In this investigated domestic dishwasher a basic heat pump cycle functions as heating source to achieve
energy saving. To ensure resource-efficient performance, the working fluid needs to have a global warming
potential (GWP) below 150, be non-toxic and have a high coefficient of performance (COP) within the system.
For the working fluid screening propane (R290) is chosen as a reference refrigerant. Besides pure refrigerants,
zeotropic blends with adapted temperature glides are of particular relevance for energy optimization. In this
investigation, the predictive screening for a low-temperature glide blend resulted in a composition of
isobutane (R600a) and dimethyl ether (DME, RE170) with a molar ratio of 0.06 to 0.94 (GWP = 1.15). An
energy saving of up to 24.8 % comparing propane with the adapted zeotropic blend and an increase of the
COP up to 171 % compared to the pure electrical heating system could be achieved.