The idea behind enhanced, or engineered, geothermal systems is to inject water underground to enhance the permeability of rock, allowing for the release and capture of more heat.
增强型的或是工程型的地热系统将水注入到地下，使岩石的渗透性提高，这样便可以吸收或释放更多热量。
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Generally resistant to animal and vegetable fats, oils, greases, ozone, heat, and strong oxidizing chemicals. Chlorobutyl has lowest permeability of all the synthetic rubbers.