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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The mass of water vapor per unit volume of air containing the water vapor. The unitss of a simple 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.

Psychrometrics – Wikipedia

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. As you move your finger around the graph, the psychrometric properties at the top of the screen dynamically update.

Common atmospheric pressure values are: It will also provide a number of other thermodynamic properties not found on a typical psychrometric chart. What is the difference between the six different humidity metrics shown? A chart is valid for a given air pressure or elevation above sea level.

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. To calculate properties, the user must enter either a site elevation from which an average barometric pressure is calculated or an actual barometric pressure.

The thermodynamic wet-bulb temperature is a thermodynamic property of a mixture of air and water vapor. The term dry-bulb is customarily added to temperature to distinguish it from wet-bulb and dewpoint temperature.

The program on the CD allows the user to plot typical psychrometric processes and perform the corresponding energy calculations on-screen, without having to first print out the individual charts. The ratio of the vapor pressure of moisture in the sample to the saturation pressure at the dry bulb temperature of the sample.


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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. In meteorology and psychrometrics the word temperature by itself without a prefix usually means dry-bulb temperature. ai

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. Chapter 2, Measurement of Temperature. In many industrial applications it is important to avoid condensation that would ruin product or cause corrosion. The range is from 0 for dry air up to 0.

The outer scale gives the ratio of enthalpy difference to humidity difference. Usually the level at which water vapor changes into liquid marks the base of the cloud in the atmosphere hence called condensation level.

Please send correspondence to: In other projects Wikimedia Commons. Android app no longer available. Common atmospheric pressure values are:. Many substances are hygroscopicmeaning they attract water, usually in proportion to the relative humidity or above a critical relative humidity.

Also, you can create templates that you can reuse over and over psychrimetric. Create an unlimited number of psychrometric chart projects.

The psychrometric chart allows all the parameters of some psychrkmetric air to be determined from any three independent parameters, one of which must be the pressure. Pwychrometric horizontal component of the condition line is the change in sensible heat while the vertical component is the change in latent heat. Psychrometrics Humidity and hygrometry Heating, ventilating, and air conditioning.

Industries that use these materials are concerned psychrlmetric relative humidity control in production and storage of such materials. The underlying psychrometric parameter data for the psychrometric chart and the Mollier diagram are identical. Humidity ratio is usually expressed as mass of moisture per mass of dry air pounds or kilograms of moisture per pound or kilogram of dry air, respectively. Pdychrometric 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.


Each line represents a constant temperature. Ai addition, you can double-tap a point to display the point properties and then edit them. Retrieved from ” https: A psychrometric chart is a graph of the thermodynamic parameters of moist air at a constant pressure, often equated to an elevation relative to sea level.

Analogous to the specific volume of a pure substance. This program is provided for ashrxe use without charge. Understanding Psychrometrics serves as a lifetime reference manual and basic refresher course for those who use psychrometrics on a recurring basis and provides a four- to six-hour psychrometrics learning module to students; air-conditioning designers; agricultural, food process, and industrial process engineers; meteorologists and others.

This is the t —axis, the abscissa horizontal axis. This on-line program calculates typical psychrometric state point properties. Technically, the temperature registered by the dry-bulb thermometer of a psychrometer.

Archived copy as title Webarchive template wayback links. Views Read Edit Cuart history. These lines are drawn straight, not always parallel to each other, and slightly inclined from the vertical position. 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, psycyrometric remediation Refrigerant reclamation Testing, adjusting, balancing.

These intersect the saturation curve at DBT point. The user then enters a desired Dry Bulb temperature and one of three humiditymetrics:

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