船舶海水冷卻泵變頻控制之節能分析

Analysis of Energy Saving with Variable Frequency Control for Sea Water Cooling Pumps on Ships

一般於船舶上，馬達為耗電的主要設備，其中又以中央冷卻系統的海水冷卻泵浦之耗電為大宗，此乃因大多海水冷卻表的設計皆將海水進水溫度設定在32°C為基準，而使所需海水流量的冷卻泵浦作全速運轉。然而，船舶在行經不同海域時，海水水溫通常低於32°C，其真正所需海水流量應是可以較低的，因而導致能源之浪費。為因應節省減碳之趨勢及降低船舶設計之成本，本文探討船舶中央冷卻系統節能控制之可行性，並提出節能策略。本文利用Matlab/Simulink模擬船舶中央冷卻系統，進而分析當海水進水溫度低於32°C情況時，在投入所提節能控制策略下，其所需海水流量是可以較低的。是故，變頻控制海水冷卻泵浦將可減少泵浦所需耗能，且又可達與全流量相同的冷卻能力，以收節能之效果。 Electricity consumption in ships mainly focuses on motors, particularly in the cooling water pumps of the central cooling system. The seawater cooling system in ships is normally designed to maintain the temperature of in-take seawater at 32°C when the pumps operate at full speed to reach the required flow rate nowadays. However, the seawater temperature is normally less than 32°C as a ship sails through different areas. Thus, the actual in-take seawater flow can be reduced to avoid waste of energy. Due to the trend in energy saving and carbon reduction from the shipping industry, this paper investigates the feasibility of energy-saving control for the central cooling system in ships and proposes a strategy of energy saving control. A ship central cooling system is implemented and simulated using Matlab/Sirnulink in this paper in order to adjust the in-take seawater flow as the seawater temperature is less than 32°C with the same cooling ability. Thus, the power consumption on seawater pumps can be reduced to reach the goal of energy saving.