Comparison of the Heat Consumption of Icelandic and Chinese District Heating Systems

Abstract

Western district heating systems usually supply heat to clients with radiator building heating systems, which requires a supply temperature to the building above 60°C. They supply heat as well for production of tap water in the buildings. The tap water production requires heat at minimum least 60°C due to the danger of growth of the Legionella bacteria in the tap water system. During the summer time the only load on the systems is the heat needed for the tap water production, and the heat losses to the soil in the distribution system account for a large part of the heat supplied to the system. The Chinese district heating systems do not supply heat for tap water production. It is most common to produce tap water by combustion of natural gas in small tap water heaters in each apartment. Most commonly of the district heating systems supply heat to buildings heated by floor heating. This results in that the Chinese systems can operate with as low building supply temperature as 45-50°C. In addition to that the systems are shut down during the summertime, so there is no distribution network heat loss at all during the non-heating season. A simulation model is made to simulate the performance of these two systems for a typical year. Data for a typical year from the “International Weather for Energy Calculations (IWEC)” is used for a few locations in China and Western Europe. The system consumption of geothermal water, heat and natural gas is calculated, for the selected locations and a cost benefit analysis is performed.