Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi University, Teknoloji Fakültesi, Enerji Sistemleri Mühendisliği, Turkey
Approval Date: 2021
Thesis Language: Turkish
Student: Emine Yağız Gürbüz
Principal Supervisor (For Co-Supervisor Theses): Adnan Sözen
Co-Supervisor: Ali Keçebaş
Open Archive Collection: AVESIS Open Access Collection
Abstract:
Diffusion absorption refrigeration systems (DARS) gain importance as an interesting and developable technology in cooling and air conditioning applications. The use of nanofluids in thermal systems also maintains its importance as a preferred method in terms of enhancing heat transfer. In this thesis, ammonia-water-helium (NH3-H2O-He) working fluid and ammonia-water-helium working fluids with different weight ratios of MgOAl2O3, ZnOAl2O3 and TiO2 nanoparticles added were experimentally investigated in a DARS without pre-cooling. Each working fluid was tested in the system by adding 0.2 wt.% surface active agent and three various nanoparticles of 1wt.% and 2 wt.% to 250 ml of ammonia-water solution. System performances were evaluated by performing energy and exergy analyzes with the results obtained. The highest cooling capacity was found in the NH3-H2O-He working fluid using 2 wt.% MgOAl2O3 while the lowest cooling capacity was observed in the NH3-H2O-He base working fluid. The highest exergy destruction occurred in the solution heat exchanger, while the lowest exergy destruction happened in the condenser. As a result, an improvement of 38% was determined in the cooling capacity and an increase of 58% was in the exergy efficiency bu using MgOAl2O3 nanoparticles.
Keywords:
Diffusion absorbtion refrigeration system, nanofluid, energy