Tunnel of plants

Hi everyone,  

I am  experimenting folding trees and connecting them. I'm planning to build a plant tunnel (like a greenhouse or growing tunnel) as part of a permaculture design. The idea is to grow Amazon cucurbits inside The tunnel ( too much sun destroy then), and outside the tunnel i'm gonna grow beans. I want to make sure the tunnel is oriented to maximize sunlight, maintain good ventilation, and work well with the local climate.  

My question is:  

What is the best orientation for a plant tunnel in permaculture, considering the sun’s direction, prevailing winds, and thermal efficiency?

For example, in terms of:  
- Long axis of the tunnel (east-west or north-south)  
- Roof inclination  
- Placement in relation to ventilation and natural shade  

Any practical experience or specific recommendations would be very helpful.  

Thanks in advance!  
`