HVAC & Dehumidification Sizing Logic
Why the transpired water and the light wattage set your latent and sensible loads — sizing dehumidification in pints/day and cooling in tons from first principles, with the night-VPD trap that low-RH rooms fall into.
Almost every drop you irrigate comes back as air you must dry
The setpoints earlier in this department describe the climate you want. This lesson is about the machinery that holds it — and the single fact that makes HVAC sizing legible: nearly all the water you feed leaves the plant as vapor. Only a few percent stays as biomass. So your daily irrigation volume, minus runoff, is very close to your daily transpiration, which is very close to the water your dehumidifiers must pull back out of the air. Feed and dehumidification are two sides of the same water balance. Undersize the drying side and the room drifts wet, VPD collapses, and you have hand-built a botrytis incubator no matter how good your setpoints look on paper.
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