Room for preecooled meat deep freezing

Rashladni sustav za duboko zamrzavanje važan je element u mesnoj industriji. Meso se zamrzava velikom brzinom u tunelu i tako se formiraju mali kristali leda, čime se ne narušava biološka struktura mesa. Tunel za duboko zamrzavanje je hladionica s intezivnim strujanjem zraka u kojem se meso zamrzava i hladi do -18 ili -20 °C u vremenskom trajanju od 18 sati. To se postiže rashladnim sustavom s amonijakom (R717) kao radnom tvari, te dvostupanjskom kompresijom i dvostupanjskim prigušivanjem s međuhladnjakom (mješalištem). Hladionica je smještena u sklopu složenog rashladnog postrojenja i izrađena je od predfabriciranih poliuretanskih panela. U uvodnom dijelu rada ukratko je opisana uloga tunela za duboko smrzavanje mesa i navedene su karakteristike amonijaka kao radne tvari. Napravljen je proračun rashladnog učina hladionice i tehnički proračun komponenti sustava. Na kraju je prikazana shema spajanja i automatske regulacije te dispozicijski crtež sustava.Deep freezing cooling system is an important element in the meat processing industry. The meat is frozen in short time in the tunnel and thus form small ice crystals, which does not disturb the biological structure of meat. Tunnel freezer is cold room with intensive air flow in which the meat is frozen and cooled to -18 or -20 °C within 18 hours. This is achieved by a cooling system with ammonia (R717) as a refrigerant, with two stage compression and two stage throttling with intercooler (mixing tank). Cold rooms are located within a complex refrigeration system made of pre-cast panels of polyurethane. In the introductory part of the paper, the role of deep freezig chambers is briefly described in the context of meat processing industry, also the characteristics of ammonia as a refrigerant are introduced. Furthermore, a calculation of refrigeration capacitiy for cold rooms and technical calculation of system components is carried out. Finally, there is the diagram of connection and automatic regulation with system disposition drawing