PDA

View Full Version : NH3 external chiller



David LIOPE
24-05-2006, 03:02 PM
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 !

colinmcmanus
24-05-2006, 04:17 PM
Hi David
J&E Hall are developing air cooled ammonia chillers with plate heat exchanger evaporators you can contact them through
jehall.co.uk

Josip
24-05-2006, 05:55 PM
Hi, David LIOPE :)

Welcome to RE forum


To use NH3 is a good solution concerning energy saving but this fluid is dangerous when the charge is big.

This is yes and no, but I prefer to say:

"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 :eek:

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 :confused: 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.


Add to this refrigerant problem, we would want to reduce cooling tower due to water consumption and water hygiene.

In another hand maybe I miss something :confused:

Guys, come here and help with your comments, please.

Best regards,

Josip :)

US Iceman
24-05-2006, 06:34 PM
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.

I would like to add to Josip's comments about this.
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

Very true. However... if you use air cooled condensers and glycol and glycol pumps you will loose any energy efficiency you wanted to gain.

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

I would think this is the least of the problems to be solved.

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.

David LIOPE
26-05-2006, 10:12 AM
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 Iceman when 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.Add to that, three years ago, some think like twenty persons (old peoples and children) are became hill due to "legionelose" . It is the French name for a microbe.
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 (http://www.stef-tfe.fr/)
Thank you again for your replies

David LIOPE
26-05-2006, 10:12 AM
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.Add to that, three years ago, some think like twenty persons (old peoples and children) are became hill due to "legionelose" . It is the French name for a microbe.
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 (http://www.stef-tfe.fr/)
Thank you again for your replies

Josip
29-05-2006, 07:49 PM
Hi, Davis LIOPE :)


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.

With all my respect I cannot agree with your regulations to forbid use of ammonia as refrigerant. I do agree with strict rules but to forbid...:confused:

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 :eek: ammonia is a natural substance :D


Add to that, three years ago, some think like twenty persons (old peoples and children) are became hill due to "legionelose" . It is the French name for a microbe.
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.

Today is possible to make a good water treatment to avoid any disease due to legionella or such. That cannot be acceptable reason, never.


Concerning Positive cold storage, it’s not so simple. There is often only one guy for technical survey.

There is not an industrial culture.

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.

This is definitely true, and we have to change perception of people regarding ammonia teaching them and telling the truth about risk.


Concerning the security, it is easy to use a secondary refrigerant like CO2 in order to reduce by 10 the nh3 quantity.

In Greece (couple of years ago, for safety purposes according to some European safety rules) we installed NC pneumatic valves at crucial points on pipelines. In case of emergency (leak) or power cut out all those valves are going to close by spring force and complete plant is devided in safety segments with smaller amount of ammonia. Expensive but very good safety solution ;)


I am convince if we can extend solution combine NH3 and security, we have a technical solution for a long time.

It seems that you answered to your doubts ;) keep on David, you are on the right way :)

Best regards,

Josip :)

Andy
30-05-2006, 08:49 PM
Hi David
J&E Hall are developing air cooled ammonia chillers with plate heat exchanger evaporators you can contact them through
jehall.co.uk
As an impartial poster I have to say Grasso have this alsowww.grasso.nl

Sabroe may well have also
www.sabroe.com

Colin you wouldn't work for JE Hall by any chance:D
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. Andy:)

David LIOPE
06-06-2006, 03:51 PM
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

Andy
07-06-2006, 08:51 PM
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
David:)
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 Andy:)