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Automa tic Vent ilation AV+ save Beat old habits and money Most people wouldn’t drive their cars with windows down and air conditioning on. But in the reefer trade, unfortunately, excessive air intake is the norm, mainly because auto-regulating technologies have not been affordable. Traditionally, many shippers have used past experience to fix the fresh air exchange settings on their reefers. This is a somewhat wasteful habit because a fixed fresh air exchange, in short AirEx, usually causes excess amounts of ambient air to enter the container with little or no relationship to the respiring cargo’s metabolic state. The solution, an automatic ventilation system, is not an MCI invention or exclusive to Star Cool units. What is new, though, is that MCI’s AV+ system is simple, easy to operate and relatively inexpensive. Reduce refrigeration cost Michael Reid, professor in post-harvest science at University of California, Davis, remarks that automatic ventilation control, solely based on the needs and behaviour of the product, is better for the cargo and the environment. “Controlled AirEx will reduce refrigeration costs and potentially improve product out-turns. Reduced ventilation reduces water loss, and if you control the CO2 concentration in the container, you may reduce storage disorders,” Reid observes. Avoid over-ventilation AV+ limits damage caused by over-ventilation; excessive warm ambient air needs to be cooled, and humid air condenses as water or frost. Both affect accurate temperature control, both use too much energy, and both can have a negative impact on cargo quality. Excessive cool ambient air needs to be heated, and it usually has a lower relative humidity than the cargo. This can contribute to dehydration and loss of weight or quality. Many perishable reefer cargos transit through different ambient conditions from loading to discharge, so they can potentially experience all the different consequences of excessive fresh air intake. AV+ saves between 10% and 25% “Operators go by old habits. As the saying goes: ‘if it ain’t broke, don’t fix it’. This is true as current practices seem to work, but old habits can in some cases prevent progress when affordable technology becomes available,” says Anders G. Holm of MCI sales and marketing. MCI has recently live-tested AV+ with Crowley (tomatoes), Chiquita (bananas) and CMA-CGM (bananas), yielding demonstrable energy savings of between 10% and 25%. For 100,000 reefer shipments with an average transit time of 20 days, this equates to a USD 3 million saving. Currently, MCI’s AV+ costs about a quarter of similar existing options on the market. Calculating automatic air exchange can be complex, but Star Cool AV+ makes it easy for the operator. AV+ is just as simple to operate as the normal temperature setting. Now, a maximum CO2 setting is used instead of fixing a set intake of ambient air measured in cubic metres per hour or cubic feet per minute. “We are sure that more and more customers and their shippers will realise the benefits of maximum CO2 settings,” says Anders G. Holm. “For most perishable cargoes, it’s simply time to kick the old ‘open-vent’ habit.” ■ AV+ also benefits fruit and produce “The longest period of time during the post-harvest life of produce is usually spent inside a reefer container. The fruit, flowers or vegetables are still consuming oxygen and give off carbon dioxide. Open air exchange vents [AirEx] are not precisely engineered, and there is much variability in the amount of air that moves through the vents. There are also varied opinions around the globe regarding what is the best AirEx for different types of fresh produce. It makes sense to manage the air exchange with an engineering solution. The AirEx vent can be mechanized and the opening controlled according to the respiration rate of the product being carried. The result will be better quality produce after the shipping voyage”. Malcolm Dodd, principal consultant, Cold Chain Solutions AV+ valves will open and close automatically to maintain CO2 and O2 levels.

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