Effects Of Condensation Temperature Research Articles

Steam distillation process for flavor enhancement of milk coffee: Effects of condensation temperature on volatile compounds and flavor characteristics.

To enhance the flavor characteristics of milk coffee, steam distillation was applied to roasted ground coffee to obtain extracts that were then added to the hot water extract of the residue. The effects of different condensation temperatures for steam distillation on the volatile compounds of condensates and the flavor characteristics of the milk coffees prepared with each condensate were investigated. The volatile compounds were analyzed by gas chromatography/mass spectrometry, and principal component analysis (PCA) was performed on the mean peak areas of the volatiles that showed significant differences between the samples. The five types of milk coffees prepared with/without condensates were evaluated by consumer panelists using the check-all-that-apply question combined with the milk coffee flavor lexicon. The results showed that the concentration of volatile compounds tended to be higher in response to decreasing condensation temperature in steam distillation. The volatile compounds were grouped into four patterns based on their concentration in the condensates, which was affected by the volatility of the compounds and the duration of the condensation process in steam distillation. PCA clarified the characteristic volatile compounds that contribute to differences between the three condensates. The check-all-that-apply results indicated that the samples prepared with the condensates enhanced some specific coffee flavors, although acceptances for them were not enhanced. Implementing a steam distillation step in the milk coffee production process could lead to enhancing the coffee flavor strength of milk coffee products, and changing the condensation temperature for steam distillation was effective for providing different flavor characteristics of milk coffee. PRACTICAL APPLICATION: Changing the condensation temperature for steam distillation is effective in differentiating the flavor characteristics of milk coffee. Increasing the condensation temperature resulted in decreased concentrations of volatile compounds, which enhanced the milk and rich flavor. Decreasing the condensation temperature resulted in increased concentrations of volatile compounds, which provided a stronger coffee flavor to the milk coffee, possibly leading to a reduction in the use of coffee for milk coffee production. The check-all-that-apply question combined with the milk coffee flavor lexicon could effectively evaluate consumers' perceptions of the milk coffee flavor characteristics and their acceptances in a single survey.

The Influence of Condenser Temperature on the Energy and Exergy Efficiencies of the ORC

From low-grade heat sources, the organic Rankine cycle may be exploited to create power. The thermal efficiency of the organic Rankine cycle is affected by the value of the lowest cycle temperature, which is the condensation temperature. This study looks at the effect of condensation temperature on the efficiency of energy systems that use organic Rankine cycles. At a condensing temperature of 10–20 °C, the ORC thermal efficiency is calculated. R134a working fluid was used in the study. The expander's power output was boosted to 0.09765 kW by decreasing the condensing temperature. Additionally, the thermal efficiency has been enhanced by 3.826 %. At a minimum temperature of 10 °C, the expander speed at 595 rpm. Exergy efficiency has an 18.26 %. is shown that lowering the condensing temperature increased the ORC system's thermal efficiency and energy output.

Thermochemical energy conversion behaviour in the corrugated heat storage unit with porous metal support

Because of the low charging temperature, salt hydrate-based adsorption thermochemical energy storage (TCES) is currently a significant technology that promises long-term energy storage. A corrugated-shaped heat storage unit (HSU) in which embedding porous metal bracket is proposed in this work to enhance heat transfer between the thermochemical material (TCM) wrapped inside and the heat fluid transfer (HTF) in the external corrugated channel. The thermo-chemical conversion behaviours, including reactive transport processes during dehydration (charging) and hydration (discharging), as well as the influence of parameters, are comprehensively investigated. The numerical results indicate that increasing the HTF temperature facilitates the charging process while the discharging can be promoted by decreasing reaction bed temperature. The time required to complete charging and discharging for the reference cases is 2990 s and 5700 s. For both charging and discharging powers of reactive bed, the values dramatically surge in a short time and then gradually decrease, with the maximum powers of 2638 W and 1866 W, respectively. Boosting evaporation temperature (water vapour pressure) accelerates hydration while the effect of condensation temperature on dehydration is insignificant. The reaction period can be further shortened by heightening the thermal conductivity of TCM, and the porosity also has a distinct influence on the reaction. Compared to the storage unit of a straight external channel without a metal bracket inside, this heat storage module saves 34% and 23% in charging and discharging times. The results of this work provide insights into the prediction and improvement of thermochemical conversion behaviours.

