D122 EXPERIMENTAL STUDY ON THE EFFECT OF HEAT SOURCE TEMPERATURE ON THE PERFORMANCE OF AN ADSORPTION COOLING SYSTEM USING ACTIVATED CARBON POWDER/ETHANOL PAIR

2014 ◽  
Vol 2014.19 (0) ◽  
pp. 117-118
Author(s):  
Fauziah Jerai ◽  
Hayato Imamura ◽  
Takahiko Miyazaki ◽  
Saha Bidyut Baran ◽  
Shigeru Koyama ◽  
...  
Author(s):  
H. M. Elgohary ◽  
H. M. Soliman ◽  
A. M. Soliman ◽  
H. H. Gouda ◽  
S.P. Chowdhury

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3753
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn

Air cooling systems are currently the most popular and least expensive solutions to maintain a safe temperature in electronic devices. Heat sinks have been widely used in this area, allowing for an increase in the effective heat transfer surface area. The main objective of this study was to optimise the shape of the heat sink geometric model using the Adjoint Solver technique. The optimised shape in the context of minimal temperature value behind the heat sink is proposed. The effect of radiation and trapezoidal fin shape on the maximum temperature in the cooling system is also investigated. Simulation studies were performed in Ansys Fluent software using the Reynolds—averaged Navier–Stokes technique. As a result of the simulation, it turned out that not taking into account the radiation leads to an overestimation of temperatures in the system—even by 14 ∘C. It was found that as the angle and height of the fins increases, the temperature value behind the heat sink decreases and the heat source temperature increases. The best design in the context of minimal temperature value behind the heat sink from all analysed cases is obtained for heat sink with deformed fins according to iteration 14. The temperature reduction behind the heat sink by as much as 25 ∘C, with minor changes in heat source temperature, has been achieved.


2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Bhargav Pandya ◽  
Vinay Kumar ◽  
Jatin Patel ◽  
V. K. Matawala

This comprehensive investigation has been executed to compare the thermodynamic performance and optimization of LiCl–H2O and LiBr–H2O type absorption system integrated with flat-plate collectors (FPC), parabolic-trough collectors (PTC), evacuated-tube collectors (ETC), and compound parabolic collectors (CPC). A model of 10 kW is analyzed in engineering equation solver (ees) from thermodynamic perspectives. Solar collectors are integrated with a storage tank which fueled the LiCl–H2O and LiBr–H2O vapor absorption system to produce refrigeration at 7 °C in evaporator for Gujarat Region of India. The main objective includes the evaluation and optimization of critical performance and design parameters to exhibit the best working fluid pair and collector type. Optimum heat source temperature corresponding to energetic and exergetic aspects for LiCl–H2O pair is lower than that of LiBr–H2O pair for all collectors. Simulation shows that FPC has lowest capital cost, exergetic performance wise PTC is optimum, and ETC requires lowest collector area. On the basis of overall evaluation, solar absorption cooling systems are better to be powered by ETC with LiCl–H2O working fluid pair.


2011 ◽  
Vol 32 (3) ◽  
pp. 57-70 ◽  
Author(s):  
Dariusz Mikielewicz ◽  
Jarosław Mikielewicz

Utilisation of bleed steam heat to increase the upper heat source temperature in low-temperature ORC In the paper presented is a novel concept to utilize the heat from the turbine bleed to improve the quality of working fluid vapour in the bottoming organic Rankine cycle (ORC). That is a completely novel solution in the literature, which contributes to the increase of ORC efficiency and the overall efficiency of the combined system of the power plant and ORC plant. Calculations have been accomplished for the case when available is a flow rate of low enthalpy hot water at a temperature of 90 °C, which is used for preliminary heating of the working fluid. That hot water is obtained as a result of conversion of exhaust gases in the power plant to the energy of hot water. Then the working fluid is further heated by the bleed steam to reach 120 °C. Such vapour is subsequently directed to the turbine. In the paper 5 possible working fluids were examined, namely R134a, MM, MDM, toluene and ethanol. Only under conditions of 120 °C/40 °C the silicone oil MM showed the best performance, in all other cases the ethanol proved to be best performing fluid of all. Results are compared with the "stand alone" ORC module showing its superiority.


2006 ◽  
Vol 326-328 ◽  
pp. 1275-1278 ◽  
Author(s):  
Chang Oh Kim ◽  
Jin Heung Kim ◽  
Nak Kyu Chung

This study aims to find out cooling characteristics of TMA 25wt%-water clathrate compound with ethanol such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at -6, -7 and -8, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as 5.1 and 5.0, 3.8 according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is 0.9 and minimum supercooling is 0.8, 0.7 according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is 3.013~3.048 kJ/kgK according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol.


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