Performance Investigation of Utilizing Nanoferrofluid as a Working Solution in a Diffusion Absorption Refrigeration System Under an External Magnetic Field Effect

Abstract

This research aims to develop diffusion absorption refrigeration system DARS' performance coefficients that can work especially with low-temperature heat sources. For this purpose, the properties of the used (Fe3O4-ammonia/water) nanoferrofluid as a refrigeration binary working solution were determined and examined its efficiency characteristics depending on separated thermophysical and visual inspection analyses. Later, in the absence and presence of an external magnetic field that affects the DARS' bubble pump-generator component, the validation of using the nanoferrofluid was experimentally investigated. Then an experimental study of obtained enhancement in DARS' performance was presented by using the solution with helium as an inert gas. No previous study has tested this nanoferrofluid based on the ammonia/water binary working solution under an external magnetic field effect as it is performed in this research. So this work can be considered an investigation of a new nanoferrofluid and a continuation of the previous studies. The experiments were performed on nanoferrofluids of 0.05 wt.% and 0.1 wt.% Fe3O4 nanoparticles concentrations in 300 ml NH3/H2O base-fluid with addition 1 wt.% concentration of polyvinyl pyrrolidone surfactant, which was equipped to DARS with and without an external magnetic field. Depending on the concentrations and presence or absence of the external magnetic field, the experiments are divided into five tests. According to the obtained results of the analyses, DARS with 0.1 wt.% nanoferrofluid under the external magnetic field was the best system with enhancements in COP, ECOP, reached 10.72%, 26.66%, respectively, and a decrease in the circulation ratio (f) by 2.70%.