Fluorocarbon evaporative cooling fluid is known as "dry water". Currently, it is mostly used in places with extremely high fire protection requirements (such as national archives). It has the characteristics of being non-flammable, non-explosive, environmentally friendly, having a high specific heat capacity, being easy to undergo phase change, having a low viscosity, a low freezing point and strong fluidity. Moreover, its dielectric strength is comparable to that of transformer oil. When applied to transformers, it can truly achieve non-flammability and non-explosiveness. At the same time, it can also make products smaller and lighter, and eliminate local overheating of products. This cooling medium product is internationally leading in multiple technical indicators such as fire protection, heat dissipation and environmental protection. It solves the "bottleneck" problem of the core technology of non-flammable and non-explosive transformers in China, and can provide strong support for the construction of a strong and intelligent power grid in cities and the realization of green development.