Economics and Environment Assessment of Urban Drainage Pipe Network's Heat Recovery in Lanzhou

This paper analyzes the current situation of environment and energy in Lanzhou. There is no doubt that the development of Lanzhou will play a significant role in the implementation of the western development, but The ecological environment is fragile and air pollution in Lanzhou is still serious, especilly, in winter dust or smoke coming from burning coal will cause further environmental degradation. These incidents have not only jeopardized our public health, but have also inflicted considerable loss to our economy so further implementing the strategy of sustainable development and broadening sources of income and reducing expenditure in Lanzhou are imperative under the situation, There is also potential and utilization for exploiting heat in urban drainage pipe network. This paper also presents the economics and environmental protection value of three systems, including urban untreated sewage source heat pump, gas direct-fired heat pump, and coal boiler plus electric water chiller. The results indicate that the economic and environmental protection value of the urban untreated sewage source heat pump is the best; on the other hand, it saved lots of primary energy, so it has a high energy value.