Renovation of domestic hot water production in 12 social dwellings.


In this social housing building, heating is supplied by a renovated district heating grid connected to a wood-fired heating plant. Until now, the Domestic Hot Water production was ensured by individual electrical water heaters. The replacement of these individual solutions (in 12 dwellings) by a collective heat pump induces in a 50% reduction on the electric bill due to domestic hot water production.

Some figures

  • Before renovating, the primary energy consumption due to DHW production was about 75 kWhep/m².yr
  • Final objective for ep consumption is 24 kWhep/m².yr.

Key facts

Building Heat pump and source
Location Soissons, France Number of HP 1
Construction 1975 Installed power 11kW
Heat distribution collective Operation mode DHW only
Heated area 841 m² living Heat source outside air
Level of insulation average
Heating system Domestic hot water
Heat demand unknown Type of system central
Heating temperature unknown Max. temperature 60 °C
Hot water storage 1500 l
Distribution System Thermodynamic loop heater
Other information
Electric energy consumption 2016 29 kWhep / (m².yr)
Investments costs unknown
Renewables ratio 50%

Description of the technical concept
The system consists of:

  • A 11 kW Atlantic® air-to-water heat pump
  • 2 storage tanks with a 750 liters capacity each
  • An Atlantic® thermodynamic loop heater

The system functioning is based on an accumulated mode : the storage tanks allow to store the daily DHW
needs. Then, the heat pump produces heat during the night, for 8 hours continuously.

Even if the outside air temperatures are lower during the night, this type of operation offers advantages in
terms of performances :

  • After a day of draw-offs, the volume of water in the tanks is completely cold  optimized COP
  • An operation during night allows to benefit from lower electricity tariffs

Case study sheet FR Soissons