Nightflush Mode (Night Purge) – Pre-Cooling Your Facility with Cool Night Air
The SunCooler™ has four autonomous operating modes. One of the most powerful is Nightflush (also called Night Purge). In this mode the SunCooler runs in Induction, pushing large volumes of cool nighttime outdoor air into the building while the onboard battery system keeps it running even after sunset.
In hot climates the outdoor temperature typically drops 15–25°F (and often more) after sunset. Nightflush takes full advantage of this natural temperature swing by flushing out the warm indoor air and pre-cooling the building’s thermal mass (concrete, steel, and air). The structure effectively becomes a free thermal battery staying significantly cooler the next day and delaying or reducing the runtime of existing HVAC systems.
- Delays HVAC start time the next day reduces energy use and maintenance costs
- Excellent humidity control without adding moisture (ideal replacement for swamp coolers)
- Works completely off-grid solar + battery powered, even on cloudy nights
- Fully programmable via SunConfig with scheduling or sensor triggers
SunCooler™ in Nightflush mode flooding the facility with cool nighttime air.
Nightflush pre-cools the building’s thermal mass for the next hot day.
How Nightflush Mode Works – Turning Your Building into a Thermal Battery
During the day, your building absorbs heat. The concrete floors, steel beams, walls, and the air inside all become warm. At night, in hot climates like Texas and other equatorial or desert regions, outdoor temperatures typically drop 15–25°F (and sometimes more) after sunset.
The SunCooler™ takes full advantage of this natural temperature swing. In Nightflush Mode (which is simply Induction Mode running at night), the unit automatically pushes massive volumes of cool outdoor air into the facility. Powered entirely by its onboard battery bank, the SunCooler continues operating in the middle od the night when the outdoor temperatures are optimal.
The result is dramatic: the building’s entire thermal mass (floors, walls, and structure) is pre-cooled overnight. The next day, it takes significantly longer for the facility to heat back up. This “thermal battery” effect delays or reduces the runtime of your existing HVAC systems, lowers energy costs, and provides meaningful comfort even before mechanical cooling turns on.
Key Technical Features of Nightflush Mode
- Battery Powered Operation: For night flush and any other suncooler mode throughout the night.
- Intelligent Battery Management: NWREC's battery management algorithms are second to none optimizing fan performance and battery life.
- Fully Programmable: Schedule any fan speed and duration through SunConfig, or trigger automatically using temperature and humidity sensors.
- High-Velocity Airflow: Unlie HVLS fans, which can't even do night flush, the SunCooler high velocity air column penetrates racks and products in storage more effectively then low velocity high volume techniques.
Nightflush actively exchanges hot indoor air with cool nighttime outdoor air.
The building’s thermal mass is pre-cooled overnight, acting as a free thermal battery.
The Dramatic Benefits of Nightflush Pre-Cooling
Nightflush turns your building into a free thermal battery. By flushing out the day’s accumulated heat with cool nighttime air, the SunCooler dramatically reduces the temperature the next day delaying or reducing HVAC runtime, lowering energy costs, and improving occupant comfort.
- Significantly reduces next-day HVAC runtime: lowers electricity and heating/cooling costs while extending equipment life.
- Excellent humidity control without adding moisture: Ideal replacement for swamp coolers in MRE storage, food processing, greenhouses, and cannabis facilities.
- Provides meaningful thermal relief the following day even before mechanical cooling turns on, making high-bay warehouses, barns, and manufacturing plants more comfortable.
- Works completely off-grid at night: The SunCooler’s battery system and intelligence keep it running reliably even during extended cloudy periods.
- Fully autonomous and programmable schedule via SunConfig or trigger automatically with temperature and humidity sensors for perfect timing every night.
- Proven across industries from distribution centers and correctional facilities, military MRE storage, and high bay warehouses.
Perfect For:
Nightflush pre-cools the entire building’s thermal mass for the next hot day.
Ready to Pre-Cool Your Facility Every Night for Free?
Turn your building into a free thermal battery with Nightflush Mode. Automatically flush out daytime heat with cool nighttime air, dramatically reduce next-day HVAC runtime, cut energy costs, and improve comfort all with the fully off-grid SunCooler™. North West Renewable Energy Corporation delivers a complete turn-key solution starting with our billable Facility Ventilation Study through manufacturing, installation, staff training, and seamless hand-off to your team.
Request Facility Ventilation Study & Quote →Call Jason in Sales at 503-515-3317 or email jason@nwrec.us or info@nwrec.us
Frequently Asked Questions – Nightflush Mode
1. What is the difference between Nightflush and regular Induction mode?
Nightflush is simply Induction Mode running at night. The SunCooler pushes large volumes of cool nighttime outdoor air into the building while exhausting the warm indoor air. The only difference is the timing: it is scheduled or sensor-triggered to take advantage of the natural nighttime temperature drop.
2. How much cooler will my facility stay the next day?
In hot climates where outdoor temperatures drop 15–25°F (or more) after sunset, Nightflush can keep the building noticeably cooler the following day, often delaying the need for mechanical cooling by several hours. The exact benefit depends on your building’s thermal mass, insulation, and local climate.
3. Do I need sensors, or is scheduling enough?
Both work great. You can set a simple schedule in SunConfig (e.g., run Nightflush from 10 PM to 6 AM). For maximum intelligence, add temperature and/or humidity sensors so the SunCooler automatically triggers Nightflush when conditions are ideal.
4. Will Nightflush work well in humid climates?
Yes. Nightflush is particularly effective in humid regions because it flushes out moist indoor air with cooler night air without adding extra moisture (unlike swamp coolers). This helps control humidity and reduces mold risk in barns, greenhouses, and processing facilities.
5. How does Nightflush affect my existing HVAC systems?
It reduces their workload. By pre-cooling the building’s thermal mass overnight, Nightflush delays when your HVAC needs to turn on and shortens its runtime the next day. Many customers see meaningful energy savings and extended equipment life.
6. Can Nightflush replace or reduce the need for swamp coolers?
Yes and very effectively. Swamp coolers add humidity, which can be problematic in many agricultural, food-processing, and storage applications. Nightflush provides powerful cooling and ventilation using only outside air and the building’s own thermal mass.
7. What happens on cloudy nights or if the battery is low?
The SunCooler’s intelligent battery management (limSOC and maxDOD) automatically reduces motor speed to preserve runtime. You will still get useful airflow even during extended cloudy periods. Daytime solar operation continues normally regardless of battery state.
8. Is Nightflush useful in winter too?
Yes. In cooler months you can run a shorter or gentler Nightflush to bring in fresh air while still using Destratification during the day to maintain comfort and save on heating fuel.
9. How do I schedule Nightflush in SunConfig?
It’s simple and graphical. Open SunConfig, connect to the SunCooler, go to the scheduling screen, and set the start time, duration, fan speed, and mode (Induction). You can also add sensor-based triggers for fully automatic operation.
10. Can I run Nightflush on the entire facility or just certain zones?
You can do both. Many customers run Nightflush facility-wide for maximum pre-cooling. Others zone it by scheduling specific SunCoolers near high-heat areas or sensitive zones (loading docks, offices, livestock areas, etc.).