PSYCHROMETRY CHARTS
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| Psychrometry |
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HVAC stands for heating, ventilation and air conditioning and refers to the all equipment, distribution system and workstations used either together or individually to provide fresh filtered air, heating, cooling and humidity control in a building.
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| Dry Bulb Temperature |
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The dry-bulb temperature of air is measured by a thermometer which is freely exposed to the air but is shielded from radiation and moisture.
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| Wet Bulb Temperature |
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The Wet-bulb Temperature of air is measured by a thermometer whose bulb is covered by a muslin sleeve which is kept moist with distilled and clean water, freely exposed to the air and free from radiation
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| Dewpoint Temperature: |
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Dew point temperature is the temperature at which moist air becomes saturated (100% relative humidity) with water vapour when cooled at constant pressure, i.e. temperature at which condensation of moisture begins when the moist air is cooled.
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| Relative Humidity : |
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Humidity ratio or relative humidity is the ratio of the actual mass of water vapor in the air to the mass of water vapor that would saturate the air at the same temperature.
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| Enthalpy: |
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The enthalpy of moist air is defined as the sum of its internal energy and the product of its pressure and volume. Specific enthalpy h (kJ/kg) of moist air is defined as the total enthalpy of the dry air and water vapour mixture per kg of moist air.
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| Moisture Content: |
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Specific humidity or moisture content of air is the ratio of the mass of water to the mass of dry air in a given volume of moist air.
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| Psychrometric processes: |
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Psychrometric processes, i.e. any changes in the condition of the atmosphere, can be represented by the movement of the state point on the psychrometric chart. Common processes include.
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| Sensible cooling / sensible heating: |
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When an air-vapor mixture is heated or cooled, without the addition or removal of moisture, the resulting "process" may be plotted as a horizontal line on the chart |
| Humidification / dehumidification: |
Humidification can be made by spraying water or steam to air.If humidification made by water, air will move through wetbulb temperature line and dry bulb temperature will decrease.If humidifaction made with steam air will move through drybulb temp line and there will be no significant change in drybulb temprature.
Cooling and dehumidification / heating and humidification
Evaporative cooling / chemical dehydration
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