Conventional dishwashers require large amounts of high-quality electrical energy. The largest share of this energy is used for heating the rinsing water, the dishes and the housing. The heating is accomplished using an electrical resistance heater. It therefore makes sense to implement measures that reduce the electrical energy required for heating purposes.
For this CTI project, a heat pump for dishwashers was developed that reduces the electrical energy demand of the dishwasher. The entire system is heated with the process water, which is heated in the condenser of the heat pump. The evaporator is embedded within a latent heat storage. By using the solidification enthalpy of the phase change, the overall size of the heat source can be minimized.
As an additional measure, a modified drying process was developed in combination with the heat pump. This process positively influences the efficiency of the heat pump by lowering the inner temperature lift of the heat pump. Through these measures the electrical energy demand can be reduced by 30-50% compared with today’s standard dishwasher models.