Techno-Economic Evaluation of Integrating Thermal Energy Storage for Solar-Powered Energy Systems

Abstract

Refrigeration is a critical process for the food industry and for global food security, yet it is associated with substantial energy consumption and Co2 emissions, contributing approximately 1% of global carbon emissions and incurring significant operational costs. As decarbonisation and net-zero targets become increasingly imperative in addressing climate change, the transition to sustainable energy solutions in refrigeration is crucial. While alternative cooling technologies and renewable energy integration have shown promise individually, their combined potential remains largely untapped. This thesis proposes the integration of evaporative cooling and solar cooling as a sustainable and cost-effective alternative to the conventional vapour compression cycle. By incorporating evaporative condensers and evaporative pre-coolers, this hybrid system enhances performance, reduces costs, and aligns with the needs of the food industry.

A comprehensive techno-economic analysis is conducted to evaluate the integration of these technologies into existing refrigeration systems at BlueSkies facility in South Africa, including thermodynamic modelling, economic assessment, and the evaluation of four energy storage strategies to identify the most cost-effective solution. The results demonstrated that integrating evaporative cooling with solar-power can achieve up to a 79% reduction in Co2 emissions and a 50% decrease in total costs over a 10-year period, compared to conventional methods. This hybrid approach not only improves energy efficiency but also provides a viable pathway for the food industry to achieve sustainability goals while maintaining economic viability.

Additionally, to further investigate the validity of the proposed system a validation survey was conducted with BlueSkies to assess the practical applicability of the proposed solutions on relevant metrics such as operability and affordability, which provided valuable insights into the feasibility and potential challenges of implementation. Furthermore, the combined system’s performance is compared with conventional vapour compression cycles, both fossil fuel-based and renewable energy-based, to underscore the potential easing of adopting renewable that this proposal enables, as this research aims to facilitate the adoption of renewable energy in existing refrigeration facilities, promoting sustainable practices within the food industry.