The above points translate to better cost optimization of the heat generation.
buildings. Finally, the case analysis considered the impact the thermal source's temperature would have on the economics of the system. The results of the case analysis are shown in Figures 4 and 5. The figures clearly show that 4 th generation district heating systems have significantly better economics than 5 th generation systems. Final words As the case study focused on a suburban setting, which is typically considered outside of the core district heating zones, which are densely populated inner cities with concentrated heating demands, it points to that the 5th generation requires specific conditions to be in place to ensure its competitiveness. These conditions are like to occur when an economy of scale from central heat generation is not achievable. These condi- tions might occur at small settlements with relatively few houses. Instead of each house operating their own ambient heat source, for example a geothermal loop, the settlement could share a larger and more cost-efficient geothermal loop. In that sense the 5th generation can also be classified as ex- tended individual heat pump system.
But there is also the fact that if there is an insulated network, the system is significantly better positioned to enable energy- efficient utilization of any heat source with a higher tempera- ture level than the ambient. In ambient loops, higher waste heat temperatures than the ambient could only be used with high heat losses in the uninsulated network. 5G claim: Cooling is an integral part of the 5G solution and effectively separates 5G from 4G This is the only part where the 5 th generation has a clear ad- vantage over the 4 th generation regarding residential cooling demands, at least compared to the original definition of the 4 th generation, which was written by Scandinavians, where resi- dential cooling demand is virtually non-existing. In principle, the cooling demand could be integrated into the 4 th generation the same way as in the 5 th generation, by us- ing the distribution network as a heat sink for end-user located heat pumps. For commercial cooling demands, which tend to be con- centrated and more prominent than residential cooling de- mands, the most efficient supply systemwould be a dedicated district coolingsystem, as is applied inParis, Stockholm, Helsinki, Copenhagen and many more cities around the world. How does the 5 th generation economically stack up to the 4 th generation? Due to the relatively few 5 th generation systems, there is a gen- eral lack of economic comparison of these solutions. This has, however, been compared in the paper “Economic compari- son of 4GDH and 5GDH systems – Using a case study” [2]. The case analysis compared the cost of these two generations sup- plying a suburb area in two locations with different climates, Copenhagen and London. The case analysis further investigat- ed the impact on the system economics if it would be supply- ing either existing high energy buildings or new low energy
References
Lund, H. et. al. , 4 th Generation District Heating (4GDH). Integrating Smart Thermal Grids into Future Sustainable Energy Systems. Energy, vol. 68, 1-11, 2014. https://doi.org/10.1016/j.energy.2014.02.089
Gudmundsson, O. et. al. , Economic comparison of 4GDH and 5GDH systems – Using a case study. Energy, vol. 238, 2021. https://doi.org/10.1016/j.energy. 2021.121613
For further information please contact: Oddgeir Gudmundsson, og@danfoss.com
Comparison of the solutions – Annual cost of heat for the average connected building in London
Figure 5: Levelized cost of heating for high energy (HE) and low energy (LE) buildings in London for various thermal source temperatures. ATDH is the 5 th generation and LTDH is the 4 th generation.
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