Modern aircraft are equipped with sophisticated air conditioning devices - but running them at optimumcapacity burns up valuable aviation fuel.
现代飞机都配备了完备的空调装置——但要使其以最佳状态运行就会耗尽宝贵的航空燃油。
2
But owing to the complexity of power transmission systems, it is hard to determine the optimumcapacity and economic benefit on adding devices for reactive compensation.
但都由于输电系统的复杂性，而不能确定增设无功补偿装置的最佳容量和经济效益。
3
Allows optimum use of spare capacity for multiple computer centres, making it more efficient.