Changing Green Into Orange – keeping it cool with IWC

Sundays River Citrus Company recently completed the erection of 10 Degreening rooms and we were contracted by Coldfact Projects to supply 2 EWK 441 package cooling towers that would be used in conjunction with two water cooled chillers.

Sundays River Citrus Company is the largest grower, packer and exporter of South African citrus and is internationally renowned for their trusted supply of citrus. Since 2006, South Africa has been the second largest exporter of fresh citrus in the world after Spain. Citrus is the second biggest agricultural foreign exchange earner, only just behind wine that stands at R7 billion.

Why is the cold chain important and what is degreening.

Citrus is cooled to maintain the quality of the fruit, to slow down the ripening process and respiration, and to stop or slow down the development of postharvest diseases. Once citrus is cooled, whether that is in degreening rooms, at the packhouse or when it reaches the harbour, the cold chain must not be broken.

Degreening is the process of removing the green colouring (known as chlorophyll) from the skin of citrus fruit. This is achieved by introducing measured amounts of ethylene gas into a temperature and humidity controlled environment. Temperature is critical to the degreening process and room conditions are controlled between 19 and 23°C with relative humidity at 98% .
Temperature is controlled with chilled and hot water and humidity with high pressure spray nozzles. The degreening process takes up to 72 hours for the fruit to change colour and then it is ready for washing and packing.

Where do our cooling towers fit into the process?

The IWC produced range of EWK package cooling towers are an integral part of the cold chain and refrigeration equipment that ensures the supply of cold/chilled water to maintain the temperature in the degreening rooms.

Coldfact’s solution encompassed two water cooled chillers using EWK package cooling towers on the condenser circuit. The selection of water cooled chillers was due to the fact that they are more energy efficient than air-cooled chillers.

The condensing temperature of the refrigerant in a water-cooled chiller is dependent on the condenser-water temperature from the cooling tower, which in turn is dependent on the ambient wet-bulb temperature. Since the wet-bulb temperature is often significantly lower than the dry-bulb temperature, the refrigerant condensing temperature (and pressure) in a water-cooled chiller is lower than in an air-cooled chiller.

Lower condensing temperatures result in lower condensing pressures, therefore the chiller’s compressor needs to do less work and as a result, uses less power for the same refrigerating capacity. All in all, a cost and energy efficient solution.

What is a cooling tower and why is it used?

In simple terms, a cooling tower is a device designed to reject unwanted heat into the atmosphere. Water is a highly effective heat transfer medium and as such is used extensively in the refrigeration industry for rejecting heat generated in the refrigeration process.

Why choose our towers?

Our iconic EWK cooling tower range are manufactured in a robust, durable and compact glass reinforced polyester casing which means they can withstand the harsh South African sun.
The towers are also corrosion resistant so they are idea for costal applications.