Simulation research on absorption refrigeration system based on NH3-H2O-LiBr vapor-liquid equilibrium calculation model

In order to investigate the ammonia + water + lithium bromide absorption refrigeration cycle process and to simulate it accurately, a vapor-liquid equilibrium calculation model was proposed to obtain thermodynamic characteristic data of the ternary mixtures. The calculation of parameters of liquid phase is based on Wilson?s equation and NRTL equation. The vapor phase, assumed to consist of ammonia and water only, is described by The Redlich-Kwong Equation of State. The data of the equilibrium vapor pressure and the ammonia concentration in liquid phase calculated by this model was compared with the experimental data, the difference is between 0.5% to 9.6% within the temperature range from303 K to 425 K. The COP obtained by the simulation matches with that obtained by experiment and the absolute deviation is less than 0.02. Therefore, this calculation model can be used for simulation to extend the temperature range and pressure range of the system, so as to determine the design parameters of the absorption refrigeration system. The simulation results indicates that under different working conditions, the optimal generator temperature and concentration of adding lithium bromide can be selected, to which the theoretical explanations were given in this paper.

Download Full-text

DESIGN OF A SOLAR ENERGY OPERATED LITHIUM-BROMIDE WATER ABSORPTION REFRIGERATION SYSTEM FOR REFRIGERATION STORAGE

Sun: Mankind's Future Source of Energy ◽

10.1016/b978-1-4832-8407-1.50389-5 ◽

1978 ◽

pp. 1997-2001 ◽

Cited By ~ 1

Author(s):

S.B. Ghosh ◽

G.L. Reddy ◽

H.V. Rao ◽

G.P. Gupta

Keyword(s):

Solar Energy ◽

Water Absorption ◽

Lithium Bromide ◽

Absorption Refrigeration ◽

Refrigeration System ◽

Absorption Refrigeration System ◽

Refrigeration Storage

Download Full-text

TESTS OF ARRANGEMENTS IN A PROTOTYPE OF A STEAM GENERATOR IN AN ABSORPTION REFRIGERATION SYSTEM

Revista de Engenharia Térmica ◽

10.5380/reterm.v18i2.70796 ◽

2019 ◽

Vol 18 (2) ◽

pp. 70

Author(s):

R. F. M. Santos ◽

K. L. Cezar ◽

P. A. C. Rocha ◽

R. J. P. Lima ◽

M. E. V. da Silva ◽

...

Keyword(s):

Heat Transfer ◽

Steam Generator ◽

Lithium Bromide ◽

Heat Transfer Process ◽

Heat Flow Rate ◽

Absorption Refrigeration ◽

Refrigeration System ◽

Governing Factor ◽

Absorption Refrigeration System ◽

Internal Convection

This paper presents a proposal to optimize the prototype II of a steam generator, developed by the Cooperativa de Pesquisa Norte/Nordeste de Gas Natural, RECOGÁS - UFPB, which is a component of an absorption refrigeration system of water and lithium bromide triggered by direct burning of natural gas. The optimization was carried out through changes in the arrangement, geometry, and number of the heat exchanger pipes. It was developed a computational code using F-Chart software Engineering Equation Solver® (EES), applying the principles of heat transfer to all the different geometries. As a result, their respective coefficients of heat transfer, heat flow rate and other parameters of the process were obtained. The findings are organized in a table and represented in graphs generated by the EES software, allowing to verify which factors had a greater influence on the process, as well as the most efficient geometries. Internal convection was identified as the governing factor in the heat transfer process. Some of the geometries presented satisfactory values to the product of overall heat transfer coefficient and surface area (UA) and also to the heat transfer rate in the steam generator. Other ones presented a better thermal efficiency relation with the amount of volume occupied in the steam generator. Some geometries did not present satisfactory values under any aspect.

Download Full-text