or RH): The ratio of the actual water vapor pressure to the saturation vapor pressure, displayed as curved lines ranging from 0% to 100%.
The old paper was the color of weak tea, stained at the edges where someone’s coffee cup had rested decades ago. To anyone else, it was a relic—a spiderweb of diagonal lines, swooping curves, and tiny numbers printed in a font that had gone out of style before the moon landing. psychrometric chart
The chart is usually bounded by the dry-bulb temperature scale on the horizontal axis and the humidity ratio (moisture content) scale on the vertical axis, with an upper curved boundary representing 100% relative humidity, or the saturation line. Key Properties on the Chart or RH): The ratio of the actual water
Her grandfather had called it "the wizard’s abacus." He had been a millwright here in 1957, back when this floor hummed with a thousand looms and the air was a thick, wet rope of heat and cotton dust. He taught her when she was nine: how dry-bulb temperature (the straight vertical lines) was just the obvious lie the thermometer told. Wet-bulb temperature (the diagonal lines sloping down to the right) was the truth of how much the air could weep. And relative humidity—those swooping parabolas—was the air’s current mood, its level of satisfied thirst. The chart is usually bounded by the dry-bulb
Highway to the Comfort Zone: History of the Psychrometric Chart
Using a psychrometric chart involves plotting the initial state of air and tracing its path through an HVAC process. 1. Finding Initial Air Conditions If you know the ( ) and relative humidity (
Moving left until the saturation line, then down along the saturation curve to remove moisture (e.g., in a cooling coil).