cairo design conditions

[ARenko]

I'm looking for standard design dry and wet bulb temperatures for Cairo, Egypt. I can't find anything on the net and I don't have access to any ASHRAE info. I'm getting wildly different numbers from suppliers quoting cooling coils. Can anyone offer any help?

TIA,
djv

 

[HVAC68]

Probably, I am deviating from the main query, but, nevertheless, thought it's important.

Since it's a once-through system, the capacities won't go by thumb rule of 400 cfm to a ton. You may have to do a proper load calculation to find this out. You also have to take into consideration any heat generation from your process. What kind of temperature and humidity conditions do you want to maintain ? You have indicated some air quantities in cfm. How was this arrived ?

Depending upon how critical your process is, you may choose 100/69 or 97/69 or 95/69. Are you planning a chilled water system or a DX system ? There are a few precautions to be taken if it's a DX system, especially for a once-through system.

HVAC68

 

[ARenko]

quark,
On the control valve, I got it now - I didn't understand that you were considering that 102/76 was the required condition.

quark/ HVAC68,
On the heat removal, we normally consider 1 ton per 50 lb/hr as a rule of thumb. At our production rate this is 32 tons. Calculating I get a similar number (BTW, you have to also consider the phase change - liquid to solid). Problem is the aerodynamics of blown film bubble cooling is very complicated and cooling efficiency is very sensitive to equipment design, air flow rate, and air flow pattern as it's adjusted by operators.

The internal air cfm comes from an analysis on the die that shows it can handle a max of 2000 CFM. The 3500 CFM outside air comes from the machine OEM.

The problem is some of the quotes are from plastics industry OEM's and their chiller loads range from a bit higher than mine to much higher than mine. I'm still trying to get some answers, but in the meantime started this thread to narrow down an appropriate temp condition since they are all over the place on my quotes. When I get some answers to my questions on the quotes I will go back to the machine OEM (they are not quoting this cooling modification) and get their opinion on the best system, considering their equipment design.

You've all been a great help. Thanks a lot.