LiBr Concentration Research Articles

Tough gelatine hydrogels reinforced with silk fibroin nanofiber

Gelatine hydrogels exhibit potential as biomaterials such as wound-healing materials, artificial organs, scaffolds for cell culture and drug delivery systems because of their good biocompatibility. However, their practical applications are limited by their poor mechanical properties and high degradability. In this study, mechanically fibrillated silk fibroin (fibroin nanofibers; FNF) was used to reinforce gelatine hydrogels. The resulting gelatine hydrogels with FNF exhibited enhanced toughness compared to those reinforced with conventional aqueous regenerated fibroin (RF), which were prepared by treatment with a highly concentrated LiBr solvent or a neat gelatine hydrogel while retaining their softness. The average pore size of the gelatine hydrogel was 2.2 μm, while the gelatine hydrogel containing 25 % FNF expanded to 6.7 μm. A web-like network was formed between the pores. The addition of FNF increased the relative β-sheet contents in the hydrogels to 60.3 %, suggesting that this may have caused structural changes such as increased crystallinity for gelatine-derived proteins. Furthermore, the addition of FNF inhibited the rapid enzymatic degradation of gelatine hydrogels. FNF, which can be easily prepared in water, is a safe material for both the environment and living organisms and holds promise as a biomaterial in the future.

Analyzing wall adhesion effects on falling film hydrodynamics for aqueous lithium bromide application

Over the past decade, there has been a concentrated effort to accurately characterize the film thickness in horizontal tube falling film evaporators (HFFEs). Despite the experimental challenges in measuring thickness across the entire tube, researchers have made advances using adaptable operational settings, such as numerical modeling, to analyze falling films. One such condition is to analyze film hydrodynamics for different wall adhesion contact angles. In this study, a 2-D computational fluid dynamics (CFD) model is developed to quantify film thickness and wetting time and to analyze hydrodynamics for aqueous lithium bromide (LiBr) applications. The variation of liquid load (Γ1/2) from 0.01–0.05 kg/(m·s) and contact angle from 0–45° are studied for LiBr concentrations (C) of 0.45 and 0.65. Results indicate that the impact of contact angle diminishes at higher liquid loads and LiBr concentrations. At C = 0.45, the film thickens by 13.8 % for Γ1/2 = 0.05 kg/(m·s). Moreover, the effects of contact angle on wetting time are more pronounced than the average film thickness. With a higher contact angle, heat transfer may deteriorate due to the poor thermal resistance caused by higher average film thickness.

Insights into the dissolution of cellulose in lithium bromide solution

Lithium bromide molten salt hydrate (∼62 wt% aqueous solution of LiBr) can dissolve cellulose, but the cellulose dissolution mechanisms are not fully understood. This study revisited cellulose dissolution in the LiBr solution and aimed to provide new insights into the dissolution mechanisms. The collected evidence suggested that cellulose dissolution in the LiBr solution is primarily attributed to the disruption of intermolecular H-bonds of cellulose by the ion-dipole coordination between hydrated Li+ and cellulose hydroxy. The coordination between Li+ and cellulose was verified by 7Li NMR and simultaneous DSC-TGA analysis. The observations in this study also suggest that polarizable, large-size, and low-electronegativity Br– plays a synergetic and supplementary role in the dissolution of cellulose. In addition, the dissolution of cellulose in the LiBr solution is greatly dependent on dissolution conditions (LiBr concentration, temperature, pH, and cellulose loading) and cellulose properties (particle size and degree of polymerization).

Water-in-Salt: Fast Dynamics, Structure, Thermodynamics, and Bulk Properties.

