District heating and cooling as part of smart energy systems 

Energy systems are evolving and energy companies are required to take action to achieve higher levels of energy efficiency. Smart cities have been widely under discussion and smart energy systems are considered as the backbone of this approach. District heating and cooling (DHC) businesses are argued to be ‘important tools’ for reaching energy targets. The major objective of this research is to study the spedial characteristics of smart energy systems and how DHC systems are adapting to them. The most important factors for smart thermal grids are intelligence, efficiency, and flexibility in production and consumption, customer involvement, integration with other energy systems, and reliability. This study will present three case studies to highlight energy efficiency measures on the consumer side of a DHC system. The first study concentrates on the benefits of remote measurements and better implementation of a district heating (DH) forecasting model when consumer’s hourly measurements are utilized. The forecasting model was formed using linear regression, based on outdoor temperature data and the social component of the heat consumption. The study shows that forecasting models are more accurate for bigger customers and aggregated groups of customers and in the best cases a rather simple model predicts heat consumption with good accuracy. The second case study focuses on the flexibility of the DH network. The demand-side management (DSM) potential of district-heated residential buildings was determined by cutting heat for one hour during the morning consumption peak. Utilising the results of an earlier study, where the thermal behavior of eight different-aged residential buildings was simulated, the object of this research was to figure out the overall DSM potential of the buildings. The results showed that the thermal behavior of the buildings varies and that the buildings with the best potential for DSM were the ones built during the years 1940-2002. In the larger scale, the momentary heat effect decreased 80 percent due to DSM actions. The last case study concentrates on the original idea of the DH system, which is that heat can be recycled from sources where it otherwise would be wasted. A new business model is presented and critically evaluated, in which heat customers can sell their waste heat back to the energy company at a predetermined price. The pricing model is estimated relative to the waste heat suppliers as well as to the energy company. The results showed that, in general, it is profitable for heat customers to sell their waste heat in situations where the price of electricity is low, because then priming the temperature of the waste heat using heat pumps is affordable. System-wide, the results showed that emission levels were increased in most of the cases due to the priming of the waste heat. Despite of the results, this concept is an important opening for the energy and heat markets to include more waste heat in an energy system and thus decrease primary energy consumption.