Energetic and exergetic analysis of a low-temperature based district heating substation for low energy buildings
2015 (English)In: ECOS 2015: Proceedings of The 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems: Buildings, urban & distributed energy systems, Pau, Fr: ENSGTI, Pau University , 2015Conference paper (Refereed)
District Heating (DH) technology contributes to low GHG emissions energy system, facilitates a renewable energy usage, and increases the overall system efficiency, while providing the necessary heating services to the built environment. However, the existing DH technology may not be technically and economically effective to service buildings with low-energy demands. Here, low-temperature based district heating (LTDH) provides a better match between supply and demand in terms of energy quality. This paper deals with the energy and exergy analyses of a LTDH substation supplying a secondary LTDH network as a subnet of the existing DH system. The substation is supplied with a mix of supply and return flows from the main DH network. An energy and exergy analysis based on modelling and simulation was employed to compare the performance of two proposed substation configurations to that of a conventional DH substation operating at low-temperature levels. The study was performed for a year round temperature range scenario under steady-state conditions. The exergy destruction for the system components were identified and compared. The results of this analysis show that by using the low-temperature flow from the DH return pipe, the final exergy efficiency of the overall system is increased. On the other hand, assuming an adiabatic system the energy performance stays the same. As compared with the conventional DH network, the integration of the proposed LTDH substation reduced the required amount of water from the main DH supply by 20-30% and improved the overall exergy efficiency from 79% to 85-87% depending on the substation configuration. Based on the results, the solution presented is seen as an effective approach to reduce the system’s losses, and to increase the quality match between the low-energy heating demands and the supply.
Place, publisher, year, edition, pages
Pau, Fr: ENSGTI, Pau University , 2015.
District Heating, Low Temperature, Substation, Exergy, Efficiency, Temperature Cascading
Research subject Energy Technology
IdentifiersURN: urn:nbn:se:kth:diva-185719OAI: oai:DiVA.org:kth-185719DiVA: diva2:923018
The 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, ECOS; 2015 Jun 29 – Jul 3; Pau, France
QC 201605102016-04-252016-04-252016-05-10Bibliographically approved