There are many ways to recycle waste heat. Generally speaking, comprehensive utilization of waste heat is the best, followed by direct utilization, and again indirectly (such as waste heat for power generation). Comprehensive utilization is based on the quality of the waste heat, and it is used in steps according to the order of temperature. The high quality can be used in the production process or waste heat power generation; the medium (120 degrees-160 degrees) can be produced by ammonia absorption refrigeration equipment to -30 degrees. The cooling capacity of up to 5 degrees is used for air conditioning or industry; the low temperature can be used for heating or using absorption heat pumps to increase the amount of heat or temperature for production and life.