The idea of banishing freezers to the cellar where they could make as much noise as they liked is a thing of the past. Nowadays, foodstuffs and the associated technology have long since become lifestyle items – new homes with open-plan kitchens are the latest fashion. This means refrigerators have to look the part and are often accompanied by special high-tech appliances to provide the best possible atmosphere for storing wine or cigars.
The sort of loud, unpleasant noises which often used to emanate from appliances in the past would be completely out of place in this modern scenario. Which is why customers now listen more closely when deciding what to buy. Alongside energy consumption, noise is therefore becoming an ever more important topic when it comes to purchasing refrigerators and freezers. So for some years now, ways of reducing noise have been a focal point in the development of new household appliances at Liebherr. The refrigerator and freezer division of the Liebherr Group concentrates primarily on the premium sector.
Refrigerators and freezers have to keep foodstuffs fresh 24 hours a day whilst at the same time consuming as little power as possible. Energy efficiency will continue to play a crucial role in future purchasing decisions. Which means there will be plenty of tasks to master from an engineering point of view. This applies not only to fridge/freezers but also to refrigerated wine cabinets and humidors. And sophisticated ventilation is always an essential element for all of these.
Refrigerators and freezers have undergone dramatic changes in recent years. Whereas in the past a single storage area with a uniform temperature was sufficient, different zones are now demanded – like the so-called BioFresh compartments for example. These provide ideal storage conditions guaranteed to keep fruit, vegetables, meat, fish and dairy products fresh for longer. Just one fan is needed to regulate the temperature in both storage areas. Although fans with shaded-pole motors are still fitted in certain models, DC fans are being ever more widely used, particularly for higher energy efficiency classes. These permit speed regulation which in turn has a favourable effect on noise and power consumption levels.
The situation is similar with regard to NoFrost technology: The convenient “No need to defrost” feature is of great benefit to customers. A special blower with DC or AC motors conveys the moisture given off by the stored items or coming in through the open door to an evaporator element, where it then condenses. So frost has no chance to form either in the storage area or on the food itself.
Both systems were developed by Liebherr in conjunction with ebm-papst. The latter has been an important direct point of contact for many years on the subject of fans.
The success of this partnership can be attributed primarily to the fact that challenges have always been quickly mastered so far. For the latest version of the NoFrost system, the two companies took the joint decision to modify the housing of the DC motor BG-15 from ebm-papst Landshut in such a way as to minimise the transmission of vibration and the resultant noise. “All to the everyday benefit of customers who can enjoy having an efficient, quiet-running freezer,” says Reinhard Sommerreißer, the ebm-papst sales representative responsible.
Perfectly cooled wine all year round
Although wine coolers only represent a smallish market segment, the Liebherr development engineers are keen to cut the noise level here as well. For testing, the appliances are taken to the noise laboratory at
ebm-papst (St. Georgen). The measurement results obtained there are used to optimise the air flow and noise characteristics. Such tests are just one link in Liebherr’s long quality assurance chain. All-in-all, the trial phase for new products takes roughly a year. All components have to survive long-term testing, as Liebherr appliances are designed to last at least 15 years.
The same is true of the humidor, despite the fact that the fans in it are exposed to a particularly high humidity level. The cigar store is fitted with a total of four fans. Two of these regulate the temperature, which can be set between 16 and 20 degrees centigrade – depending on what is needed for the cigars. The other two fans regulate the humidity to between 68 and 75 per cent as required. These two fans in particular are specially designed to guard against moisture. For this and other applications, it is important to Liebherr that the fans take up as little space as possible to maximise the storage space available.
ebm-papst fans are in operation in thousands of Liebherr appliances altogether. “The number of projects alone shows how intensive our association with Liebherr is,” says Reinhard Sommerreißer. He is in no doubt that the future holds plenty more projects with Liebherr. Gourmets, amateur chefs and cigar lovers the world over can rest assured: They will always be able to rely on top quality household appliances.