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kasperDK
10-03-2006, 10:03 PM
Chillers?

What is the best?

R717
R290
R1270
R22
R404a
R407c
R410a
ect

plate
shell/tube
shell/plate
ect

Josip
10-03-2006, 11:22 PM
First one from both group :)

Definitely ;)

Lc_shi
11-03-2006, 12:10 AM
First one from both group :)

Definitely ;)

Based on what?

Most chiller are R22+shell tube :)
KasperDK,what the spec for the best?


rgds
LC

US Iceman
11-03-2006, 03:30 AM
Ammonia for the low mass flow and very high latent heat and good physical properties.

AND,

A plate heat exchanger. Low refrigerant charge required, higher heat transfer per unit of heat transfer surface, and smaller size and lower costs.

These should work well for the majority of the applications.

kasperDK
11-03-2006, 08:48 AM
last year installed a Shell/plate(condenser and evap.) ammonia chiller with hp float vavle, with sabroe smc 106mk.4, Vacon Inverter(VLT), ca. 500kW at 6/12C
cond.40C with only 13 kg of ammonia!!!!

And in my new job iam installing 180 kw og R290 chiller plate/plate,this can be put together to produce more with 6 kg of propane(R290) no olie problems,no service problems,

kasperDK
11-03-2006, 08:51 AM
are you using Freecooling wenn the temp outside is under the temp of the chiller water, iam servicing a systemther produce ca. 2 mW 14/10C water outer temp -3C

Josip
11-03-2006, 03:12 PM
Hello KasperDk,

please come with some more details like piping diagram, description...;)

Thanks

US Iceman
11-03-2006, 05:04 PM
Hi kasperDK,


are you using Free cooling when the temp outside is under the temp of the chiller water, i am servicing a system ther produce ca. 2 mW 14/10C water outer temp -3C

This sounds like the chiller is being used as a thermosyphon with the outdoor air temperature as the heat sink.

A very good idea. I have proposed this several times for various applications.

Dimitris
12-03-2006, 07:03 AM
410 plate,proper D.P on heat exchanger

Andy
12-03-2006, 08:21 PM
Hi all:)

I am tending to go for Plate and Shell both on Evaporator and Condenser. Sabroe now build a package where the evaporator is the a plate and shell, which is also the surge vessel. The condenser is a Plate and shell also with the oil separator and the HP float built into the Plate and Shell. With Ammonia Refrigerant.:)

There is nothing wrong withShell and tube heat exchangers, they have less pressure drop, but the refrigerant charge goes up along with the size;)

R22 was a good refrigerant, but we can't use it in new plant:(

R404a would be next best, but it pays to check R134a as it can be more effecient in some cases
:eek:

What abot the Turbocor option, R134a with very high COP's at part load, which is the majority of the year:D

Kind Regards. Andy:)

US Iceman
12-03-2006, 11:18 PM
What about the Turbocor option, R134a with very high COP's at part load

Is this better than a recip. compressor?? A recip. is almost linear for part load power and capacity.

kasperDK
13-03-2006, 07:14 PM
Hi all:)

I am tending to go for Plate and Shell both on Evaporator and Condenser. Sabroe now build a package where the evaporator is the a plate and shell, which is also the surge vessel. The condenser is a Plate and shell also with the oil separator and the HP float built into the Plate and Shell. With Ammonia Refrigerant.:)



Hi andy

This is the unit or Chillpac for sabroe i have installed in denmark, its a super concept and works OK


Andy what corp. are you working for?

KasperDK

Tycho
14-03-2006, 12:17 PM
I like the spray chillers, range from 300 - 1100 Kw with a charge of 3 - 6 bottles of NH3.

the tubes are not submerged in refrigerant, rather the refrigerant is pumped from the lower drum and sprayed over the tubes via several nozzles mounted on two pipes running side by side over the tubes.

we also use plate exchangers as a condenser on these units.

http://www.pbase.com/kimmo98/image/56112421.jpg

bruceboldy
14-03-2006, 05:59 PM
I also like the spray chiller design. A company i was with designed and sold spray chill comopnents for others to complete. The ability to approach 32 degree f water without the problem of freeze up is a very popular design, espically in food processing.

