Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Influence of Condensation and Evaporation Modeling in the Simulation of Split Air Conditioning Systems
Submission Author:
Gabriel Lisbôa Verissimo , RJ , Brazil
Co-Authors:
Fabiano Aragao, Gabriel Lisbôa Verissimo
Presenter: Gabriel Lisbôa Verissimo
doi://10.26678/ABCM.COBEM2023.COB2023-1280
Abstract
Air conditioning is an essential part of the Heating, Ventilation, Air Conditioning, and Refrigeration industry. Its use is linked to thermal comfort. Currently about 2 billion units of residential equipment are in operation in the world, and only 8% of the 2.8 billion people living in the hottest regions have air conditioning in their homes. As the world population grows and the climate becomes hotter due to the global warming, it is expected an increase in the use of air conditioning, especially in the emerging economies of the world, thus providing a greater consumption of electricity. With the increase in the thermal sensation and the cost of the electric tariff, air conditioners that have high coefficients of performance and compressors with low electrical power become essential. Computational studies play an important role in the development of more efficient air conditioning systems. In that sense, a reliable modeling of the system is crucial to obtain accurate results. In order to understand the impacts of the computational modeling of the heat transfer process in air conditioning systems, the present work analyzes the influence of convective coefficient correlations for evaporation and condensation process in the simulation of split type air conditioning system working with R410a. Evaporator and condenser geometries are composed of flat fins with louvers, which, due to their compactness, allow a high heat transfer area compared to their volume. Steady state operation is assumed. The compressor is modeled using a correlation from literature, which follows the AHRI (Air-Conditioning, Heating, and Refrigeration Institute) 540 standard. The heat transfer between R410a, and the air in the evaporator and condenser are done discretizing both in small sections. Then, the global heat transfer is evaluated locally, allowing the determination of the heat exchanged in each section. The computational modeling is developed in an open source programming language called Python. In the present work, thermophysical properties of the refrigerant fluid and humid air are obtained using the open library Coolprop database. Consumed power, cooling capacity and coefficient of performance of the system operating with R410a refrigerant fluid are studied. Initially, the computational implementations are validated against experimental data available in literature. Then, results are generated from the analysis of six correlations reoffering to the convective coefficient during condensation and two correlations during evaporation in order to find the set of heat exchangers that provide the highest COP value.
Keywords
air conditioning, Louvered Fins, mathematical modeling, Heat transfer coefficient
