Air Conditioning - Cooling of Air and Condensate Generated

Water may condensate when air is cooled in air conditioning systems.

In air cooling processes condensate water may be generated from the moist air.

Cooling moist air - generating condensate water

If we know the condition and the specific humidity of the air before and after an air conditioning unit - the condensate generated can be calculated

q_cond = q_air dw_lb/ (8.33 v_da) (1)

where

q_cond = condensate generated (gallons per minute, gpm)

q_air = air flow (cubic feet per minute)

dw_lb = difference in specific humidity (lb_water/ lb_{dry air})

v_da = specific volume of air (cubic feet/lb_{dry air})

With specific humidity expressed in grains water per lb dry air (1) can be expressed as

q_cond = q_air dw_gr/ (7000 8.33 v_da)

= q_air (w_gr-out - w_gr-in) / (7000 8.33 v_da) (2)

where

q_cond = condensate generated (gallons per minute)

q_air = air flow (cubic feet per minute)

dw_gr = difference in specific humidity (gr_water/lb_{dry air})

w_gr-out = specific humidity in air out (gr_water/lb_{dry air})

w_gr-in = specific humidity in air in (gr_water/lb_{dry air})

v_da = specific volume of air (cubic feet/lb_{dry air})

7000 = grains per lb_m of water (1 grain = 0.000143 lb_m = 0.0648 g)

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