The latest refrigeration technology for Kaufland

Transcription

1 The latest refrigeration technology for Kaufland Kaufland logistics centre in Möckmühl: One of the most modern logistics centres for deep-frozen goods (TIKO) and fresh produce Line of Business: Commercial Refrigeration Application: Supermarket cooling Country / City: Germany / Möckmühl Fluid: NH3, Glycol Product: Ceiling air cooler DGN, insulated unit cooler GIKS, wall/ceiling aircooler GGN, wall/ceiling aircooler GGHN, drycooler GFH, condenser AGVH Europe's biggest logistics centre for deepfrozen goods (TIKO) and fresh produce has been constructed within just one year next to the A 81 motorway in Möckmühl, near Heilbronn. A wide range of refrigeration logistics and meat dissection innovations are planned to give Neckarsulm-based Kaufland Stiftung & Co. KG a market advantage for several years. The refrigeration concept, which is considered to be unique within specialist circles, was planned in close collaboration with the Kaufland construction/shopfitting business area and the Brunnenkant engineering office in Wiesloch. The company that built the system was the Mannheim branch of York Industriekälte GmbH & Co. KG. The company, which is part of the globally successful York refrigeration group, specialises in the development and in- Page 1

2 stallation of cutting edge refrigeration systems for a variety of industries. The insulated unit coolers that were specially developed for the logistics centre were supplied by Güntner, as were the brine coolers, the condensers and the drycoolers. Not only was Möckmühl the biggest individual order so far in Güntner's history, but it was also one of the company's greatest challenges with regard to technical specification, adherence to extremely tight delivery deadlines and the use of well thought-out supply logistics. Completeness by omission One of the most modern logistics centres for deep-frozen goods (TIKO) and fresh produce was created in Möckmühl in accordance with the saying "take the latest refrigeration technology, optimise it until it is simple and practical, subject the different variants to absorption costing and then implement it in the field within a few months". This was possible because optimisation and simplification are top priority at Kaufland and on the agenda at all decision-making levels. To put it simple, Kaufland wants to provide the best possible quality at the lowest prices. Since other chains also work in accordance with this principle, Kaufland sees its market advantage in logistics, particularly in the deep-frozen goods and fresh produce area. A novelty in the industry is that a meat factory and refrigeration logistics have been combined for the first time and closely interlinked under one roof at the Möckmühl logistics centre. At a glance: With 12 Güntner type AGHV NH3 condensers on the roof, the Kaufland logistics centre is perfectly equipped for the future. Extraordinary refrigeration concept The high strategic value of refrigeration logistics forced new measures to be used when designing the refrigeration systems. "Similar to other industries, we also developed completely new concepts for our refrigeration systems", says Rolf Semelink, area manager at Kaufland construction/shopfitting business area and among other things, responsible for the refrigeration systems. "We did not make our decision easily and viewed a large number of reference sites, visited specialist trade fairs and obtained advice from specialist planners". In collaboration with the Brunnenkant engineering office in Wiesloch, which specialises in food refrigeration technology, a refrigeration concept was created that will be unique in European refrigeration logistics for years to come. Semelink: "Europe will never see the likes of this kind of system again. Together with Mr. Rehberger from the Brunnenkant engineering office we have subjected different system variants to absorption costing and not just looked at the energy costs but also checked environmental aspects, examined the maintenance costs and included the consequential costs of certain systems in the equation". Page 2

3 Only NH3 is economical on this scale "As far as the refrigerant was concerned it was clear from the start that there was little flexibility, says Semelink. In this performance segment only NH3 comes into question. That is the most economical and therefore cheapest solution as far as we are concerned. Narrow aisle warehouse for deep-frozen goods at -28 ºC: Special combination of ventilation ceiling and insulated unit coolers After about two years of operating experience Rolf Semelink came to the conclusion that "The system runs perfectly, just like we imagined. The Brunnenkant office and York Industriekälte as the system contractor performed excellently. Particularly Michael Broser, the York project leader, made a major contribution to creating this top class, extremely modern refrigeration system". View of the refrigeration centre: Installation of ten NH3 compressors with total refrigeration capacity of about 7,910 kw York only had four months to install the mammoth system consisting of ten NH3 compressors, 140 aircoolers and 25 insulated unit coolers. There is about 14 km of pipeline for cold brine and NH3 alone! In order for the refrigeration systems to go online on schedule, York deployed four site foremen and about one hundred fitters, with a certain amount of 2-shift operation. Impression of the insulation cooler: View from insulation cooler via open defrosting flap into the narrow aisle warehouse A two-stage NH3 system has been installed consisting of six high-pressure compressors with a total refrigeration capacity of 5,400 kw at 11/+45 ºC, two low-pressure compressors with a total refrigeration capacity of 1,100 kw at 9/-39 ºC and nine air-cooled condensers with a total condensing capacity of 6,700 kw with a tk of +45 ºC. The cold brine is cooled in the associated plates and delivered to the heat exchangers using two frequency-controlled pumps per brine circuit. For example, ten insulated unit coolers in the fruit and vegetable area and other insulated unit coolers in the fresh produce area are supplied with the cold brine. Several rooms in the meat factory are also supplied with cooling via another brine circuit. As well as the two-stage system a so-called eco-system has been installed, consisting of two compressors with a total refrigerating capacity of 1,360 kw at 19/45 ºC, three aircooled condensers with a total condensing capacity of 1,940 kw with a tk of 45 ºC and the associated separators and plates, that provide cold brine for the fresh produce chamber and the meat factory. Here, too, the brine is distributed using two frequency-controlled pumps for each refrigeration circuit. Page 3

