Comparative Performance Analysis of Two Atmospheric Water Harvesting Technologies Under Identical Field Conditions

Abstract

Atmospheric Water Harvesting (AWH) is a promising alternative for water-scarce regions; however, direct field comparisons between active technologies are scarce. This study compares a vapor compression prototype (AWH-C) and a Peltier thermoelectric prototype (AWH-TEC) operating simultaneously under identical field conditions in Lima, Peru (BWh climate). Three test series of 12, 4, and 3 h (n=16, 16, and 15 trials) were conducted, recording temperature (T), relative humidity (RH), energy consumption, and volume produced. The AWH-C consistently outperformed the AWH-TEC in all test series: the average hourly production rate was 11.6–15.6 mL/h compared to 2.1–2.7 mL/h (ratio ≈ 5:1), and the Specific Energy Consumption (SEC) was 3.30–6.38 kWh/L versus 19.83–24.54 kWh/L. All differences were statistically significant (Mann-Whitney U, p < 0.001, r ≈ 0.85). Relative humidity was the most decisive environmental factor; at 43% RH, the AWH-TEC barely exceeded 2.0 mL/h. Limitations identified include the lack of absolute calibration of temperature sensors and the absence of recorded control variables. In hot desert climates, vapor compression is clearly superior; the Peltier system would only be viable in very small-scale applications with persistently high humidity.