new pre-cooler to improve the quality of export table grapes was recently installed at Wynkeldershoek, Malmesbury, for Neethling Broers. The pre-cooler was designed to cool freshly harvested grapes from between 35 and 32 ° C to between 20 and 18 ° C at the rate of seven tonnes per hour.

The pre-cooler’ s plenum wall has a total of 12 openings against which lugs of grapes, stacked on a pallet, can be placed. Cooled air from three 50kW chilled water blower coils is drawn through the lugs of grapes. The suction plenum is sub-divided into three so that each blower coil services four hatches. Short circuiting of air is prevented by PVC sheets, which seal off the top of the lugs stacked on a pallet. After pre-cooling, the grapes are packed and sent to another site where the packed cartons of grapes are further cooled ahead of being sent to Cape Town Harbour for export.

An existing 160kWR air-cooled chiller was moved from another site to Wynkeldershoek and connected to the new pre-cooler.

The removal of field heat as soon as possible after harvesting adds to the quality of grapes that reach foreign customers. Many pack houses use evaporative cooling in pre-cooling, but it is not as effective as forced cooling. After using evaporative cooling at other sites, Wynkeldershoek approached Jacques Mouton of Coldfact in Paarl to improve their pre-cooling. Kevin Schlemmer and Danie van Zyl of CoolCheck was asked to design a suitable system and Koos Botha of Colcoil was asked to design and supply the blower coils.

The new pre-cooler was commissioned on schedule ahead of the 2016 harvesting season.“ The project team with Coldfact as contractor and Colcoil as supplier,

with design input of CoolCheck, proved a winning combination and we have already seen the benefits of forced air pre-cooling,” said Chris Auret, manager of Wynkeldershoek.“ Our thanks go to Koos Botha of Colcoil and Jacques Mouton of Coldfact and the design input of Kevin and Danie of CoolCheck.” CLA

1. Danie van Zyl, left, holding a plastic crate with 8kg of freshly harvested table grapes next to Chris Auret.

2. Wynkeldershoek farm is in the Malmesbury area.

3. Jacques Mouton of Coldfact, right, and Chris Auret view the plenum wall, which has 12 openings with PVC sheeting( blue coloured) to seal off the top row of lugs when stacked on a pallet. Each drawthrough blower coil has four axial tube fans.

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Pretoria

INCORPORATING COLD CHAIN

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