scholarly journals Electrical conductivity of concentrated LiBr Ethylene-Glycol and water ternary system

2021 ◽  
Vol 2116 (1) ◽  
pp. 012069
Author(s):  
J Zheng ◽  
J Chiva ◽  
J Castro ◽  
Y Liu ◽  
A Oliva
Keyword(s):  
Electrical Conductivity ◽  
Ethylene Glycol ◽  
Empirical Relation ◽  
Experimental Result ◽  
Absorption Refrigeration ◽  
Mass Ratio ◽  
Refrigeration System ◽  
Absorption Chiller ◽  
Simple Method ◽  
Absorption Refrigeration System

Abstract LiBr/H2O as working pair in absorption chiller is widely used in the absorption refrigeration system, and the electrical conductivity is used as secondary properties as an empirical relation with temperature and concentration as a simple method to measure the concentration. In this paper, another working pair Carrol/H2O is chosen, more suitable for air-cooled cycles. Carrol contains ethylene glycol and LiBr with a mass ratio at 4.5:1 and has advantages of low risk of crystallization and reduce the LiBr charge. The working range for the LiBr/H2O solution is temperature 25-80°C, at concentration 50–64%, in term of Carrol/H2O system, the temperature range is 25-80°C, concentration range is 50%-75%. The electrical conductivity will be measured according to the working range and a typical used solution extracted from an absorption chiller prototype will also be measured to compare with the experimental result.

scholarly journals Investigation of a Solar Thermal Driven Refrigerated Warehouse in Tripoli-Libya using TRNSYS

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mukhtar BenAbeid
Keyword(s):  
High Performance ◽  
Freezing Point ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Chiller ◽  
Load Model ◽  
Solar Fraction ◽  
Evacuated Tubes ◽  
Absorption Refrigeration System ◽  
Solar Powered

This paper, illustrates a design and simulation of a solar powered absorption refrigeration system preserves food above freezing point. The main system is modified from a commercial conventional system located at Tajoura, Libya. The target is to design and operate the system at high solar fraction and efficiency. The simulation is performed by TRNSYS to evaluate the annual thermal performance of the solar system that consists of 50-kW absorption chiller producing cold for three refrigerated rooms. The model could be classified into two main parts; refrigeration load model and solar powered refrigeration system model. The results demonstrated that the optimum system achieves 51% solar fraction consists of 48 m2 of high performance evacuated tubes solar collectors and 5000-litre thermal storage tank, in order to power a 50-kW absorption chiller that offers cold for three refrigerated rooms of vegetables.

Model-Free Adaptive Nonlinear Control of the Absorption Refrigeration System

2021 ◽  
Author(s):  
Na Dong ◽  
Wenjin Lv ◽  
Shuo Zhu ◽  
Zhong-ke Gao ◽  
Celso Grebogi
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Tracking Control ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Chiller ◽  
Model Free ◽  
Temperature Tracking ◽  
Single Effect ◽  
Absorption Refrigeration System

Abstract Based on the model-free adaptive control (MFAC) theory, the temperature tracking control problem of single-effect LiBr/H 2 O absorption chiller is explored. Due to the complex nonlinearity and strong coupling characteristics of the absorption refrigeration system, model-free adaptive control strategy is designed for its temperature tracking control. Nevertheless, the traditional model-free adaptive control has a slow tracking speed and poor denoising ability. In order to improve its control effect, output error rate is added to the objective function and new control laws of model-free adaptive control with output error rate (MFAC-OER) have been derived through an exhaustive convergence and stability analysis. The input and output information of the absorption refrigeration system, namely the hot water pump frequency and frozen water outlet water temperature, are combined. The data model of the absorption refrigeration system is subsequently deduced using a compact format dynamic linearization method. Next, based on the single effect absorption chiller experimental platform in our laboratory, its sixth-order dynamic model is built. Finally, the effectiveness and practicability of the improved control strategy are validated by numerical simulations and experimental operating data from our laboratory as well as by the dynamical model of the absorption chiller.

Modeling and Simulation of the Absorber of an Absorption Refrigeration System

2018 ◽  
Author(s):  
Leonardo Cavalheiro Martinez ◽  
Wellington Balmant ◽  
Iago Costa ◽  
Matias Nicolas Muñoz ◽  
Luiz Rigatti ◽  
...  
Keyword(s):  
Modeling And Simulation ◽  
Absorption Refrigeration ◽  
Refrigeration System ◽  
Absorption Refrigeration System
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