ASHRAE PSYCHROMETRIC CHART NO NORMAL TEMPERATURE. BAROMETRIC PRESSURE: INCHES OF MERCURY. Copyright 0. 5. DRY BULB TEMPERATURE – °C. 5. Psychrometric Charts . .. . ASHRAE Fundamentals Handbook (SI) Mass of water added per unit mass of dry air is (W.* – W), which.

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Android app no longer available. Many substances are hygroscopicmeaning they attract water, usually in proportion to the relative humidity or above a critical relative humidity. Specific humidity is defined as the proportion of the mass of psychromwtric vapor and mass of the moist air sample including both dry air and the water vapor ; it is closely related to unlts ratio and always lower in value.

The dew point temperature is equal to the fully saturated dry bulb or wet bulb temperatures. At first glance there is little resemblance between the charts, but if the chart is rotated by ninety degrees and looked at in a mirror the resemblance becomes apparent. Each line represents a constant temperature. A sling psychrometer requires manual operation to create the airflow over the bulbs, but a powered psychrometer includes a fan for this function.

The psychrometric ratio is an important property in the area of psychrometry, as it relates the absolute humidity and saturation humidity to the difference between the dry bulb temperature and the adiabatic saturation temperature. Architectural acoustics Architectural engineering Architectural technologist Building services engineering Building information modeling BIM Deep energy retrofit Duct leakage testing Environmental engineering Hydronic balancing Kitchen exhaust cleaning Mechanical engineering Mechanical, electrical, and plumbing Mold growth, assessment, and remediation Refrigerant reclamation Testing, adjusting, balancing.

Display a fully customizable psychrometric chart in both landscape and portrait modes. Pressure Liquid water Avogadro’s law Nucleation Thermodynamic equilibrium. Psychrometrics Humidity and hygrometry Heating, ventilating, and air conditioning.

The underlying psychrometric parameter sk for the psychrometric chart and the Mollier diagram are identical.


Email a list of chary the points and their properties for a completed chart, along with a PDF of the chart itself. Default when Elevation is selected User may override default input by selecting and entering new sj. Also, you can create templates that you can reuse over and over again. 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.

Heating, ventilation and air conditioning. Home Technical Resources Bookstore. Views Read Edit View history. In industrial drying applications, ashraae 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 increases. It will also provide a number of other thermodynamic properties not found on a typical psychrometric chart.

Retrieved from ” https: Mixtures of air and water vapor are the most common systems encountered in psychrometry. These intersect the saturation curve at DBT point. The name implies that the sensing bulb or element asrae in fact dry.

The psychrometric ratio of air-water vapor mixtures is psychrometriv unity, which implies that the difference between the adiabatic saturation temperature and wet bulb temperature of air-water vapor mixtures is small. Such substances include cotton, paper, cellulose, other wood products, sugar, calcium oxide burned lime and many chemicals and fertilizers.

The psychrometric chart allows all the parameters of some moist air to be determined from any three independent parameters, one of which must be the pressure. The horizontal component of the condition line is the change in sensible heat while the vertical component is the change in latent heat. Although the principles of psychrometry apply to any physical system consisting of gas-vapor mixtures, the most common system of interest is the mixture of water vapor and air, because of its application in heating, ventilating, and air-conditioning and meteorology.


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.

The range is from 0 for dry air up to 0. Many psychrometric properties are dependent on pressure concept:. Create psychrometric processes by plotting points then connecting them with process lines.

However, no warranty, either expressed or implied, is given with respect to the accuracy or the sufficiency of the information provided herein, and the user must assume all risks and responsibility in connection with the use thereof.

Why does this program show two different values of specific volume?


Common atmospheric pressure values are: The mass of water vapor per unit volume of air containing the water vapor. These are not parallel to wet bulb temperature lines. Chapter 2, Measurement of Temperature. You show a ‘Virtual’ Temperature under Thermodynamic properties. These are the horizontal lines on the chart. The value indicated by a wet-bulb thermometer often provides an adequate approximation of the thermodynamic wet-bulb temperature.

Psychrometrics – Wikipedia

Common atmospheric pressure values are:. No part of this web page and associated script may be produced, transmitted, transcribed, stored in a retrieval system, or translated into any language in any form without the express written consent of the author. 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.

These lines are drawn straight, not always parallel to each other, and slightly inclined from the vertical position. Industries that chartt these materials are concerned with relative humidity control in production and storage of such psyxhrometric.