Efficiency assessment of integrated Atmospheric Water Generators (AWGs) using the Global Evaluation Index (GEI): a case study

Abstract

Atmospheric water can represent a potential solution to address the global water scarcity issue affecting an increasing proportion of the population. Two of the main issues related to its production and use are represented by the energy consumption and the need of meaningful quantities of liquid extracted per day. They can be addressed through an integrated approach, which consists in employing a single process to achieve more than one useful effect, with the same energy consumption. In this perspective, in the last decade, advanced Atmospheric Water Generators (AWGs) have been developed. Such a kind of machines are based on a compression reverse cycle and, besides a considerable water production (up to thousands of litres per day) are capable to exploit all the useful effects of the said cycle, consuming about the same energy of the only water extraction. The global evaluation index (GEI) has been developed to provide a metric for the efficiency evaluation of integrated solutions. In the research literature there is a lack of examples of GEI application. The current paper aims to provide a first fulfilment of the research gap, providing a case study where the index is applied and discussed. In particular, the analysis concerns an integrated AWG connected to an electrolyser and a photovoltaic field for green hydrogen production. The GEI is employed to carry out a comparison between pre and post configuration of the plant. Results underline the index capability to provide an efficiency evaluation by means of a single number.