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What is the dew point on a psychrometric chart?

What is the dew point on a psychrometric chart?

The dew-point temperature is the temperature below which water condenses out of air. You can also read the dew-point temperature directly from a Psychrometric chart. Simply draw a horizontal line from the current point until you hit the 100% relative humidity line, and then read the temperature.

How do you find specific humidity using a psychrometric chart?

Calculate relative humidity from psychrometric chart example Draw a vertical line from dry bulb temperature axis at 300C (line 1). Draw the line of 250C of wet bulb temperature axis (line 2). Those two lines intercept at one point (point 3). Interception point lies between humidity curves of 60% and 70%.

How is psychrometric chart calculated?

Take a ruler and draw a vertical line at the dry bulb temperature of 70 and draw a horizontal line where the dew point is 50. The point where these two lines intersect is known as a ‘state point’. Plot the state point and you can also read the rel- ative humidity, wet bulb, enthalpy, vapor pressure and humidity ratio.

What is humidity ratio in psychrometric chart?

Boundaries of the psychrometric chart are a dry-bulb temperature scale on the horizontal axis, a humidity ratio (moisture content) scale on the vertical axis, and an upper curved boundary which represents saturated air or 100-percent moisture holding capacity.

What is called WBT?

The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked cloth (wet-bulb thermometer) over which air is passed. The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only.

Who uses psychrometric chart?

Psychrometric charts are complex graphs that can be used to assess the physical and thermodynamic properties of gas-vapour mixtures at a constant pressure. They are often used to assess the properties of moist air.

How do you calculate grain depression?

French translation: diminution de la proportion de grains de vapeur d’eau. Gain depression is calculated by taking temperature and R/H of the air going into your dehumidifier and the processed Air coming out with the thermo hygrometer. Calculate the GPP and subtract the out going grains from the in coming grains.

What is the highest recorded humidity?

Generally, the most humid cities are in South and Southeast Asia. The highest humidity ever recorded was a 95°F dew point in Saudi Arabia in 2003.

How humidity is calculated?

Calculating the RH requires the correct equation(s). The RH is the amount of moisture in the air (via moisture mass or vapor pressure) divided by the maximum amount of moisture that could exist in the air at a specific temperature (via max moisture mass or saturation vapor pressure). The RH = E/Es*100%.

What is difference between DBT and WBT called?

The difference between the DBT and WBT is called as wet bulb depression.

What is the difference between DPT and WBT?

i) WBT: Wet bulb Temperature twb : It is the temperature recorded by a thermometer when its bulb is covered by a wet cloth exposed to the air. ii) DPT: Dew point temperature tdp :It is the temperature of air recorded by thermometer, when the moisture (water vapour) present in its, begins to condensed.

How is a psychrometric chart made for standard atmospheric conditions?

The psychrometric chart below is made for standard atmospheric conditions. The psychrometric chart is made with the PsycPro software available from The state of air with dry bulb temperature 70 oF and relative moisture 60% can be visualized in a psychrometric chart as indicated below:

How many grains of water are used in a psychrometric?

*grains of water is commonly used in psychrometrics. 1 grain = 0.000143 lb m = 0.0648 g (7000 grains per lb m) Heating, Cooling, Mixing, Humidifying and Dehumidifying Air Processes by Adding Steam or Water – Visualized in the Mollier diagram.

How does the psychrometric chart determine the outlet relative humidity?

Using the psychrometric chart determine (a) the outlet relative humidity [ 45% ], (b) the amount of water added [ 5.4g-H20/kg-dry-air ], and (c) the lowest temperature that could be realized [ 18.5°C ]. This type of cooler is extremely popular in hot, dry climates, and is popularly known as a Swamp Cooler.

How to solve problem 10.2 of the psychrometric chart?

Solved Problem 10.2: Assume that the outside air temperature is 8°C. If the air in a room is at 25°C with a relative humidity φ = 40%, use the psychrometric chart to determine if the windows of that room which are in contact with the outside will become foggy. The air in contact with the windows will become colder until the dew point is reached.