Efficiency Of Ahu

Ask the Administrasi Hukum Umum (Indonesian: General Legal Administration) they'll tell you

The same way you calculate any efficiency!

100% ahu out / ahu in

Ok, ahu = air handler unit? Air temp in, air temp out, air flow rate verses temp of the heating/cooling unit located in it.

I know there more to this, I just did not want to get the books out and do the homework.

Also Google AHU Efficiency.

Main function of ahu is non contact heat transfer from air to chilled water (for cooling). You should have a 'standard value of heat transfer rate' at standard operating conditions like chilled water inlet temp, chilled water flow rate, air flow rate inlet temp & relative humidity etc. Now with similar conditions calculate the heat transfer rate and divide it by 'standard value of heat transfer rate' to get ahu efficiency.

In ahu's the main reasons causing efficiency loss are clogging of water tubes and dust deposits on fins surface on air side. If you have reliable digital temperature gages for chilled water inlet & outlet and water flow rate measurement, you can easily calculate heat transfer rate. If other parameter like air flow rate & inlet temp, water flow rate & inlet temp are same as standard calculation then ahu efficiency is approximately equal to the following ratio of chilled water differential temp:

ahu efficiency = delta T(actual)/ delta T(standard)

AHU efficiency =deltaTactual/deltaTstandard of manufacturer

AHU efficiency largely depends on level of cleanliness of coils & filters, coil design giving air bypass factor, slip of belt