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Lc_shi
17-03-2005, 06:35 AM
there are 3 kind of condenser in chiller: air cooled\water cooled\evaporative cooled and the evaporative have highest COP ,but i found it's not widely used. what the major concerns?

Peter_1
17-03-2005, 08:05 AM
At least in Belgium for bigegr machines, centrifugals and ammonia, they only use evaporative types.

For small types, they cost too much because you must treaten the water very carefully. Otherwise it'll become a place where bacteria grows very fast.

Lc_shi
17-03-2005, 10:05 AM
you mean cooling tower or evaporative cooler?
BTW,have you got the software of cap size :)

Argus
17-03-2005, 10:57 AM
There is no problem with using Evaporative condensers in the UK and we all know the advantages, except that the main considerations stacked against are:

1 Roof space:. Many new buildings here are lightweight structures and do not have the roof space available, plus the structural strength to take the weight of the thing.

2 Cost.

3 Most importantly, they have been found to contribute to Legionella and in the UK there have been some fatalities over the last 20 years. This means that ALL evaporative condensers MUST be notified to the local authority, by law, (here?s the UK SI)

http://www.hmso.gov.uk/cgi-bin/htm_hl.pl?DB=hmso-new&STEMMER=en&WORDS=health+safeti+cool+tower+&COLOUR=Red&STYLE=s&URL=http://www.hmso.gov.uk/si/si1992/Uksi_19922225_en_1.htm#muscat_highlighter_first_match

Operators MUST carry insurance (extra cost) and they MUST have a viable maintenance schedule.

This last one is the main reason why they are comparatively rare in the UK. There is in fact a prosecution in progress and I don't want to comment further, because it is still going on.
The state of the law in the UK means that company owners directors and employees are personally liable.

http://www.ehj-online.com/archive/2000/april2004/april3.html

I hasten to add that there is nothing intrinsically wrong with this type of condenser - it is just that they demand a higher level of maintenance than other forms of cooling and presented with the options, many users do not want to expose themselves to the risks of certain prosecution if they get it wrong.
________
bho hash oil (http://trichomes.org/hashish/bho-hash-oil)

S.W.Lee
22-03-2005, 02:50 AM
Because of high initial cost, water treatment, and sometimes noise problem...

TXiceman
26-03-2005, 09:20 PM
Generally the issues are:
Water treatment is required,
cleaning is required.
Make up water is required
Blow down line to sewer is required.

Like in the UK, most larger ammonia plants do go in with evaporative condenser to keep operating power down. Typically we see ammonia condensing tempepratuess of 95 or 96 dF.

Being an evaporative cooling device they work much better in the less humid climates. Even with the penaty for high wet bulb areas, they are still used in coastal areas.

One big problem is like a cooling tower, they are great air scrubbers. All of the dirt and trash is picked up in them. Water treatment varies depending on the area of operation. To combat corrosive areas, most manufacturers (such as BAC, Evapco and IMECO) all offer varing degrees of stainless steel construction or special polymer coatings.

Another problem we are seeing is the requirement for plume abatement in some areas. People do not want to see a vapor plume even if it is harmless water vapor. This requires a desuperheating coil be mounted above the condenser coil, in the outlet air stream to heat the leaving.

Another issue is winter operation or preparation. If winter operation is required, you need to consider an indoor sump and or/dry coil operation.

We build a line of evaporative cooler water chilers and I believe the smallest we have built to date is a 50 HP screw water chller. It is not an inexpensive unit.

I like to see the evaporative condensers used, but some areas havve a concern with water usage and blow down .

Ken

Lc_shi
28-03-2005, 03:55 AM
Hi Txiceman,
We manufacture small unit evaporative condensing chiller for household (less 20HP,scroll compressor). The evap condenser is made by copper tubes. The scaling is dependent on application area. How about your chiller? The condender is made by steel tube? drafting fan or blowing fan? which screw compressor?

regards
lichuan

TXiceman
29-03-2005, 07:28 PM
We have been using the Evapco LSCB with a centrifigual fan for the most part. Mostly using Copeland/Bitzer screws.

We have a pair of 560 HP units on the floor now. Has two large LSCB Evapco condensers, four 140 HP Copeland screws, all in an enclosure with dual primary water pumps and secondary water pumps and a 500 gallon surge tank. Secondary pumps are on VFD as are the condenser fans.

Unit is 13' wide x 42' long.

Ken

frank
29-03-2005, 09:30 PM
That would make some nice photo's. Any chance you could post some?

TXiceman
30-03-2005, 04:08 AM
Frank, I'll get some as the units progress. We are just setting equipment now. The condensers are to arrive this week if all goes according to plan.

I like your signature. One thing I like about the UK is good beer. Some of the Microbreweries are pretty good here, but Bud and Miller have folks convinced that beer is watered down and flavorless. I live in Oklahoma and they have some really strange laws regarding the bubbly. Like in a bar (pub) all they can serve you is 3.2% beer. If you want stronger, you have to buy it at a liquor/beer store....warm.... and take it home.

Ken

abbasi
11-04-2005, 07:51 AM
:rolleyes: Yup

In our part of the world Pakistan. These werenot used significantly due to very high initial cost but trend is now changing as there is no water shortage in our part unlike Gulf countries and other places that are deficient in water.
we are the largest manufacturers of HVAC in pakistan but if we anylyse evaporative condenser they are used only 10% compared to only 2% some 10 years back

but grey area is the price and water treatment but once u can make feasibility and calculate the breakeven, which ultimately tells us about profit corridor and loss coridor of investment it can be worthwhile.

Regards

Ali :)

bersaga
28-07-2005, 08:26 AM
I've seen a mini Evaporative Condensor in Thailand that look like an Air Cooled Condensing Unit at a glance - but at closer look - you could see that the fan (that should be blowing upwards ) is actually taking the ambient air inside and forcing it through a fin-coil arrangement. On the fan motor shaft, is attached a centrifugal impeller that gets sprayed with a single water jet. The centrifugal force nicely spashes the the heat excahnge surface and the excess water is drained out ( timer-set) .So, no water treatment is required. The compressor and other accessories are placed beneath - within a fibregalss enclosure. Claim to save 25% more energy than a normal air-cooled condensor !

afeef
09-09-2005, 12:19 PM
hi everybody:
in the central a/c ,using the water as seconary refrigerant,what is the nominal flow rate of water per ton refrigeration?
thanks
afeef

dogma
09-11-2005, 02:00 PM
Waste and bacteria due to poorly maintained swampies are a major concern in Australia. Mineral deposits which effect valve operation can lead to massive losses in poorly maintained units.

Check out the AIRAH site and take the links to ecolibrium.

star882
09-11-2005, 10:13 PM
Couldn't it be possible to use a high voltage transformer to power an ozone generator to help keep the water clean?
I know about a design that used a neon sign transformer (run at lowered voltage using a 25v transformer used as an autotransformer) to energize some corona wires in a chamber. Air is pumped through the chamber and the ozone that comes out is bubbled though a swimming pool.

I'm actually interested in making my central A/C water cooled (hopefully without replacing the condenser). Would the reduced operating costs be worth the cost of parts? I've heard something about just aiming a hose at the condenser, but wouldn't that eventually damage the unit?

fazalrb
21-11-2005, 05:11 PM
What is the best availble product for refrigerant circuit cleaning and flushing, not R-11.

yhruhteb
02-05-2006, 08:25 AM
HELLO...................................................