Investigating thermal supplementation of an aquaponics system under severe climate conditions

Abstract

Purpose Climate change strains scarce water resources and food production infrastructure, necessitating establishment of sound scientific basis for operation of sustainable alternative food production methodologies - such as aquaponics, which promises high yield versus small footprint. In a climate (such as in Bloemfontein, South Africa) including temperatures below freezing, real-time aquaponics monitoring and control is necessary to mitigate thermal losses and to ensure sustainability of fish stock and bio-filter micro-organisms. The system thermal energy also needs sustainable supplementation during wintertime. This study/paper aims to address the problem of monitoring and controlling thermal energy in a medium sized aquaponics system, to ensure biological sustainability, especially during extreme cold weather events. Design/methodology/approach Required supplementation was determined and the aquaponics system described and quantified in terms of mass-flow power transfer by measuring loop differential temperature and flow rate. Cold front temperature data evaluation determined implementation suitability and -sustainability. Subsystem temperature contributions to the main reservoir, and their cumulative influence on the biological component, were considered. Findings Results indicate thermal supplementation enabled 1.3 °C temperature loss mitigation for a 42-kl water reservoir over a period of three days, offsetting severe system temperature decrease during a cold front event, and preventing organism mortality Originality/value Quantification of flow loop power transfer, and successful supplementation monitoring and control, demonstrates the approach and implementation merit in the Bloemfontein area. Wi-Fi-enabled online real-time data potentially facilitates incorporation into the concept of “Sustainable Smart Cities”.