The air relative humidity is 20% and its absolute humidity is 0.0045 lb_w / lb_d.a.Using the British units’ map, determine the temperature of the dry bulb (TD.B.) andenthalpy (h)

To determine the temperature of the dry bulb (TD.B.) and enthalpy (h), we can follow the steps below:

Step 1: Convert the absolute humidity from lb_w / lb_d.a. to grains of moisture per pound of dry air (GPP).

To convert lb_w / lb_d.a. to GPP, we can use the conversion factor of 7000 grains per pound.

Absolute humidity in GPP = Absolute humidity in lb_w / lb_d.a. * 7000

Step 2: Use the psychrometric chart to find the intersection point of the given relative humidity (20%) and the converted absolute humidity (in GPP) from Step 1.

Locate the point on the chart where the relative humidity line intersects with the absolute humidity line.

Step 3: Read the dry bulb temperature (TD.B.) and enthalpy (h) values from the chart at the intersection point found in Step 2.

The dry bulb temperature (TD.B.) is the temperature indicated by the horizontal line passing through the intersection point.

The enthalpy (h) is the value indicated by the diagonal line passing through the intersection point.

By following these steps, you should be able to determine the temperature of the dry bulb (TD.B.) and enthalpy (h) using the given air relative humidity and absolute humidity.