Is your building brick, timber, or stucco?
Can the a/c condensate be plumbed into the Lot’s internal kitchen or bathroom plumbing?
If not, the external drainage pipes could be painted a similar colour to the wall colour and thereby be ‘camouflaged’.
The main issue is whether the comfort of the occupants is more important than the slight change that the piping will make to the aesthetics of your building.
The sick, the elderly and the young are often those who benefit most from the a/c. Is your Committee being unreasonable in denying the occupants of your building a level of comfort that benefits their health and well being?
An occupant probably spends less than 2 minutes a day looking back at their building from the street and pondering the piping …. but the same occupant can spend 24 hours within their apartment either wishing they had a/c or being grateful that they have a/c.
Does 2 mins trump 24 hrs?