We present concentration-dependent dynamics of highly concentrated LiBr solutions and LiCl temperature-dependent dynamics for two high concentrations and compare the results to those of prior LiCl concentration-dependent data. The dynamical data are obtained using ultrafast optical heterodyne-detected optical Kerr effect (OHD-OKE). The OHD-OKE decays are composed of two pairs of biexponentials, i.e., tetra-exponentials. The fastest decay (t1) is the same as pure water's at all concentrations within error, while the second component (t2) slows slightly with concentration. The slower components (t3 and t4), not present in pure water, slow substantially, and their contributions to the decays increase significantly with increasing concentration, similar to LiCl solutions. Simulations of LiCl solutions from the literature show that the slow components arise from large ion/water clusters, while the fast components are from ion/water structures that are not part of large clusters. Temperature-dependent studies (15-95 °C) of two high LiCl concentrations show that decreasing the temperature is equivalent to increasing the room temperature concentration. The LiBr and LiCl concentration dependences and the two LiCl concentrations' temperature dependences all have bulk viscosities that are linearly dependent on τcslow, the correlation time of the slow dynamics (weighted averages of t3 and t4). Remarkably, all four viscosity vs 1/τCslow plots fall on the same line. Application of transition state theory to the temperature-dependent data yields the activation enthalpies and entropies for the dynamics of the large ion/water clusters, which underpin the bulk viscosity.

Self-rehydrating and highly entangled hydrogel for sustainable daytime passive cooling

Daytime passive cooling technology supported by coupling effects of daytime radiative cooling and evaporative cooling has drawn significant attention for alleviating the burdens of energy consumption and greenhouse gas emissions. Incorporating a hygroscopic agent allows the daytime radiative/evaporative cooler to replenish water itself at night, thus ensuring evaporative cooling during the daytime. However, the mechanism of the relationship between daytime passive cooling and nighttime rehydration is not fully understood. Besides, the design of circulating daytime radiative/evaporative coolers is segmented at present, and the poor mechanical properties of hydrogel restrict the practical application. Hence, a tough and elastic hydrogel with a highly entangled structure was prepared by dense polyacrylamide chains, exhibiting the 18-fold tensile stress and 9-fold compressive stress of the control group. Integrating zirconium dioxide (ZrO2) particles as a spectral regulator, the composite hydrogel possessed solar reflectance of 0.90 and mid-infrared emission of 0.88, realising daytime radiative cooling. After swelling in lithium bromide (LiBr) solution, the composite hydrogel achieved a cycle of daytime evaporative cooling and nighttime rehydration. Besides, the effects of LiBr concentrations on the evaporation and hygroscopicity of the composite hydrogel were investigated. Furthermore, two indoor experiments and one outdoor field test were performed, and the findings suggested that the design of strong hygroscopicity and effective evaporation was a contradiction, and it is crucial to narrow the gap between evaporation and rehydration instead of only pursuing the best cooling performance to achieve sustainable daytime passive cooling. Thus, it is hoped that this study could broaden the field of sustainable daytime passive cooling technologies.

Mathematical model and experiment investigation on electrodialysis separation process of LiBr from NH3-H2O-LiBr ternary solution in ammonia absorption refrigeration system

The utilization of NH3-H2O-LiBr ternary working fluid is effective to improve the COP of the ammonia absorption refrigeration system (AARS). However, LiBr impairs the absorption of NH3 in the absorber and consequently limits the COP promotion. To address this limitation, electrodialysis (ED) is introduced into AARS to reduce the LiBr concentration in the absorber because it has been widely applied in ion separation from industrial waste solutions. In this study, a simulation model for the NH3-H2O-LiBr ternary solution ED separation process was developed based on the overall mass transfer equation. Experiments were conducted to measure and verify the coefficients in the model. The results showed that the NH3 transport was hard to be separated by ED. For the LiBr, the overall transport number and the overall electro-osmotic permeability were −3.49 × 10−3 kg min−1 A−1 and -1.33 × 10−4 L min−1 A−1. The overall diffusion permeability, overall osmosis permeability, and average resistance were dependent on the LiBr concentrations in the solutions. Moreover, the influences of ED parameters on the LiBr separation were studied using the model and the energy efficiency was applied to evaluate the separation performance. The energy efficiencies were 0.0325 and 0.323 when the membrane pair exceeded 10 and the membrane effective area (Aeff) surpassed 0.0325 m2. The energy efficiency increased with the decrease of current density and the increase of LiBr concentration difference between the two solutions. Moreover, an effective method was built to obtain a set of suitable ED parameters that meet high ED energy efficiency and the LiBr separation requirements in AARS.

