Assessment of the efficiency and reliability of the district heating systems within different development scenarios

Abstract

Renovation of multi-apartment buildings and district heating distribution system is aimed to reduce the final energy consumption. Directive 2012/27/EU of the EU on energy efficiency it is defined that as from 2014 3% of the public buildings owned and occupied by its central government should be renovated each year to meet at least the minimum energy performance requirements. Moreover, Directive 2010/31/EU and national regulation require the application of minimum requirements to the energy performance of existing and new buildings as well as increasing the number of nearly zero-energy buildings, which will have a significant impact on the consumption of thermal energy. In order to predict the influence of the future energy efficiency measures on the efficiency of the existing DH systems, District Heating Planning Tool was used for evaluation of the particular DH system. At the output, the tool provides twelve efficiency and balance indicators with the recommended permissible limits for the evaluation of DH system development scenarios. The tool validation is based on the results of comprehensive research of already renovated buildings. As a result of complex renovation decrease in thermal energy consumption can be achieved from 35 to 50% (average 42.3%). Consistent simulations of the proposed future development scenarios for a particular DH system with different building renovation rates of 3, 5 and 7% have shown a natural reduction in thermal energy consumption in a 15-year perspective by 13.5, 22.5 and 30%. Simulation results of the last three scenarios, which consider the use of renewable energy sources, have shown that CO2 emissions have been considerably reduced by about 40% compared to the actual state and the share of biomass has reached 47% of the total fuel consumption for thermal energy production.