The planning tool for district energy systems

Load profiles for buildings and districts

For the planning of districts, the correct estimation of demand profiles is crucial. To properly account for seasonal and daily variations, annual profiles with hourly resolution are recommended.

Load profiles for district planning

Depending on the planned energy system, different demand or load profiles are important for district planning. These include:

Whereas standard load profiles can often be used for plus load demands, the generation of load profiles for domestic hot water and cooling is more complex. Often, dynamic simulations have to be carried out. Important attributes of a demand profile is the maximum demand and the annual demand (heat load and annual heat demand).

Load profiles for different building types

A variety of building types are available in nPro for which demand profiles can be generated with hourly resolution. These building types include:

In the nPro tool, load profiles for plug loads, e-mobility, space heating, domestic hot water, space cooling and process cooling can be generated with an hourly resolution.

Generation of load profiles

For district energy planning, at least a full year and an hourly resolution should be considered. Only in this way, it is possible to map seasonal fluctuations as well as daily fluctuations in generation and consumption with sufficient accuracy. Energy calculations based on monthly or daily averages are not sufficient. For example, if electricity generation from photovoltaics is averaged for a day and overlaid with a building's demand profile, the calculated self-sufficiency rate is much higher than if the overlay is calculated with an hourly resolution, because a coarser temporal resolution reduces the generation peaks of the photovoltaic system at noon. For electricity, a 15-minute resolution is considered in some cases because electricity-based systems, unlike thermal systems, do not exhibit temporal inertias, which would justify averaging.

Generation of demand profiles for heating and cooling

To generate heating and cooling demand profiles, either detailed dynamic building simulations can be used or simplified calculation approaches based on degree hours can be resorted to. The advantage of simplified calculation approaches is that far fewer input parameters are required, which, for example, are not yet known at an early planning stage.

In the nPro tool, to generate load profiles for space heating and space cooling, calculation approaches are used which require only a few input parameters and can therefore be used very flexibly.

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