Evap pre-coolers

[Blackbird]

A few years back a TAFE lecturer mentioned to me that a better way of making sure that your struggling systems perform in the hot weather (as opposed to spraying them with water) was to fit a cowl to the front of your condenser and fit a celdeck evaporative pad of the appropriate size together with a water tray underneith with a ball valve to the mains water and a pump switched via HP (You could even fit a dump valve if your fussy).

Sounds great - a bit expensive but could save $$$ in peak summer when all the systems usually start falling over in the heat, and with the added advantage of much less corrosion than water sprays together with set and forget operation. The celdeck pads also have very minimal air resistance and could also act as a bit of a filter for the condenser making maintanence eaiser.

The idea seems simple enough but i've yet to try it because of the time involved in sourcing the different parts, and making up a water tray and drippers for on top completely blows out the cost--plus I don't have the time!! The lecturer did mention that some companies make kits up...I've asked around at a few places with no avail...Anybody heard of any or want to start making 'em!? :D

Cheers

Perth WA

[taz24]

..I've asked around at a few places with no avail...Anybody heard of any or want to start making 'em!? :D

Cheers

Perth WA

In principle this sounds like a good solution.

But I would be weary of!!

Legonella. Water in that environment is a prime contender for the "kill the older and infirm awards".

How will the water get to the filter / pad?
will it wick up through evaporation.

You need the evaportive effect to take place over as much of the cond as possible.

taz.

[wambat]

This technology has been around for some time, here is more info: This paper describes how direct evaporative coolers can be used to improve the energy efficiency of air-cooled chillers in various operating conditions and with different strategies for staging condenser fans.

These coolers are installed in front of air-cooled
condensers to precool outdoor air before entering the condensers. A simulation analysis on an air-cooled chiller equipped with a direct evaporative cooler showed that when head pressure control is used, the cooler enables the condensing temperature to drop by 2.1–6.2°C, resulting in a 1.4-14.4% decrease in chiller power and a 1.3–4.6% increase in the refrigeration effect.

When the chiller with the cooler operates under condensing temperature control, where condenser effectiveness is enhanced by staging all condenser fans, there is a savings in chiller power of 1.3-4.3% in some operating conditions in which the drop in compressor power exceeds the additional condenser fan power due to the pressure drop across the cooler.

I found when I uesd them, that over time, they had a tendensy to scale and damage the aluminum fins and they require increased maintenance, that said, I found they work great

[PaulZ]

Hi Blackbird
We have used these precooler pads on air cooled conds, they were Munters Pads. You can contact Munters on 03 9562 3677, I think they will make up whatever you want.
To reduce the Legionella problem make sure you have the auto dump valve fitted.
Paul

[momo]

The pads and tray can accumulate dirt, bacteria, etc. - everything floating in the air and concentrate and breed them.

However, the regular changing (every day) and use of appropriate chemicals in the water will avoid the worst scenario.

With respect to Legionella - it is mainly distributed by water spray drops that infiltrate the lungs etc carrying the bacteria: showers and badly regulated drip/rain type condenser/coolers with updraft fans are the worst culprits.

In some areas of the world (where water is desalinated) the total environmental energy efficiency is reduced due to the need to produce the fresh water:confused:

[smpsmp45]

Condensers & coolers of Uk has a patented design for this. They use special fine wire mesh screen & the special nozzles. They had shown a demo here in India & works very well. The timer for the System is the crux of the design. I think you can more details on their web.

[Bones74]

We service a place that does exactly that. We also gave that idea up and put a large over sized air cooled condenser in line with the old condenser.:cool:

[Darshi]

you can have a look at www.torgreentech.com
They seem to have a product called ID pre cooler. There is an intersting FAQ and PPT explaing the product

[lawrence1]

Blackbird,
These are fine in au where there are no water restrictions.,,,where might that be now????I have seen a mechanic doing a repair with an oxy set on a condenser and set the pads alight,,,,,not a pretty site,,,, lost all refrigeration.
It is better to size the condenser correctly in the first place and there is no need for these,,,,water sucking swamp box revived.

[gregd1401]

We recently sent one of our air cooled chillers to Alice Springs on a portable ice skating rink. We fitted fog cooling to this machine to overcome high ambient temperatures. Works very well and no legionella problems.

[joncro55]

Condensers & coolers of Uk has a patented design for this. They use special fine wire mesh screen & the special nozzles. They had shown a demo here in India & works very well. The timer for the System is the crux of the design. I think you can more details on their web.


Any idea how fine the wire mesh is?

Belleville Wire Cloth's website has a way to measure wire cloth,

Based on these concepts, is it like a 100 x 100 mesh or more of like a 250 x 250 mesh? Also any idea what the material is that it is made of? Thanks for any info.