Normally, with central hot water supply circulation pipe, a circulation pipe is laid in the riser duct parallel to the hot water pipe. A cost-effective alternative to this is offered by Smartloop Inliner technology with a flexible circulation pipe in the metallic riser pipe.
With the one-pipe principal of Smartloop Inliner technology, supply and return are combined into one pipe. A separate pipe for the circulation water is not required. This does not only reduce the installation costs and save space. It also saves energy thanks to the 20-30 % lower heat radiation. In contrast to conventional circulation, the lowest system temperature with Inliner technology is not at the re-entry to the tank, but at the end connection pieces of the hot water riser pipes.
Internal circulation pipes can be used in every drinking water heating system. The hot water temperature should not drop below the exit temperature at any point by more than 5 K. The manufacturer must prove this function is in place by thermal and hydraulic measurement and be able to provide proof of it.