Temperature control along the fresh fruit chain is energy demanding but key to preserve quality and avoid spoilage and waste. Dynamic controlled atmosphere (DCA) is an innovative technology being implemented in this ENOUGH demonstrator (read more here), to explore the energy saving potential in industrial fruit storage rooms.
With DCA storage, the oxygen (O2) level in the storage rooms is dynamically optimized based on real-time measurements of the low oxygen stress response of the fruit (respiratory quotient, RQ). This enables fruit storage at the lowest O2 level possible, ensuring maximal quality, lower respiratory heat production and decreased need for energy demanding cooling actions.
In ENOUGH, the DCA technology was developed into an industry solution comprising robust, reliable and safe to use sensor and control systems that can be easily integrated into existing and new storage facilities. The operational performance and the impact on fruit quality and energy use reduction is measured and analysed at an industrial storage facility of a Belgian fruit grower running a pear fruit storage facility, representative for the EU fruit sector.
The baseline is the commercial standard for controlled atmosphere (CA) fruit storage under ultra low oxygen (ULO) conditions, which is an advanced solution that already saves 50% of CO2 and heat production by reducing the oxygen concentration. The DCA system is an add-on to CA storage facilities, which can contain several storage rooms with a capacity of 50-500 tons of fruit. Each room is equipped with an evaporator and gas sampling/supply and individually controlled from central control hubs. For DCA, each room is equipped with a dedicated sensor and gas sampling unit that is connected to a central controller. The system is flexible and can be implemented for any number and size of storage rooms. Also, smaller stand-alone units are now being developed and offered that can service customers requiring lower volumes (e.g. for soft fruit producers, or for research purposes).
Measurements of energy savings of DCA compared to CA has started and will continue throughout the next season. Demonstrated advantages of the system include:
- Up to 15% lower energy consumption compared to ultra low oxygen (ULO) storage technology
- 100% organic (no chemical treatments needed during storage)
- Eliminating fruit disorders such as superficial scald
- Tailored to each specific batch of fruit
- Longer shelf life compared to ultra low oxygen (ULO) storage
- Total savings expected for the Belgian pome fruit sector alone on a year basis, for switching from ULO to DCA are estimated as 1813-2720 ton CO2
Energy efficient DCA (master module and field node attached to the cold room).
