Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
A COMPARATIVE ANALYSIS BETWEEN AMMONIA-WATER ABSORPTION AND VAPOR COMPRESSION REFRIGERATION SYSTEMS
Submission Author:
Erick Pereira Cerqueira , SP , Brazil
Co-Authors:
Wellorzzon Ronnan Ibide Novais, Erick Pereira Cerqueira, Beethoven Narváez-Romo, José Roberto Simões Moreira
Presenter: Wellorzzon Ronnan Ibide Novais
doi://10.26678/ABCM.COBEM2021.COB2021-0990
Abstract
Refrigeration systems applications are broadly used in food and drug conservation and air conditioning. Commercial buildings demand up to 80% of total electrical power just for powering air-conditioning based on conventional vapor compression refrigeration systems (VCRS), which contributes to reach peaks on the electrical distribution network that could cause an unstable condition. Implementing absorption refrigeration systems (ARS) producing cooling effect driven by thermal energy could decrease this power consumption. Thermodynamic models of these systems can be found in the literature with a variety of working fluids and also integrated with other cycles such as power generation plants, however, just some have a direct comparison between ARS and VCRS employing the same conditions. Thus, the current study aims to simulate and compare two different types of refrigeration technologies: single stage ammonia-water absorption refrigeration cycle, and vapor compression refrigeration cycle working with R-134a and R-717. Thermodynamic simulation was carried out by evaluating heat transfer rates of main devices, coefficients of performance and specific areas of evaporator and condenser. As evaporator temperature decreases, ARS requires 16.9 kW or 67.5% more heat in generator and COP decreased from 0.601 to 0.359. Utilizing the same comparison parameter, VCRS needed 3.26-3.54 kW or 154-160% more compressor power, depending on refrigerant used, and COP decreased from 6.77 to 2.60 with R-134a and 7.07 to 2.79 using R-717. Compared to ARS, condenser specific area required for VCRS is smaller, evaporator is two times smaller when using R-134a, and is equal when using R-717. Those results can justify the usage of ARS in facilities with high amount of heat waste, mainly on applications working with lower evaporator temperatures.
Keywords
absorption refrigeration cycle, compression refrigeration cycle, Heat transfer, Ammonia-water, thermodynamic simulation
