Nice topic. The important point is, the shed must be well ventilated during the hot periods of the day. u may use sprinklers on the top of the shed to cool down the temperature. foggers can be used in the shed. if possible, tall trees which spreads well shadow can be planted around the shed which maintains the cooling. provide plenty of water to the dairy cows and avoid crowding if possible.

check this links maybe help you

https://www.arch-anim-breed.net/55/325/2012/

https://www.appliedanimalbehaviour.com/article/0168-1591(84)90097-2/fulltext

Thank you Jaime! Actually, one of those papers is mine and of colleagues. Do you maybe have some experiences from your country?