Where the GDH-50E and GDH-58E Fit Best
This series is sized for 40–80 m² spaces with a moderate-to-high moisture load — typical conditions in document archives, switchgear rooms, server rooms, warehouse aisles, vault storage, light workshops and home or commercial garages. It is not an LGR (low-grain refrigerant) class machine for flood restoration; if you need 80–170 PPD restoration capacity, the design intent here is different. What this unit does well is run quietly for weeks at a 30–60 % RH setpoint, where consistent low-noise low-touch operation matters more than peak extraction.
As a portable industrial dehumidifier in the compact category, the GDH series fills the gap between household 20-pint plastic units and the 50 kg+ rotomolded restoration machines. The 31 kg weight, 380 × 480 mm footprint and rear wheels make it a true small portable dehumidifier in operational terms — one person, one trip, no lifting equipment. At the same time, the all-copper coil and steel housing keep it firmly in the industrial-grade build tier, not the consumer tier.
Compressor-Cycle Refrigeration with All-Copper Coils
The GDH series runs a sealed compressor refrigeration cycle — the same operating principle as a window air conditioner, optimized for condensation rather than cooling. Warm humid air is pulled across an oxygen-free copper evaporator coil where moisture condenses out, then reheated slightly by the condenser coil before being returned to the room. As a portable compressor dehumidifier for small spaces, this configuration extracts moisture far faster than peltier or rechargeable desiccant types in the same room volume, and it needs no installation work like a whole-house ducted system would.
Coil construction matters more than most buyers realize. The condenser and evaporator use oxygen-free copper tubing with aluminum fins and a hydrophilic coating. Copper handles thermal cycling and corrosive damp ambient air far better than the aluminum-tube assemblies found in lower-cost portable units — relevant here because facility-grade machines cycle on and off across multi-year service life. The hydrophilic fin coating sheds condensate film quickly, which keeps airflow resistance low as humidity climbs.
R290 or R134a Refrigerant — How to Choose
Both refrigerants are factory options. The right choice depends on your destination market and after-sales setup:
- R290 (propane) — natural hydrocarbon, ODP of 0, GWP of 3. Required for export to the EU and several Asian markets under low-GWP regulations (EU F-gas). Charge volume stays under 150 g per unit, with the sealed circuit meeting IEC 60335-2-40 safety construction requirements.
- R134a — HFC refrigerant, non-flammable, still accepted in many markets outside the EU. Easier to service where R290-trained technicians are scarce.
Capacity and energy consumption are essentially identical on both options within the rated working range. Refrigerant selection is locked at order.
Control Panel and Humidity Sensor
The LCD touch panel shows real-time RH, target RH, fan speed and timer status. The integrated humidity sensor reads to ±3 % RH and triggers compressor cycling once the target is reached, so the unit will not over-dry an already-conditioned room. The 24-hour timer supports unattended overnight or weekend operation. Fault codes appear on the panel when the controller detects high-pressure, low-pressure, sensor fault or tank-full conditions, which shortens diagnosis time on a service call.
Drainage — Tank and Continuous Hose
Two drainage paths are built in:
- Internal 4 L tank — removable bucket with full-tank float switch. Unit auto-shuts when the bucket fills.
- Continuous gravity drain — corrosion-resistant 3 m drain hose connects to the rear G1/2" port. The hose must run downward from outlet height with continuous slope to a floor drain, utility sink or sump.
The drain hose is reinforced PVC with brass fittings, rated for long-term operation in industrial environments where ordinary clear PVC tubing tends to crack or kink within months.
Auto Defrost and Low-Temperature Operation
Minimum working temperature is 5 °C. Below that point, refrigerant-cycle dehumidifiers form frost on the evaporator coil faster than the defrost cycle can clear it, and extraction drops sharply. The auto-defrost system here uses hot-gas bypass to clear coil frost on schedule, which keeps extraction stable through the 5–18 °C range where unprotected portable units typically stall. For sustained operation below 5 °C — cold storage, unheated archives in winter, walk-in freezers — switch to a desiccant-type rotary dehumidifier instead. The working principle is different (adsorption rather than condensation), and effective extraction continues down past –20 °C.
Build and Protection
The outer housing is 1.0 mm thickened cold-rolled steel with electrostatic powder coating. Internal electrical components receive a moisture-proof conformal coating before assembly — this matters when the unit runs in 90 %+ RH ambient air for extended periods, since that moisture has to pass through the PCB before it reaches the coil. Built-in safety includes high-pressure cut-out, overcurrent protection, defrost interlock and tank-full shutoff.
OEM and ODM Service
Standard customization includes badge and logo silk-screening, color code (RAL or Pantone), power cord and plug type for the destination market (Type B, F, G, I and others), and packaging artwork. ODM scope covers panel layout, control firmware language, refrigerant selection, capacity-rating label and certification routing (CE, RoHS, ETL, SAA depending on target market). MOQ for OEM is 50 units per model; ODM with structural changes is quoted case-by-case. Production lead time is 25–35 days after artwork sign-off, FOB Ningbo or Shanghai.
For higher-capacity portable units or large-room desiccant models, browse our full commercial dehumidifier range.
