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frank
13-05-2005, 04:50 PM
We've just been asked to take over the maintenance of a Thermax Hot Water Fired chiller.

Does anyone have any experience with these machines?.

We are going through the motions of checking the vacuum level, refrigerant quality, absorbant concentration etc. but have a problem with the machine not getting down to temperature. The lowest leaving temp is 16C with a hot water temp of 80C. The design is for a hot water temp of 90C. The cooling water inlet temp of 29C is within spec. The machine is not crystallised.

Any ideas?

rbartlett
13-05-2005, 05:20 PM
turn it upside down and leave it over night -never fails...;-))

cheers

richard

chemi-cool
13-05-2005, 09:47 PM
Dear Richard, ;)

Frank is talking about a WATER CHILLER
And you talk about a domestic fridge.

Unless you joke :D

Chemi :)

bobjob
14-05-2005, 09:57 AM
Hi Frank

Thermax Hot Water Fired Chiller.
I guess that your measured temperature of 80c is the temperature into the generator? if the design is for 90c you will not get the machine to work correctly and get the chilled water temperature down.
Many year ago when i done some work on gas fired absortions,there was always a problem with gas pressures, and flues etc
you need to measure the temperature of the hot water in and out of the generator to make sure the correct temperature and flow rate are to design.
I know that Axiar (Climate) are the importer of these machines so they may be able to help,
tel no 0121 705 7601

Best of luck Bob

frank
14-05-2005, 04:54 PM
Hi Richard

As my van is only an Astra I'm going to struggle to take the chiller out as it weighs 3.5 tonnes :D

Hi Bob

Thanks for that.
I've been reading the O & S Manuals and am in the process of taking all the measurements etc to pinpoint the cause of low effeciency. Even with the low generator temperature I would expect more than 16C chilled water leaving temp. Someone has removed the Torre Gauge so this is the first thing I am going to replace. Solution concentrations are next, flow rates etc.

I'll post results as progress reveals results. It would be nice though if someone with experience of these machines could short circuit the legwork. :rolleyes:

Peter_1
14-05-2005, 05:56 PM
Have you worked ever before on such a machine Frank?

I visited last week a plant (the central hospital of Bruges, a staff of more than 2000 peoples) with 2 huge York absorption chillers ( 2 x 1600 kW) for the Belgium magazine Cool & Comfort for whom I'm writing articles.

http://www.azbrugge.be/html/index.asp?hoofd_id=1&rubriek_id=1 last picture on the page

They were cooled by the canal flowing aside Bruges and the waste heat comes from the central huge burners of Bruges where they burn all the garbage from the wide region.
http://www.ilva.be/afvalverwerking/verbranding/

Temperature entering = 115įC.
The university of Gent - division Applied Thermodynamics - is following this project very close

We there installed last year 2 Carrier chillers to cool the 3 switcupboard rooms and the 6 watercooled VFD's

From what I learned there, this is work for specialists, you have to be familiar with these sort of machines.
The noise these machines made was also horrible: just like as they were pumping iron marbles through the circuit. It seemed that these are the crystals that were pumped through the pumps.

I was considering some time ago to follow some courses at York or McQuay in the US to do some work for McQuay or York as a subcontractor.
They have special workshops for this. But they're rather expensive, espacially if you have to travel to the US for this.

Snowman123
14-05-2005, 07:32 PM
http://www.thermaxindia.com/v2/ContactUs.asp?objectid=21&levelno=0&Pageno=1



Thermax Europe Ltd.
Suite 7A, Britannia House,
Leagrave Road, Luton,
Bedfordshire, LU3 1RJ
Ph : 00-44-1582-727756
Fax : 00-44-1582-731538, 00-44-7980915693
Contact :
Dinesh Kamath - dinesh@thermax-europe.com
Vinay Raj - vinayraj@thermax-europe.com

frank
15-05-2005, 06:34 PM
Thanks Marc, I've sent a PM.

