Assuming you're taking about a window AC or the outdoor unit of a split AC unit, it is unlikely you can do this because the weight of the unit would be over 32kgs. Which is the max per piece allowance.
Then there are issues of safety (gas), and dimensions (max 119x119x81) and overall weight which would means in the unlikely event you're allowed to you'd have high baggage fees.
I'd talk to the airport office at I5 first before booking.