Maintenance and Energy Efficiency
Maintenance operations are fundamental for energy efficient operation of machineries and systems. Deterioration of ship systems condition takes place due to normal wear and tear, fouling, maladjustments, long periods of operation outside design envelopes, etc. As a result, equipment downtime, quality problems, energy losses, safety hazards or environmental pollution may result. The end result is a negative impact on the operating cost, profitability, customer satisfaction and probable environmental impacts if maintenance is not properly done.
The major challenge of maintenance optimization is to implement a maintenance policy which maximizes availability and efficiency of the equipment, controls the rate of equipment deterioration, ensures the safe and environmentally friendly operation and minimizes the total cost of the operation which includes energy cost. In this section, various aspect of benefits of good maintenance for energy efficiency are further demonstrated (MariEMS 2017).
Hull and propeller cleaning:
Keeping hull and propeller in clean good condition can lead to major energy saving. Engines are the subject of frequent maintenance actions for a variety of reasons, one of the main reason being the impact of burning low quality fuel and its impact on engines. Engine condition monitoring is normal practice on-board ship and engine adjustments and tuning could lead to energy saving.
Shaft and coupling alignment:
Any shaft misalignment will not be good for machinery maintenance as well as for transmission energy efficiency. This would lead extra losses in the system in the form of heat.
Improved tension in belt-driven transmissions would prevent slippage loading on the belt as well as during high loading. This would reduce frictional losses due to slippage.
Chain and gear misalignment:
In chain-driven systems, any misalignment will lead to loss of energy and at the same time will not be good for upkeep and maintenance of the system.
Proper bearing lubrication:
Over-lubrication and under-lubrication are not good for energy efficiency. If bearing have excessive lubrication, it may need to churn more of the lubricant, increasing the fluid friction in the lubricant and thus energy losses. Typical energy losses occur in poor operating conditions for electric motors. For example, when a motor is fouled with dirt and moisture, this would inhibit the thermal heat transfer process. This condition results in increased resistance of the wiring which further increases the temperature of the motor and subsequently its energy consumption.
Compressed air system:
Compressed air systems can experience similar problems as steam system such as air leaks, excessive end-use air consumption and air compressor conditions. Maintenance not only will look at compressed air production but also the compressed air distribution and end-use areas (MariEMS 2017).