A convenient, precise and customizable psychrometric chart & calculator tool for 25 26 27 28 29 30 m^3/kg(d.a) 10% 20% 30% 40% 50% 60% 70%. Psychrometrics, psychrometry, and hygrometry are names for the field of engineering . The ASHRAE-style psychrometric chart, shown here, was pioneered by. Use chart to analyze processes involving moist Psychrometric chart: Example 1 . Given: T = 25°C . m wide x m long, and the boards are separated by.

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Knowing both the dry-bulb temperature DBT and iyve temperature WBTone can determine the relative humidity RH from the psychrometric chart appropriate to the air pressure.

The dew point temperature is equal to the fully saturated dry bulb or wet bulb temperatures. However, you can also use relative humidity, enthalpy, and specific volume to make estimated conclusions.

From Wikipedia, the free encyclopedia. The various lines shown in the chart are as follows please refer the figs below: This type of cooler is extremely psychrkmetric in hot, dry climates, and is popularly known as a Swamp Cooler.

The scale of the DP and WB temperature is the same, however, while the constant WB temperature lines are diagonal lines extending downwards, the constant DP temperature lines are horizontal lines. These are oblique lines drawn diagonally downward from left to right across the chart that are parallel to each other. This property of air-water vapor systems simplifies drying and cooling calculations often performed using psychrometic relationships. A sling psychrometer requires manual operation to create the airflow over the bulbs, but a powered psychrometer includes a fan for this function.


Look on the right side of the chart to find the vertical dew point line. The major simplifying assumption in the construction of the chart is that the enthalpy of the mixture is assumed to be constant throughout the adiabatic saturation process described in Section a.

The thermodynamic wet-bulb temperature is a thermodynamic property of a mixture of air and water vapor. This is the t —axis, the abscissa horizontal axis. The constant WB temperature lines are the diagonal lines extending from WB temperature curved scale downwards towards the right hand side of the chart.

Psychrometric Chart Use

The dry-bulb temperature is the temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation. Indicate all the values determined on the chart. Technically, the temperature registered psychromehric the dry-bulb thermometer of a psychrometer.

This article was co-authored by our trained team of editors and researchers who validated it for accuracy and comprehensiveness. The value indicated by a wet-bulb thermometer often provides an adequate approximation of the thermodynamic wet-bulb temperature. Locate the uppermost curved line on the chart to find the saturation curve. Cookies make wikiHow better. The term dry-bulb is customarily added to temperature to distinguish it from wet-bulb and dewpoint temperature. A psychrometer is a device that includes both a dry-bulb and a wet-bulb thermometer.


Molds and fungi can be controlled by keeping relative humidity psychromstric. The “Mollier i – x ” Enthalpy – Humidity Mixing Ratio diagram, developed by Richard Mollier in[12] is an alternative psychrometric chart, preferred by many users in Scandinavia, Eastern Europe, and Russia.

As the relative humidity increases at a certain temperature, the specific volume of the air also increases. Pressure Liquid water Avogadro’s law Nucleation Thermodynamic equilibrium. It may be evaluated with the following equation: Industries that use these materials are concerned with relative humidity control in production and storage of such materials. From psychtometric two independent ones of the six parameters dry bulb temperature, wet bulb temperature, relative humidity, humidity ratio, specific enthalpy, and specific volume, all the others can be determined.

For other pressures relevant corrections have to be applied. The Mollier diagram coordinates are enthalpy and humidity ratio.

These intersect the saturation curve at DBT point. The horizontal lines starting from this vertical scale are constant moisture lines.

Try to be as exact as possible when using the chart to read other measurements, and mark your answers in the proper units for that measurement.