Heat networks high temperature households (district heating) – small-scale

A typical small scale district heating network consist of a main heat source, peak/back-up heat source(s) and a distribution network including connections to the dwellings. Inside a dwelling a heat delivery set is installed (Dutch: afleverset) in order to transfer hot water to the pipes and radiators. In contrast to a large scale network there is no primary transport pipeline. Whether a substation is needed/included in a small scale network depends on the sort of network. Different heat sources can be used for instance a biomass heat plant, collective aquifer thermal energy storage (ATES), or natural gas fired CHP. In case of a biomass heat network with about 1.000 dwelling-connections there is a substation with heat exchanger. In case of a smaller network such as collective aquifer thermal energy storage (ATES) there are no substations.

A small scale heat network in the Netherlands supplies less or equal than 0,15 PJ of heat per year (ECN, 2017). These networks can also supply heat to other sectors such as to non-residential buildings. An average small scale network supplies heat to 50.000/219=230 dwellings per network and average heat supply is 2.000TJ/219= 9TJ per network. In case of a biomass plant typically 1.000 dwellings or more are connected (based on VESTA model). A typical ATES network is smaller (about 200 dwellings, for example).A network with 100 dwellings would supply 3,4 TJ per year based on a heat demand of 34 GJ/dwellings (based on VESTA model).