The influence of NH3-H2O-LiBr ternary working fluid on the performance and solution circulation in ammonia absorption refrigeration system

The ammonia absorption refrigeration system(AARS) has been widely applied in the recovery of industrial waste heat. Using NH3-H2O-LiBr ternary working fluid is an effective way to promote the performance of AARS. While previous studies mainly focused on the vapor–liquid equilibrium of the NH3-H2O-LiBr solution and the performance variation of the ternary system under specific working conditions, this paper aims to experimentally investigate the influence of LiBr on performance and solution circulation under various operation conditions. Experiment results indicated that 15%(w/w) was the optimum LiBr concentration across all working conditions. The COP of the ternary system was 7.55% higher than the binary system at most and the heat source temperature of the ternary system can be reduced by 25 °C to reach the same COP of the binary system. The COP was promoted because the rectifier cooling duty decreased by 53% at most, resulting in a reduction of its proportion in the heating capacity from 28.6% to 17.0%. Although the circulation ratio increased by 52% when the LiBr concentration increased from 5% to 15%, the absorber cooling duty experienced an average increase of 6.19%. The effectiveness of the solution heat exchanger was improved from 66.8% to 76.3% when the LiBr concentration increased from 5% to 20%. As the rise of the circulation ratio leads to higher pump power, the viscosities of the NH3-H2O, H2O-LiBr, and NH3-H2O-LiBr solutions were measured. The results demonstrated that solution temperature and NH3 concentration had more influence on solution viscosity than LiBr concentration. The viscosity increased by 6.2%, 17.1%, and 7.1% when the LiBr concentration increased by 11.26%, NH3 concentration increased by 9.5%, and solution temperature dropped by 2 °C, respectively.

Analytical study of the absorber performance of a Hygroscopic cycle for low concentrations of LiBr solutions

Nowadays, higher ambient temperatures and water scarcity, primarily due to climate change, represent a challenge for the refrigeration systems of traditional thermodynamic power cycles. The novel Hygroscopic Cycle Technology arises as a solution to mitigate those drawbacks by means of hygroscopic compounds, which lead to a condensation process by absorption in a mixing chamber, called absorber. Consequently, heat rejection can be achieved at higher cold sink temperatures in a closed loop, avoiding water consumption. In this work, the influence of the concentration of the hygroscopic salt LiBr in the condensation process inside the absorber, key element of the cycle, has been analyzed with EES software. The analysis is divided into very low (0% to 0.01%) and low (0.01% to 5%) concentrations of LiBr-H2O solutions. Absolute pressure at the absorber ranges between 3 kPa and 21 kPa. Results show that properties of very low concentration mixtures can be approximated to those of pure water, showing errors lower than 0.11%. As concentration rises from 0.01 to 5 % specific enthalpy decreases, leading to lower consumption of the refrigeration system of the cycle.

Electrochemical Investigations on the Corrosion Behavior of 904L Stainless Steel in LiBr Solutions

The pitting corrosion susceptibility of 904L stainless steel in aerated LiBr solutions was investigated. The influence of various experimental variables, including electrolyte concentrations, pH, scan rate, temperatures, and constant potential has been studied using electrochemical measurements, such as cyclic potentiodynamic polarization, potentiostatic techniques, and electrochemical impedance spectroscopy (EIS). The surface morphology of 904L stainless steel was examined by scanning electron microscope (SEM). The rate of uniform corrosion and susceptibility toward pitting corrosion increases with an increase in LiBr concentrations and temperature. Increasing the pH of the solution decreases the rate of both uniform and pitting corrosion. An increase in the scan rate enhances the uniform corrosion, but suppresses the pitting corrosion. EIS diagrams displayed a depressed semicircles with the center under the real axis. Bode plots support the result that the uniform corrosion resistance of the alloy in LiBr solutions decreases with increasing Br− anion concentration. The observations suggest that this one time constant may actually be the overlap of two-time constants.

