Why cold spaces need a desiccant rotor
A refrigerant dehumidifier works by condensing water on a coil that has to run colder than the room. In a cold space there is little room left before the coil hits freezing, so ice forms and the unit switches to defrosting — in a cold store near 0°C it can spend most of its energy defrosting rather than drying, and in a freezer anteroom it effectively stops. A desiccant rotor removes moisture by adsorption, with no cold surface in the loop, so it keeps working as the air gets colder. These units hold their humidity target across the full -20°C to 50°C range, which is what makes them the right choice for cold and freezer environments that a compressor cannot serve.
Cold spaces also carry a specific moisture problem: warm, humid air leaking in through doors and openings hits cold surfaces and condenses, causing frost on evaporators, ice on floors and racks, fogging, and packaging damage. Holding the space at a low, stable RH stops that condensation at the source — which is exactly what the rotor does, steadily, at low temperature.
Highest airflow in the range
These are the largest units we build, pairing the rotor's low-temperature strength with the most dry-air delivery. All four are 380V three-phase with large Φ500×400mm ducting:
- XR-3500XF-01 — 22 kg/h, 3,500 m³/h, 28 kW, 380 kg. The entry unit in the tier, for a large cold store or low-temperature hall.
- XR-4000XF-02 — 25 kg/h, 4,200 m³/h, 30 kW, 380 kg. More airflow through large rectangular ducting for a bigger cold or process space.
- XR-4500XF-01 — 27 kg/h, 4,500 m³/h, 31 kW, 370 kg. A higher moisture load for a large refrigerated or low-temperature area.
- XR-5000XF-01 — 29 kg/h, 5,000 m³/h, 36 kW, 380 kg. The top of the range, the highest airflow and capacity of any single unit we make.
For cold spaces larger than one unit can cover, run several in parallel — sized to the building's air changes and door traffic, and placed so dry air reaches the whole floor and moves across the cold surfaces you're protecting.
How the rotor holds a cold, large space
Process air passes through the 270° process sector of a slowly rotating desiccant wheel (8–12 revolutions per hour); the desiccant adsorbs the moisture and dry air leaves through the process fan. A separate regeneration airstream heated to 100–140°C drives the captured moisture off the wheel and carries it outside, and the wheel rotates back into the process air restored. Adsorption does not slow down as the air cools, so the unit holds a low RH target at -20°C as steadily as at room temperature — and reaches a lower RH than a compressor can at any temperature. The rotor uses a silica-gel and molecular-sieve composite chosen for strong adsorption and clean regeneration, and it warms the process air slightly as it dries, which is often useful in a cold space.
Build and control
- Rotor — fire-resistant desiccant wheel, rated -20°C to 50°C, gear-motor driven at 8–12 RPH with rotation-stop protection.
- Regeneration — SCR-controlled heating in an insulated chamber; heater starts with the regeneration fan and cuts out automatically if the rotor stops; sealed independent process and regeneration ducts keep the two airstreams apart.
- Control — 5–95% RH, fully automatic with manual/automatic switching, real-time RH on the LED display, fault self-detection with a fault code, and running/standby/fault indicators.
- Industrial protection — IP44 enclosure, electrical protection to IP54, plus phase-sequence, over-temperature, overload, and high/low-voltage protection for a three-phase supply.
- Integration — DI signal and RS-485 Modbus for remote monitoring and control, reporting RH, mode, and fault status to a facility BMS; multiple units coordinate across a large cold space.
- Build — stainless-steel or powder-coated housing for corrosion resistance in damp cold air, continuous operation over 720 hours with stable low-temperature performance, 10-year-plus designed service life, components from established brands (Siemens, ABB, Omron, Schneider, Delixi and similar).
Global voltage and OEM/ODM
All models are three-phase 380V, available for 50Hz or 60Hz and for the destination market's three-phase voltage. We support OEM branding and ODM changes: cabinet color and layout, control interface and BMS protocol, duct and drainage configuration (including drain routing protected against freezing in cold-store use), filter grade, rotor and heating selection for the temperature and target, and labeling — built to CE, ETL, and RoHS with ISO 9001. Send us the space, its operating temperature, the moisture load and target RH, and the supply available, and our application team will recommend a model, a multi-unit layout, or an engineered system.
