Applied Problems and Methodological Approaches to Planning and Implementation of Operating Conditions at District Heating Systems

Problems in planning and implementation of the operating conditions for district heating systems (DHSs) are directly related to the controllability and permissibility of the conditions and the reliability, quality, and efficiency of the heat supply systems’ operation under various operating conditions. The operating conditions’ development should be aimed at minimizing operating costs related to implementing the operational modes taking into account the entire set of technical and technological restrictions. The decisive factor in implementing competent adjustment and planning DHS operating conditions is the performance of preliminary calculations directly by the operators. In this case, the condition-development engineer receives a computer model of the operating DHS at his disposal that allows justifying and conducting constant correction of the thermo-hydraulic conditions during the entire heating season under changing operational conditions. For example, when connecting new consumers, varying loads, and under forced changeovers caused by emergencies, they can calculate the postemergency modes and correct the control values when the operating variables exceed the permissible values. At the Institute for Energy Systems (Siberian Branch, Russian Academy of Sciences), a system of mathematical models and methods has been developed for calculating and analyzing the thermo-hydraulic conditions at DHSs. This system was implemented in the Angara-TS information–software package (ISP). The ISP an is integration of models, methods, and software with information technologies intended for automation of workplaces for condition-development engineers. Technology for developing operating conditions for large-scale DHSs that satisfy all technical restrictions, including the required heat supply level, is presented. The technology based on multilevel modeling has been verified when implementing the operating conditions of real DHSs in Irkutsk, Angarsk, Bratsk, Baykalsk, Petropavlovsk-Kamchatsky, and other cities. This article deals with the development of the operating conditions for the DHS of Cheremkhovo, a town in Irkutsk oblast, to supply heat power from a combined heat and power plant according to a new temperature schedule. Practical application of the technology developed for planning the real DHS operating conditions has revealed its great potential for energy saving and has significantly improved the quality of the heat supply. The operating conditions and adjustment measures developed using the Angara-TS information–software package allowed for a significant reduction in the circulating heating-medium flow rates, the consumption rate of the make-up water, the water drain by consumers, the energy consumed for transfer of the heating medium, and the cost of chemical water preparation and has ensured the required level of heat supply.