Investigations on Solar Powered Vapour Absorption Refrigeration based Air Conditioning

A solar-operated vapor absorption refrigeration cycle is environment-friendly refrigeration system that holds the potential to be used for refrigeration and air conditioning systems. Such a system requires a solar concentrator to run the vapor absorption refrigeration cycle using LiBr-H2O-based refrigeration/air conditioner for small capacity applications. With the solar-powered pumping process, this refrigeration system becomes completely free from electricity requirements. However, the limitations of all time solar radiation availability, low-pressure maintenance requirement of the LiBr-H2O system, low efficiency, and low COP as compared to other vapour compression refrigeration based air conditioning system are the key deterrents. In the present study, the modeling and analysis of various components used in the proposed arrangement of solar vapor absorption refrigeration - air conditioning system has been carried out to improve the performance It is seen that altering the geometrical property of the bubble pump, as well as heat input through a solar concentrating collector, use of hydrogen as a third fluid increases the rate of evaporation which in turn increases the cooling effect as well as COP of the cycle. At 54% concentration of LiBr and 4.5kW heat input, the COP of the proposed layout is found to be 0.61.

Empirical model for fitting the viscosity of lithium bromide solution with CuO nanoparticles and E414

To research viscosity fitting model of stable nano-lithium bromide solution (nano-LiBr), the stability of the nano-LiBr and the dynamic viscosity of LiBr were measued by Ultraviolet-visible spectroscopy (UV-vis) and rotational viscometer respectively. Two LiBr with different additives were measured, i.e., LiBr with dispersant (E414) and LiBr with dispersant + copper oxide nanoparticles (CuO). The ranges of measuring temperature were from 25°C–60°C, the concentrations of LiBr were from 50%–59%, the volume fractions of the dispersants were from 0%–4%, and the fractions of nanoparticle volume were from 0%–0.05%. Results indicated that the nano-LiBr with E414 had good stability. The viscosity of the LiBr decreased when temperature increased, and increased when LiBr concentration and dispersant amount were increased. It is also found that the viscosity was directly proportional to the volume fraction of the nanoparticles. This study also showed that the higher the concentration of the base fluid was, the more significant increase of the viscosity was. An empirical viscosity model of stable nano-LiBr with a maximum error of 13% was developed.

Influence of LiBr concentration in the generation of superheated vapor for a Hygroscopic Cycle

The novel proprietary Hygroscopic Cycle Technology (HCT) is a power cycle distinguished for using hygroscopic compoundswater mixtures as the working fluid to optimize the condensation process of the turbine exhaust steam by absorption phenomena. Previous works focused on the performance of the condensation/cooling section of the cycle as well as in the main improvements achieved by HCT in comparison to traditional thermal power generation cycles in terms of efficiency and profitability. Nevertheless, the thermodynamic characteristics of the steam generated from hygroscopic-water mixtures in the HCT boiler are yet to be studied. In this article, a theoretical analysis of temperature and pressure conditions of pure water steam generated from different concentrations of LiBr-water mixtures is carried out by using the Engineering Equation Solver (EES) software. Results show that LiBr-H2O mixtures display higher saturation temperatures than pure water, which enables the cycle to directly generate superheated vapor with no need for superheating equipment inside the boiler. This fact further improves the economic advantages previously shown by HCT, since erection, operation and maintenance costs related to the superheating process are avoided.

High-Productivity Single-Pass Electrochemical Birch Reduction of Naphthalenes in a Continuous Flow Electrochemical Taylor Vortex Reactor.

We report the development of a single-pass electrochemical Birch reduction carried out in a small footprint electrochemical Taylor vortex reactor with projected productivities of >80 g day–1 (based on 32.2 mmol h–1), using a modified version of our previously reported reactor [Org. Process Res. Dev.2021, 25, 7, 1619–1627], consisting of a static outer electrode and a rapidly rotating cylindrical inner electrode. In this study, we used an aluminum tube as the sacrificial outer electrode and stainless steel as the rotating inner electrode. We have established the viability of using a sacrificial aluminum anode for the electrochemical reduction of naphthalene, and by varying the current, we can switch between high selectivity (>90%) for either the single ring reduction or double ring reduction with >80 g day–1 projected productivity for either product. The concentration of LiBr in solution changes the fluid dynamics of the reaction mixture investigated by computational fluid dynamics, and this affects equilibration time, monitored using Fourier transform infrared spectroscopy. We show that the concentrations of electrolyte (LiBr) and proton source (dimethylurea) can be reduced while maintaining high reaction efficiency. We also report the reduction of 1-aminonaphthalene, which has been used as a precursor to the API Ropinirole. We find that our methodology produces the corresponding dihydronaphthalene with excellent selectivity and 88% isolated yield in an uninterrupted run of >8 h with a projected productivity of >100 g day–1.

