Effect of Design Static Pressure Level on Energy Efficiency at Low Energy District Heating Systems

Low-Energy District Heating (DH) systems with low-temperature operations, such as 55 °C in terms of supply and 25 °C in terms of return, were considered to be the 4th generation of the DH systems for the low-energy future with energy efficiencies focused to be achieved at newly built and existing buildings by the Danish building regulations.

Therefore focus has been given to reduce the heat demand of the consumer site with integration of low-energy buildings, to be considered for new settlements and with renovation of existing buildings to low-energy class. The reduction of heat demand increases the ratio of heat loss from the DH network in comparison to the heat supplied to the district.

In our former studies, the low-energy DH system was optimized with the aim of reducing the heat loss from the low-energy DH network in a certain limit of static pressure level of 10 bara. Thus, in this present study different levels of static pressure were investigated in design stage to discover the effects of different pressure levels on optimal pipe dimensions observed by use of the dimensioning method defined for low-energy DH networks.