How to Read a Psychrometric Chart-stepwise animated explanation

The Practical Study9 minutes read

The psychometric chart is a graphical tool used in air conditioning to represent air properties like dry bulb temperature, relative humidity, and enthalpy. Parameters such as humidity ratio and dew point temperature can be calculated by drawing lines parallel to the parameter scales from the intersection of given parameters on the chart.

Insights

  • Dry bulb temperature, wet bulb temperature, humidity ratio, relative humidity, and enthalpy are essential parameters plotted on the psychometric chart for air conditioning analysis.
  • Dew point temperature, specific volume, and enthalpy are crucial values derived from the chart through intersections and parallel lines, aiding in precise calculations for air properties.

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Recent questions

  • What is a psychometric chart?

    A psychometric chart is a graphical representation of air properties used in air conditioning, displaying parameters like dry bulb temperature, relative humidity, and enthalpy.

  • How is dry bulb temperature measured?

    Dry bulb temperature, the normal air temperature, is measured with a thermometer to determine the current temperature of the air.

  • What is wet bulb temperature?

    Wet bulb temperature is measured by wrapping a wet cloth around a thermometer to determine the lowest temperature that can be reached through evaporation.

  • How is humidity ratio defined?

    Humidity ratio is the amount of water in air per gram, measured on the vertical axis of a psychometric chart to understand the moisture content in the air.

  • What is relative humidity?

    Relative humidity is the percentage of water vapor in the air, shown on a psychometric chart with specific lines and a scale to indicate the moisture level in the air compared to its maximum capacity.

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Summary

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Understanding the Psychometric Chart in HVAC

  • Psychometric chart is a graphical representation of air properties used in air conditioning.
  • Parameters like dry bulb temperature, relative humidity, and enthalpy are plotted on the chart.
  • Dry bulb temperature is the normal air temperature measured with a thermometer.
  • Wet bulb temperature is measured by wrapping a wet cloth around a thermometer.
  • Humidity ratio is the amount of water in air per gram, measured on the chart's vertical axis.
  • Relative humidity is the percentage of water vapor in the air, shown on the chart with specific lines and a scale.
  • Dew point temperature is the temperature of saturated air, found using the intersection of dry bulb temperature and humidity ratio.
  • Specific volume and enthalpy are the volume and heat per gram of air, drawn on the chart with specific lines and scales.
  • To calculate parameters on the chart, draw lines parallel to the parameter scales from the intersection of given parameters.
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