2 Sisters Storteboom - Zeewolde


In 2011 Bort de Graaf Refrigeration Technology built, commissioned by 2 Sisters Storteboom (department Zeewolde), the total refrigeration for this company.

In this project the whole location was built from scratch but the existing NH3 cooling and freezing installations were reused. To garantee very low freeze temperatures the installation was rebuilt and extended to a NH3/CO2 installation.


  • About 7500 m2 refrigeration area;
  • NH3 as refrigerant for the  cooling areas;
  • CO2 as refrigerant for the freezing, evaporation temperature -48℃;
  • Two IQF-tunnels (spiral tunnels), three shock freezers, temperature -40℃;
  • All production areas below 4℃. 
 Piping on roof  CO2-compressors  IQF-tunnels
Leidingwerk op dak CO2-compressoren IQF-tunnels