know
Kind Regards AndyIf you can't fix it leave it that no one else will:rolleyes:
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