Peter, I have done maintenance on Absorp machines before so they are not that much of a strange animal. This machine is fairly quiet in operation and I'm only just getting a feel for it. From what I've seen so far the HW inlet temp is low and the Torre guage is missing. I've done a De-crystalisation cycle and purged the machine but don't yet know what the internals are like as I'm waiting for the bush to be delivered which will allow the new Torre gauge to be fitted.

I've arranged to return next week to take samples of the refrigerant (de-ionised water) and the absorbant so that they can be analysed. Until I know what the vacuum level is, whether it has an air leak, what the concentrations are etc. I'm just guessing as to the cause.

just like normal though, we have only been called in when the "on site maintenance" team have been tinkering :( and the company who used to carry out planned maintenance have not bothered to leave passwords for the controller, log books etc. so we are starting from scratch.

Peter_1
15-05-2005, 09:38 PM
Just interested Frank, where have you learned this because you don't find these machines very often.
I must admit, I was realy impressed when I saw these machines.

Peter_1
16-05-2005, 12:27 PM
Some pictures I took when I was there.
Note the big 4way watervalve to clean the tubes automatically by reversing the flow where the small brushes (left picture) are pushed to the other side of the condenser. Seems that this is realy innovating.

jamcool
16-05-2005, 12:59 PM
marc,try having a chat with Tim Lawton might still be at York in nottingham,good luck

jamcool
16-05-2005, 01:02 PM
sorry its early in the morning where i am,this post is ment for frank not marc

frank
18-05-2005, 09:10 PM
I've worked on the small Robur units in the past - gas fired.

Well, the adapter was delivered today so I went to site and fitted the Torre gauge. Opened the vessel valve to take a reading and the gauge didn't move. it took 3.5 hours before the purge pump (built into the machine) started to show any sign of a reading. I've left it purging overnight and will return in the morning to see how it's going.

Looks like it's either a serious lack of maintenance or the vessel has a small leak.

Brian_UK
18-05-2005, 10:49 PM
I've worked on the small Robur units in the past - gas fired.Yep I've done some work on those old beasties too.

Got to give it to the Yanks, who else would have thought about using a GM power steering pump to move the solution around.

frank
19-05-2005, 09:20 PM
Today's update.

Left the unit on purge all night and arrived on site at 11.00am.

the Torr gauge was reading 18 and not shifting. it looks like either the purge pump oil is knackered or else I'm dealing with a small leak. I'm going back tommorrow to change the oil and see if that works. :(

Ever tried to leak test an absorption chiller at 2 bar? No oil to put glo sticks into :( A nightmare.

I'll keep you posted.

Peter_1
19-05-2005, 09:23 PM
Ever tried to leak test an absorption chiller at 2 bar? No oil to put glo sticks into
How do you leaktest these units and how and with what solution do you refill it?

frank
19-05-2005, 09:31 PM
You don't need to empty the chiller to leak test. You introduce nitrogen up to 2 bar gauge and then supposedly seek out the leak with a bubble test. You can of course introduce helium and use a sniffer probe.

As the vessel is covered with armaflex insulation it is not going to be easy.

I just hope it is the purge pump.

frank
31-05-2005, 07:38 PM
Just a quick update.

We've had to order a replacement vacuum pump as the original one fails to pull less than 21mbar.

ordered it last week from Ireland with an expected delivery period of 7 days but - well we'll see :rolleyes:

frank
28-06-2005, 09:02 PM
Finally, we received the pump but it was damaged in transit :mad:

Ordered the replacement part which took 10 days to arrive - now thats what I call service :D

Anyway, we've fitted the new purge pump and we now have refrigeration taking place but this has uncovered new problems. The trend control is giving a fluctuating signal causing the machine to switch on and off repeatedly every now and again (maybe every 25 minutes or so). When the machine switches off it goes into Dillution cycle and the leaving temps are hunting like mad. We've sent for the controls guy to sort that one out but it's been 6 days so far and no sign of him.

