A boiler uses a flame burner to heat water or to boil water to generate steam. Steam boilers are used to heat spaces and to perform certain industrial processes such as in steam engines and power generation. Hot water can be used for heat and to satisfy the hot water demands of a facility. There are fire-tube and water-tube boilers. Fire-tube
This method is not the same as fracking. Fracking involves the fracturing of rock deposits in order to extract oil or gas.