Experimental study on the performance of the internally-heated ultrasonic atomization liquid desiccant regeneration system

Highlights: • Performance of IH-UARS was studied via experiments and model predictions. • Effects of the operating parameters on the performance of IH-UARS were clarified. • Thermal efficiency was 34.6% higher in IH-UARS than the adiabatic UARS. • Lower desiccant temperature (36.6 °C) was required for regeneration in IH-UARS. • Regeneration performance was improved by 48.2% in IH-UARS, compared to IH-FPR. -- Abstract: Liquid desiccant dehumidification system has been attracting increasing research interests due to its great energy saving potentials. Moreover, the desiccant solution can be regenerated with thermal energy for recycling use. However, due to the limited contact area and significant temperature drops within the regenerator, the regeneration performance has been restrained, and the necessary desiccant temperature tends to be exorbitant. To this end, this work proposed a new internally-heated ultrasonic atomization liquid desiccant regeneration system (IH-UARS) to improve the desiccant regeneration performance. The proposed IH-UARS was thoroughly studied, in comparison with the adiabatic UARS and the conventional internally-heated flat-plate regenerator (IH-FPR), via extensive experiments and a prediction model developed from the conservation laws of mass and energy. It was found that the regeneration performance, together with the thermal efficiency, was substantially improved by 45.2% and 34.6%, respectively, in the UARS after adding internal-heating. Besides, the necessary desiccant regeneration temperature (NRT) was lowered markedly to merely 36.6 °C in the IH-UARS. Further, better regeneration performance was also presented in the IH-UARS than that of the IH-FPR, with the NRT dropped by 5.9 °C. The results may help improve the performance of the liquid desiccant system and facilitate its fuller utilization of low-grade thermal energy.