The adiabatic cooler (cooling water) is also playing up. The dump selonoids are energising rapidly when a start signal is received causing the spray heads to fail. I think this is connected to the control problem.

I'll take some pics next time I'm on site. Problem is I always have trouble posting pics as the file size is always too large - any tips on posting pics?

wambat
28-06-2005, 10:07 PM
Frank, If the purge pump had to be replaced then I suspect this unit has had a keak for a long time, if that is the case then you may have a tiger by the tail because when air enters the chiller as the result of a leak, it reduces both the chillerís efficiency and its capacity. Equally important, oxygen from the air causes the lithium bromide in the chiller to become extremely corrosive, damaging the unitís steel components. Like those used with centrifugal chillers, purge units should be inspected regularly for proper operation, and their run time should be monitored to identify any developing leaks. I recall working on 2-1000 ton lithium bromide chillers where we had to replace all the tubes on the condensers because of improper maintenance. They had been leaking for a long time so we removed the pumps and piping and as I put my gloved hand into the evaporator section I was pulling out large chunks of flaked metel, it looked like shale,quite messy!well we eventually got them going but they only lasted about a year before the Hospital replaced them with Centrifigals. I would look at the pump seals very carefully.Non-condensable gases migrate to the area of lowest pressure in the absorption chiller (the evaporator) where a small portion of the vapor is extracted The non-condensables are then evacuated by the vacuum pump. In normal operation, the purge system should operate about one hour a week. I have seen where operatore have been running their purges 24/7. Good luck! :)

frank
29-06-2005, 08:25 PM
Hi Wambat

Please read the original post. We have inherited the problem and are trying to sort it out. The inhibitor concentration has been analyzed and requires to be topped up, something we are about to do. it is nice to finally get some refrigeration effect after so long.

Obviously, the previous service company were not doing their job or not able to look after the machine. it's certainly nice to see a result.

rbartlett
29-06-2005, 08:45 PM
I'll take some pics next time I'm on site. Problem is I always have trouble posting pics as the file size is always too large - any tips on posting pics?

if you highlight the pic's from your camera and right click 'send to' then email address it will ask if you want to reduce them for sending

click yes and the pic's will shrink to an acceptable size

then drag them to the desktop and there you have 'em all shrunk and ready to upload

cheers

richard

frank
30-06-2005, 01:31 PM
if you highlight the pic's from your camera and right click 'send to' then email address it will ask if you want to reduce them for sending

click yes and the pic's will shrink to an acceptable size

then drag them to the desktop and there you have 'em all shrunk and ready to upload

Many Thanks :) I'll give it a try

frank
07-07-2005, 07:31 PM
well, I hope this works.
I've attached some piccies (hopefully) of the chiller. See the torr gauge before and after then the 6C flow temp. Looks like I've finally cracked it

(looks like I'm not allowed to upload all the photo's :( )

frank
07-07-2005, 07:34 PM
Here's the rest of the photo's

But I still don't know how to put pictures in to the post as some members do :confused:

frank
07-07-2005, 07:36 PM
Ooop's - can't find the 6 torr photo

frank
07-07-2005, 09:34 PM
Here it is :)

Josip
23-04-2006, 05:56 PM
Some pictures I took when I was there.
Not the big 4way watervalve to clean the tubes automatically by reversing the flow where the small brushes are pushed to the other side of the condenser. Seems that this is realy innovating.

Hello, Peter_1

This is one older thread (found it by following your note in "Never ending cleaning condensor".

Those small brushes sound very interesting. Can you, please, explain that a little bit more?

If I am right, brushes are installed inside of the pipes and move from one side of condenser to another side by changing of water flow direction by four way water valve. Do you have some more info regarding construction of condenser's water covers because there must be some water flow obstruction :confused: or.....

I believe this can be interesting thing for others too...

