Energy Efficiency

ENERGY EFFICIENCY

Growing environmental concerns and an increased awareness of the impact our daily lives have on the environment has led to domestic appliance manufacturers focussing more on the energy consumption of their products. Many technologies have also been redesigned to comply with implementations of more energy efficient regulations. DEFY’s acquisition by Koç Holding’s domestic appliance arm, Arçelik, has resulted in large investments being made to improve the brand’s energy efficiency standards to world class. As a result, DEFY has become one of the most energy-efficient, sustainable domestic appliance brands in South Africa.

ENERGY RATINGS

The South African Bureau of Standards (SABS) has aligned their strategy to that of one of two global energy-rating systems, namely the European Union energy labels, as declared in the European Directive 1997/17/EC. This rating system makes use of an energy efficiency index (EEI) rating between A (most efficient) to G (least efficient). A+, A++ and A+++ were added in later years to further drive energy efficiency. DEFY is also aligned to the energy directive of the Department of Energy.

This is how we achieve world-class energy efficiencies:

Fridges and freezers

Fridges and freezers account for the largest single energy consumption for domestic appliances. Reducing the amount of energy that these units consume rests on two actions:

  • Improving the thermodynamic (“cooling”) efficiency of the refrigeration cycle
  • Reducing the amount of heat gain (“heating”) from the environment

UNDERSTANDING THE TECHNOLOGY

Refrigeration products make use of a thermodynamic refrigeration cycle.

refrigeration cycle

The cycle starts when the compressor increases the pressure on the low-pressure refrigerant gas, elevating the temperature. The refrigerant emits this heat to ambient surroundings as it moves along the condenser coil behind the fridge or freezer. The condenser coil is cooled with the heat being transferred to the passing air, as illustrated below.

airflow

As the refrigerant cools down, it starts to condensate and pool as a hot liquid. The refrigerant is then lead into the fridge cavity where it is pushed through an expansion valve. This results in a sudden decrease of the pressure on the liquid refrigerant, causing the liquid to start evaporating and the temperature to drop. The cold evaporated refrigerant proceeds along the evaporator coil, drawing heat from the fridge until it is lead back to the condenser where the whole cycle starts again.

HOW CAN WE IMPROVE?

Commercial refrigeration has been around since John Gorrie invented the freezer in 1842. In the following 170 years, the evolution of technology and refrigeration has vastly improved and continues to do so.

Apart from improvements in the mechanical equipment, two major aspects where we can still improve on are increasing the “cooling” effect while reducing unwanted “heating”.

DEFY currently uses a R600 refrigerant, more commonly known as Butane, in all its domestic refrigeration products. R600 is a readily available naturally occurring hydrocarbon that has less of an environmental impact compared with its synthetic equivalent, R134 (Tetrafluoroethene).

Keeping the inside of fridges cool is also no easy task. The ideal insulation would consist of a hyper-reflective surface held at a vacuum to eliminate radiation and the transfer of heat. Unfortunately, current technology combined with product durability and manufacturing costs limits the extent to which this approach can be pursued. The next best thing we can do is decrease heat conduction by improving insulation materials. DEFY uses self-expanding closed cell insolation to achieve optimal coverage within the fridge cavity and reduce the conduction of heat.

Recent investments at DEFY’s Ezakheni and East London refrigeration manufacturing facilities allows DEFY to bring world class manufacturing to the South African market. So while our products already rank among the best in energy efficiency in terms of electrical and thermodynamic performance, we can add peace of mind that our products also incur less environmental effects caused by transportation.