We also sold plate and shell chillers but have pulled back from these units in the large sizes. There seems to be some thermo shock problems causing leaks in the large units

The unit design and concept is excellent just a few tech problems espically with flooded ammonia.

rbartlett
14-03-2006, 07:08 PM
good to see you here bruce

tell us about yourself...

cheers

richard

Andy
14-03-2006, 08:04 PM
Hi andy



Andy what corp. are you working for?

KasperDK

Large Independant company.

www.crossref.com

Not a corporation:eek: big firms have plenty of room for idiots, generally in abundance:D

Kind Regards. Andy:)

bruceboldy
14-03-2006, 08:50 PM
hi richard

nice of you to inquire about me.
I am doing consulting on cold storage facilities and a few ice plants had a design build contracting company for many years in the us. Use to be a sales engineer for frick before they were controlled by york, and who knows who

Some what of an expert in freezing and blast freezing, and system design for large and small facilities.

Also worked for a specilaty heat exchanger company, enhanced surface exchangers with a specialty towards ammonia to a fluid. Lots of titanium designs for brine .

thanks again, hope i can be of help....
david bruceboldy usa

US Iceman
14-03-2006, 09:26 PM
Spray Chillers...

Can anyone provide some links for review information? I would be interested in seeing some of the design criteria, GPM/sq. ft., nozzle types, and heat transfer rates.

Thanks.

David, can you send me an email with contact information please? It appears you and I are doing similar work. It would be nice to talk to you and share some stories.

Best Regards,
US Iceman

Lc_shi
15-03-2006, 12:26 AM
I like the spray chillers, range from 300 - 1100 Kw with a charge of 3 - 6 bottles of NH3.

the tubes are not submerged in refrigerant, rather the refrigerant is pumped from the lower drum and sprayed over the tubes via several nozzles mounted on two pipes running side by side over the tubes.

we also use plate exchangers as a condenser on these units.

http://www.pbase.com/kimmo98/image/56112421.jpg
what type compressor? looks like centrifugal one

Outside Rep
15-03-2006, 03:42 AM
Hi all:)

I am tending to go for Plate and Shell both on Evaporator and Condenser. Sabroe now build a package where the evaporator is the a plate and shell, which is also the surge vessel. The condenser is a Plate and shell also with the oil separator and the HP float built into the Plate and Shell. With Ammonia Refrigerant.:)

There is nothing wrong withShell and tube heat exchangers, they have less pressure drop, but the refrigerant charge goes up along with the size;)

R22 was a good refrigerant, but we can't use it in new plant:(

R404a would be next best, but it pays to check R134a as it can be more effecient in some cases
:eek:

What abot the Turbocor option, R134a with very high COP's at part load, which is the majority of the year:D

Kind Regards. Andy:)


well I am new guy but 134a with wmc is the only way to go for the smalller chillers 110-300ton but dual with 134a

but i am slightly bias :D

Outside Rep
15-03-2006, 03:44 AM
Is this better than a recip. compressor?? A recip. is almost linear for part load power and capacity.


recips are basiclly a waste now in the 100-300ton market you need to add a vfd with that to reach the IPLV of the turbo core

Tycho
15-03-2006, 04:38 PM
I also like the spray chiller design. A company i was with designed and sold spray chill comopnents for others to complete. The ability to approach 32 degree f water without the problem of freeze up is a very popular design, espically in food processing.

We also sold plate and shell chillers but have pulled back from these units in the large sizes. There seems to be some thermo shock problems causing leaks in the large units

The unit design and concept is excellent just a few tech problems espically with flooded ammonia.


We take seawater down to 28.9 F

Maybe you worked for the company we are gonna start buying or spraychillers from, it's located in Texas.

cant remember the name, but they have a new kind, with an allow they call Titek (or titech) where the tubes are welded to the endplates like on all steel chillers, instead of "rolled" when you have steel endplates and alloy tubes.

:D

Tycho
15-03-2006, 04:39 PM
what type compressor? looks like centrifugal one


It's a Howden XRV (twin screw)

Andy
15-03-2006, 09:40 PM
well I am new guy but 134a with wmc is the only way to go for the smalller chillers 110-300ton but dual with 134a

but i am slightly bias :D

McQuay Rep I presume.;) R134a is not that popular this side of the pond, not that effecient when compared to say R404a, which would be popular. Green Peace is trying to ban all HFC refrigerants in Europe and making head way, new Fgas regulation coming in.:(

Anyway it is a little hard to know which ***** to use:confused:
At present I am using mostly R404a where possible in the ***** line.

