Hydraulic Stabilization of Heat Network

Abstract

The article analyzes changes in pressure in the heating network taking into account the variable daily heat consumption. The simulation assumes diversification of heat demand during the day due to significant differences in the distribution of hot water. Taking the decreases in hot water consumption by up to 70%, pressure losses were calculated on the sections of the district heating network. Changes in the flow rate are taken into account. The simulation assumed changes in water flow from 10% to 70% respectively. Completed calculations and results are presented in diagrams drawn up for different amounts of hot water consumption. They allowed determining the size of the changing pressure of the available heat network. Graphs of dependencies between changing flows and the corresponding pressure values illustrate the magnitude of these changes. In the case of central heating, the heat demand is determined in the so-called external air temperature calculation conditions. The heating plant works in accordance with an ordered diagram of heat loads. The amount of heat delivered to the recipient for central heating depends on the outside temperature. It is calculated on the basis of the heat load factor and the average heat demand of individual customers. In relation to the production of hot water, the unevenness of the hot water demand should be taken into account. This variable size, as a result of the day, is described by the hourly diversity factor. For such calculations, daily schedules of hot water consumption are developed. On their basis, the operation of the heat network was analyzed. The heating network section and the hydraulic system of the network were analyzed for existing pressure changes, which are caused by the variability of the heat demand for heating domestic hot water. The calculations and simulations carried out show that the calculated flows, and thus also the pressure losses in the considered network, are variable and depend on the distribution of hot water to consumers. These differences are significant and affect the choice of pumps, which can bring significant financial benefits throughout the year.