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Find (i) DBT of the air leaving dehumidifier. (ii) Capacity of the dehumidifier,

### A class room of 60 seating capacity has to be air conditioned. Outdoor conditions are 32°C DBT and 22°C WKT. Required comfort conditions are 22°C DBT and 55% RH. The quantity of outdoor air supplied is 0.5m3/min/student/ The comfort conditions are achieved first by chemically dehumidifying the air and then cooling by coil. Find (i) DBT of the air leaving dehumidifier. (ii) Capacity of the dehumidifier, (iii) Capacity of cooling coil in tons of refrigeration, iv) Required surface temperature of the cooling coil if the bypass factor of the cooling coil is 0.3

$t_d3=22℃,∅3=55%, t_d1=32℃, t_w1=22℃,$ $V ̇_1=0.560=30 \frac{m3}{min},BPF=0.3$ ![enter image description here][1] Capacity of cooling coil in TR =$m ̇_1(h_2- h_3)=34.1(56-45.5)=358.05 \frac{kJ}{min}=\frac{358.05}{(603.5)}$=1.705 TR Let required surface temperature of cooling coil be $t_d4$ BPF=0.3=$\frac{(t_d3-t_d4)}{(t_d2-t_d4 )}=\frac{(22-t_d4)}{(32-t_d4 )}$ ∴$t_d4$=17.71℃