Heat accumulators

Heat accumulators are insulated tanks usually with a vertical axis, which are used to store thermal energy in the form of hot water at temperatures up to 95°C (130 °C).

The basic benefit of using a heat accumulator in a district heating system is to balance the load of the heat source with the customers changing energy demand.

Advantages of the heat accumulator are listed below:

  • Reduced fuel consumption and as a consequence emission
  • Haircut heat demand peaks without having to run an additional source
  • Cogeneration operational efficiency increase due to stable and continuous operation of power source
  • Reduced network water losses
  • Economic benefits due to power prices spread supported by flexible heat generation regime

Heat accumulator cross-section

Basic parameters:

  • Average volumes from 100 to 45.000m3 or more
  • Thermal power > 600 MWt
  • Heat capacity > 1000 MWh
  • Diameter 7÷40m
  • Height 16÷70m
  • Hot water temperature 95 – 130°C
  • Network retention 3-4 days


With our long track record the construction and design of heat accumulators we offer:


  • Support in selection of heat accumulator size basing on individual parameters
  • Engineering, construction and workshop designing
Przekrój poglądowy akumulatora ciepła

Two-chamber heat accumulators

Two chambers in the heat accumulator allow the storage of water at a temperature exceeding 100°C in atmospheric tanks. This is allowed by special technical solution described below.

Picture of two-chamber heat accumulator. Four cross-sections with temperatures written on different parts of the accumulator.

To date, we have built over 90 heat accumulators with a total volume exceeding 1,000,000 m3 of water, of which 5 pieces are two-chamber batteries.

At 30.01.2019, Midroc Rodoverken Production began prefabricating the equipment of 3 heat accumulators built in Sweden.

Gothenburg (H= 57 600 mm ; Ø = 23 000 mm ; V = 24 000 m3)

Hässleholm (H = 56 000 mm ; Ø = 21 000mm ; V = 20 000 m3)

Jönköping (H= 57 600 mm ; Ø = 23 000 mm ; V = 24 000 m3)