Refrigeration / Distribution Centers

This is sustainability put into practice and is booming in times of food scandals and climate change. To meet growing demand of consumers in northern Germany Grell Naturkost GmbH (organic food) has increased its capacity substantially as a regional wholesaler, headquartered in Kaltenkirchen /Schleswig- Holstein. A new cold storage facility was constructed on an area of over 4000 m2 with eight different climate zones in which 22 Kelvion air coolers ensure constant, safe storage conditions. The old, still existing warehouse was redesigned alongside the new plan and the reconstruction of the cold storage warehouse and was converted into storage for dry goods only. This was a challenge from a refrigeration point of view because over 90 tonnes of dry goods (cheese, sausage, vegetables etc.) are being delivered every day. Rather than a classical airlock, which would restrict the work process, dry and job warehouses are often connected to one another. A doorway air curtain at the connecting point ensures that no air exchange can take place. This was not the only challenge that Thies Oelrichs, a refrigeration contractor with the company ‘FIELES - Dithmarscher Kältetechnik’, the renowned specialist for chilling of fruit and vegetables, had to take into account during the planning of this rack system.

Besides the room layout the customer also specified that the cooling system was to be as energy-efficient as possible. A CO2 system was not possible as all the goods are stored at temperatures above freezing. “That would have used much too much primary energy”, says refrigeration contractor Thies Oelrichs. In its place he chose an integrated system with R134a as a refrigerant, with two different evaporating temperatures and an external liquid subcooler. “Each additional degree of evaporating temperature saves 3 percent on energy”, says Thies Oelrichs. Two of the eight cold rooms need to be kept at a constant 1 to 4°C and thus require a lower evaporating temperature. These are the fruit store and the meat store. Together that is just about 270 m2 and thus over 5% of the entire cooling area. “It is pointless to design a system with a low total – t0 in accordance with these two product groups because it would have simply increased the energy costs”, says Thies Oelrichs. That is why we have two evaporating temperatures in a satellite combination. The cheese store (175 m2) has a Küba SGA 35-F62 high-performance unit cooler with epoxy coated fins that cools gently with a low air flow in accordance with the special ripening and storage conditions of the cheeses.

With a room volume of 1000 m3 the unit cooler achieves an air renewal rate of 5 per hour – which is no more than a gentle breeze. This prevents the cheese from drying out. The epoxy coated fins are necessary, in order to meet hygiene requirements and achieve the necessary corrosion protection. In the vegetable store (512 m2) four ceiling air coolers of the type Küba DZA 45-F61 blow cold air across the shelves. The airflow hits the sidewalls, is diverted and cools potatoes, onions, carrots, cabbage & Co. The stacked boxed are thus perfectly ventilated. The same is also true for the fruit store (199 m2). Two ceiling air coolers that blow out on both sides, type Küba DZAE 40-F62 with electrical defrosting, are installed here. In the job store, the central room for incoming and outgoing goods, there are eight ceiling evaporators that blow out both sides, type Küba-DZA 56-F61. They keep the 1600 m2 trans-shipment area at a constant 5 to 7 °C – even if trucks are docked at all twelve dock levellers, are loaded and unloaded and goods are delivered in parallel from the dry store system.

The dairy store has three, two-fan Kelvion unit coolers of the type Küba-DZA 56-F62 that blow out both sides. There are two more air-conditioned rooms next to this. Mediterranean vegetables are stored in one at 10°C. The other is designed specially for the requirements of tropical fruits, which are stored at 12 degrees. The unit cooler was fitted with electric radiators in order to ensure that the temperature can always be kept constant, even in winter. In the winter the cold store runs very slowly because the cooling of the goods is not necessary. The building envelope of the cold storage is optimally insulated and therefore hardly permits any transmission. We need enormous know-how and specialist knowledge in order to plan an exactly tailored refrigeration system with parameters such as sequence of rooms, energy efficiency and optimum insulation. FIELES Dithmarscher Kältetechnik, headquartered in Marne, is a renowned specialist for the cooling of fruit and vegetables and a preferred partner for refrigeration, air conditioning and air treatment systems, outside of Germany too.