The effect of condenser temperature on the performance of the evaporator in a wickless heat pipe performance

The Constrained Vapor Bubble (CVB), a simple, wickless, heat pipe design that depends on interfacial forces to drive corner flow in a square cuvette, was studied in the microgravity environment aboard the International Space Station (ISS). In this paper, we consider the effects of different condenser temperatures on the heat transfer and fluid flow behavior using pentane as the working fluid. As the condenser temperature was decreased, the performance of the system decreased. This performance decrease using the pure working fluid was opposite to the behavior observed when using a mixture of 94 vol% pentane and 6 vol% isohexane. The mechanism for the decline in performance as the condenser temperature was lowered was a stronger than expected increase in the apparent strength of Marangoni flows at the heater end of the system. A simple mathematical model was fit to the experimental data and used to extract an evaporator heat transfer coefficient for experiments where we held the condenser temperature constant while increasing the heater power and where we held the heater power constant while decreasing the condenser temperature. All the results could be collapsed onto a single Nusselt number vs. Marangoni number curve. In this formulation, the Nusselt number was found to decrease with increasing Marangoni number to the 1/3 power.

Effect of Condenser Temperature on the Flow of Refrigerant R134a and its Alternative through a Capillary Tube

Effect of Condenser Temperature on the Flow of Refrigerant R134a and its Alternative through a Capillary Tube

An efficient optimization and comparative analysis of ammonia and methanol heat pipe for satellite application

In this work, a satellite heat pipe operated with the ammonia and methanol are investigated for the multi-objective optimization. Optimization results are used for the comparative analysis of both the heat pipe. Optimization problem of the heat pipe is formed considering minimization of the thermal resistance and total mass of heat pipe and solved using the heat transfer search algorithm. An application example of satellite heat pipe is presented, and results are obtained in the form of Pareto-optimal points. Seven geometric parameters which include the length of evaporator and condenser section, tube wall thickness, vapor core diameter, mesh number of wick, thickness of wick, and diameter of wick wire are investigated in the optimization study. Further, the effect of condenser temperature, heat load, and length of the adiabatic section on ammonia and methanol heat pipe is explored and discussed. Furthermore, the effect of the design variables and its sensitivity to performance parameters of the heat pipe are also presented. Comparative results revel that, for any given value of the total mass of heat pipe, 82.17–57.16% lower thermal resistance is observed with the ammonia heat pipe as compared to methanol heat pipe. Finally, uncertainty propagation analysis of the obtained Pareto solutions are carried out with the different uncertainty levels and observed that the results have relatively good robustness performance for uncertainty less than 5%.

Template-free synthesis of graphitic carbon nitride hollow spheres for photocatalytic degradation of organic pollutants

Graphitic carbon nitride (g-C3N4) hollow spheres have been prepared via one-step solvothermal method without templates. The effects of condensation temperature on the structural, optical and photocatalytic properties of the samples were investigated. The X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) results show that the samples synthesized at dissimilar temperatures have graphitic and heptazine-based conjugate structure. Optical analysis results evidence that the absorption edge shifts toward longer wavelength and PL intensity quenches quickly as the treating temperature increases from 120°C to 180°C. The results demonstrate that higher condensation temperature improves the visible-light absorption and migration rate of photo-induced carriers of samples. The g-C3N4 sample prepared at 180°C presents a highest photocatalytic degradation activity in the degradation of RhB under visible-light irradiation. This study demonstrates a novel strategy for one-step synthesis of hollow spheres shaped polymer semiconductor photocatalyst without templates.

