Theoretically, the basic boundary conditions that affect the critical heating value of garbage include the excess air coefficient of the furnace face (), the theoretical air volume for incineration of garbage (L0), and the air preheating temperature (tk). The calorific value of waste determines the temperature of waste combustion The characteristic parameter of waste combustion temperature is the adiabatic flame temperature (ta). The adiabatic flame temperature refers to the temperature that can be reached by heating the incineration product by all the heat released by the garbage during the incineration process. For the designated domestic garbage, the adiabatic flame temperature decreases significantly with the increase of the air excess coefficient; it increases rapidly with the increase of the air preheating temperature. The relationship between the critical heating value of garbage and the adiabatic flame temperature can be established through energy balance, and there are two methods: accurate calculation method and approximate calculation method. Because the instability of garbage is far greater than that of coal, oil or gas, and the precise calculation is too cumbersome, engineering calculations usually use approximate calculation methods. The following calculation examples are based on heat balance calculation models, and some research results in the United States and Japan are introduced.