To analyse measurements is to know!

Sammanfattning: Renewable energy sources dominated the world energy supply until the beginning of the 20th century, when fossil energy became the dominant energy source worldwide. Today, fossil fuels contribute to over 80% of world energy supply. But there are two major reasons why fossil energy use has to stop. First, fossil energy is limited and will not last forever. Second, emissions of carbon dioxide change the climate with a risk for huge changes in the conditions of life for a large part of the world. A conversion back to renewables is necessary, but must be done at a major increased efficiency compared to the pre-fossil era. This change in energy supply is occurring, and district heating can play a major role in a renewable energy supply system. However, in order to stay compatible, district heating technology has to develop to increase system efficiency. Traditionally, district heating systems are divided in three parts: heat generation, distribution, and substations, but from a system point of view the system border has to be put in the climate shell of the connected buildings. Heat supply and distribution have been contentiously supervised and controlled by the district heating operators. The secondary heating systems in the heated building have building control systems in various extents and managed by the building operators. But, to increase system efficiency, all parts of the system have to be included in the optimisation. Automatic meter reading systems that up through 2015 will be installed in all district heating substations in Sweden can be used to overcome the lack of information to optimise the entire district heating system. This work is an initial analysis of substations and secondary systems using hourly meter readings. District heating systems are rather homogenous from a heat load point of view while the attached buildings are heterogeneous. The heterogeneity is what makes fault detection for district heating customers so difficult. The most difficult is not to detect what is wrong but to know what is right. To know what is right, knowledge of each individual customer is necessary. In this study, it is estimated that 75% of all connected customers have fault in substations and secondary systems. In today’s district heating systems, this is compensated for by increased supply temperature. In future district heating systems with essential lower distribution temperatures, this will not be an available option. Continuous commissioning of substations will be necessary to detect faults quickly.