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dolezsa / thermal_comfort

Thermal Comfort sensor for HA (absolute humidity, heat index, dew point, thermal perception)
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Feature Requests - Vapor pressure sensor #366

Open Torgrima opened 8 months ago

Torgrima commented 8 months ago

This is a very important sensor value, when growing plants.

WPD of the leaves tell you about the resperation of the plant.

VPD = VPleaf - VPair VPleaf = 610.7 107.5Tleaf/(237.3+Tleaf) / 1000 VPair = 610.7 107.5Tair/(237.3+Tair)/1000 * RH/100

VPleaf - vapor pressure of the leaf (canopy) in kPa VPair - vapor pressure of the air in kPa Tleaf - leaf temperature in Celsius Tair - air temperature in Celsius RH - air relative humidity VPD - vapor pressure deficit in kPa

Or simply, use the a chart VPD chart and calculator. You need a thermometer/hygrometer to measure the grow room temperature, RH and ideally an infrared thermometer, so you can measure the canopy temperature. If you don't have an infrared thermometer, position your thermometer's remote probe at canopy level and take the reading after a few minutes, or assume that leaf temperature is 2°C cooler than air temperature.

In depth PDF article: https://journals.ametsoc.org/downloadpdf/journals/apme/6/1/1520-0450_1967_006_0203_otcosv_2_0_co_2.xml

4rianton commented 2 months ago

+1 to this.. It would be great to allow the user to set the parameters of calculating VPD for a specific plant while configuring the integration.