Al B. Fuct
once had a dog named
I hope that's enough.
As mentioned, black duct (or alu type painted black inside) might help prevent back conduction. Bends between the two lamps will help trap light... but they will impede airflow. If there's several 90s, it may call for a centrif blower. The cost of a 150mm centrif would easily exceed the cost of two 150mm axials. If there's enough obstruction to cause problems, the surfaces of the cooltubes will get hot and allow heat to transfer into the room's airmass. If that's the case, it will be most practical and cost effective to split the systems and use two 150mm blowers.
As mentioned, black duct (or alu type painted black inside) might help prevent back conduction. Bends between the two lamps will help trap light... but they will impede airflow. If there's several 90s, it may call for a centrif blower. The cost of a 150mm centrif would easily exceed the cost of two 150mm axials. If there's enough obstruction to cause problems, the surfaces of the cooltubes will get hot and allow heat to transfer into the room's airmass. If that's the case, it will be most practical and cost effective to split the systems and use two 150mm blowers.