Restaurangventilation - Frånluftsrening och värmeåtervinning

Abstract

In kitchens and especially big kitchens in restaurants, schools and hospitals often cause a coating of fat in the ventilation ducts, as well as odor of rancid caused by the cooking. Institutional kitchen ventilation is an area that has developed rapidly in the last few years, introduction of new methods to clean the extract air has been on the market for some time but has not been reviewed extensively consider to effectiveness and the environmental view. This report identifies and review the different systems used to process the extract air in an institutional kitchen. The cleaning methods described in the report are ozone treatment, UV-light treatment and treatment with bacteria. The report explores the possibility to use heat exchanging and the theoretical savings it can bring. The report showed that the examined cleaning methods were all effective against fat coatings if they were correctly projected, properly maintained and adapted to the environment. The ozone and UV treatment seemed to be less dependent on how many hours the restaurant were in use each day and could be applied to a wider range of kitchens. Though, those systems turned out to generate harmful byproducts if not a complete reaction between the fat and ozone occurred. This was not the case with the bacterial system. There was diversity among the sources about in which extent the systems worked. There was as well diversity about using a rotary heat exchanger, some sources stating that it was fully viable, and others claiming there are high risks considering the transferring of smell and substances. The calculations done in the report displayed a theoretical possibility to save energy by heat exchanging. It also showed that there could be a possibility to save additional excess heat prior to other systems operating in a facility. A cost analysis was done and the result showed that using a cleaning system accompanied with a heat exchanger was the best method after a time period of two years and six months.