Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
EXPERIMENTAL STUDY AND MODELING OF A H2O/NH3/H2 SOLAR DIFFUSION-ABSORPTION REFRIGERATOR FOR VACCINE STORAGE IN REGIONS WITHOUT ELECTRIFICATION
Submission Author:
Gustavo Sana Trindade , MG
Co-Authors:
Gustavo Sana Trindade, Willian Moreira Duarte, Fabiano Drumond Chaves, Nathália Beatriz Amorim Santos , Luiz Machado
Presenter: Gustavo Sana Trindade
doi://10.26678/ABCM.COBEM2023.COB2023-0745
Abstract
The objective of this work is to present a distributed condenser steady state mathematical model, written in Python language, of a H2O/NH3/H2 diffusion and absorption fridge for vaccine storage in regions without electrification. The refrigerator thermal input in ammonia vapor generator set was originally promoted by Joule effect through an 80.7 W electrical resistance. To supply the system with solar energy, the resistor is going to be replaced by a coaxial heat exchanger, in which thermal oil heated in a solar concentrator flows in annular space of the outer tube. Condenser, generator and rectifier models were based on the energy, mass balance equations applications for ammonia and water and the energy balance equation application for heat exchangers walls. Condenser input variables were obtained through peripheral components models. Thus, the ammonia mass flow rate and enthalpy at condenser inlet derive from generator set model, as well as the output mass flow rate resulting from Bernoulli’s equation application, corrected for viscous effects, for ammonia flow along the pipe that connects condenser and evaporator. Total system operating pressure that does not vary spatially is the main model output variables. This variable is the result of a series of convergences involving model’s equations, one of which is based on ammonia flows equality at condenser inlet and outlet. Model simulations carried out revealed that total single pressure is equal to 1477000 Pa (14.77 bar). In addition, the ammonia, ammonia/water solution, and wall temperature profiles were determined for these components. Finally, the model was validated by comparing the calculated values and the experimental data obtained by measurements performed with thermocouples and infrared thermography. Differences between theoretical and experimental values were a maximum of 6.1%.
Keywords
modeling, Vaccine storage, Heat transfer, Solar Energy, Diffusion absorption refrigerator