Stable Phase Equilibria in the Quaternary Systems LiBr–NaBr–SrBr2–H2O and LiBr–KBr–SrBr2–H2O at 288.15 K

Aiming at the composition of underground brines in the Sichuan Basin of China, stable phase equilibria in quaternary systems LiBr–NaBr–SrBr2–H2O and LiBr–KBr–SrBr2–H2O at 288.15 K are studied using the isothermal dissolution equilibrium method. The solubilities of salts in the quaternary systems listed above are measured, and the corresponding equilibrium solid phases are identified using X-ray powder diffraction. As a result, the corresponding phase diagrams of the two quaternary systems are plotted, respectively. In the two stable phase diagrams, there is no solid solution or complex salt at 288.15 K. For the quaternary system LiBr–NaBr–SrBr2–H2O, there are two invariant points, five univariate curves, and four solid crystallization regions, which are LiBr·2H2O, NaBr, NaBr·2H2O, and SrBr2·6H2O, respectively, of which LiBr·2H2O has the smallest crystallization field, indicating that its solubility is the largest and it is the hardest to be precipitated from the saturated solution. There are one invariant point, three univariate curves, and three solid crystallization fields, corresponding to LiBr·2H2O, KBr, and SrBr2·6H2O in the quaternary system LiBr–KBr–SrBr2–H2O, respectively. The experimental results show that the solubilities of salts KBr, NaBr, and SrBr2 in the saturated solution decrease with the increasing concentration of LiBr, which indicates that LiBr has a strong salting out effect on KBr, NaBr, and SrBr2 in the solution.

Proposing a new method for waste heat recovery from the internal combustion engine for the double-effect direct-fired absorption chiller

The use of waste heat in absorption refrigeration cycles is always one of the effective methods of heat recovery that leads to efficiency improvement, energy consumption and pollutants emissions reduction. Accordingly, in this study, a new method is proposed to utilize the waste heat from the exhaust gas of the internal combustion engine (ICE) for a double-effect direct-fired absorption chiller cycle, numerically and experimentally. According to high distance of ICE with absorption chiller, should be used water as working fluid. In this paper, the main goal is to design a new generator for the absorption chiller which provides the required heat from high temperature water instead of combustion heat. In this regard, in the first step, a numerical model is developed to introduce the optimal generator inlet temperature based on energy, exergy, ecoexergy and environmental analysis. Then, the results obtained from modeling is compared with the experimental results. In addition, the inlet temperature of superheated water to the chiller is optimized with multi objective optimization (TOPSIS) method at different concentration of LiBr. Results show that a fuel consumption reduction of 467.7 m3/hr is obtained using the waste heat of the ICE which causes significant decrease 3461.832 kg/year and 1919743.2 kg/year in NOX and CO2 emissions, respectively. It is also concluded that the optimal inlet water temperature of chiller becomes equal to 138 ℃, 137 ℃ and 136 ℃ for of lithium bromide concentration of 0.62, 0.6 and 0.58, respectively.

Processing Parameters and Ion Excipients Affect the Physicochemical Characteristics of the Stereocomplex-Formed Polylactide-b-Polyethylene Glycol Nanoparticles and Their Pharmacokinetics.

To optimize the characteristics of stereocomplex polylactide-b-polyethylene glycol nanoparticles (SC-PEG NPs) in terms of pharmacokinetics (PK), we chose continuous anti-solvent precipitation with a T-junction as a preparation method and investigated the effect of using solvents containing an ion excipient (lithium bromide, LiBr) on the characteristics of SC-PEG NPs by changing the processing temperature and total flow rate (TFR). Processing temperatures above the melting temperature (Tm) of the PEG domain produced a sharper polydispersity and denser surface PEG densities of SC-PEG NPs than those produced by processing temperatures below the Tm of the PEG domains. Response surface analysis revealed that a higher LiBr concentration and slower TFR resulted in larger and denser hydrodynamic diameters (Dh) and surface PEG densities, respectively. However, a high concentration (300 mM) of LiBr resulted in a decreased drug loading content (DLC). 14C-tamoxifen-loaded 111In-SC-PEG NPs with larger Dh and denser surface PEG densities showed a prolonged plasma retention and low tissue distribution after intravenous injection in mice. These results indicate that the novel strategy of using solvents containing LiBr at different processing temperatures and TFR can broadly control characteristics of SC-PEG NPs, such as Dh, surface PEG densities, and DLC, which alter the PK profiles and tissue distributions.

