Design, development and evaluation of solar powered DC cold box for sustainable supply chain of food and medicine

Food waste is still a major worldwide problem, especially in developing countries where poor cold storage infrastructure aggravates post-harvest losses. The design, implementation, and evaluation of a solar-powered DC cold box meant to lower food spoilage and increase the sustainability of food supply chains in off-grid and resource-limited environments is presented in this work. High-efficiency monocrystalline solar panels, IoT-enabled real-time monitoring driven by an ESP32 microcontroller, sophisticated thermal insulation, and a vapour-compression refrigeration system running on R134a are all combined in the cold box. With a battery-backed runtime of up to 42 hours without solar input and strong thermal performance maintaining internal temperatures within ±0.5°C and relative humidity levels of 85–90%, the system was built for portability and energy autonomy. Showing a 35–40% reduction in post-harvest losses and 27% higher energy efficiency than conventional AC-powered systems, field tests validated its dependability and impact. Consistent with world sustainability objectives, the solution proved both financially and environmentally feasible. The study provides a scalable, modular framework for distributing clean-energy cold storage in rural areas and offers a useful blueprint for infrastructure supporting climate-resilient food preservation.