The food manufacturer asked JJ Loughran to assess the feasibility of achieving energy savings in the air handling installation without impairing the quality of ventilation. The manufacturer had noted in particular that there were regular periods at the ends of the line operatives’ shifts when almost the only operation in progress was washdown and, as a result, ventilation requirements were much lower than when the plant was in full production.

JJ Loughran engineers found that its six fans – one of 90kW, one of 18.5kW and four of 11kW – were controlled by conventional star-delta starters that allowed the fans to operate only at full speed.

 It was clear that fitting variable speed drives (VSDs) would allow significant energy economies to be achieved but there were two potential problems. The first was that there was no room to accommodate the VSDs within the existing motor control centre, and the second was that the customer had specified that its manufacturing operations should not be interrupted by the work involved in fitting the drives.

Engineers at JJ Loughran chose VACON 100 FLOW drives. These are specifically designed for flow control applications, which means that they allow high levels of efficiency and are fast and easy to set up. Another key factor is that the drives are available in two versions – IP54 models that can be installed without additional protection and IP21 versions for mounting within a control panel.

 For this project, JJ Loughran, working closely with VACON, chose IP54 drives for all of the fans except the largest, for which an IP21 drive fitted in a panel designed and built by JJ Loughran’s control panel division was used. The IP54 drives were mounted adjacent to the existing motor control centre, an arrangement that allowed for quick fitting and changeover, and also minimised installation costs for the end customer.

Realtime clock function 

A particularly useful feature of all of the new VSDs proved to be their built-in realtime clock function. This allowed them to be programmed so that, without the need for additional equipment, the speed of the ventilation fans is automatically reduced at specified times. The times vary according to the day of the week to match the shift patterns and the clock function in the VACON 100 FLOW VSDs even compensates automatically for daylight saving time, so that once the clocks have been set up, no further adjustments are necessary.

 The operating program for the drives was developed by the JJ Loughran engineering team and was downloaded into the drives, where it was fine tuned to meet the individual requirements for each fan. The installation of the five smaller drives was completed within a two day period and, because of the extensive preparation work that had been carried out, no changeover of any fan to VSD operation took longer than 30 minutes. The 90kW control panel for the largest fan was subsequently fitted, connected and commissioned in less than two hours.

John Loughran, a director of JJ Loughran, comments: “Using VACON 100 FLOW drives for this project certainly made our lives much easier as they are very easy to use and set up in this type of application. Our customer is very pleased that we were able to complete the job quickly with negligible disruption to its operations, and is also delighted with the energy savings that the VSDs are providing. Not only do these savings mean a substantial reduction in the plant’s carbon footprint, they also means that the VSDs will very quickly pay for themselves.”