Annual heat demand
The annual heat demand is a calculation parameter for the energy demand in countries in which residential and commercial buildings are heated due to seasonal climate fluctuations . Depending on the climatic zone as well as on the lifestyle and comfort requirements, the specific annual heat requirement differs according to regions and countries.
Technically defined, the annual heat demand is the heat energy that can be used for heating purposes and to cover the heat demand of accompanying components such as hot water preparation during a year. The annual heat demand Q is given in kWh, MWh, kJ or MJ and can be measured with a heat meter.
If the heat meter is attached to the boiler flow and return, the amount of heat given off to the boiler's distribution system during a heating period is obtained. This is shown as the area under the red curve in the diagram on the right.
For more detailed considerations, the annual heat consumption is classified, for example according to the outside temperature or the number of operating hours. In these diagrams, switching points can be read off for mono- or bivalent operating modes and for storage loading and unloading processes.