Heat meters - Heat cost allocators

Energy efficiency is at the heart of the national policy of rational energy use. Measuring energy, and in particular thermal energy, is one of the keys to this efficiency. Ecological issues and the need to control consumption costs are just some of the reasons for the development of measuring instruments to quantify heat exchange.

Heat quantities can be evaluated either by considering the conditions of heat transport, or by considering the conditions of heat emission.

In the first case, the heat quantity is measured using the flow rate and enthalpy by mass of the heat transfer fluid at the inlet and outlet of the exchange circuit, using a thermal energy meter (§ 1 ).

In the second case, the evaluation of the thermal emission of heat emitters, carried out :

• either from the temperature of the heat emitters, the ambient temperature or the configuration of the heat emitters;

• or on the basis of the room temperature, the outside temperature and the configuration of the premises, is done by a heating cost allocator (§ 2 ).

There are therefore two types of device: heat meters, which measure the amount of heat supplied, and heat cost allocators, which determine the value of a quantity representative of the amount of heat.