Optimization of a thermoelectric cooler-based system for atmospheric water production in terms of temperature of condensing surface

The extraction of water from the atmosphere is considered as a potential solution to alleviate the problem of water shortages. Therefore, it is crucial to improving the efficiency of water production from atmosphere. In this work, the effect of temperature of the condensing surface below 0 degrees C on the water productivity of thermoelectric water generator (TWG) has been studied for the first time. The experimental results indicate that the average water productivity increases with the decrease of the condensing fin surface temperature and there is a maximum increase of 186 % in the average water productivity of TWG when the temperature of condensing fin surface decreases from 5 degrees C to -10 degrees C, which is due to the increased temperature difference and the enhanced thermal conductivity of the ice layer. When the form of condensation on the surface of condensing fins is changed from condensing to frosting, the water productivity is increased by 22.1 % at maximum, which can be attributed to the higher thermal conductivity of ice than water. The effect of the sampling time on average water productivity of TWG has also been studied. With the increase of sampling time (0.5 h-3.5 h), the average water productivity of the device gradually decreases by 30.3 %. And the highest average productivity of TWG has been observed at a sampling time of 0.5 h. In addition, the effects of flow rate of water in water block heat exchanger, air flow rate of the cooling fan, voltage of TEC on water productivity are experimentally investigated as well. This study provides a strong theoretical foundation for enhancing the water productivity from humid air.