Kind Regards Andy.:)

Andy
15-03-2006, 09:42 PM
Is this better than a recip. compressor?? A recip. is almost linear for part load power and capacity.

Apparently not :D

Check the web site out.www.turbocor.com

and decide for yourself.

Me I am using a lot a screws and VSD's;)

Kind Regards. Andy.:)

Outside Rep
15-03-2006, 10:49 PM
McQuay Rep I presume.;) R134a is not that popular this side of the pond, not that effecient when compared to say R404a, which would be popular. Green Peace is trying to ban all HFC refrigerants in Europe and making head way, new Fgas regulation coming in.:(

Anyway it is a little hard to know which ***** to use:confused:
At present I am using mostly R404a where possible in the ***** line.

Kind Regards Andy.:)

cool 404a whats that LOL yeah 134a is the new thing here 404 407 410 is only used on refigeration around here but just qouted a Airhandler with 407 since its mostly refigeration there its a abnormaly around here althought

NoNickName
15-03-2006, 10:56 PM
404 has a very low exponent, side effect of which is the low discharge temperature, in turn leading to high oil dilution and oil transport in the system. Efficient oil separators are required, especially when coupled with twin screws. When 404a is required, I normally recommend customers with 507, or setup the chiller with extremely high SH and generous oil heaters

Outside Rep
15-03-2006, 11:26 PM
Interesting around here the only chillers around here with those refigerents are Industrial Cooling wichs is far and few between and Ice Rinks and Ice making machines but always intrested in finding out new stuff

US Iceman
16-03-2006, 12:14 AM
There was not very much useful information on the link provided. Where energy efficiency was shown on the website, it linked to an article discussing energy reduction becoming more important. Nothing was shown to provide efficiency of this compressor.




Energy savings with part load performance as low as 0.375 kW/ton IPLV, full load performance is as low as 0.62 kW/ton



0.62 kW/ton is nothing to really brag about. Not bad, but not too impressive. You can get better than this with a recip. compressor with ammonia at full load.

If you account for the utilization of all of the heat transfer surface when part load is encountered (which is what I seem to remember about IPLV ratings) the performance actually seems to improve due to the closer approached temperatures.



Apparently not

I disagree. the literature does not seem to support the claim. Can someone provide data?


...are Industrial Cooling which is far and few between...

Not that many because the new refrigerants are used, or, not that many you have seen?

No doubt, the comfort cooling sector is a much larger market and more systems have been installed with the new refrigerants. But then again, not too many companies would install large ***** systems for industrial use.

The biggest reason for large ***** systems (in industrial use) is when the use of ammonia is not politically correct or restricted due to occupancy class.

Outside Rep
16-03-2006, 01:23 AM
The whole thing is that yes amonia is better but its not being used for comfort cooling

also on the industrial refigeration side it is far and few between in the area I live except for the three chocolate plants that are righ down the road


Amonia around here is very seldom used since there is not a large amount of people that know how to use it and its only used in process cooling ie chicken plants and the chocolate plants thats it

r134a is the majority of the reffer used around here since its all basicly office space and some light industrial

Andy
16-03-2006, 08:50 PM
404 has a very low exponent, side effect of which is the low discharge temperature, in turn leading to high oil dilution and oil transport in the system. Efficient oil separators are required, especially when coupled with twin screws. When 404a is required, I normally recommend customers with 507, or setup the chiller with extremely high SH and generous oil heaters

You could always use a secondary colesant filter as you would in Ammonia:D

High superheats damage compressors:confused: and reduce the effeciency of the compressors, not to be recomended:)

507 is one people are investigating, effeciency is similar or better than R404a, maybe an answer to the chiller problem, but I still prefer what I know and what our engineers are familiar with.:)

R404a is very good for screws on low temp, very small oil cooler loads, if any at all:)

Kind Regards. Andy:)

NoNickName
16-03-2006, 09:13 PM
You could always use a secondary colesant filter as you would in Ammonia:D

Been there, done that, not working. Worse of all, counter rotation while compressor stopping takes refrigerant back in the suction together with oil, which is compressed back in the discharge when it starts once again.
Or don't start anymore :eek: and seizes for oil compression.


