Efficiency analisys of the heat pump system for raw milk cooling with precooler and possibility for waste heat recovery through sanitary water heating

Abstract

Contemporary livestock production implies production of highly valuable, biologically and chemically safe products. Dairy production has no exception too. On the contrary, the quality standards for raw milk are highly increased. The quality of raw milk is defined by its chemical composition and the total count of microorganisms in control volume. In this paper we discussed the performance of advanced system for heat recovery from raw milk and its application in the process of preheating and preparation of process water. The energy and exergy efficiency of one of such systems were analyzed. It was determined that the implementation of the system for milk cooling with precooling and using the waste heat for preheating process water could achieve significant savings. The system consists of 'milk to water' heat pump, pre-cooler for milk cooling and storage tank for process water with heating possibility. Values of exergy efficiency of each component of system and potential improving of components performances were determined. Also, the exergy efficiency and potential improvement of complete system were determined.

Savremena stočarska proizvodnja podrazumeva proizvodnju visoko vrednih, biološki i hemijski bezbednih proizvoda. Proizvodnja mleka nije izuzetak, naprotiv, norme kvaliteta sirovog mleka su sve strožije. Kvalitet sirovog mleka je određen njegovim hemijskim sastavom i ukupnom brojnošću mikroorganizama u kontrolnoj zapremini. U ovom radu biće razmatran rad naprednog sistema za rekuperaciju toplote iz svežeg mleka koja se potom koristi u procesu dogrevanja i pripreme potrošne vode. Primenom sistema za hlađenje mleka sa predhlađenjem i korišćenjem dobijene toplote za zagrevanje potrošne vode mogu se postići značajne uštede. U radu je analizirana energetska i eksergetska efikasnost rada jednog ovakvog sistema. Sistem se sastoji od toplotne pumpe 'mleko-voda', predhladnjaka za hlađenje svežeg mleka i skladišnika potrošne tople vode sa mogućnošću njenog dogrevanja. Ustanovljene su veličine eksergetske efikasnosti komponenata sistema i potencijal poboljšanja svake od komponenata u sistemu. Takođe, ustanovljena je eksergetska efikasnost celokupnog sistema i potencijal njegovogpoboljšanja.