Question
A water-cooling tover for a power plant cools $45^{\circ} \mathrm{C}$ liquid water by evaporation. The tower receives air at $19.5^{\circ} \mathrm{C}, \Phi=30 \%,$ and $100 \mathrm{kPa}$ that is blown through/over the water such that it leaves the tower at $25^{\circ} \mathrm{C}$ and $\Phi=70 \% .$ The remaining liquid water flows back to the condenser at $30^{\circ} \mathrm{C}$ having given off $1 \mathrm{MW}$. Find the mass flow rate of air, and determine the amount of water that evaporates.
Step 1
Here, $Q$ is the heat given off by the water, $m_a$ is the mass flow rate of air, $h_{in}$ is the enthalpy of the air entering the tower, and $h_{exit}$ is the enthalpy of the air leaving the tower. Show more…
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A water-cooling tower for a power plant cools $45^{\circ} \mathrm{C}$ liquid water by evaporation. The tower receives air at $19.5^{\circ} \mathrm{C}, \phi=30 \%, 100 \mathrm{kPa}$ that is blown through/over the water such that it leaves the tower at $25^{\circ} \mathrm{C}, \phi=70 \%$. The remaining liquid water flows back to the condenser at $30^{\circ} \mathrm{C}$, having given off $1 \mathrm{MW}$. Find the mass flow rate of air and the amount of water that evaporates.
The cooling water from the condenser of a power plant enters a wet cooling tower at $40^{\circ} \mathrm{C}$ at a rate of $90 \mathrm{~kg} / \mathrm{s}$. The water is cooled to $25^{\circ} \mathrm{C}$ in the cooling tower by air that enters the tower at $1 \mathrm{~atm}, 23^{\circ} \mathrm{C},$ and 60 percent relative humidity and leaves saturated at $32^{\circ} \mathrm{C}$. Neglecting the power input to the fan, determine $(a)$ the volume flow rate of air into the cooling tower and $(b)$ the mass flow rate of the required makeup water.
Water at $30^{\circ} \mathrm{C}$ is to be cooled to $22^{\circ} \mathrm{C}$ in a cooling tower which it enters at a rate of $5 \mathrm{~kg} / \mathrm{s}$. Humid air enters this tower at 1 atm and $15^{\circ} \mathrm{C}$ with a relative humidity of 25 percent and leaves at $18^{\circ} \mathrm{C}$ with a relative humidity of 95 percent. Determine the mass flow rate of dry air through this tower.
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