Editorial Feature

Energy-Efficient Lighting for Refrigerator Cabinets

This article was updated on the 11th September 2019.

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Owners of supermarkets, convenience stores, butcher’s shops, and cafés want their food products to be well lit and attractive to customers, but refrigerator or freezer cabinets are an impractical place to install lighting systems.

Firstly, the heat produced by a light inside a refrigerator or freezer places an additional load on the refrigeration system. Secondly, at freezing or near-freezing temperatures, fluorescent lights produce only a fraction of their normal light output while using just as much electricity.

Australian company Poly Optics Australia Pty Ltd. has taken on the challenge of developing a lighting system for commercial refrigeration systems that provide comparable levels of illumination and is both attractive and energy-efficient.

Poly Optics has developed specialized technology to produce fiber optic cables for transporting and emitting light for specialized applications. They have coupled this expertise with the latest lighting technology using light emitting diodes (LEDs).

The company received funding assistance through the Queensland Sustainable Energy Innovation Fund to develop such an energy-saving lighting system for commercial refrigerators.

LEDs were invented in 1962, with the first being a red LED. Since 1968, LEDs have been widely available for use as small indicator lights. Initially, white LEDs were relatively inefficient and extremely expensive; however, LED technology has improved dramatically and new LED lamps that are easily accessible are more efficient, lower in cost, and work to a higher power.

Throughout Poly Optics’ project, as more efficient and higher-power LED light sources were developed, the company has produced a range of prototype systems. By the conclusion of the project, Poly Optics had developed an LED refrigerator lamp that used half the power of a standard fluorescent tube, while producing the equivalent light output and ambiance. By producing less heat within the refrigeration cabinet, the prototype LED lamp reduced overall power consumption by nearly one-third and reduced the risk of food spoilage.

The LED lighting unit can be mounted within the refrigerator cabinet as a direct replacement for a fluorescent tube or can be mounted with the LED lamp located outside the refrigerated section of the cabinet.

Since the fiber optic cable is made from polymer materials, the technology eliminates the use of glass within the refrigerated cabinet. This removes the potential risk of broken glass mixing with food and drink products.

Efficiency and light output of fluorescent lamps declines dramatically at reduced temperatures. Light output for a typical fluorescent tube is less than half normal illumination at temperatures inside a refrigerator cabinet, and less than 20% normal light output for operation at freezer temperatures.

Poly Optics continues to refine their technology as LED technology evolves and efficiency improves. By mid-2007, Poly Optics was able to produce a refrigerator light containing a single 10-watt LED, producing 500 lumens of light. When operated continuously over ten years, the lamp would provide electricity costs savings of about $700, compared to a conventional fluorescent fitting.

Although the lighting technology developed by Poly Optics through the QSEIF program was originally intended for commercial refrigeration, it could be applied cost-effectively in many other applications. Any lighting system requiring long tube lifetime and low maintenance, low heat dissipation, and high efficiency might benefit from this innovative product.

Poly Optics won the EPA’s Innovation in Sustainable Technologies Award for its fiber optic lighting systems integrating optical cables and LEDs.

Source: The Queensland Sustainable Energy Innovation Fund (QSEIF) - assists Queensland organisations to develop innovative technologies that reduce environmental impacts associated with consumption of fossil fuels and water.

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