Papers Published

1. Lorente, S. and Wechsatol, W. and Bejan, A., Tree-shaped flow structures for human-scale and small-scales applications, Heat and Technology, vol. 22 no. 1 (2004), pp. 15 - 25 .
   (last updated on 2007/04/06)

   Abstract:
   Tree-shaped networks provide maximum access for currents flowing between discrete points (sources, sinks) and infinite numbers of points (lines, areas, volumes). This is a growing area of research. The first part of this paper reviews the main features and qualities of newly generated tree architectures at human scale: hot water distribution networks. Optimized are not only the diameters and layout of pipes, but also the distribution of thermal insulation over all the pipes. Three types of architectures are optimized and compared (in order of increasing performance: string layout, growth by adding one new user at a time, growth by pairing existing optimized constructs). The second part of the paper reviews the progress on networks of small channels distributing a stream over a disc, by flowing from the center to the periphery. Tree-shaped architectures are generated based on global optimization, by optimizing every geometric detail. A powerful, fast, but approximate alternative is the local optimization by which every tube length is minimized for a fixed area element. The area element derives its shape from the minimization of tube length. The similarities and relative advantages of globally and locally optimized networks are discussed.

   Keywords:
   Thermal insulation;Pipe;Electricity;Trees (mathematics);Approximation theory;Optimization;