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Energy-efficient cooling saves you money

30 April, 2006

Groentehof BV, a supplier of ready-to-cook vegetables, expanded its production site in Helmond with two dispatching areas. They are fully isolated. We also placed an extra refrigeration system that meets the latest technical standards. The high energy prices, energy savings and the EIA (Energy Investment Allowance) more than make up for the necessary investments. At Groentehof everything revolves around quality, freshness, shelf-life and hygiene. This becomes clear during a tour around the production and dispatch areas. Groentehof uses specifically developed devices to cut the vegetables since the cutting devices that were available on the market did not comply with their requirements. Now, all vegetables are washed differently. For the drying treatment large in line blowers and centrifuges are used instead of the traditional, small hand-driven centrifuges. The products are internally transported between the various production areas by means of a pump system with shiny stainless steel trays instead of conveyor belts.” The past few years we have examined and upgraded our entire mechanical and handling process” says Stef Janssen, head of the Technical Department at Groentehof. “It matches our philosophy to produce high quality products. “

New despatching areas
We walk towards the recently build despatching areas. Stef Janssen: “We have always produced our products under the Fresh Quality flag. But nowadays, there is an increasing demand for home brand packaging. They need sortation on store-level and this leads to more product flows. Furthermore, the product range is continually extending with all kinds of convenience-products. Think, for example, of the variety in little vegetable salad bowls. Our market share has been increasing for years as well. All these developments have led to shortage of space. For the foreseeable future, we have tackled this problem by building these two dispatching areas.” Groentehof focussed on minimising the energy consumption in the cooled areas. Janssen points at the roof and ceiling: “12 and 24 centimetres of insulation went on them. It costs a bit more than the usual insulation thicknesses of 8 to 10 or 16 to 20 centimetres would, but the energy investment allowance covers the extra charges. You would be crazy not to make use of these arrangements.”

Refrigeration system

The most innovative part of the two new areas is the refrigeration system, designed by Ernens Consult from Rolde. Consultant Ben Ernens: “Groentehof wanted the installation to be as energy efficient as possible because when considering the entire despatching costs, this turns out to be the most beneficial. Based on this idea, I have designed a compression refrigeration system containing three compressors with valve control. One compressor has variable frequency drive for capacity control.

For condensation of the refrigerant within the system I came up with an air-cooled condenser and a separate air-cooled sub cooler. This enables you to reach a temperature difference between the condensation and outside air temperature of 10 degrees maximum under any kind of circumstances. A lot of energy is saved by using fresh outside air during the largest part of the condensation process. For cooling the rooms, we installed twelve dual discharge coolers and four single discharge coolers. Because of lack of space in the engine room, the complete compressor installation was placed on the roof. This meant we could only use low-noise equipment.”

Controlling system

After the design had been approved by Groentehof, Ben Ernens also drafted the specifications. Three companies were invited to tender Voets & Donkers from Schijndel was chosen to be the best party for the job.
Director Marc Voets: “The tender document contained clear objectives concerning the machinery and the components. It was hardly possible to compete in this area. Afterwards I heard that the main reason we had won was the fact that we had come up with a clever controlling solution. Groentehof used a Scada-system to monitor the existing refrigeration system. The control however, was arranged by all kinds of different systems. We developed software to link the PLC for the new refrigeration system to the Scada-system. Groentehof can now use the PLC to steer and monitor both the new, as well as the already existing refrigeration system. Stef Janssen: “In just a few mouse clicks I can get all the information I need on my screen. That is wonderful, not only for managing the system but also for example to detect errors or disturbances. If I receive a complaint, I can take a look at the monitoring information and see whether the cooling has been functioning well during the production process and in specific areas. That is quality assurance.”

Check and copy
Just as for the isolation of the roof and walls, Groentehof also received Energy Investment allowance for the new refrigeration system. It was applied for by Ben Ernens. Stef Janssen: “He designed the system so it was easy for him to fill in all proper details.” Ben Ernens: “Yes, that’s right.” And I always ask for all-in quotations that show where deduction is possible and what the benefits will be. First and foremost, to get quotations that can be easily compared, but it is also convenient that we can check the specifications of the installer and then copy them for further use” Marc Voets: “I welcome this approach. It allows us to improve on energy-efficiency without raising the installation costs for our clients.”

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