According to some post in the past the fresh air system provides:
Temperature = outdoor temperature - 2 degree
Humidity around 60% ~ 70%
And there should be a figure for air flow (volume in sec) as well. But I can't remember. I think it can help when the outside humidity is high but won't too much on the temperature. So Fortree said that Fresh Air system may help to cold down room temperature is ridiculous.
The fresh air system pump in air 2 degree lower than outside temperature. Say it's 32 degree outside fresh air will pump in air around 30 degree. I think larger the air flow higher loading for your air conditionner. So it's better to strike the balance. Don't be mistaking that refresh air is to help your air conditioner's cooling. It just provides fresh air!!