useful heat的意思|示意

Energy efficient process converts up to 80% of the expended energy into useful heat to save costs.

能量的有效转换过程中，高达80%的能源转化成为有用热，以节省成本。

In practice, not enough heat is generated to make a useful amount of electricity.

实际上，产生的热量并不足以用来发电。

When the magnesium is mixed with water, it produces heat, boiling the water to produce steam, which can then drive a turbine and do useful work.

当镁与水混合在一起时，它就会产生热量，让水沸腾产生蒸汽，而产生的蒸汽然后就可以驱动涡轮机，而且也可用来做些有用的工作。