Thermodynamic investigations on PDC based solar air conditioning system

Global warming is raising the ambient temperature and thus resulting in increased air conditioning requirements. The increase in power requirements of air conditioning systems, in turn, burdens the electricity needs and more electricity generation further adds to global warming. In such situations, the availability of solar energy and its utilization for air conditioning systems appears a potential solution to a certain extent. This paper deals with the thermodynamic analysis of a parabolic dish based air conditioning system working on vapour absorption refrigeration cycle for the H2O and LiBr combination as working fluid. Thermodynamic modelling was used to assess the impact of changing the initial concentration of lean solution and the varying condenser temperature under the atmospheric conditions of that region during peak air conditioning demand months on several parameters such as coefficient of performance, cooling effect, and exergetic efficiency of the system. At 45 percent of the initial LiBr concentration in weak solution, the system’s highest coefficient of performance is attained.

Enhanced critical current density of Garnet Li7La3Zr2O12 solid electrolyte by incorporation of LiBr

Cubic garnet Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolytes have a strong potential to allow solid-state lithium-ion to become the next-generation energy storage systems and for addressing the safety issues. However, the applications of LLZO solid electrolytes are seriously limited by the relatively low critical current density of LLZO. In this study, we introduce lithium bromide (LiBr) with a low melting point as the sintering aid to prepare a high-performance garnet with high ionic conductivity, high relative density, and excellent critical current density. The prepared LLZO solid electrolyte with a LiBr concentration of 0.15 ( x LiBr–LLZO with x = 0.15 mol) exhibited a high ionic conductivity of 7.62 × 10 −4 S cm −1 at 25 ℃ with an excellent relative density of 96.27%. The critical current density (CCD) of the symmetric Li | 0.15LiBr–LLZO | Li cell was 1.0 mA cm −2 at 25 ℃. Furthermore, this cell can stably operate for 1000 h under a current density of 0.3 mA cm −2 . In addition, quasi-solid-state batteries of Li | LiFePO 4 with 0.15LiBr–LLZO electrolyte delivered excellent capacity retention (141.1 mAh g − 1 ; ∼89.7%) after 300 cycles, excellent rate performance, high coulombic efficiency and cycling stability. Furthermore, Li | LiNi 0.8 Co 0.1 Mn 0.1 O 2 with 0.15LiBr–LLZO electrolyte could run normally with high coulombic efficiency (>99%). These research results show that the solid-state batteries developed using 0.15LiBr–LLZO electrolyte are highly promising for the practical applications.

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

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.

Experimental Investigation of the Heat Transfer Characteristics of Plate Heat Exchangers Using LiBr/Water as Working Fluid

In this study, the heat exchange characteristics of water–LiBr solutions used as working fluid in a plate heat exchanger (PHE) were experimentally investigated at various concentrations. To analyze the heat transfer characteristics under LiBr/water conditions, a brazing type plate heat exchanger was installed, and the LiBr concentration on the high-temperature side was controlled at 56%, 58%, 60% and 60%. The results showed that the average heat transfer rate under water/water conditions was higher than that under LiBr/water conditions and the average heat transfer rate decreased as the LiBr concentration on the hot side increased. In addition, under both water/water and LiBr/water conditions, the average heat transfer rate and overall heat transfer coefficient increased as the mass flow rate of the working fluid on the hot side increased. When LiBr was used, the Reynolds number (Re) of LiBr on the hot side was more than nine times lower than that of water at the same mass flow rate owing to the influence of the increased viscosity. Based on the data obtained from the water/water and LiBr/water experiments, a correlation for predicting the Nusselt number (Nu) on the hot side in a wide range was developed.