The statements concern psychrometric chart.1. Constant relative humidi...
Constant relative humidity lines are uphill straight lines to the right:
- This statement is incorrect. Constant relative humidity lines on a psychrometric chart are not uphill straight lines to the right. Instead, they are curved lines that slope upwards as the temperature increases. This is because relative humidity is the ratio of the actual water vapor content to the maximum water vapor content at a given temperature.
Constant wet bulb temperature lines are downhill straight lines to the right:
- This statement is correct. Constant wet bulb temperature lines on a psychrometric chart are indeed downhill straight lines to the right. Wet bulb temperature represents the lowest temperature that can be reached by evaporative cooling, and it decreases as the amount of moisture in the air increases. Therefore, as the wet bulb temperature decreases, the lines on the chart slope downward.
Constant specific volume lines are downhill straight lines to the right:
- This statement is correct. Constant specific volume lines on a psychrometric chart are downhill straight lines to the right. Specific volume is the volume occupied by a unit mass of dry air and is inversely proportional to the density of the air. As the specific volume decreases, the density increases, and thus the lines on the chart slope downward.
Constant enthalpy lines are coincident with constant wet bulb temperature lines:
- This statement is incorrect. Constant enthalpy lines on a psychrometric chart are not coincident with constant wet bulb temperature lines. Enthalpy represents the total energy of the air and is a combination of sensible heat and latent heat. While wet bulb temperature is related to the latent heat component, enthalpy takes into account both sensible and latent heat. Therefore, the lines representing constant enthalpy will have a different slope and direction compared to the lines representing constant wet bulb temperature.
In conclusion, the correct statements are:
- Constant wet bulb temperature lines are downhill straight lines to the right.
- Constant specific volume lines are downhill straight lines to the right.