In line with their mission to respond to client needs and to farm in an ecologically friendly and sustainable way, Bridelia has installed a solar assisted, energy friendly, macadamia curing facility to ensure the safe, post-harvest processing of their highly valued product. The new facility is designed to use smart, modern processing methods and sophisticated control to both retain and maintain the finest quality and shelf-life of farm produced macadamias. The new macadamia curing and storage facility was commissioned in March 2017 and has the potential capacity to receive and cure 300 ton of dehusked nut-in-shell (NIS) from field moisture content to 2% kernel moisture per month. This translates to an approximate potential of 1500 tons in a typical 5 month season.
The EMC curing method is used to ensure that the dehydration process achieves a precise, uniform moisture content throughout a batch of nuts and is achieved at low temperature (< 40°C). Cured macadamias are thereafter conveyed to specialized equipment for sorting, sizing and bagging to meet client requirement. The facility also has the capacity to store at least 80 tons of cured loose or bagged macadamias in a safe, controlled dry, cool environment for a maximum of 3 months from abscission. Storage of NIS in a safe environment is essential to ensure that farm dispatch or factory receiving delays and/or deferments do not impact negatively on harvest quality.
The new macadamia curing facility is an all-electric, solar assisted system that captures available solar irradiation for use in both daytime and for storage for heating during non-solar hours. The solar heat is captured directly in the air in a purpose designed ceiling void in the building and transferred by differential temperature control to 250 tons of concrete bricks in a ‘top hat’ heat store. The solar heat store combination is designed to have a nominal heat storage capacity of 1200 heat units (HU) and, depending on seasonal weather, may provide 60 – 80% of the total heat energy demand for curing. The balance of the heat requirement is provided by electric elements.
The curing of NIS is achieved in low-height, purposed designed batch bins using fans with efficient motors and correctly selected air flow and pressure parameters. The bins are installed in an insulated, vapour proof room constructed with a highly efficient energy profile. The temperature and relative humidity of the recirculated process air in the system is precisely controlled using a sophisticated, management friendly SCADA PLC. An on-site generator backs-up the municipal electricity supply to ensure that both curing and storage can continue safely and uninterrupted during power failure.
