Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Modelling and Simulation of the Thermal Generator and Rectifier of an Absorption Refrigeration Prototype
Submission Author:
Leonardo Cavalheiro Martinez , PR
Co-Authors:
Wellington Balmant, luciana martinho, JOSÉ VIRIATO COELHO VARGAS, Leonardo Cavalheiro Martinez
Presenter: Leonardo Cavalheiro Martinez
doi://10.26678/ABCM.COBEM2017.COB17-1534
Abstract
Considering the increasing energy demand and the increasingly significant use of refrigeration and HVAC-R equipment on the world, the utilization of absorption refrigerators is an excellent alternative to minimize this problem. In addition, the use of this equipment becomes energy-efficient when compared to the steam compression refrigeration cycles because it is possible to operate with residual heat in the generator as an energy source, even if its performance is lower. Thus, in order to became absorption refrigerators increasingly commercially competitive, both economically and thermodynamically, this study presents a proposal for semi transient mathematical modeling and the computational simulation of the thermal generator and rectifier of a absorption refrigeration prototype by fuel gas (LPG) developed in NPDEAS (Self-Sustainable Energy Research and Development Center) at UFPR. The modeling, which aims to describe mathematically the physical principles of the refrigeration prototype, was based on the application of the mass and energy conservation principles in a transient regime for the control volumes (CV1, CV2, CV3, CV4 and CV5) that describes the thermal generator and rectifier. Finally, with the developed mathematical model, a computational code was elaborated in Fortran® 95 language, which allowed to obtain the numerical and transient thermal and mass responses of the generator and rectifier. The mathematical model considers both components, e.g. thermal generator and rectifier, in a transient regime, which resulted in a system of ten ordinary differential equations, which were integrated at time and using the 4th/5th order Runge-Kutta method, that are interacting, simultaneously, with the empirical mass flow equations. An investigation of the model sensitivity was conducted, so that a qualitative assessment of how the numerical model results agree with the system expected response could be made, and the results showed that the physically expected trends were captured by the model. As a result, the proposed model can be a useful tool for simulation of single-stage absorption refrigeration systems in operation because presents the temperature and mass fraction distribution over time and that, subsequently, used for testing different conditions of operation and optimization procedures.
Keywords
mathematical modeling, Absorption Refrigeration System, Thermal Generator, Rectifier, Computational simulation
