Design and Analysis of a Solar Energy Driven Tri-generation Plant for power, Heating and Refrigeration

A tri-generation plant producing power, heat and refrigeration has been designed and analyzed. Using solar energy as input. The power side of the plant employs supercritical carbon dioxide (sCO2) recompression cycle. The refrigeration side includes an aqueous lithium bromide absorption system. Thermal energy has been extracted from many places in the plant for heating purposes. A detailed thermodynamics model has been developed to determine performance of the plant for many different conditions. Thermal efficiency, energy effectiveness and exergetic efficiency of the system has been calculated for different operating conditions. It turns out that the pressure ratio of the recombination cycle and effectiveness of the energy exchanger for transferring energy from the power side to the refrigeration side play important roles.

Analysis of Aqueous Lithium Bromide Absorption Refrigeration Systems

Aqueous lithium bromide absorption refrigeration systems have been studied in recent years and their advantages like environmental safety and utilization of low-grade energy have been proved. Research on improving their performance has been increasing lately. In this paper, single effect and parallel flow double-effect aqueous lithium bromide absorption refrigeration systems have been studied. Mass, energy, entropy and exergy balances have been used to model the absorption refrigeration systems. Parametric studies have been done to investigate effects of cooling load, evaporator exit temperature, condenser exit temperature, generator vapor exit temperature, absorber exit temperature, solution energy exchanger effectiveness on the performance of the system. The analyses show coefficient of performance and exergetic efficiency of double-effect absorption refrigeration is higher than those of a single-effect refrigeration. The effect of other parameters on performance of both single and double-effect systems have been described in detail in the article.

Vapor Pressure and Physicochemical Properties of {LiBr + IL-Based Additive + Water} Mixtures: Experimental Data and COSMO-RS Predictions

In recent years, many compounds have been proposed as additives to conventional working fluids to improve the performance of the absorption refrigeration system. The main aim of this research is to show the influence of ionic liquid based additives on thermodynamic and physicochemical properties of {LiBr + water} solutions. The following additives: 3-(1-methyl-morpholinium)propane-1-sulfonate, N,N-di(2-hydroxyethyl)-N,N-dimethylammonium bromide, and N,N,N-tri(2-hydroxy-ethyl)-N-methylammonium bromide have been added to aqueous lithium bromide solutions (IL to LiBr mass fraction, w2 = 0.3). The physicochemical and thermodynamic properties of {LiBr (1) + additive (2) + water (3)} and {LiBr + water} systems including (vapor + liquid) phase equilibria (VLE), density (ρ) and dynamic viscosity (η) were determined over wide temperature and composition ranges. The conductor-like screening model for real solvents (COSMO-RS) was used for the VLE data prediction. For the density and dynamic viscosity correlations, empirical equations were applied. A comparison of experimental data for {LiBr + additive + water} with those for {LiBr + water} systems shows the influence of using the additives proposed in this work. The data presented are complementary to the current state of knowledge in this area and provide directions for future research.

Relationship between the Photoluminescence Spectra and IR Spectroscopy of Mesoporous Silicon Samples during Long-Term Storage: The Effect of Immersion in an Aqueous LiBr Solutions

Studies are devoted to determining the effect of long-term storage (up to 200 days) of untreated and immersion-treated layers of mesoporous silicon in an aqueous lithium bromide solution obtained by anodizing with a current density of 10 mA/cm2 in electrolyte HF: CH3OH = 2: 1. It was found that an increase in the PL intensity and its saturation with a storage time of more than 100 days in all samples is observed. A detailed analysis of absorbance on bonds in m/por-Si showed that during storage, hydrogen bonds are destroyed, and the PL peak intensity is proportional to the increasing concentration of non-stoichiometric oxide, in which oxygen atoms forms radiative states. It was shown that in the treated samples, the PL intensity decreases with increasing immersion time, but the mechanism of photoluminescence through the quantum size confinement (QSC) effect in mesoporous silicon without and with immersion in an aqueous LiBr solution is not significant.