Modernization of local heat distribution stations of city heat supply system

The PURPOSE of this work is to develop technical solutions to increase the efficiency of functioning of centralized urban heating systems by modernizing local heat distribution stations. The article considers the issues of functioning of district heating systems with open water intake. The work presents technical solutions that increase the efficiency of the local heat distribution station with a hot water supply unit. A technological scheme has been developed, the selection of equipment has been made. The feasibility of using the developed technical solutions is confirmed by technical, economic and investment indicators. The objectivity of determining the technical and economic effect of the modernization of the local heat distribution station is ensured by comparing the obtained indicators of the modernized and similar facilities.

METHODS. To fulfill the objectives of the study, the following methods were applied: full-scale tests on a real object; processing of experimental data using application programs; feasibility study in the municipal heat power industry.

THE RESULTS show an improvement in the technical and economic performance of the heating and hot water supply system of an apartment building in Yoshkar-Ola city: reduced network water consumption by 36–39%; temperature drop in the return pipeline was 13.5%; the heat content of hot water has been reduced to 0.168 Gcal/m³ (normative heat content is 0.145 Gcal/m³), the required circulation was ensured in all risers of the hot water supply system. The total losses from October 2021 to September 2022 are 3486,4 Gcal or 11.4% of heat supplied to consumers, which is less than 13% set by the tariff. Compared to a similar house without a regulation depending on the outside air temperature, the consumption of thermal energy during the heating season is reduced by 80 Gcal (10.9%).

CONCLUSION. The new scheme of a local heat distribution station has been proposed, including the regulation of domestic hot water (DHW) recirculation, as well as the installation of a hydroelevator with weather regulation. The developed technical solution is relevant for district heating systems with open water intake. For the first time, an experimental study of the effect of the joint installation of the following equipment was carried out: a pump and a control valve on the DHW recirculation line before the recirculation mixing unit with the return pipeline of the heating system; hydraulic elevator with weather regulation. The results of the study can be used in the feasibility study of similar circuit solutions for the modernization of DHW systems. Operating experience has shown that the application of the developed technological scheme of local heat distribution station has positive effects: reduction of network water consumption, temperature in the return pipeline and heat losses; improvement of circulation in all risers of the DHW system; reduction of thermal energy consumption during the period of the “lower” cutoff of the temperature graph; curbing the growth of tariffs for thermal energy.

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