Enhancement of domestic refrigerator’s energy efficiency index using a hydrocarbon mixture refrigerant

This article presents an experimental investigation of substituting R134a with R436A (a mixture of R290 and R600a with a mass ratio of 56/44) in a 238 L single evaporator domestic refrigerator without any modification in refrigeration cycle. The refrigerator’s compressor was charged with different amount of R436A, and in addition to refrigerator’s power consumption during operation, the temperatures in different sections of the refrigerator were measured. Results showed that in comparison to the base refrigerator working with R134a, the ON time ratio and the energy consumption per day were reduced by 13% and 5.3%, respectively. Although the original R134a charge for this refrigerator was 105 g, the optimum charge for R436A was reduced to 55 g that exhibits 48% reduction in refrigerant charge. Also replacing R134a charge with R436A raised the energy efficiency index of the refrigerator from label “E” to label “D” according to Iranian National Standard No. 4853-2.

► Replacing R134a with hydrocarbons improves the appliance energy efficiency index.
► Using hydrocarbons is more economical than R134a due to their lower prices in Iran.
► Much lower charge of hydrocarbons is required for the same refrigeration capacity.