English

Refrigerator is one of the home appliances utilizing vapour compression cycle in its process. Performance of the system becomes main issue and many researches are still on going to evaluate and improve efficiency of the system. The main objective is to improve performance of the refrigeration system in term of refrigeration Capacity, Compressor work and Coefficient of performance (COP) by determining three important parameters during in operating mode which are temperature, pressure and refrigerator flow rate. A household refrigerator designed to work with F-12 which is use as an investigation unit to assess the prospect of using refrigerants. Work on condenser in domestic refrigeration is pretty development. We are going to introduce the thermoelectric module in a model of domestic refrigerator for sub cooling the refrigerant and the effect of condenser temperature on COP and refrigerating effect is in investigated. The energy consumption of the refrigerator during experiment with refrigerant F-12 will be measured.

Thermodynamic Performance Comparison Using HFO-1234yf and HFO-1234ze in the High Temperature Cascade Refrigeration Systems and Ecofriendly Refrigerants in Low Temperature Applications

The present paper relates to a cascade refrigeration system which circulates a HFO refrigerant in the high temperature circuit and HFC-134a in the low temperature (173K) circuit for cryogen applications .The thermodynamic analysis using entropy generation for finding exergy destruction ratio indicating that R1234ze (GWP=6) gives better performance than R-1234yf (GWP=4) in the high temperature circuit. The numerical computation has been carried out for 173 K evaporator temperature for ten ecofriendly refrigerants in the low temperature circuit and HFO-1234yf, HFO-1234ze, R152a and R717 in the high temperature circuit. The effect of condenser temperature from temperature (303K to 333K), cascade evaporator range (253K to 293K) and evaporator temperature range 173K to 223K and temperature overlapping (Approach) rages from zero to 10 on thermodynamic performance have been investigated. It was observed that R1234ze in high temperature circuit and R 134a in lower temperature circuit is a best alternative than R1234yf in high temperature circuit and R 134a in lower temperature circuit.

Effect of Condenser Temperature and Speed on one A/C System

This study describes the results on the performance of one vehicle air conditioning system. The coefficient of performance, evaporator cooling capacity, compressor power consumption, total mass flow rate, vapor mass flow rate, liquid mass flow rate and oil in circulation, pressures and temperatures of refrigerant at every component (inlets and outlets) are measured and analyzed with the variation of the outside temperatures at the evaporator and condenser, the speed of the compressor, refrigerant charge and oil charge. The systematical experimental results obtained from this real-size test system depict the relations between the above parameters in a vehicle air conditioning system, which constitute a useful source for vehicle air conditioning systems design and analysis. The vapor quality (two-phase flow) measurements realized in this work provide an extremely important tool for diagnosing the system performances.

Effect of Condensation Temperature on Formaldehyde Release from Durable Press Fabrics

We investigated formaldehyde release from cotton and polyester/cotton materials treated with DMEU and DMDHEU resins at different condensation temperatures. In the samples treated with DMEU, the amount of free formaldehyde was greater at lower condensation temperatures. Samples treated with DMDHEU gave similar results when the AATCC method for determining formaldehyde was used, but when the MITI method was used, the condensation temperature-formaldehyde curves showed a minimum at about 140°C. The release of formaldehyde is a slow process, because both methods gave similar curves when longer extraction times were used. Changing the extraction temperature gave a quantitative difference.

Effect of condenser temperature on the performance of intermittent solar refrigerators

A thermodynamic analysis for the theoretical constant-temperature absorption-refrigeration cycle is utilized to investigate the effect of varying the condensing temperature on the performance of an intermittent solar refrigerator using water-ammonia solutions. For certain specified initial temperature and solution concentration and a given maximum generator temperature, decreasing the condensing temperature causes an increase in the COP of the cycle. However, for every condensing temperature, there is an optimum maximum generator temperature beyond which the COP decreases gradually.

Electron Diffraction Studies of the Epitaxy of Cu Single Crystals. I. Epitaxy of Evaporated Cu Films on Cu Crystals

The epitaxy of evaporated Cu films on Cu single crystals has been investigated in situ under high-vacuum conditions with reflection HEED techniques. Spherically shaped Cu single crystals with high quality surfaces were used as substrates. The effects of condensation temperature and the annealing behavior were studied for the main low-index planes. A completely developed twin orientation of the film was found in all cases. For films deposited at room temperature the diffraction diagrams additionally contained a complete set of double diffraction spots.