Performance evaluation of a closed-air circulation household water purifier with heat-recovery based on thermoelectric cooling method and humidification-dehumidification principle.

To address the problems that household filter-type water purifiers require frequent replacement of filter cartridges and that heat pump humidification-dehumidification (HDH) household water purifiers produce noise during operation, this paper proposes a new type of closed-air circulation household water purifier with heat recovery, based on the thermoelectric cooling method and the humidification-dehumidification principle. Water inlet temperature (5 to 25 ◦C) effects on system operation, air circulation state, and water production performance were experimentally investigated. Results indicate that as the water inlet temperature increases, the refrigeration coefficient of performance (COPref) and the comprehensive system coefficient of performance (COPsys) of the novel water purification system both improve, while both the production rate and the production per unit energy consumption of pure water decrease. These latter two metrics reach their highest values at a water inlet temperature of 5 ◦C, at 414 g/h and 401 g/(kW⋅h), respectively. When the water inlet temperature is high, measures such as reducing the circulating air volume or increasing the spray water volume should be taken to increase the energy efficiency of humidification and dehumidification process, thereby synergistically enhancing the energy efficiency of the thermoelectric coolers (TECs) and the water purification system. At least 8.3 L/d of pure water can be produced by the system every day, which can meet the drinking water needs of a typical household while maintaining water quality that meets or exceeds related drinking water cleanliness standards.