The energy consumption for distributing heating and cooling media in buildings depends on the flow resistance in the hydraulic systems. During the course of evolution, nature has developed various energy-efficient solutions for reducing drag. In addition, there are already numerous bionic developments, such as the bionic pipe elbow or optimised surfaces, which can reduce pressure losses in thermal networks. However, these have not been used so far in heat and cooling distribution networks.
2 to 3 per cent of the total electrical energy demand is caused by circulating pumps in single family and apartment houses (EU, Barthel, 2006). The German Energy Consumers' Association estimates the energy demand for circulating pumps in all German heating systems, including non-residential buildings, to be around 15 terawatt hours per year (TWh/a). This corresponds to 3 per cent of the total electricity consumption in the Federal Republic of Germany. In addition, if all the cooling in private households and for commercial and industrial use is also included, an energy demand for all circulating pumps of about 20 TWh can be assumed. This value is higher than the energy required by all German rail transport, including all trams and metro systems. There are therefore considerable possibilities for saving energy.
The project is focussing on reducing the power requirements for distributing heating and cooling media in buildings by employing new as well as already proven bionic principles.To this end, the pressure loss reductions resulting from employing different optimised fittings, pipe surfaces and drag reducing additives were proved, firstly for individual components and ultimately for overall systems: for example with pipe bends, pipe materials and modified carrier media. The scope is to optimize the hydraulics of heating and cooling networks so that the interaction of the individual components produces the lowest possible pressure loss.
Bionic fittings for deflection and flow separation which reduce the individual pressure losses by 20-30 per cent have been developed. Practice-based tests are being conducted on carrier media additives that reduce pipe friction resistance in heating networks by about 40 per cent.
For newly installed domestic heating and heat distribution networks, the carrier media additives and the new fittings can be used in combination to reduce pressure losses by a total of about 40 per cent – or to enable the use of smaller pipes. The new fittings can be used in all pipe networks with a high proportion of fittings. The new fitting geometries can be used with minimal space requirements in integrated systems and components such as combi boilers and compact heat generators.