Sorry for not making any sense.
I am helping out a colleague who is evaluating a pack house and has not given me all the information initially. I stumbled across this site today and showed it to him so he suggested I join and post the thread as it reads (forgive me I am a green engineer).
He requires the ACH to determine whether;
1. The fans installed are capable of providing enough ventilation.
2. Or the design of the crates and pallet height impede on flow over the product.
The squash in question are grown and stored in New Zealand
I believe this is more a question of optimizing controlled environment (temperature and humidity optimized for the product and ripening development/hindering) combined with working area permissable conditions for humans.
Sensible air exchange rate and dimensions would then have to be adapted according to indoors requirement and outdoors conditions. Air excjange rate could probably (I'm no HVAC engineer) vary between a relatively wide range, provided first set of conditions satisfied.
ASHRAE lists 'Thermal and related Properties of Food and Food Materials" which list both summer and winter squash. The information in ASHRAE may point you in the right direction regarding ventilation as you requested.
Fruit and vegetable storage facilities often fill the whole warehouse up with nitrogen (ie remove all oxygen) to prolong the shelf life of fruit and vegetables.
This does mean no continuous ventilation and if anyone enters the warehouse they will need breathing apparatus. I assume there would some sort of vent system to purge the place.
