The air exchange rate is 10 changes/hr. I had assumed that was on the high side.
It seems I may be a bit lost. I've oriented myself to the psychrometric chart, but most of the formulae [Q = 4.5 x CFM x (delta h), or Btu/hr = CFM x Density Factor x (T1-T2) + CFM x 0.69143 x (G1 - G2)] require...