APR Control for Indoor Grow Rooms

The grow-room challenge

Growers are constantly managing the amount of moisture in the space. Too much humidity in a grow room puts the crop at risk, and grow facilities can have more exacting temperature and humidity criteria than most operating rooms and laboratories. Load profiles shift in a very short period as the lighting schedule and plant development change, so it is critical that conditions are held through all of those load changes.

Standard air conditioning is generally sized for the maximum load on a peak design day, which leaves it oversized roughly 90%+ of the time. An oversized system cycles on and off, delivers inconsistent temperature and humidity, can frost the coil, and stresses the compressor. In a grow room those swings are especially costly, because the environment drives yield and quality.

When the lights go off, the load flips

A simple change to the lighting schedule during the flowering cycle greatly changes the load. When the lights are on, the load entering the evaporator is mostly sensible heat and there is a clear demand for DX cooling. When the lights go off, the sensible load drops but moisture remains in the air, and the plants continue releasing water vapor through transpiration. The room's need shifts from cooling to dehumidification in the amount of time it takes to turn off a switch, and unmodified DX equipment cannot adapt to that shift without overcooling or short cycling.

Continuous modulation follows the load

The APR Control modulates to match the load profile coming across the evaporator coil in real time. That ability to load-match proportionally to widely varying and rapidly changing loads lets a standard DX system adapt through the stages of plant development, running at part load instead of cycling, which protects the compressor and keeps conditions steadier.

The APR‑E Valve adds electronic control of discharge air, so a standard DX system can manage dewpoint in response to the vapor pressure deficit (VPD) the plants need. Controlling discharge air as part of the grow-room control scheme is a direct lever on plant yield and quality.

What it delivers

• Continuous capacity modulation that follows the lights-on to lights-off load swing instead of cycling against it
• Steadier temperature and humidity through every stage of plant development
• Discharge-air (dewpoint) control with the APR‑E Valve for VPD-driven strategies
• Fewer compressor starts, which protects the DX system from the wear that drives premature failure
• Lower initial cost than replacing the platform, and support to reduce reheat needs and coordinate with humidifier output