An experimental study of the influence of orientation on water condensation of a thermoelectric cooling heatsink

Abstract

An experimental investigation of thermoelectric cooling using a Peltier element to dehumidify moist air under controlled, high relative humidity conditions has been conducted. The influence of the cold side heatsink orientation on the water collection rate was experimentally determined. One finned heatsink-fan combination was used on the heat rejection side. On the cold side flat plates, uncoated and Polytetrafluoroethylene (PTFE) coated, a fanned plate with four fins, and a heatsink having 15 fins were used. The PTFE coated plate showed up to a 30% higher water collection rate (expressed in L/kWh) compared to the uncoated flat plate that has the same surface area. Clearing the surfaces—removing all condensate every hour—increased the water collection rate by up to 18% for the flat plates. The finned heatsink and the PTFE coated flat plate were used for the orientation experiments. The finned heatsink was rotated from 0° to 90°, as well as tilted from 0° to 90° (vertical to horizontal). To investigate the effect of surface orientation on a single-side collection surface in isolation, the PTFE coated flat plate was tilted from 15° to 165° in 15° increments. The highest collection rates are found for a rotation angle of 60° and a tilted angle of 75° for the finned heatsink, 0.249 L/kWh and 0.221 L/kWh respectively. The highest measured collection rate for the PTFE coated plate is 0.319 L/kWh at an orientation of 15° from the horizontal. Experiments for the horizontal orientation of the finned heatsink show that once the spaces between the fins are completely filled with water the collection rate drops by an order of magnitude, from 0.203 L/kWh to 0.026 L/kWh. The experiments show that the orientation of a thermoelectric heatsink should be considered when optimizing the water collection rates under high humidity conditions for thermoelectric cooling heatsinks.