Case of Success on the project of the first forced pre-cold avocado hass in Colombia.
By Daniel Puerta *
Westfalia Fruit inaugurated last January's 18 in Sonsón, Antioquia (Colombia), one of the most modern hass avocado packing in Latin America.
From these beautiful lands of Eastern Antioquia, Westfalia Fruit hopes to continue with the growth in the markets of North America and Europe of this precious fruit. For this task, the new packinghouse has a fruit selection machine of the latest technology from the Neozelandesa Compac brand; which is capable of processing up to 16 tons per hour.
But nevertheless; To comply with the high import standards, the fruit must be in a temperature range of 5 to 6 degrees centigrade, so Westfalia Fruit turned to the design services of MB Ingeniería, a company specializing in industrial cold chain design, for its refrigeration system consisting of an entrance hall, 4 rooms with capacity to cool and store 250 tons of fruit in 24 hours, two dispatch springs and a forced pre-cold.
This forced pre-cold for avocado hass stands out as the first in Colombia and one of the few existing in Latin America (Only some exist in Peru and Chile). This system is able to cool the fruit from 19 to 6 degrees centigrade in only 5 hours, with a capacity of 10 pallets; equivalent to 12 tons, reducing by 58% the time necessary for Westfalia Fruit to have a complete container ready to be shipped.
To achieve these figures, the forced pre-cold has a reversible flow evaporator, from the German brand Thermofin, which has 4 powerful fans of 4 HP each, with capacity to overcome the pressure drop between the boxes of the pallets, and that maintains a constant speed of 2m / s on the product; so it allows a uniform cooling without drying the fruit.
With the help of the Colombian company Sutrak; responsible for the installation of the cooling system, the pre-cooling has a logic programmer switched (PLC) for the control, which receives the 6 signal sensors that record both the internal temperature of the fruit, and the temperature of discharge and of air suction. The key to the correct functioning of the forced pre-cold avocado is the distribution of the sensors, where two are located on the outside and two on the inside of the pallets, both at opposite ends.
The system works initially for 3 hours, during which it is expected that the external temperature of the pallets will reach 7 degrees centigrade. If this does not happen in this period of time, the system continues operating for 30 more minutes, to guarantee that the established parameters are obtained. After reaching the desired temperature in the external pallets, the fans stop completely and begin to turn in the opposite direction for the remaining time of the cycle: Between 1 hour and a half and 2 hours, to obtain a high degree of uniformity in temperature of avocado hass, with temperature differential of only 0.5 degrees and an average final temperature in the center of the fruit of 6 degrees centigrade.
The function of the sensors of ambient temperature of discharge and suction of the air is to avoid that the temperature in the chamber is inferior to 1 degree centigrade, because this could dry and damage the fruit, and it would not be detected until the moment of being consumed, for which MB Ingeniería specified the need to carefully control the air temperature, generating an alarm if the ambient temperature of the room decreases below what is desired. In addition, the system has an electronic expansion valve, which allows to control the overheating of the evaporator all the time, prevents decompensation of the system by the variation of the load throughout the cycle, in order to obtain the maximum efficiency of the evaporator in at all times, while generating energy savings of 15% and extending the life of the compressor and the system in general.
To achieve the maximum efficiency of the system, MB Ingeniería specified a retractable tent to direct the flow of air, so that it is forced to pass through the openings of the boxes and no losses or short circuits are generated in the system; In turn, in the company of the company in charge of the installation of the tent, Andertec, a system of barriers was designed so that the air can not circulate through the wooden pallets. This system adapts to the different types that Westfalia Fruit handles for the different destinations, varying between pallets for boxes of 4 or 10 kilograms.
With this design of forced pre-cold for avocado hass, MB Ingeniería managed to generate a practical and efficient solution for the need of Westfalia Fruit to adapt to the current market times that do not give wait. At the same time, it provided constant technical support, uniting different companies with their respective products and disciplines to make this project today a reality.
Thanks to the excellent results of the system, Westfalia Fruit already has in his sights the next step in his modernization: the installation of two additional forced pre-cold to reduce in an 80% the time necessary to have a complete container ready to be sent, and at the hand of MB Ingeniería soon this new objective will come true.
Note: Colombia exports hass to more than 20 countries in the world, spread across North America, Europe and Western Asia.
Note: Colombia is positioned as the fourth country in hass avocado production, but hopes to reach the first position in 2020.
* Daniel Puerta is an engineer of the MB Ingeniería company. firstname.lastname@example.org