District Heating

District Heating

Apros can be used to model and analyse district heating networks and also long-distance district heat transmission circuits. District heating is a system for distributing heat generated in a centralised location for residential and commercial heating requirements such as space heating and water heating. Apros is an excellent tool for detailed dynamic simulations of these complex networks.

Apros software includes comprehensive component libraries for modelling all the components found from district heating networks including pipes, valves, pumps, heat exchangers and heat reservoirs. Also automation and electrical components can be used to model the I&C of the whole network (controlling pump power, valve positions, modelling operator actions etc).

Apros includes components for modelling even the services tunnels of the district heating network. Thus environmental conditions inside the service tunnel can be calculated e.g. in the case of a steam or hot water leak.

The district heating pipeline can be connected directly to a CHP (Combined Heat and Power) plant model. In this case, it’s possible to run dynamically different plant transients and study the behaviour of the entire district heating system.

District heating case: Loviisa 3 new build NPP project

“Apros has been used in the Loviisa 3 new build nuclear power plant project to study the possibility of combining heat and power production. Preliminary studies of the 77-km-long district heating transmission line have been calculated with Apros. These studies have solved many uncertainties in the technical design of the system and we have gained confidence in the technical solution. Pump trip and pipeline leak simulations are essential to see how the system can cope with different operational transients.”
Olli Kymäläinen, Project Manager, Loviisa 3 new build NPP project

Read more about the Loviisa 3 analyses from the conference papers:

SMiRT 20 Conference, Finland, 9-14 August 2009
Investigations of a Long-Distance 1000-MW Heat Transport System with Apros Simulation Software
Matti Paananen and Tommi Henttonen
Fortum Nuclear Services Ltd

ENC 2010 Conference (European Nuclear Conference), Spain, 30 May – 2 June, 2010
Nuclear Combined Heat And Power – Analyses of Hot Water Pipeline Breaks in a Service Tunnel with Apros Simulation Software 
Tommi Henttonen and Matti Paananen
Fortum Nuclear Services Ltd

Advantages of Apros:

Detailed modelling of thermal hydraulics:

  • Accurate two-phase calculation methods (six equation models with gas and liquid phases)
  • Mass flows, flow velocities, pressures, temperatures, void fractions etc
  • Pressure losses, heat losses
  • Different insulation materials can be defined

Comprehensive component libraries:

  • Many pump and motor types and the possibility to give detailed technical specifications of the components as input
  • Different valve types (basic, control, shut-off, safety, check, flap valve)
  • Electrical and automation component libraries
  • Calculation components for modelling the environmental conditions inside the service tunnel (temperatures, flow velocities, steam fractions etc)

Dynamic system response is easy to calculate:

  • Pump trips
  • Changes in supply and consumption of heat
  • Pipe leaks (even double-ended break, 2*100% can be calculated)
  • Malfunctions
  • Operator actions

Apros model of a district heating transmission system can be used:

  • To improve network performance and service reliability
  • To study the dynamic behaviour of a system in transients
  • To study network bottlenecks
  • In preliminary planning and testing of different designs
  • In safety analyses