Technical site visit: Silver Fern Farms, Belfast

Silver Fern Farms were gracious enough to let IRHACE members take a tour through both the old and new ammonia engine rooms at their Belfast site

Ammonia refrigeration systems are made to last decades, and this is certainly the case with the old engine room here.

The original building was constructed before 1885 and is still standing, although it will be demolished in due course. It was being used up until the new plant was commissioned and pipework cut over to the new engine room in October/November 2023. There have been a number of changes over the literal centuries as the plant upgraded from the steam Hercules water-cooled compressors to the multiple belt compressors in place today. The compressors in the room today all date from approximately the 1960s and 1970s and were showing it.

Silver Fern determined the need for a new engine room some years ago and embarked on the design and construction in 2021 with the entire construction process taking almost two years. The project involved two ammonia refrigeration subcontractors with the refrigeration works split between the heat pump

installation and main refrigeration systems, along with many consultants and project engineering companies. Thousands of man-hours were expended in design, review, LUME modelling, and construction.

Like many others, this pumped ammonia system and vessels are limited to an MT and LT pot. The swing compressors swing between high and high-high-pressure discharge lines to provide the source for the heat pump, which is already drastically reducing the heating costs for the site. New SCADA systems replace the older manual valve actuations with time savings for operational changes going from 40 minutes to the flick of a button.

Perhaps the most significant item in this plant, however, is the lack of a cooling tower. On-site water storage and usage means that all the HOR of the plant can be discharged into the site’s consumables, removing the need for towers and the maintenance requirements they need.