Application of Intelligent Thermal Battery in district heating systems.

Intelligent Thermal Battery can support district heating systems in various ways. The main benefits that can be achieved are:

1.     Optimization of substations: reducing peak demand or increasing the performance of overloaded branches.

2.    Optimization of heat generators' operation: improving the efficiency of central heat generators, boilers, and heat pumps.

3.     Unit cost optimization: prioritizing renewable, non-controllable, or waste heat sources.

Optimization of substations

In the diagram on the left, the cooling demand is shown in blue and the available capacity is shown in red. Higher capacity is required to meet the morning and evening peaks. The morning and evening peaks can be reduced by using thermal batteries. During the off-peak periods, the available heat generators (even at partial load with better efficiency) charge the thermal battery, and the stored energy covers the peaks, thus balancing the demand.

Overloaded branches may occur in the pipe network when the system is unable to fully meet the demand of certain consumers. In such cases, instead of expanding the pipe network, thermal batteries can also be used to cover the demand during challenging periods.

By using local thermal batteries during off-peak periods, when the district heating system's capacity is sufficient, the thermal battery is charged, which later covers the challenging peak demands.

The optimization of heat generator operations

As we have shown in our previous articles, the efficiency of different heat generating equipment (e.g., boilers, heat pumps, etc.) depends on the external temperature and the partial load.

With the help of thermal batteries, we have the opportunity to use this equipment not when the demand is highest, but when the system efficiency is at its best. This way, operating costs can be reduced.

Optimization of unit costs

In a district heating system, there are typically several types of heat sources. With the help of a thermal battery, we can prioritize between them.

The share of uncontrolled and waste sources can be increased in the energy mix, such as biomass (uncontrolled), solar panels, solar collectors, industrial waste heat (in case of intermittent availability), and heat pumps (operated more efficiently during the day).

The above diagram shows the district heating production, with the blue colour representing the case without a thermal battery and the green colour representing the case with a thermal battery. The photovoltaic (PV) panel production is shown in grey. Since PV production is highest between 12 and 16, when the demand is lower, some of the generated energy is not used. With the help of a thermal battery, this energy can be stored and utilized later.

Thermal batteries offer numerous benefits for district heating systems, such as reducing peak demand by optimizing substations and increasing the performance of overloaded systems. Furthermore, the efficiency of heat generators can be improved, as thermal batteries allow for optimal operation of equipment during periods of highest efficiency. In addition, unit costs can be reduced by prioritizing renewable and waste heat sources in the district heating energy mix, with stored energy being utilized at later times.