High superheats damage compressors:confused: and reduce the effeciency of the compressors, not to be recomended:)

Your mileage may vary here. To me, SH in excess of 15K is not an issue, as it isn't with R290 and R1270. I normally install a air to refrigerant finned coil exchanger to be installed behind the condenser coils or pipe2pipe direct transfer. Two beneficial effects: lower heat rejection in the condenser and higher SH with subsequently better refrigerant reevaporation in the oil demister.


R404a is very good for screws on low temp, very small oil cooler loads, if any at all:)

Oil cooler? What oil cooler? :)

Tycho
16-03-2006, 10:08 PM
Been there, done that, not working. Worse of all, counter rotation while compressor stopping takes refrigerant back in the suction together with oil, which is compressed back in the discharge when it starts once again.
Or don't start anymore :eek: and seizes for oil compression.


If you have a Non-return valve on the suction line (close to the comp.), counter rotatating should not happen.


We have colesant filters on all our units, regardless of refrigerant, never had any problems at all with them.
do you have a line from the colesant filter section back to the compressor suction line?
just have to ask, as I've seen those without, and the point of having one without a return to the suction quite eludes me :)

Andy
16-03-2006, 10:16 PM
Been there, done that, not working. Worse of all, counter rotation while compressor stopping takes refrigerant back in the suction together with oil, which is compressed back in the discharge when it starts once again.
Or don't start anymore :eek: and seizes for oil compression.

Sound like a design flaw on the unit, suction and discharge check valves needed and possibly a bleed solinoide to depressurise the compressor at off cycle



Your mileage may vary here. To me, SH in excess of 15K is not an issue, as it isn't with R290 and R1270. I normally install a air to refrigerant finned coil exchanger to be installed behind the condenser coils or pipe2pipe direct transfer. Two beneficial effects: lower heat rejection in the condenser and higher SH with subsequently better refrigerant reevaporation in the oil demister.
Suction or discharge superheat, I assume discharge, finned coil would be a good point for heat recovery



Oil cooler? What oil cooler? :)

Oil coolers are often used on low temp 404a screws

Kind Regards Andy:)

jamcool
16-03-2006, 10:19 PM
more limitations here than even in the USA:cool: only 134a chillers used for comfort cooling like hotels there was a vilter ammonia on island but the company went out of business so its no more :o ,but atleast the weather is good:)

Andy
16-03-2006, 10:22 PM
more limitations here than even in the USA:cool: only 134a chillers used for comfort cooling like hotels there was a vilter ammonia on island but the company went out of business so its no more :o ,but atleast the weather is good:)

Can't say the weathers great here, but it is nice and green:D

Kind Regrads. Andy:)

NoNickName
16-03-2006, 11:32 PM
Oil coolers are often used on low temp 404a screws

Kind Regards Andy:)

I know. The smilie was on purpose: no oil cooler, because it is not required, according to the compressor manufacturer literature. If I had an oil cooler, refrigeration dilution would be even worse.

And for Tycho: no non-return valve on suction, no customer will pay for such a plus (4 inches suction pipe check valve costs an arm and a leg). And it would add pressure drop to the suction line.

US Iceman
17-03-2006, 03:18 AM
no customer will pay for such a plus (4 inches suction pipe check valve costs an arm and a leg). And it would add pressure drop to the suction line.

The suction check valve should not be considered an optional item. The disc type check valves have low pressure drops.

You could also use a high performance butterfly valve with a motorized actuator. On start-up the valve opens. On shutdown the valve closes. Very low pressure loss during operation.


no oil cooler, because it is not required, according to the compressor manufacturer literature. If I had an oil cooler, refrigeration dilution would be even worse.

I have seen some applications like this. The low specific heat ratio of some refrigerants require additional suction superheat to prevent condensing close to the compression cycle.. R-114 was similar to this also.

In some cases you have to add a heat exchanger in the suction line to specifically superheat the suction gas.

NoNickName
17-03-2006, 04:33 PM
Thanks Iceman, I'm considering disc type check valve at the moment, and it seems it can be usable in my case.
And you are correct for the SH thing. An air to refrigerant superheater was added in order to increase the suction temperature from -15 to +5. This is useful SH and does not affect negatively the compressor.
Also an increased oil heater was installed to reduce refrigerant dilution at standstill.

