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Handbook of air conditioning and refrigeration / Shan K

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Dry Part<br />

<strong>air</strong>stream <strong>and</strong> water stream<br />

AIR SYSTEMS: COMPONENTS—FANS, COILS, FILTERS, AND HUMIDIFIERS 15.49<br />

FIGURE 15.31 Dry-wet boundary <strong>of</strong> a dry-wet coil.<br />

V˙ a� ac pa(T ae � T ab) � 8.33V˙ galc pw(T wl � T wb)<br />

where V˙ a � volume flow rate <strong>of</strong> conditioned <strong>air</strong>, cfm<br />

V˙<br />

gal � volume flow rate <strong>of</strong> chilled water, gpm<br />

(15.44)<br />

Because the temperature <strong>of</strong> chilled water leaving the coil T wl is a known value, from Eqs. (15.43)<br />

<strong>and</strong> (15.44), T ab <strong>and</strong> T wb can be determined.<br />

The sensible cooling capacity Q cs, in Btu/h (W), <strong>of</strong> the dry part <strong>of</strong> the dry-wet coil can be calculated<br />

from the left-h<strong>and</strong> side <strong>of</strong> Eq. (15.44) as<br />

Q cs � 60V˙ a� ac pa(T ae � T ab)<br />

(15.45)<br />

The average temperature <strong>of</strong> the <strong>air</strong>stream in the dry part Tad, m, in °F (°C), is approximately equal to<br />

1�2 (Tae � Tab), <strong>and</strong> the average temperature <strong>of</strong> the chilled water corresponding to the dry part <strong>of</strong> the

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