4 Cost The biggest air-cooled refrigeration system in Europe Wet cooling towers Air-cooled condensers and drycoolers Rolf Semelink particularly emphasized the making of the decision as to whether the drycooling of the two NH3 refrigeration systems (direct cooling for deep-freeze, brine cooling for fruit, vegetables, fresh produce and meat factory) could be achieved more economically using wet cooling towers or air-cooled condensers. That was a lengthy decision, since we included many secondary aspects such as power costs, availability of cooling water, water treatment and disposal of sludge water in our considerations, says Semelink. 25 Year er rter rter er art a a art Qu nd Qu d Qu th Qu r st Operating cost comparison for supercooling plant The warm brine defrosting system proved to be particularly economical in the brine system. The warm brine is produced by the compressor oil coolers and buffered in a store with a 3 volume of 16 m. When the stores are charged, the excess heat is used to heat the ceiling cavity. Depending on the operating conditions, excess heat can be led outside via the two glycol coolers, but this procedure rarely occurs. The brine insulated unit coolers are defrosted via a variable PLC program in accordance with the specific requirements, and the aircoolers in the meat factory are defrosted by the building conducting equipment. Since each aircooler is individually defrosted, the temperature in the room does not increase. The temperature of the deep-frozen goods is unaffected by this defrosting process. Fresh produce areathe air intakes of the insulated unit coolers wereplaced just beneath the insulated ventilationceiling with air ducts. In spite of having a large installation area, additional steel scaffolding on the roof to support the drycooler and longer pipelines with a larger diameter, the absorption costing has convincing benefits for air-cooling. However, some engineering companies advised us not to do this. But we are certain the air-cooled system was the correct choice, which has been backed up by the operating statistics. The cooling plant at the Kaufland logistics centre consists of twelve Güntner AGVH air-cooled NH3 condensers. There is also a GFH air-cooled glycol cooling tower unit with capacity of 2 x 880 kw. Insulated unit coolers and ventilation ceilings Kaufland was taking a new direction by equipping the deep-freeze, fruit and vegetable warehouse and the meat factory with air coolers. In- Page 4

5 stead of fitting individual aircoolers to walls or the ceiling, Kaufland decided on Güntner insulation coolers that blow their air directly into a prism-shaped stainless steel ventilation ceiling. This keeps the premises free of supply pipes, air coolers and air ducts. In all deep-freeze and fresh produce warehouses that are approximately 8 or 18 metres high we originally used the combination of insulated coolers and air distribution ducts developed by the Brunnenkant engineering offices, says Semelink. This solution is also the result of absorption costing including friction points between logistics on the one hand and possible maintenance work on the aircoolers on the other. "Here, too, we were able to fall back on the comprehensive know-how of our planner. Mr. Rehberger from the Brunnenkant office achieved an extraordinarily economical solution with a combination of insulated unit coolers and a ventilation ceiling that also has an attractive appearance, says Semelink. Defrosting the insulated unit coolers The Güntner insulated unit coolers installed at Kaufland were prepared in the factory so that they only had to be connected to the air duct system. The NH3 insulated unit coolers are defrosted using hot NH3 gas, controlled by a York PLC. The defrosting tank is heated separately. This is the only way to ensure that defrost water back-ups do not occur because of blocks of hoar frost sliding down. Function diagram of GIKS insulated unit cooler with radial fan in cooling operation... The following arguments led Kaufland to a combination of insulated coolers and a ventilation ceiling: Excellent air distribution over the entire surface of the ceiling Also easy to adjust after installation Low noise generation by air flow/fans (important for legal reasons) No restriction to goods movements The maintenance work that is needed on the insulated unit coolers can be carried out at normal room temperatures outside the deep-freeze/refrigeration warehouse. No dust deposits on ducts, aircoolers or pipelines Simple, rapid defrosting of insulated unit coolers by closing air intakes/outlets... and in defrosting. The brine insulated unit coolers are defrosted in the heat exchanger coil using warm brine (25 ºC) and in the tray using electrical power. Here, too, the tray is preheated so that the outlet does not block with ice. In all insulated unit coolers, defrosting always takes place with the flap to the cooling compartment closed. In order to prevent unnecessary steam formation during defrosting, the coil defrosting temperature is recorded and defrosting stopped immediately if the coil temperature exceeds 5 ºC. After the defrosting process a dripping period takes place and then the freezing period. As soon as the coil temperature has reached an appropriate value the flap to the cooling compartment opens and the insulated unit cooler is ready for operation. The following insulated unit coolers are installed: Page 5

6 4 air coolers of type GIKS 25-45/626/ for NH3 direct evaporation in flooded operation, each with 200 kw of refrigerating power at an evaporation temperature of 37 ºC and a room temperature of 27 ºC (TIKO 1), set up for hot gas defrosting. 1 of same type for TIKO 2 with refrigerating power of 90 kw at 37/-27 ºC 1 of same type for TIKO 3, switchable for positive storage at t = +4/+2 ºC and +10/+12 ºC 2 of same type for TIKO 1 chamber with refrigerating power of 70 kw at an evaporation temperature of 9 ºC and a room temperature of 2/+4 ºC 3 insulatied coolers for brine circuit I, each with 170 kw of refrigerating power and chamber, designed on cold brine with 7/-2 ºC and a room temperature of +4 ºC; the hoar frost in the coil is defrosted using warm brine. 14 insulatied coolers for brine circuits II and III, each with refrigerating power of 150 kw for supplying the fresh produce warehouse and the fruit and vegetable area All other refrigeration rooms in the refrigeration logistics and the meat factory are equipped with slimline unit coolers with differing power and design temperatures. The majority of these aircoolers are defrosted using warm brine, and the trays have electric heating. In many cases an air heater is installed for room drying. A total of 140 aircoolers are deployed in the Möckmühl logistics centre. Page 6