District heating network ? District heating

District heating is the name given to the distribution of heat to a number of buildings in a city, district or housing complex, using a heating fluid circulating in a network of pipes.

In recent years, there has been a tendency to refer to these installations as heat networks, but it is preferable to reserve this name for the network itself, i.e. the heating fluid transport pipes that link the heat source to the substations (points where heat is delivered to users).

The article "Heat networks. Transport" [BE 2 170] essentially deals with the transport of energy between the source, substations and users, while the present article [BE 2 172] deals with heat sources and substations.

The advantages and disadvantages of distribution by heat networks are discussed at [BE 2 170] , along with the concepts of :

• of power to be supplied to the network ;

• a load curve giving the power to be supplied to the grid over the course of a year as a function of the calendar;

• rated flow curve showing the number of hours during the year when a given percentage of the maximum installed power was supplied;

• load factor, ratio of the sum of power demanded by users at a given time to the sum of subscribed power;

• instantaneous efficiency, ratio of the power supplied to all users to that supplied to the network at the same instant;

• average annual yield: ratio of the sum of annual consumption by customers to that supplied to the network over the same period.

District heating systems, which use high-pressure, high-temperature fluids and distribute them across the public domain and residential buildings, must take into account the potential hazards these fluids may present: installations must be built in compliance with all applicable regulations, and every effort must be made to ensure safety.