To achieve lower temperatures in existing district heating systems, the first step is to rank all the substations by their influence on the primary return temperature. The overflow method seems to be the most common and easy tool, based on each substation’s annual energy and volume use data, ideally monthly. This allows for the detection of temperature faults and prioritizes interventions between substations.
In the second step, visiting problematic substations allows gathering useful information and looking for the most obvious temperature fault sources. Monitored data can identify if the cause is due to setpoint and control problems, inadequate substation architecture, or issues with components in the secondary circuit of substations. Optimization of the secondary circuit will involve the building’s owner.