Thanks,

Josip

Peter_1
23-04-2006, 08:57 PM
The brushes are indeed pushed to the other side and are injected in special "brush- holders".They stay tehre in some sort of standby position till they're pushed to the other side.

Some pictures tell more then thousand of words
Josip I think you will need no more explanation I think after visiting these links.

http://www.atbsystems.com/home.htm

http://www.wsaes.com/brush.asp

http://www.angelfire.com/biz/themoclean/ccs.html

http://www.hpac.com/member/archive/0208want.htm

Josip
24-04-2006, 08:41 AM
Thanks Peter_1

Yes Peter_1, you are right, one picture can say almost everything :) . Good technical solution.

Thanks,

Josip

grump
01-01-2008, 03:55 PM
I am new to RE had many years experience HVAC
Absorbtion Chillers Arkla Servel Acron Ohio. Worked on them 1974-76 in the UK Please accept that if they have not been commissioned strictly to manufacturers figures on have not been properly maintained you will have problems.When checking a chiller for the first time,we started with the basics.Water filters,flow rates,temperatures.Gass fired,pressure, etc,etc
We used mercury filled thermometers which were placed in various locations throughout the maze of pipes i never did fully understand what was going on, in the meantime dont mess with these babes unless you are going to treat them propper. Grump

frank
01-01-2008, 09:56 PM
Hi Grump

Thanks for your input.

This post is over 1.5 years old but to update you, I found that the safety bursting disc was ruptured. Since this was replaced I've had the machine running 'as sweet as a nut' :)

grump
03-01-2008, 12:49 PM
Hi Frank,pleased to hear you got it sorted.
I drank gallons Benskins Mild for many years.
Brewed in Watford previously Taylor Walker

swaminathan van
08-04-2008, 11:06 AM
hi frank
i suppose you are talking about a single effect chiller.you have mentioned the leaving chilled water temp of 16 deg c .what is the inlet temp?
also if the vacuum is good (measured by a torr gauge) then you need to check the solution concentration to see if it has come up to the desired level (1.7 or so as near to the commissioning data)
it is very important to have the hot water temp as near to 90 deg c as this makes a lot of difference towards capacity.
hope this helps!!!

frank
08-04-2008, 01:14 PM
Hi swaminathan van and welcome to the forum.

Thanks for the reply to my post, but if you read the recent posts you will see that I managed to find and fix the problem about 20 months ago.

Nice to have another Absorption tech on board. I see that you are not currently working - did you work for Thermax?

swaminathan van
08-04-2008, 02:56 PM
Hi swaminathan van and welcome to the forum.

Thanks for the reply to my post, but if you read the recent posts you will see that I managed to find and fix the problem about 20 months ago.

Nice to have another Absorption tech on board. I see that you are not currently working - did you work for Thermax?
thanks for the welcome frank, no,i did not work for thermax,when i was working in hotel in bombay in 1977(god it was so long ago) i had two of those ,carrier make,16 JA 600, one with chromate inhibitor and one with nitrate inhibitor. we had the cooling towers on top of the building 34floors high and the fans were pulling in boiler flue gas and before you know it the tubes gave way and we were swimming in the plant room at -3 level!!!i had retubed the condenser and changed all the spray nozzles to plasti ones and commissioned the plants and they were running well after that.they bring down the temp very quickly as they seem to have more capacity when the chilled water return is higher than design. well nice to tell you the story after a long time.have a nice day!!!!!

absorptionkid
24-04-2008, 02:41 PM
Hi guys,

Just a few word to say it's nice to see that there's still people interested in absorption. I was commissioning some big chillers (few MW) but we have now stop this activity and was wondering how is the market now... Have you guys heard of any new big projects???

I miss thoses chillers... more complicated than my ex but so interesting ;-))

absorptionkid
24-04-2008, 02:55 PM
Franck,

I was a bit surprised by your test at 2 bar g. Was the vessel ever certified for such a pressure before. From what i know they were usually certified to 0.5 bar g only and presurrisng above might lead to trouble.

