Demo 13 – Next generation refrigerator

With the recent update of the eco-design domestic energy labelling system (A-G labels), the average energy consumption in the domestic refrigerator market is projected to decrease by up to 30% by 2025. To contribute to this goal, Demo 13 explores innovative technologies and control strategies to enhance household refrigerator energy efficiency.

The demonstrator integrates multiple advancements:

• Refrigerant Optimization: Experiments with R600a/R290 blends demonstrate the potential for fast and energy-efficient cooling when the optimal mixing ratio is achieved. Tests in a domestic freezer suggest that a 90-10% mass percentage (R600a-R290) reduces energy consumption by 2.5%.

• Advanced Insulation: New high-performance polyurethane (PU) foams and vacuum insulation panels (VIPs) have been tested, leading to a 4% reduction in total heat gain. Optimizing the number of VIPs has further minimized heat gain.

• Electronic Expansion Valves (EEVs): The application of EEVs enables flexible cooling under different ambient conditions, improving defrost efficiency and reducing total energy consumption by approximately 2%.

• Parallel Cooling System: By ensuring operation at high evaporation temperatures, the system coefficient of performance (COP) has improved. This includes new defrost strategies that provide an additional 2% reduction in energy use.

• Component Enhancements: Further efficiency improvements are expected with the integration of higher-performance compressors, evaporators, condensers, and fans.

Prototype evaluations have confirmed a 10% reduction in energy consumption, with ongoing refinements targeting even greater efficiency. These results are crucial for designing high-energy-efficiency class refrigerators in line with updated regulatory requirements.

Publications:  

1) “Performance evaluation of a domestic freezer with R600a and zeotropic mixtures of R600a/R290”, 15th IIR- Gustav Lorentzen Conference on Natural Refrigerants (GL2022). Proceedings. Trondheim, Norway, June 2022. 

2) “Energy Consumption Performance Evaluation of a Household Refrigerator with Electronic Expansion Valve”, The 26th International Congress of Refrigeration (ICR2023). Proceedings. Paris, France, August 2023. 

3) “The Effect of Capillary Tube Parameters and Use of Multi-Capillary on Energy Consumption in Vapor Compression Cycle”, Cukurova 9th International Scientific Researches Conference. Adana, Turkey, October 2022