Akademik Veri Yönetim Sistemi
Thermal Science and Engineering Progress, cilt.68, 2025 (SCI-Expanded, Scopus)
It is well known that the smaller the size of nanoparticle additives used in cooling systems, the more effectively they enhance cooling performance and reduce energy consumption. Conversely, larger particles may lead to sedimentation and blockages within the system. In this study, long-term experiments were carried out under controlled laboratory conditions using household refrigerators of the same type and model. The experiments were conducted in 15-day periods, during which compressor performance was evaluated both before and after the tests. The oil removed from each compressor was reintroduced in equal amounts. Compressor oils were measured in grams, and nanoparticles (3 nm, 13 nm, and 18 nm in size) were added at concentrations of 0.05 %, 0.2 %, and 0.5 % by weight. Additionally, a surfactant was added at a concentration of 0.5 % v/v (ml/ml). Temperatures of the refrigerator, freezer, condenser, compressor, and ambient environment were recorded, along with energy consumption values (W, Wh, and kWh per 24 h), and daily averages were taken. Initially, a short-term test lasting 2.5 h—following methods found in the literature—demonstrated up to 37.5 % improvement in energy efficiency. In long-term tests, a 5.55 % energy saving was recorded after the first 30 days. These experiments were repeated four times, but a gradual performance decline was observed beyond day 30. This decline is believed to result from nanoparticle sedimentation and capillary blockage. While this study shows the potential of nanoparticle-enhanced compressor oils to improve energy efficiency, the sustainability of this method depends on overcoming the precipitation issue within the closed-loop system.