The purpose of this study is to compare and analyze the conventional constant-speed compressor driven by an induction motor and the BLDC-applied capacity variable compressor in order to improve the energy efficiency of the refrigeration system. Through this study, it was found that, when a reciprocating hermetic compressor is operated, more power is consumed than a BLDC compressor due to the consumption of current through the instantaneous starting capacitor when operating at a constant voltage than a BLDC compressor.

This study aimed to develop an algae reduction device using bubbles to improve algal blooms occurring in lakes or reservoirs in summer, and to design a venturi, a major core device for bubble generation and supply. As a measure to improve the bubble generation effect of the venturi, the venturi was devised to change the air intake characteristics, and the flow characteristics were analyzed through CFD simulation to achieve the optimal design.