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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Technically, the temperature registered by the dry-bulb thermometer of a psychrometer. Retrieved from ” https: However, in psychrometrics, the term quantifies the total volume of both the dry air and water vapour per unit mass of dry air.

Cjart many industrial igve it is important to avoid condensation that would ruin product or cause corrosion. The value indicated by a wet-bulb thermometer often provides an adequate approximation of the thermodynamic wet-bulb temperature. On the chart, you will notice various lines that follow the curve of the saturation curve.

What is Psychrometric Chart? Introduction to Reading the Psychrometric Properties of Air

Many substances are hygroscopicmeaning they attract water, usually in proportion to the relative humidity or above a critical psychromefric humidity. Tips Before you begin to read the chart, make note of the units of measurement used in each scale. Various Lines and Curves in the Psychrometric Chart All the properties of air indicated in the psychrometric chart are calculated at the standard atmospheric pressure. Look along the bottom of the chart to find the dry bulb temperature. Refer to the link: So the temperature value that allows this process condensation to take place is called the ‘dew point temperature’.


The psychrometric ratio of air-water vapor mixtures is approximately unity, which implies that the difference between the adiabatic saturation temperature and wet bulb temperature of air-water vapor mixtures is small.

It is not to be confused with Psychometry.

The dry-bulb temperature is the temperature indicated by a thermometer exposed to the air in a place sheltered from direct solar radiation. Industries that use these materials are concerned with relative humidity control in production and storage of such materials.

Changes in statesuch as when two air streams mix, can be modeled easily and somewhat graphically using the correct psychrometric chart for the location’s air pressure or elevation relative to sea level. The outer scale gives the ratio of enthalpy difference to humidity difference.

Knowing both the dry-bulb temperature DBT and wet-bulb temperature WBTone can determine the relative humidity RH from the psychrometric chart appropriate to the air pressure. The various lines shown in the chart are as follows please refer the figs below:.


The horizontal lines starting from this vertical scale are constant moisture lines. By continuing to use our site, you agree to our cookie policy. The Mollier diagram coordinates are enthalpy and humidity ratio. The accuracy of a psychro,etric wet-bulb thermometer depends on how fast air passes over the bulb and how well the thermometer is shielded from the radiant temperature of its surroundings.

Pick any 2 known measurements available and plot them on the chart where the lines intersect.

In industrial drying applications, such as drying paper, manufacturers usually try to achieve an optimum between low relative humidity, which increases the drying rate, and energy usage, which decreases as exhaust relative humidity psychroometric.

The psychrometric ratio is the ratio of the heat transfer coefficient to the product of mass transfer coefficient and humid heat at a wetted surface. 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. Thus we introduce an oblique enthalpy axis and enthalpy black lines psycjrometric follows: The term dry-bulb is customarily added to temperature to distinguish it from wet-bulb and dewpoint temperature.

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Psychrometrics Humidity and hygrometry Heating, ventilating, and air conditioning. From any 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.

The region above the saturation curve is a two-phase region that represents a mixture of saturated moist air and liquid water, in thermal equilibrium. Not to be confused with Psychometricsa discipline of psychology and education. The range is from 0 for dry air up to 0.

Chapter 10b: The Psychrometric Chart (Updated 7/22/)

Reading Health Print Edit Send fan mail to authors. Together, they cited information from 12 referenceswhich can be found at the bottom of the page. As the relative humidity increases at a certain temperature, the specific volume of the air also increases.

This is the series of articles that describes psychrometric chart and various psychrometric processes like sensible heating, sensible cooling, humidification, de-dumidification, evaporative cooling etc. Such substances include cotton, paper, cellulose, other wood products, sugar, calcium oxide burned lime and many chemicals and fertilizers. Help answer questions Learn more.