Evaporative Condensor Condensing Temperature (for Dubai)

[samiam]

Hi All,


Can someone tell me what the deisgn condensing temperature for Dubai should be - when utilising evaporative condensers.

I've been given the values of 45Dry Buld and 30Wet Buld. (The units are SI.)

You input is much appreciated.

[US Iceman]

Can someone tell me what the design condensing temperature for Dubai should be - when utilising evaporative condensers.

I think you need to turn this question around somewhat. Let me paraphrase it like this:

If you have a location that has a 30°C entering air wet bulb temperature and want to use evaporative condenser, how much are you prepared to pay for the condensers and the cost of operation for the compressors?

Granted, in Dubai money may not be an object however, if they are concerned about operating costs the condensing temperature chosen for the design can have a direct impact on this.

If you want to be aggressive with energy savings you could use a small approach temperature. This would require very large condensers to be selected, but it would minimize the energy impact.

For example: 30°C + 2.8°K = 32.8°C condensing temperature (or, 86°F + 5° = 91°F condensing temperature).

I think others concerns also have to be quantified. The higher the condensing temperature is, the greater the design working pressure will have to be.

Any increase in condensing temperature can change the water chemistry, which could impact the scale formation rate.

And most importantly in my opinion, how expensive is electricity and how concerned is the owner with the cost of operation versus initial costs?

What's a samiam? Another member from South Africa used a similar screen name.

[GXMPLX]

Maybe this can help:
http://www.climate-charts.com/Locations/u/UE41194.php

[bruceboldy]

We did several refrigeration jobs in Kuwait city. It was really hot there also, with R-22 300 tons approx . We used Imeco evap condensers based on the weather charts at 1 percent of the time.
Everything worked very well on condensing temperatures and pressures. but, they were big condesers I must say.

bruce

[Karl Hofmann]

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[Karl Hofmann]

Oops posy deleted 'cos I cant read the question

[wambat]

I think your best bet would be to consider a BAC-Closed Circuit Hybrid Tower because it runs
Dry - no water usage because it performs just like Radiator
or in pre cool where it performs like radiator with pre coolers or dry/wet where it performs as an evaporative condenser cooling t.ower.

In the dry wet mode both sensible and evaporative heat transfer are used and significant water savings can be acheved at peak designs conditions. In the Adiabatic (precooling)mode the incoming air is precooled 20-30*Fand the fluid to be cooled completely bypasses the the evaporative prime surface coil.

During the dry operation mode the spray water mode is turned off, saving on pump energy and water usage.

Then of course you can always use sea water where conventional water cooled chillers selected in this region are designed around 95 F entering condenser water temperatures.

Sea water temperatures in Dubai rarely if ever go above 95 F.and conventional chiller selections can be used for Sea water cooling applications