NOWA is a program for calculating the stationary flow distribution in heated pipe networks under the influence of gravity. With water as the medium, it allows both the simulation of single-phase flows, as they occur in central heating and district heating systems, and of water-steam or steam flows, as they occur in steam generators. When a two-phase flow occurs, the pressure loss and the vapor advance can be calculated using various models commonly used in technology.


Due to the versatility in the simulation options, such as the simulation of

  • natural circulation systems
  • forced circulation systems
  • once-through systems

as well as the

  • pump design
  • throttle optimization

NOWA is used by well-known boiler manufacturers worldwide.


[1] P. Nowotny: Ein Beitrag zur Strömungsberechnung in Rohrnetzwerken, Fortschr.-Bericht VDI, Reihe 6, Nr.: 102, VDI Verlag, Düsseldorf, 1982

[2] A. Stribersky, W. Linzer: Ein Beitrag zum Problem der Stabilität beim Naturumlauf, Fortschr.-Bericht VDI, Reihe 6, Nr.: 154, VDI Verlag, Düsseldorf, 1984

[3] K. Ponweiser, W. Linzer und Y. Josifi: Stabilitätsbetrachtungen an einem Dampferzeuger mit einem Zwei-Trommel-Bündel, VGB Kraftwerkstechnik, Vol. 77, Nr. 3,  Seiten 178-180 (1997)