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Blueberries: The superfood of choice

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By Henk Mac Donald, General Manager at HC Engineering Solutions

A new blueberry facility at the Ambrosia Citrus Estate, located in Hoedspruit, Limpopo Province, was the latest addition to this operation owing to growing demand for this product.

From left: Henk Mac Donald (Engineering Solutions), Mr Bezuidenhout (ACE), and Bryan Carrol (HC Group). Image credit: HC Engineering Solutions

From left: Henk Mac Donald (Engineering Solutions), Mr Bezuidenhout (ACE), and Bryan Carrol (HC Group). Image credit: HC Engineering Solutions

The HC Group (HCG) were delighted to be chosen as the service provider of choice for this greenfields site, and it allowed a design with a total fit-for-purpose solution focusing on energy efficiency.

The final proposal was accepted by the client in early December 2020, and the project kick-off meeting was held in January 2021. Here the project charter was proposed and accepted by all the parties involved. Following this, the detailed design was completed within a week and the project plan was rolled out.

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The installation started on 15 March 2021 and the facility was handed over to the client on 14 June 2021.

The project was not without challenges. However, HCG were extremely fortunate to have an amazing project team and an involved client who worked tirelessly together to ensure they were able to deliver a successful project. The facility was completed just in time and allowed harvesting to begin right after handover.

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HC Engineering Solutions (HCES) was responsible for the full turnkey offering armed with their valued group of affiliates. At early stages, a site visit was planned with the client – Mr. Bezuidenhout – to ascertain his specific project requirements. In that meeting it was clear that Bezuidenhout and the team were excited to have their new dedicated blueberry facility up and running as soon as possible to meet the growing demand for this globally rated superfood.

Client brief

The client requested a packing facility that would fit on a 30m x 80m footprint including a 10m x 30m receiving/pre-cooler area, a 50m x 30m packing area, and a holding/dispatch room of 20m x 30m.

The facility needed to include a pre-cooling area, packing area, and holding rooms able to process 5 tonnes of blueberries per hour at an average temperature of 1°C. The facility location necessitated the system be able to handle fruit entering at 40°C in the summer.

Our affiliate partner EP Engineering performed detailed heat load calculations and designs in line with GLOBAL GAP standards to ensure that the client had optimally cooled and stored product.

Design and system process details

There were a few design challenges that had to be overcome, however most of them were quickly resolved due to the experience of the design team and affiliate partners. It is amazing how collaborating and working as a team can achieve great results – giving truth to the proverb, “If you want to go fast, go alone. If you want to go far, go together”.

The design was completed to meet the clients’ requirements without compromising product quality or process flow. The receiving area operates at 1°C and can receive and hold 12 tonnes of berries whilst maintaining temperature in a 40°C ambient. The berries are received on crates and transferred to dollies to easily move around in the facility.

After being received, the berries get weighed, stacked, and then loaded 3 dollies at a time into the 8 tunnels to pre-cool them to 5°C. The tunnels are automated and designed to maximise airflow through the crates.

Each tunnel has a dedicated evaporator, automated in-and-out doors, canvas sealing, manual on/off control, and an indicator light that signifies the fruit is at the setpoint temperature. EBM RadiPac fans are used with a dual discharge configuration to provide the correct air volume flow and pressure.

The system allows for refrigeration use on-demand instead of cooling a big room or conventional tunnel. Once the berries reach temperature, the tunnel is switched off, the automated doors are opened, and the dollies are moved to the holding or packing area where they are processed.

“The facility needed to include a pre-cooling area, packing area, and holding rooms able to process 5 tonnes of blueberries per hour at an average temperature of 1°C.”

The holding rooms and packing area maintains an air-on coil of no more than 3°C. The cooling in the packing area is provided by two HC-HVAC air-handling units which include a fresh air supply to limit CO2 build-up. Continuous sterilisation is applied with UVC Lights and filters.

The holding/dispatch room is designed to store 200 pallets of blueberries at 1°C to allow the product to be loaded onto trucks via a Maxiflex docking system.

Cooling for the packing facility is supplied from a central plant room with 2 off 400 kWr HC-Systems racks running at -5°C/35°C on R407F, utilising 4 Dorin compressors each.

The plant room hosts all electrics and controls, racks, liquid receiver sets, the main electrical distribution board, as well as an automated ventilation system.

The racks are connected to a dual circuit evaporative condenser from Evapco to maintain a condensing temperature of 35°C or lower when the ambient permits. The condenser is connected to a CaRE CUBE unit which continuously filters the condenser sump, flushes automatically and controls and removes any scale or dirt.

H Control Systems was the controls partner of choice and is used to control the climate, lights, energy, pull down technology, and maximum kVA demand.

