Experimental investigation on stepped-cooling dehumidification system under variable conditions

Vapor compression dehumidifiers are widely used in small-capacity dehumidification occasions, but their evaporating temperature is lower than the dew point temperature of supply air, resulting in low operating efficiency of the dehumidifier. To improve energy efficiency, a new dehumidification system using non-azeotropic refrigerant is proposed. The system uses a single rotor compressor to achieve dual evaporating and dual condensing temperatures. The performances of the new dehumidification system and the conventional dehumidification system under different working conditions are experimentally studied. The results show that compared with the R134a conventional dehumidification system, the dehumidification capacity per unit power consumption of the new dehumidification system using R407C is increased by 4.3% to 14.0%. The dehumidification capacity per unit power consumption of the new dehumidification system using R32/R1234ze(E) (30%/70%) is increased by 9.7% to 27.2%.