I'm currently working in a project that is a hotel facility.

The HVAC system type are 100% DOAs across the project and FCUs. However I'm having a problem regarding the minimum ventilation rate of 0,3 cfm/sf since the hotels rooms have very low outside airflow rate.

I'm struggling to:

1) Renovate 14.000 cfm/sf, because at the design conditions hotel rooms need to be running 72 days before occupancy (path 1);

2) Achieve the minimum ventilation rate of 0,3cfm/sf (path 2) due to the rooms' very low cfm/sf of outside air (path 2);

Is there an option to include natural ventilation in the calculations (opening windows) to achieve the credit through path 1? This could be a viable option to do in Portugal, due to its mild and dry climate during the day. This way, the 60/60 requirement would't be a problem and path 1 would be achievable.

Please advise on this mater and thank you all in advance!