Two single uninsulated pipes in a trench
Twin pipe in a trench
Figure 3: Trenches of uninsulated pipes, left, and twin pipes, right.
5G claim: End-user heat generation leads to higher efficiencies This is a fascinating point. Without a doubt, the efficiency of heat pumps is higher the lower the temperature lift, i.e., the less you need to increase the supply temperature, the more efficient your operation becomes.
a. In principle the savings of losses in the power grid can go long way towards the heat loss in the 4 th generation dis- trict heating system, considering the COP of the central- ized heat pump 5. Centralized heat pumps can access power at lower cost due to the aggregated demand and by connecting with the high voltage grid 6. In a combination with a district cooling system both sides of the heat pump can be exploited, creating a uniquely high system energy efficiency a. While this is commonly mentioned as inherent part of the 5G systems its is not to the same extent, as waste heat from the cooling operation in 5G systems is not delivered at a useful temperature level to the loop, it is mainly tak- ing over part of the loop regeneration purposes of the heat source 7. Centralized heat pumps and centralized thermal storages are uniquely positioned to decouple the heat/cool demand and the heat/cool generation, enabling it to take greater ad- vantage of electricity tariffs, low carbon power periods and provide power grid balancing services
There is, however, more at stake here than one might initially consider. For example:
1. Centralized heat generation enables economy of scale by taking advantages of simultaneities and the aggregation of the heat demand
2. Large scale centralized heat pumps are both more cost and energy efficient than small end-user heat pumps
3. Large scale centralized heat pumps are professionally main- tained and the operation is optimized, leading to stable and energy efficient operation and long lifetimes 4. Centralized heat pumps connect to a higher voltage grid, which avoids potential power losses in the power transfor- mation stations and distribution grid
Comparison of the solutions – Annual cost of heat for the average connected building in Copenhagen
Figure 4: Levelized cost of heating for high energy (HE) and low energy (LE) buildings in Copenhagen for various thermal source temperatures. ATDH is the 5 th generation and LTDH is the 4 th generation.
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