Experimental study of an absorption-based refrigeration driven by ocean thermal energy

Establishing an island-based cold chain is essential for ensuring food storage, vaccine preservation, and fish freezing on islands, which is indispensable for the sustainable development of island communities. The compression-absorption refrigeration system that uses ocean-thermal-energy is ideal for cold storage on islands as it efficiently utilizes local renewable energy sources and can meet refrigeration needs below 0 degrees C. Therefore, a refrigeration prototype has been constructed and thoroughly experimentally investigated to obtain refrigeration characterization under variations of refrigeration demand and environmental conditions. The system's energysaving potential is evaluated by conducting comparisons with conventional refrigeration techniques. The results indicate that refrigeration temperature plays a crucial role in determining refrigeration capacity, with an increase of approximately 8.2 % observed for every 1 degrees C rise in refrigeration temperature. Lower cold-seawater temperatures or higher warm-seawater temperatures do not have a significant effect on the refrigeration capacity, but contribute to a reduction in compressor power due to increased thermally-driven compression force. Consequently, for every 1 degrees C change, the refrigeration capacity per unit compressor power increases by approximately 4 %. Additionally, the refrigeration capacity of the system is three times greater than that of a vapor-compression-refrigeration-system. The findings provide theoretical and experimental guidelines for the design and operation of refrigeration using ocean-thermal-energy.