US Iceman
17-03-2006, 07:02 PM
Also an increased oil heater was installed to reduce refrigerant dilution at standstill

You could also insulate the oil separator and oil lines. The large surface area of the separator rejects a lot of heat you cannot afford to loose in this condition. ;)

Is the superheat you are adding to the suction gas coming from the refrigeration system? If the superheat comes from the ambient air, the superheat is non-useful to the net refrigeration effect. The additional superheat only helps with the oil dilution problem by keeping the oil warmer.

And, if the superheat is non-useful it could cost you some compressor capacity due to the increase in specific volume.

NoNickName
17-03-2006, 11:58 PM
Is the superheat you are adding to the suction gas coming from the refrigeration system?

Yes, it is. I wrongly wrote air to refrigerant, but it is head to back superheater

Andy
18-03-2006, 09:18 AM
US Iceman

You could also insulate the oil separator and oil lines. The large surface area of the separator rejects a lot of heat you cannot afford to loose in this condition. ;)



That would be the big one:)
We took over a problem NH3 plant with all sorts of oil trips, oil heaters burning out by the arm full. Fitted the insulation and ordered trace heating, well the trace heating is still in the warehouse and the plant is a new plant:)

Kind Regards. Andy:)

Andy
18-03-2006, 09:36 AM
Is the superheat you are adding to the suction gas coming from the refrigeration system? If the superheat comes from the ambient air, the superheat is non-useful to the net refrigeration effect. The additional superheat only helps with the oil dilution problem by keeping the oil warmer.

And, if the superheat is non-useful it could cost you some compressor capacity due to the increase in specific volume.

Suction liquid heat exchangers are commonly on R404a plants and are necessary in low suction superheat applications (water chillers and DX with electronic expansion valves)
We had one plant with open recips, eating shaft seals, the manufacturer advised us to increase the superhaet settings on the electronic valves, someone did and it seemed to help. To be honest I changed the oil, realigned the compressors and set up the head pressure control, (up and down, you couldnot beleive) and oh raised the suction set point from -18deg c to -4 deg c, then the plant stopped eating seals:D

Moral, proper design needed;)

And proper commissioning;)

As will all refrigerants:)

US Iceman
18-03-2006, 04:28 PM
Hey Andy,


the manufacturer advised us to increase the superheat settings on the electronic valves, someone did and it seemed to help.

This sounds like an oil dilution problem. Were the carbon faces on the shaft seal pitted and cracked?

Also, when you changed the oil... did you change to a different type or viscosity grade?

US Iceman
18-03-2006, 04:32 PM
We took over a problem NH3 plant with all sorts of oil trips, oil heaters burning out by the arm full. Fitted the insulation and ordered trace heating...

Was the engine room temperature cool?

I have seen several systems where a similar thing occurred due to the cool air in the engine rooms.

One question for you. Why were the oil heaters burning out this fast? Where they not submerged in the oil sump, or bad power quality? :confused: That sounds unusual!

Andy
18-03-2006, 06:46 PM
Was the engine room temperature cool?

I have seen several systems where a similar thing occurred due to the cool air in the engine rooms.

One question for you. Why were the oil heaters burning out this fast? Where they not submerged in the oil sump, or bad power quality? :confused: That sounds unusual!

Engine room well ventilated, with louvres in the wall next the most of the winter weather:eek:

Heaters burning out:confused: Sabroe MK4 163 Female drive, with an oil tank below the oil separator, basically a 6" tube below the main 24" separator, with three or four 3" vertical pipes along the 7' length joining the oil tank to the separator. One heater only:D Sabroe are not for saying that thee is a design fault.

Anyway the apart from the 128 and the 163 male for rotatune (inverter speed drive) these packages are dead, having been replaced by the York corporation by Fricks

We in fact have just insulation on one tank, with a faulty heater that is to be changed next week when the oil and filter are changed. This plant has no oil temp problems since the insulation was fitted;)

You can take a look athttp://www.sabroe.com/Products/Screw%20compressors/SAB%20163/index.html

Kind Regards Andy:)

latent heat
18-03-2006, 10:08 PM
I cant really say what is the best refrigerant because centrifugal chillers are a high volume low pressure differential systems unlike rotary screw like I run which are lower volume high pressure differential system. I do know that for the years I ran centrifugal chillers R-123 was a very popular refrigerant but it is a dangerous refrigerant classified here in the U.S.A as a B-2 refrigerant