Drives & Controls January 2024

32 n VARIABLE-SPEED DRIVES January 2024 Remote VSD monitoring ensures that apples keep their cool Italy’s Rivoira Group produces, stores and processes apples. At its Verzuolo site, it has more than 70 cold storage rooms, allowing it to store up to 70,000 tonnes of product. The apple harvest season typically starts in mid-summer and extends into the late autumn. Farms deliver their harvest to the site, where the apples are checked and sorted into the various stores. The part of the harvest destined for longterm conservation is kept in cold rooms with a controlled atmosphere. Here, oxygen content is reduced to about 1% and the temperature maintained at about 0–2° C. These conditions ensure that the fruit will not perish, without altering its characteristics. Consistent and reliable cooling is the main challenge in cold rooms such as these. It is vital to avoid unexpected failures of the refrigeration system, which could result in huge product damage or loss. Rivoira’s cooling systems have been designed and built by a local industrial refrigeration specialist Gaudino Refrigerazione, which was a pioneer of ammonia-based cooling systems. The refrigeration plants run on an indirect refrigeration system, using ammonia refrigerant in the primary circuit and glycol as an intermediate ‡uid. Modulating valves control the air outlet temperature from the air coolers precisely. Gaudino has developed a data acquisition platform that provides preventive and predictive maintenance services tailored to the customer. In 2022, Rivoira Group needed to expand its cold storage capacity and turned to Gaudino which created a refrigeration system that serves seven cells. Two compressors were installed, both equipped with high-eŠciency Danfoss FC 102 VLT HVAC drives. The drives include a conditionbased monitoring function, allowing Rivoira to perform predictive maintenance remotely, thus ensuring the reliability of the refrigeration system, while cutting maintenance costs. The condition-based monitoring (CBM) function uses vibrational analysis of rotating components to provide monitoring and advanced diagnostic functions. The drives correlate parameters – such as speed, current and torque – in real time with data from external sources such as accelerometers mounted on the electric motors of the screw compressors, oil pumps, and evaporative condenser fans. These are connected to an analogue signal acquisition board in the drives. The refrigeration system is also equipped with a customised, cloud-based DrivePro remote monitoring system which gives Gaudino engineers 24/7 access to detailed drive information from three applications: an evaporative condenser; a suction separator; and a 15,000-litre inertial and pumping tank for glycol. This allows them to monitor and analyse performance, and to keep production running while minimising downtime. If a fault arises, the system sends a warning allowing a service team to react immediately. The data collected and processed by the drives is transmitted and stored in a cloudbased management platform, together with other plant data and related maintenance activities. Using this data, Gaudino and Rivoira can develop maintenance strategies customised for each item of plant. “The data acquired and continuously processed by the drives constitutes a baseline that represents the normal operating conditions of the plant,” explains Paolo Asteggiano, Gaudino Refrigerazione’s head of r&d,. “Starting from these values, two diŸerent warning thresholds are then established which, if exceeded, provide the operator with the ¡rst indications of malfunction. “The ‘sensor ecosystem’ provides information to the refrigeration system operator about the state of health of the critical components of the system.” “In this way,”adds Roberto Testa, technical director of the Rivoira plant, “it is possible to keep the introduction of fresh air at a value very close to that of the fruit in the cell and to ¡nely adjust the conservation parameters in terms of humidity and temperature, according to the speci¡c needs of the type of apple stored in the single cell, ensuring optimal conservation.” n An Italian apple producer is using new refrigeration techniques to ensure that the fruit retains its freshness for most of the year. A key to this is the ability to monitor VSDs in the plant, thus maintaining ideal cooling conditions and minimising downtime. The Rivoira Group stores and processes tens of thousands of tonnes of applies at its Verzuolo plant