Analysis of Energy and Soft Dirt in an Urban Untreated Sewage Source Heat Pump System

When using urban untreated sewage as a cool and heat source of heat pump, it is unavoidable to form soft dirt. Based on the method of exergy, an analysis is given of the impact the dirt growth of a tube-shell sewage heat exchanger will have on transfer intensity, flow pressure drop and exergy loss. The conclusions are deduced by an example showing that the middle flow velocity is good for energy conservation and economical efficiency, and it is also needed to remove the dirt in time at low flow velocity.