Aroom in a building has the following characteristics: sensible heat gain: 90,000 btu/hr, latent heat gain: 40,000 btu/hr, supply air: 3,600 cfm @ 55 deg. f db

air ventilation: 700 cfm, the room is kept at 78 deg. f db and 45% rh. outdoor air is 92 deg. f db 76 deg. f wb.

what is the wet bulb wb air temperature entering eat and wb temperature of air leaving the cooling coils lat in the room?

[lat = 55 deg. f db, given, need to calculate eat db, lat wb. the eat db of the air entering the cooling coils is the mixed temperature = [(room temp db)(2,900) cfm + (outside air temp db)(700)]/3,600 cfm. find eat wb and h of eat from chart. find h of outside air from chart. then q for outside air = (4.)(cfm) where cfm is outside air ventilation = about 26,800 btu/hr (show this), then total q = (sensible heat gain) + (latent heat gain) + (outside air heat gain) = about 157,000 btu/hr (show this), then total q = (4.)(total cfm), then find (? h) from total q, then find h of leaving air from ? h, then find wb temp of leaving air lat wb from chart. we get eat = 80.7 deg. f db/66.2 deg. f wb, lat = 51.7 deg. f wb.]