Psychrometrics is the name given to the study of the air and water vapor mixture. … Saturated air, for example, has a relative humidity of 100 percent, and near the Earth the relative humidity very rarely falls below 30 percent.Īir-conditioning processes are usually shown on a psychrometric chart, which was developed in the early 1900s by a German engineer named Richard Mollier. When a volume of air at a given temperature holds the maximum amount of water vapour, the air is said to be saturated. By multiplying by 7000, this value may be expressed in grains of water per pound-mass of dry air. Humidity Ratio (W) Humidity ratio is measured in units of pound-mass of water per pound-mass of dry air.
Plot the state point and you can also read the rel- ative humidity, wet bulb, enthalpy, vapor pressure and humidity ratio. The point where these two lines intersect is known as a ‘state point’. 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 properties of air such as wet bulb temperature, dry bulb temperature, dew point temperature, relative humidity, humidity ratio, specific enthalphy and specific volume are shown on this chart. Psychrometric chart is one of the chart that is commonly used in solving HVAC problems.
Which type of chart is used in air conditioning system? Cooling and Dehumidifying> a psychrometric process that involves the removal of water from the air as the air temperature falls below the dew- point temperature. 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.Ī psychrometric process that involves the simultaneous increase in both the dry bulb temperature and humidity ratio of the air. … The difference between the DBT and WBT is called as wet bulb depression. Wet Bulb Temperature of Air (WBT): The wet bulb temperature of air is also measured by the ordinary thermometer, but the only difference is that the bulb of the thermometer is covered by the wet cloth. What is the difference between DBT and WBT?
wet bulb temperature (also known as saturation temperature).Which are the 5 factors indicated on a psychrometric chart? Moist air on a psychrometric chart ranges from Dry Air to Saturated Air. Moist air is defined as an air-water mixture. The Psychrometric Chart describes the various properties (Dry Bulb Temperature, Wet Bulb Temperature, Enthalpy, Humidity Ratio, Relative Humidity and Specific Volume) of moist air. A psychrometric chart can be used in two different ways. Psychrometric processes include physical and thermodynamic properties such as dry bulb temperature, wet bulb temperature, humidity, enthalpy, and air density. What is psychrometric chart? A psychrometric chart is a graphical representation of the psychrometric processes of air. They are often used to assess the properties of moist air. Psychrometric charts are complex graphs that can be used to assess the physical and thermodynamic properties of gas-vapour mixtures at a constant pressure. It can be very helpful in troubleshooting and finding solutions to greenhouse or livestock building environmental problems. A psychrometric chart presents physical and thermal properties of moist air in a graphical form.
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