Heat recovery can be integrated into a dehumidification route. Compare where water leaves and where the recovered heat goes before comparing the equipment.
Water removal and recovered heat
| Route | Where water leaves | Where heat goes |
| Ventilation with sensible recovery | Moist greenhouse air exits; removal depends on replacement air having a lower humidity ratio | An exchanger preheats incoming air with outgoing sensible heat |
| Internal condensation and direct return | Water condenses on a cold surface and is drained | A compressor cycle returns heat to the greenhouse air |
| Hydronic heat pump with buffers | Condensation occurs in an air-handling unit | Heat or cold moves through water circuits and can be buffered |
Wageningen’s 2017 abstract describes ventilation exchangers and internal condensation as distinct principles. (WUR 2017) WUR’s 2025 report supports the direct-return and hydronic-buffer rows. (WUR 2025)
Humidity ratio means water-vapor mass per dry-air mass. Comparing indoor and outdoor RH percentages alone does not establish the drying potential of ventilation. (ASHRAE psychrometrics)
Why a wet exchanger is not an energy result
In the passive air-to-air arrangement described by WUR, exhaust-side condensation helps warm incoming air. Seeing condensate does not establish that all latent energy remains inside the greenhouse. (WUR 2025)
Check what the recovery core transfers
A DOE building-research example describes a moisture-permeable membrane that transfers heat and water vapour between supply and exhaust air. It is useful as a counterexample to assuming every recovery core transfers heat only, but it is building research rather than greenhouse performance evidence. (DOE ERV core)
Compare conditions before costs
A historical Dutch simulation compared cold-surface, forced-ventilation/exchanger, and hygroscopic routes under specified weather and investment assumptions; its result was conditional, not a current economic winner. (WUR historical simulation) WUR’s 2025 report also cautions that published performance figures may use different air conditions. (WUR 2025) For broader context, see ventilation vs dehumidification in controlled agriculture.
Related project questions
After identifying the water and heat paths, review direct-air and duct-connected layouts and humidity variation between crop zones. For the wider project context, return to agricultural humidity control.
