Energy-Economic Analysis of Plate Evaporator using Brine-based Hybrid Nanofluids as Secondary Refrigerant

Abstract

Energy and economic analyses of corrugated plate evaporator have been performed in this study by using brine-based hybrid nanofluids as secondary refrigerant for low temperature applications (milk chilling, ice making and fish freezing). Various hybrid nanofluids containing alumina with different nanoparticles (copper, silver and multi walled carbon nanotube) dispersed in ethylene glycol/water, propylene glycol/water, calcium chloride/water and potassium acetate/water brines have been considered. A comparison has been made based on overall heat transfer coefficient, evaporator size (heat transfer area), pump work, COP, annual cost and payback period. The maximum reduction in heat transfer area has been observed for PG brine-based alumina–silver hybrid nanofluid. Whereas, the maximum reduction in pump work and augmentation in COP have been obtained for PG brine-based alumina–MWCNT hybrid nanofluid. EG brine-based Alumina–Cu hybrid nanofluid yields minimum annual cost. Most of the nanofluids (except PG brine-based Al2O3–Ag nanofluid) seem to be not beneficial for practical use due to comparatively long payback period; however, that can be significantly reduced in future by decreasing nanoparticle cost and increasing nanofluid stability. The present study reveals that the brine-based hybrid nanofluids may be the potential option as next generation secondary refrigerants for low temperature applications.