Development of a New Energy Efficient Combined Refrigerator/Freezer

Abstract

A development work was commenced in 1998 with the aim to develop an energy efficient, combined refrigerator/freezer optimised in relation to Energy Class A. The work is a co-operation between Vestfrost, the Danish Technical University and the Danish Technological Institute. The work is supported by the Danish Electricity Saving Trust.

In phase 1 of the project simulation models and several prototypes have been tested including a concept based on an idea from the Vestfrost company. In this concept the appliance has one refrigeration system with a variable speed compressor. The temperature in the freezer compartment controls the speed compressor.The temperature in the fresh food comparment is controlled by a small fan blowing cold air intermittently form a remote part of the evaporator in the fresh food compartment.

Two different appliances according to this principle were test by the National ConSumer Agency of Denmark showing excellent resulst, The energy effciency indies were 40 and 46 %, well below the 55 % index limit energy effciency class A.

Results froom the lab tests are in fine agreement with simulation resulst. An economic calculation shows that the cost of the appiance carries a modest 5 % penalty only, and the simple pay back time will be 1 – 2 years.

Phase 2 of the project is now progresssing and 60 units will be tested in typical apartments over the next 12 months.