Framtidens Fjärrvärme : Teknik och Integrering

Sammanfattning: The world's energy consumption has been a high priority in the recent years, and the development is constantly going in the direction to reduce this. Energy covers many needs, including heating of real estate. In Sweden, about half of all heating is conducted via district heating. Thus developing district heating towards becoming more energy-efficient is therefore an essential part of reducing the worlds energy consumption. Much indicates that the development will go towards a new generation of district heating, the fourth generation. This means lower distribution temperatures, where forward and return pipes will assume temperatures of 55 ° C and 25 ° C, instead of 70-120 ° C and 40-50 ° C, respectively. This report describes what the fourth generation district heating (4GDH) probably will look like. This was done with a focus on energy perspective. A major challenge will be the integration of this new technology into the already well-established district heating network. The lower temperatures will be able to supply both new and old houses with their respective demanded heat. Older houses are generally poorer isolated and moreover adapted to the higher distribution temperatures, while new construction is easier to integrate into the new system. The report also lists the technical solutions that are likely to be relevant. The establishment of 4GDH denotes that renewable sources will be able to be utilized to a greater extent. This is because these sources usually produce low-temperature heat. This applies mainly to geothermal and solar heating. In addition, it will be easier to integrate waste heat from the networks, from industries as well as larger refrigeration systems, such as server halls.The district heating network is made up of primary and secondary networks. When connecting the secondary network to the primary network, three different methods have been identified that are compatible with 4GDH. These are mixing shunt, three-way shunt and heat exchanger. Coupling principles for hot water heating and heating with radiators are also objects for change with regard to 4GDH. Instant DHW preparation and indirect coupling of heating systems are the principles found to be applicable.Integration of older settlements into a low temperature network has proved possible, but it will entail extensive renovation projects or installation of, for example, radiator fans. Renovations can be expensive, thus in many cases radiator fans are preferred. However, the installation of pipes adapted for low-temperature district heating will be less costly and the construction time will decrease. District heating is therefore facing major development opportunities, but there are other measures to take, to further optimize this technology. Such a method is to introduce so-called smart metering of district heating. This allows consumers to become aware of their energy consumption, which according to previous research is an important factor in changing individuals behavior. In addition to 4GDH, the term U-LTDH is presented, a district heating network with even further lower temperatures.A low-temperature district heating network, together with the community becoming more aware of energy consumption, are both necessary to optimize district heating.