What are the temperatures occured in fahu as per dubai condition?

Actually your question is very general. The temperature conditions of Dubai you can take from HAP or ASHRAE for specific zone data but for dubai it will be minimum42Deg C and it depends what is the return\\exhaust air temperature for heat recovery wheel. If it is for example26 Degree then now it is time to select the unit with recovery wheel which make normal difference of8 to13 deg C. So with these conditions I think the inlet of O/A is42 and exhaust air is26 and after recovery wheel it will be around32 -34 degC for both airs.

But as i mention it depends on so many factors.

Hope this will work for reference.

Regards

ASHRAE has vital weather data for estimating cooling/heating loads for almost all region across the globe. But I recommend to use the local weather data (if possible from the meteorological dept.). I reside in riyadh, KSA. ASHRAE says46 deg C, but as per the weather history, the worst conditon has occured51.5 deg C. I use50 deg C as outdoor weather for design of HVAC.

According to HAP4.6 data the outdoor temperature:

- Summer design DB41.7 dc

- Summer design WB23.9 dc

* Assumption:

- zone temperature =23 dc or as mentioned in spcs

- inlet of energy wheel = temperature of EXH or return ( around30 dc)

* for accurate temperature calculate the load for the FAHU as normal AHU supply & return, then find out the return temperature after living the zone which indicated on the psychometric chart, then use it as the inlet temperature for the energy wheel