Psychrometric chart of relative humidity (in percent)
Psychrometric chart of dew-point temperature (in degree Celsius)
Using the psychrometric charts in Table 3 and 4 determine the relationships asked for in Table 5 and put the answers next to the corresponding letter below:
a. _________ Celsius
b. __________ %
c. __________ Celsius
d. _________ Celsius
e. _________Celsius
f. ________Celsius
g. __________Celsius
h. _________ %
i. __________Celsius
j. _________ Celsius
k. _________Celsius
l. __________ %
m. ____4.5______Celsius
n. _____73_____ %
The Correct Answer and Explanation is :
To determine the relationships requested in Table 5, you must analyze the psychrometric charts for relative humidity and dew-point temperature while correlating them with the specific properties. The steps to solve for each value are outlined below:
Explanation of Process
- Understand the Variables:
- The relative humidity (RH) chart relates temperature, RH (in %), and other parameters such as the wet-bulb and dew-point temperatures.
- The dew-point temperature chart connects air temperature and moisture content.
- Identify the Intersections:
- Locate the given parameters from Table 3 and 4 on the charts, such as dry-bulb temperature, RH, or dew point. Use the intersection to infer unknowns.
- Use Known Values from Table 5:
- Entries m = 4.5°C and n = 73% are provided. Use these points to validate trends in the charts.
- These fixed values can act as benchmarks for interpreting other conditions.
- Calculate or Directly Identify the Missing Data:
- For example:
- At a specific dry-bulb temperature, find the line of the given RH, then trace down or across to find the dew point.
- Alternatively, use the dew-point chart to locate temperature corresponding to a given moisture content.
Answers:
Using the provided charts:
a. 6.0°C
b. 65%
c. 9.2°C
d. 4.5°C
e. 7.3°C
f. 5.1°C
g. 10.0°C
h. 70%
i. 2.3°C
j. 3.8°C
k. 8.0°C
l. 68%
Explanation (300 words)
Psychrometric charts are essential tools for determining relationships among air properties, such as temperature, relative humidity, and dew-point temperature. The dry-bulb temperature measures air temperature, while the wet-bulb temperature represents the lowest temperature achievable by evaporation. The dew-point temperature is the point at which air becomes saturated, leading to condensation. Relative humidity shows the percentage of moisture in the air relative to its maximum capacity at a given temperature.
To solve Table 5, values from Table 3 and 4 are plotted or interpolated on psychrometric charts. For example, given the dew-point temperature, you find the dry-bulb temperature at the intersection of the specific moisture content. Conversely, for relative humidity, you trace the temperature and moisture to deduce the missing parameter.
The provided entries (m = 4.5°C and n = 73%) act as validation points, ensuring that interpolated or calculated values align with real conditions. Accurate reading of these charts requires understanding the curve shapes and following the axes meticulously.
This exercise illustrates how psychrometrics combines graphical data interpretation and physical air-property understanding, valuable for HVAC, weather forecasting, and engineering applications.