Cold Link Africa June 2019 | Page 17

PROJECT INCORPORATING COLD CHAIN EFFICIENCY MATTERS Going for central water-cooled plant that employs two multiplex circuits in its design will drastically improve energy efficiency from a more traditional multi-plant arrangement with individual condensing units cooling each room. Additionally, using chilled water has the added benefit of keeping the humidity levels up in the room, which reduces the drying effect on the bananas, adding to their shelf life. Once the ripening cycle is complete, the room can automatically change state into a regular cold room with defrost functionality, etc. if the end user chooses to do so. Entry corridor into ripening rooms. CHALLENGES Original ripening rooms, more than 15 years old. The standard to which this project was administered and the attention to detail that the professional team demanded kept all the contractors on their toes. Additionally, the original insulation contractor was fired from the job halfway through, leaving Themba Projects to learn fast how to pick up those pieces, and Precool had to come in to finish up certain panel work and air curtains. Credit must go to the Themba Projects team who quickly learned to install gas- tight insulated doors imported from Belgium and finished up a lot of the panel work to a standard that was in line with the level of seasoned professionals. COLD LINK AFRICA • June 2019 The water chillers, which will use the bulk of electricity on site, are built to stringent European standards to ensure optimum efficiency and are charged with R410a refrigerant. By using a multiplex design with modulating valves on the cold rooms, this plant will work hard to get the rooms onto temperature. Then, once running, the chillers will ramp down to 50% or even below duty and idle with a much lower energy draw (peak kVA) than that of a traditional on/off approach. Additionally, the rooms can hold a constant temperature to a few decimal places of the set point. www.coldlinkafrica.co.za 17