Energy which is also called energy resources, it can produce all kinds of energy (such as heat, electricity, light and mechanical energy, etc.) or can be generally referred to work of the material, including coal, crude oil, natural gas, coal-bed methane, hydroenergy, nuclear power, wind energy, solar energy, geothermal energy, biomass energy and other primary energy and electric power, heat, oil product and so on as secondary energy, and other new energy and renewable energy.

The lack of energy requires people to improve the efficiency of energy use. To insure the high efficient utilization, the power of electrical equipment is increasing, that cause thermal power is increasing, so the corresponding cooling needs are also increasing. At present, common high-power electronic equipment such as converter, power quality control products, electrical transmission, transformer and other electrical equipment need to be equipped with different cooling devices.