One option for the latter is the use of speed-controlled compressors. Household refrigerators and freezers are usually operating in- termittently through a simple on/off control.The application of speed-controlled compressors would enable for a transition to a sustained operation.This would decrease friction and throttling losses in the compressor, increase the evaporator temperature and decrease the condenser temperature, avoid shifting of the refrigerant due to pressure equilibration during standstill and result in a reduction of power consumption by up to 30% (Binneberg et al., 2002).