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The system is also connected to the HCES 24-hour monitoring centre. This manned monitoring service notifies the client or contractor whenever there is a fault or when there is no available internet connection on site and the equipment can’t be monitored. The system also manages all event logs, temperature logs and maintenance schedules.

The facility was designed with a grid-tied solar system with generator backup, allowing the facility to benefit immensely from solar as a renewable source of energy. This solar plant provided the much-needed additional electrical supply to enable the project to move forward.

The client was in the process of consolidating the various power supply points from Eskom into one point and added a 1.2 Megawatt solar plant with a generator backup to the supply. This meant that all the electrical supply points had to be connected to a new privately-owned reticulation network.

DTS – Standard Refrigeration was appointed as the affiliate contractor of HCES for both the refrigeration and electrical installation. Mr. Byrne, managing director of DTS mentioned, “We are proud to be part of the team working together towards a common goal of supplying innovative solutions”.

Using Revit design software allowed HCES to minimise clashes on site with the different services, and they were able to guarantee correct routing of refrigeration piping and electrical wiring. It allowed the customer to get the real feel of the facility and comment prior to build as the drawings were all done in 3D.

The as-built plant was installed and commissioned to satisfy all the initial design requirements from the client.

Project challenges

The original project completion date was scheduled for 31 May 2021. This date moved to 15 June 2021 due to rain hampering civil works and resulting delay of the electrical supply from external suppliers.

The biggest challenge was to design the pre-cooling area and tunnels to work optimally while ensuring correct product flow patterns. This was achieved by designing a fit-for-purpose customised cooling tunnel. The cooling tunnel proved its worth and met all design criteria in practice. It was a great sense of achievement for the design team when the facility was operational, and the cooling tunnel was put through its paces.

Efficiency and sustainability aspects

Energy efficiency, sustainability, equipment life cycle cost and overall environmental impact were central to the design philosophy of the facility.

The integrated solar power plant provided the facility with a renewable energy solution – ensuring high levels of sustainability.

The latest control philosophies were employed to guarantee plant optimisation and ensure they achieved the best possible coefficient of performance (COP), regardless of ambient conditions.

The on-demand cooling facility also ensures minimal energy waste throughout the season. Furthermore, the use of variable frequency drives, soft starters, and high efficiency electronically commutated (EC) fans guaranteed an overall energy-efficient refrigeration plant design.

The integrated control system, incorporating the relevant energy meters, gives the client the option to manage the maximum demand requirements at his fingertips.

Unique elements

The cooling tunnels were a special design for the client and numerous developments were made to allow for optimisation of product flow, cooling capacity and energy efficiency. Each tunnel can cool one, two or three dollies at a time.

The vertical airflow design of the tunnels means that there are no height limits to how the dollies are packed. The tunnel sides are also pressurised to ensure no air bypasses the product.

Further to this, each tunnel is individually operated which limits energy usage to only that which is necessary. This solves the problem of cooling a product that is very seasonal and varies so much in harvesting quantities.

The farm is also supplied with high quality water from the Blyde River dam which helps maintain the correct TDS levels in the condenser to prevent scale forming against the heat exchanger in the condenser. CareCube automated system was used to filtrate the water, constantly removing solid particles or scale by creating a vortex in the sump of the condenser and filtering it through a sand filter. This filter is flushed four times a day.

This means that the TDS and pH levels are managed within the best operating parameters. A chemical is also dosed with the makeup water to keep any scale in suspension. The biological condition of the water is further maintained by using ozone in the sump.

Project name:

ACE Blueberry Packing Facility

Name of Company
Owner Gert Bezuidenhout Ambrosia Citrus Estate
Developer Architect/Designer Gert Bezuidenhout & Henk Mac Donald Ambrosia Citrus Estate
HC-Engineering Solutions
Project Manager Gert Bezuidenhout and ES Project Team HC-Engineering Solutions
Consulting engineer Electrical HC-Engineering Solutions
Mechanical HC-Engineering Solutions & EP Engineering
Wet Services Ambrosia Citrus Estate
Civil Ambrosia Citrus Estate
Contractors Main Building Ambrosia Citrus Estate
HVAC&R DTS Standard Refrigeration
Wet Services Ambrosia Citrus Estate
Electrical DTS Standard Refrigeration
Product Suppliers Product Supplier
Air Handling Units HC-HVAC
Evaporators HC-Heat
Racks, Plant room & electrical HC-Systems
Refrigeration, piping, and insulation HC-Value Add
Insulated Panels and Doors Pre-Cool Manufacturing
Control System H Control Solutions
Canvass SA Canvass
Air-Curtain CFW
Evaporative Condenser Evapco
BG Automated Doors F & F Cooling
Docking Bay Maxiflex

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