Condensing devices constitute quite a bulky—in terms of overall dimensions and metal intensity—part of the thermal process circuit of power facilities implementing the organic Rankine cycle (ORC) during operation on various working fluids. In constructing such devices, it is very important to carry out rational designing, which can help make them with essentially better weight and overall dimension characteristics, and technical and economic indicators. This objective is of special importance for ORC facilities, because there is rather a small amount of commonly accessible information on the optimal structural design of such devices for each capacity level (output) of their equipment. The article presents the results of a computational study aimed at determining the effect the geometrical parameters of finned copper tubes have on the thermal, hydraulic, and mass and overall dimension characteristics of a shell-and-tube condenser for the ORC facility operating on pentane as working fluid for electrical capacities equal to 500 and 1000 kW. In carrying out the analysis, the optimal Rankine thermodynamic cycle parameters and the output of the devices in the nominal mode of their operation were determined. A specific feature relating to the solution of this research problem was the use of a systematic approach to analyzing the distribution of loads among the vapor generator parts (the heater and evaporator) in varying the saturation temperature in it and, hence, in changing the ORC facility efficiency and pentane flowrate. However, the major part of this work deals with the results of variant calculations of the shell-and-tube condenser operating on pentane as working fluid with using GEWA-K tubes produced by Wieland-Werke AG (Ulm, Germany). The calculations were carried out for devices having thermal capacities equal to 2280 and 5560 kW made using tubes having different diameter, wall thickness, and finning, of GEWA-K19, GEWA-K26, and GEWA-K40 types. The article presents the results of a study aimed at determining how the contamination of tube inner surface affects the condenser characteristics: key regularities have been revealed; device optimal design versions have been determined, and recommendations for the developers of the ORC facility shell-and-tube condensers have been formulated.
Антаненкова et al. (Sun,) studied this question.