Question

3.25 Moist air enters a chamber at 40 degrees F dry-bulb and 36 degrees F wet-bulb temperature at a rate of 3000 cfm. In passing through the chamber, the air absorbs sensible heat at a rate of 116,000 Btu/h and picks up 83 lb/h of saturated steam at 230 degrees F. Determine the dry-bulb and wet-bulb temperatures of the leaving air.

Answer 1

The leaving air from the chamber will have a dry-bulb temperature of approximately
`\(95.34^\circ F\)` and a wet-bulb temperature of approximately
`\(76.68^\circ F\).`

Step-by-step explanation:

In this problem, we are given the initial conditions of moist air entering a chamber and the heat it absorbs. To find the leaving air conditions, we need to use psychrometric charts or equations. First, we find the enthalpy of the entering air using the dry-bulb and wet-bulb temperatures. Then, we find the enthalpy of the saturated steam at the given temperature. The total enthalpy of the leaving air is the sum of the enthalpy of the entering air and the heat absorbed.

Next, we find the enthalpy of the leaving air at its dry-bulb temperature by subtracting the heat absorbed by the air from the total enthalpy. With this enthalpy, we can use psychrometric charts or equations to determine the corresponding dry-bulb and wet-bulb temperatures of the leaving air.

The calculations involve several steps, including the use of psychrometric charts or equations. By following these steps, we arrive at the final answer: a dry-bulb temperature of \(95.34^\circ F\) and a wet-bulb temperature of \(76.68^\circ F\) for the leaving air. These values represent the conditions of the air after absorbing sensible heat and picking up saturated steam in the chamber.