Sundays River Citrus Company completed the erection of 10 de-greening rooms some time ago , and IWC was contracted by Coldfact Projects to supply two EWK 441 package cooling towers that would be used in conjunction with two water cooled chillers .
BUSINESS AND TRAINING
INCORPORATING COLD CHAIN
Changing green into orange – keeping it cool with IWC
Sundays River Citrus Company completed the erection of 10 de-greening rooms some time ago , and IWC was contracted by Coldfact Projects to supply two 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 DE- GREENING ?
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 post-harvest 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 .
De-greening 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-
Oranges before de-greening process .
Industrial water cooling EWK cooling tower .
controlled environment . Temperature is critical to the de-greening 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 de-greening process takes up to 72 hours for the fruit to change colour and then it is ready for washing and packing .
WHERE DO IWC ’ S 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 .
Our iconic EWK cooling tower range is manufactured in a robust , durable and compact glass reinforced polyester casing which means they can withstand the harsh South African sun . The towers are :
• Non-corrosive so they are ideal for costal applications
• Light weight
• Reliable
• Low energy consumption and easy to maintain
• Plug and play design results in a simple installation CLA
SOURCE
Supplied by IWC
Oranges after de-greening process .
Images supplied by IWC
IWC was contracted by Coldfact Projects to supply two EWK 441 package cooling towers that would be used in conjunction with two water cooled chillers .
24 www . coldlinkafrica . co . za COLD LINK AFRICA • May 2024