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Providing continuous capacity modulation for HVAC/R DX systems since 1993 · 100,000+ valves installed in the field

Home / Industries / Indoor Agriculture

VPD stability through every light cycle

Indoor Agriculture

Your crop lives inside a VPD window your HVAC keeps punching through. APR‑E Valve, a variable capacity enhancement for standard DX systems or heat pumps, modulates on command from your environmental controller and matches capacity to the canopy's changing load, lights-on ramp to dark-period low.

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APR-E Valve

Indoor Agriculture facility
77%
Fewer compressor starts
↓
~53%
RH held all summer
Longer run-time keeps the coil dehumidifying
±0.88°F
Discharge-air precision
Stratus field study ↓
0.128 kPa
VPD band vs 0.40
Stratus field study ↓
100K+
Valves installed
Since 1993 · UL Listed

Why the APR‑E Valve fits indoor agriculture

Hold VPD through lights-on, lights-off, and everything between.

  • Every cooling cycle is a VPD excursion: stomata close, CO2 uptake stalls, yield pays
  • ±0.88°F discharge air, independently field-verified in a live flower room
  • 0–10VDC or 4–20mA from any environmental control platform
  • Complimentary sizing and selection for every application by Rawal Devices Engineering
  • No impact on the unit's rated capacity during design day conditions

Where it matters most

Inside the Facility

Flower Rooms

Tight VPD, yield protection

Veg & Clone Rooms

Stable low-load operation

Propagation

Sensitive early plant stages

Greenhouse

Supplemental cooling support

Field-verified performance

The Proof, with Qualifiers

Discharge air temperature before and after APR‑E Valve: swings collapse to a tight band
Discharge air temperature, before and after APR‑E Valve: cycling swings of 10 to 14°F collapse to about 0.88°F max deviation on DAT control (Independently Field-Verified).
  • ±0.88°F max discharge-air deviation through a full lights-on ramp (Independently Field-Verified)
  • VPD band 0.128 kPa with APR‑E Valve vs 0.40 uncontrolled (Independently Field-Verified)
  • 77% fewer compressor starts in a 3-month independent field study

Stop losing yield to HVAC cycling.

Complimentary application sizing for indoor agriculture projects, with a one-business-day response.

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[email protected] · 800‑727‑6447 · rawal.com