I agree that leak test on those units are a nightmare and other than helium there's no real solution. On small chillers maybe an ultrasonic tester would help ( i hvae not test it my self on such low vacuum but it works higher leak rate) but helium is definetely the best solution availble. ***** was better but too bad we can't use this anymore....

Paul-in-Sydney
08-07-2008, 09:19 AM
Thank-you all, most informative thread, down here in Sydney we (as design+construct builders) are putting in a Thermax LiBr 400kW hot water abs chiller into the the FIRST speculatively-developed office building in the country to be given 6 Green Stars (which are GBCA stars, somewhat akin to LEEDS).

And as we get close to handover and start-up of this system, well we have started to try and look ahead and see what can and does go wrong with the things.

So it was good to get a sort of de facto "what to watch for" lesson.

Thanks all.

minimoose
17-02-2010, 02:01 PM
I hope someone can assist me with the following:

We are in South Africa and absorption chillers are still very new for us.

Could you possibly advise me on any good and bad experience you have had with absorption chillers with lithium bromide?

As there are a few companies to choose from (Broad, Trane, York, Sanyo), we are not sure how to go about choosing a company, what suggestions would you make?
What are the most common problems experienced with these products?

Thanks:confused:

wilko123
24-02-2010, 05:13 PM
Hi Minimoose,

Id fly Dave Bonner out from JSA Service, he is good at abbo's. Not sure about the OEM's these days, Trane dont build them sono one knows in the UK about them Maybe SANYO, doubt it though? Absorption kid and Frank also know what there talking about-so long as Frank does not get carried away with any pressure testing :)

wilko123
24-02-2010, 05:17 PM
Read what previous guys have said on here and you wont go far wrong....there is not much that will go wrong, just make sure of correct flow rates, temperatures, Solution and vacuum. Abbo's with DDC controllers have more failure points but then that is a controls thing. Crystallisation and Air is biggest problem. All suspect from non-design FR, T, S and V

Cheers Wilko

The Saint75
01-04-2010, 07:57 PM
Hi All, newbie here
I know this is an old thread but, I have a few of these on my portfolio, I don't work on them directly but have had involvment.

A good way of finding leaks is to wrap all the joints with clingfilm, then get the thing down to a decent vac and remove the clingfilm piece by piece and monitor the rise to see which joint is leaking.

These are very complex bits of kit if you do not fully understand them, maintenance is the key. Keep the solution levels correct and keep them running, it's when they stop they can be trouble.

We just replaced a concentrator impeller which from Trane was around £10k, the pump motor £45k.......plus all the work of fitting the things, draining solution, washing if req'd etc.....they can cost a lot to repair.

leadengg
21-05-2010, 06:39 AM
Dear Frank, for overahuling of hot water chiller need service engineer? we are expert in absorption chiller,
Please call ++919825117905
regards,
gavhane BC



We've just been asked to take over the maintenance of a Thermax Hot Water Fired chiller.

Does anyone have any experience with these machines?.

We are going through the motions of checking the vacuum level, refrigerant quality, absorbant concentration etc. but have a problem with the machine not getting down to temperature. The lowest leaving temp is 16C with a hot water temp of 80C. The design is for a hot water temp of 90C. The cooling water inlet temp of 29C is within spec. The machine is not crystallised.

Any ideas?

leadengg
21-05-2010, 06:42 AM
hi, which absorption chillers you service?
info@vacengineers.com

leadengg
21-05-2010, 06:43 AM
Dear for best absorption chiller , you go with Thermax Limited,
info@vacengineers.com

robert strong
06-08-2010, 03:37 PM
Frank,
Do you know of any engineers looking for some work on Absorption Machines. I have landed an order to commission 2 units in the uk.
Thanks in advance,
Rob.

frank
06-08-2010, 08:15 PM
Hello Robert
What make are the machines?
If the machines are new, why are the manufacturers not doing the commissioning ? (warranty issues)