An adaptive space-step simulation approach for steam heating network considering condensate loss

Steam heating plays an irreplaceable role in industrial productions and occupies a specific proportion of the total heating load. High-precision and efficient simulation is of substantial significance to the economical operation, safety and reliability and energy utilization efficiency of the steam heating network. Widely applicable and adequately accurate simulation approach for the steam heating network is in necessity. A novel adaptive space-step simulation approach for steam heating network considering the condensate loss is developed in this paper. The model equations are precisely derived from the primitive differential equations based on the trapezoidal formula and reorganized into the matrix form for computation acceleration. Meanwhile, a quasi-linear fitting method is proposed to simplify the calculation of steam enthalpy. To solve the model, the computation process is decoupled as hydraulic calculation and thermal calculation, and the converge is achieved through alternating iterative algorithm. The condensate check is introduced after the thermal calculation, in which the condensate loss can be calculated. To acquire the expected simulation precision, an adaptive space-step determination method is developed, in which minimum number of nodes are automatically added to divide long pipes into shorter segments. Finally, case study is conducted on single pipeline cases and a 20-node network. Results show that the proposed approach is applicable to networks containing superheated and saturated steam simultaneously. The error can be controlled to the initially set precision of 0.1 kPa and 0.1 °C through space-step adaption, and nodes are mostly added near the transition point from superheated steam to saturated steam for precision need.