Substations

A substation is a technical facility located in every building served by the water loop that transfers the heat between the building and the loop water:

• if it takes heat from the loop, it transfers that heat into the building: the building is heated and the loop water is cooled;
• if it takes heat from the building, it transfers that heat into the water of the loop: the building is cooled down and the loop water is heated.

The heat pump

Every substation has one or more heat pumps, a thermodynamic device doing exactly what it name suggests: pumping the heat from a place to put it in another one. Everyone has at least one heat pump in his home: a refrigerator! This appliance indeed takes heat that is inside its cavity (that’s why it’s cold inside and you must keep the door closed) to put it outside its cavity (touch the grid located in the rear of your refrigerator: it’s hot when the refrigerator in in operation).

Of course a substation is a more complex thing than a mundane fridge, but the operating principle is similar:

• the refrigerator transfers the heat in only one way: from the air inside to the air outside, in the kitchen for instance;
• the substation facility transferts heat between the building air and the water of the loop in both ways: putting heat into or taking it from the building.

Substation operation

The video below briefly describes how a substation operates