Optimal frequency of temperature change of a heat transfer agent on a heat source and the influence of the rate of change thereof on heat energy loss

Abstract

THE PURPOSE. In modern realities, the operation of heat networks of the district heating system involves a constant search for ways to minimize heat energy losses. METHODS. Therefore, the task of minimizing heat energy losses while controlling the temperature of the supplied heat transfer medium from the sources of heat becomes very important. When operating district heating networks in the Russian Federation, regulation of heat supply to consumers during the heating period is carried out depending on the outside air temperature, as a rule, in two ways: qualitative method by changing the water temperature in the supply main of the heating network; qualitative-quantitative method by changing the temperature and water consumption in the supply main of the heating network. The methods of regulation used are related to the need to maintain a stable hydraulic mode of heat networks. Actions on the regulation of heat supply to consumers are performed at the heat source in accordance with the indication of the heat network dispatcher according to the approved temperature schedule for the heat supply system. RESULTS. This paper presents the results of a study of the dependence of changes in the actual heat losses for the section of the heating network, which is during the operation process in a non-stationary mode. Criteria for setting the temperature of the heat carrier at the heat source required to meet the temperature schedule by the heat network dispatcher are proposed. The results obtained can also be used in organizations operating district heating networks to ensure the regulation of the heating network operation mode with minimum heat losses. CONCLUSION. The nature of changing the temperature of the supplied coolant in the network (the interval of setting a new value and the rate of temperature change) directly affects the heat energy losses in the surrounding pipeline environment, resulting from the temperature gradient of the coolant in the pipeline and the environment. Given the fact that the values of the temperature of the outside air, heat-carrier, affecting the operating mode of the heating system is constantly changing over time, the processes of heat-exchange (heat transfer) between the coolant and the environment surrounding the pipeline are unsteady. The work reviewed the current requirements of regulatory and technical documents on the setting of the heating network operation mode, analyzed the factors affecting changes in the mode of the heating system.