From heat demand to heat supply: How to obtain more accurate feed-in time series for district heating systems

Abstract

Using the heating demand of the final customer as the heat supply input time series in investment or dispatch models of district heating systems could lead to erroneous results. Both thermal losses and the network’s transient behavior lead to a mismatch between heat demand and required heat supply and should be considered. Following the methodology of standard load profiles for natural gas usage, standard load profiles for district heating systems at the plant level are developed by analyzing the measured heat supply of four different district heating systems for multiple years. The derived standard load profiles can be used to consider network transients without a complex physical model. The correction of the transient behavior is coupled with three different options to consider thermal losses in the network. Considering the transient behavior leads to an average reduction in Root Mean Square Error of 35 % compared to the neglection of the transients. Compared to a direct forecast method, the proposed approach shows a 5 % decrease in Root Mean Square Error with an increase in peak load estimation accuracy by 7 percentage points. The proposed methodology is best coupled with loss distribution methods relying on a constant share of the actual load or on the grid’s flow and return temperatures. The proposed method and the published dataset aim to develop annual load profiles for data-scarce district heating networks to serve as an input parameter for long-term dispatch or investment problems.