Heat Transfer Forms and Efficiency Analysis of Urban Sewage Delivery Heat Transfer System

The thimble delivery heat-transfer (TDHT) system is one of the primary modes to utilize the energy of urban sewage. Used the efficiency-number of transfer units method (ε-NTU), the heat-transfer efficiencies of the parallel-flow and reverse-flow TDTH forms are analyzed and the calculation formulas and characteristic are also given. The results indicated that the efficiency of parallel-flow is larger than it of reverse-flow, so the TDTH system must choose the parallel-flow form. The definition of distance-load ratio (DLR) has been defined and the minimum DLR has been obtained by the technical and economic feasibility analysis. The thesis will provide reference for heat-transfer calculation and schemes determination of urban sewage cool or heat source applied delivery heat transfer method.