Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2018
Student: ÖNDER ŞAHİN
Supervisor: TAYFUN MENLİK
Open Archive Collection: AVESIS Open Access Collection
Abstract:Turkey is a country that is largely outsider dependent on energy supply. Although investments in renewable energy technologies have increased, they are far from being self-sufficient in energy production. The fact that the supply of energy as well as the use of energy is efficient is of great importance in terms of the country's economy. In this study, a DAR system, which allows to work with renewable energy sources, has been designed to improve the system performance by designing the heat exchanger in the thermal compressor zone. For analysis, six winged (6-8-10-12-14-16) and one commercially available wingless (flat pipe) heat exchanger were modeled. In the designed heat exchanger, the wings are designed flat and placed on the surface of the part where the heating fluid contacts. NH3-H2O (25%-75%) was used as the refrigerant-absorbing fluid in the system. The modeled heat exchangers were numerically solved using the Fluent software, which is a Computational Fluid Dynamics (CFD) program, and the boiler temperatures used in calculating the system Cooling Efficiency Coefficient (COP) were determined. The thermal performances of poultry and wingless heat exchangers have been compared. In the wingless heat exchanger, the boiler temperature was determined as 150.09 °C. In the 16-blade heat exchanger, the boiler temperature was 161.63 °C. At the end of the work done, 7.7% increase was achieved at the boiler temperature. COP values calculated based on the specified boiler temperatures were found to be 17.10% for the wingless model. Within the winged models, the highest COP value was reached in the 8-wing model, at 17.81% level. It was determined that system performance increased by 4.2% with numerical analysis. It has been theoretically analyzed that the system can operate continuously with renewable energy sources which can be provided with sufficient and uninterrupted supply.