Harnessing Renewable Energy Sources in CO2 Refrigeration for Eco-Friendly Fish Cold Storage

This study explores innovative strategic solutions within a sustainability framework, focusing on four viable options for an integrated refrigeration system designed for fish preservation in Tarrafal de Santiago, Cape Verde. Tarrafal is a coastal town on Santiago Island, characterized by its reliance on fishing activities and the challenges posed by limited energy infrastructure and local environmental vulnerabilities. The evaluated solutions range from grid-dependent systems to fully autonomous configurations powered by renewable energy sources, incorporating various refrigeration facility designs adapted to regional conditions. The primary objective is to assess the energy efficiency, economic viability, and environmental impact of these options within the specific geographic and socioeconomic context of Tarrafal de Santiago. Four approaches were analyzed: Strategy A involves two R134a refrigeration systems powered by conventional grid electricity; Strategy B employs a transcritical CO2 (R744) system combined with grid electricity; Strategy C integrates an R744 refrigeration system powered by autonomous renewable energy sources; and Strategy D utilizes R744 refrigeration combined with seawater-based heat exchange and autonomous renewable energy generation. The results indicate that Strategy D offers the greatest advantages, with emissions amounting to 15,882 kg of CO2 equivalent and a return on investment within five years. Autonomous electricity generation in Strategy D leads to a 95% reduction in CO2 emissions. Although Strategy C entails a higher initial cost, it proves financially viable and significantly enhances energy sustainability. Its autonomous energy production results in a reduction of 360,697 kg of CO2 emissions compared to conventional systems, highlighting the substantial environmental benefits of integrating local renewable energy sources into coastal communities such as Tarrafal de Santiago.