Experimental investigation and evaluation of the thermodynamical performance of a novel hybrid design for milk pasteurization

In this study, a novel pasteurization system with an electrical-assisted, waste heat-recovered hybrid design was proposed for more clean and more versatile production. The novel system is designed to recover both the dissipated and extracted heat for milk pasteurization in a single thermodynamic cycle, thus enhancing energy and exergy efficiency. For experimental design, system parameters were selected as an LTLT and the target temperature was set to 65 & PLUSMN; 5 degrees C. It was experimentally determined that 2.328 kW of heat was recovered in the specifically designed heat exchanger. The novel pasteurization system had 0.71% energy efficiency whereas the pasteurization system without energy recovery shows 0.48% energy efficiency. It is concluded that heat recovery thanks to a specific condenser may increase energy efficiency by about 148%. Considering computed exergy input (4.303 kW) and output (0.3096 kW), the exergy efficiency of the whole pasteurization system was nearly 7.2%. It is found that the compressor had a 0.9884 kW exergy destruction rate corresponding to a 25% exergy destruction percentage. It is followed by the evaporator with 0.5662 kW, the secondary condenser with 0.2297 kW, by condenser with 0.1555 kW, and by expansion valve with 0.08221 kW, respectively. Consequently, the novel system has a promising design by performing good thermodynamic efficiency and recovering waste heat to reduce secondary heating energy requirement which is not valorized in conventional systems. The novel system causes approximately 33% fewer carbon emissions compared to a pasteurization system without energy recovery for the same amount of milk processing.