scholarly journals Thermodynamic analysis of absorption cooling system with LiBr-Al2O3/water nanofluid using solar energy

2020 ◽  
pp. 340-340
Author(s):  
Bayram Kiliç ◽  
Osman İpek
Keyword(s):  
Heat Transfer ◽  
Solar Energy ◽  
Cooling System ◽  
Nano Particles ◽  
Working Fluid ◽  
Nanoparticle Concentration ◽  
Operation Condition ◽  
Absorption Cooling ◽  
Absorption Cooling System ◽  
Nano Fluids

Together with the developing nano technology, nano-fluids and nano-particles are used as working fluid in energy applications. It is foreseen that nanoparticles have high heat conduction coefficient and it will increase system performance by using as a working fluid in energy systems. Many studies in the literature show that nano fluids increase the heat transfer rate by improving heat transfer. In this study, a performance analysis of an absorption cooling system using solar energy was performed as numerically. LiBr-Al2O3/water nano-fluid has been used in the cooling system as working fluid. The thermodynamic values and calculations used in the analyses were performed with Engineering Equation Solver program. Heat load necessary for the generator is provided with a flat plate solar collector. For different operation condition, the variation of COP values was determined depend on Al2O3/water nanoparticle concentration ratio. When the Al2O3/water nanoparticle concentrations are changed as 0%, 0.5% and 0.1%, it was determined that the COP values increased. Nanoparticles added to the refrigerant at certain concentration values affects the COP values positively of cooling systems. Maximum COP value is 0.86 for 85?C generator temperature and 0.1% Al2O3/water nanoparticle concentration. The lowest COP value was obtained for the 75 oC generator temperature. When the Al2O3/water nanoparticle concentration was increased together with the generator temperature, COP values also increased. When the nanoparticle concentration of the working fluid increases, the viscosity of the nanofluid can be increases. Due to, increased viscosity increases the pressure drop in the flow channel and the pump power required for the flow. Thus, 'minimum viscosity with maximum thermal conductivity' optimisation in applications is very important.

scholarly journals Thermoeconomic Cost Analysis of Solar and Geothermal Energy Powered Cooling and Power Cogeneration

2020 ◽  
Vol 3 (1) ◽  
pp. 609-618
Author(s):  
Ozan Sen ◽  
Ceyhun Yilmaz
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Solar Energy ◽  
Cooling System ◽  
Energy System ◽  
Geothermal Water ◽  
Heat Transfer Fluid ◽  
Geothermal Resource ◽  
Absorption Cooling ◽  
Absorption Cooling System

In this study, geothermal and solar energy assisted cogeneration energy system has been modeled to supply residences' electricity and cooling requirements. The geothermal water from the geothermal resource and the heat transfer fluid heated in the parabolic collector is used as the heat source in the absorption cooling system. Electricity is generated in the binary power plant with geothermal water and heat transfer fluid from the absorption cooling system. The generated electricity is supplied to the grid. Thermoeconomic analysis of the system is performed by using the Engineering Equation Solver (EES) program by using geothermal and solar energy values of Afyonkarahisar. The geothermal resource's temperature and mass flow in the system is 130 ºC and 85 kg/s, respectively. The parabolic trough collector operates in the range of monthly average solar radiation values (500-600 W/m2) calculated for the summer season, where cooling is planned. The LiBr-H2O solution is chosen as the refrigerant of the absorption cooling system. The system's parametric study is performed by considering the different geothermal resource temperatures and solar radiation values. According to these results, the unit electricity and unit cooling costs produced in the system will be investigated. The optimum working conditions are investigated in producing and using the energy form (electricity-cooling) requirements.

scholarly journals Thermodynamic Analysis of a Solar Combined Ejector Absorption Cooling System

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Doniazed Sioud ◽  
Raoudha Garma ◽  
Ahmed Bellagi
Keyword(s):  
Cooling System ◽  
Lithium Bromide ◽  
Cooling Water ◽  
Double Effect ◽  
Cycle Performance ◽  
Working Fluid ◽  
Absorption Cooling ◽  
Single Effect ◽  
Absorption Cycle ◽  
Absorption Cooling System

The objective of this paper is to investigate theoretically a solar driven 60 kW absorption cooling system. The system is constituted of a combined ejector single-effect absorption cycle coupled with a linear Fresnel solar concentrator and using water/lithium bromide as working fluid. The combined ejector single-effect absorption cycle exhibits high performances, almost equal to that of double-effect absorption device. However, higher driving heat temperatures are required than in the case of conventional single-effect machines. A mathematical model is set up to analyze the optical performance of the linear Fresnel concentrator. Simulations are carried out to study the overall system performance COPsystem and the performances of the combined absorption machine COPcycle for generator driving temperatures and pressures in the ranges 180°C – 210°C and 198 kPa – 270 kPa, respectively. Further, the effect of operating parameters such as the cooling medium and chilled water temperatures is investigated. A maximum cycle performance of 1.03 is found for a generator pressure of 272 kPa and chilled and cooling water temperatures of 7°C and 25°C, respectively. A case study is investigated for a typical summer Tunisian day, from 8:00 to 18:00. The effect of ambient temperature and solar radiation on cycle and system performances is simulated. The optical performances of the concentrator are also analyzed. Simulation results show that between 11:00 and 14:00 the collector efficiency is 0.61 and that the COPcycle reaches values always higher than 0.9 and the COPsystem is larger than 0.55. Globally the performances of the investigated cycle are similar to those of double-effect conventional absorption system.

Effect of nano-fluid types on the improvement of heat transfer in a micro-channel with regular hexagonal pattern

2020 ◽  
Vol 234 (6) ◽  
pp. 657-664
Author(s):  
S Emami ◽  
MH Dibaei Bonab ◽  
M Mohammadiun ◽  
H Mohammadiun ◽  
M Sadi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Cross Section ◽  
Transfer Rate ◽  
Nano Particles ◽  
Working Fluid ◽  
Micro Channel ◽  
Hexagonal Cross Section ◽  
Micro Channels ◽  
Nano Fluids

Micro channels are widely used in different industries. The investgations on heat transfer improvments of these instruments are of significant inportance. At hte present study, the influence of different nano-fluids and geometrical charectrestics on the thermal performance of a heat sink which is especially for for micro-channels are investigated. In the present study, the authors investigated the Nusselt number and pressure drop in differential geometries and Reynolds numbers (Re). Then the micro-channel was investigated with different heat flux (q).In the first step, the micro-channel was examined and the final numerical results showed that the hexagonal cross-section can improve heat transfer about 9%. At the second step and after selecting appropriate parameters, the effect of three nano-particles (Al2O3 - CuO- TiO2) were studied. The results presented that aluminum oxide (Al2O3) has the best heat transfer rate among the mentioned nano-fluids. With the presence of nano-particles (Al2O3, φ = 4%) an increment of 40% in heat transfer rate, for the hexagonal cross section was achieved compare to rectangular cross section with water as working fluid.

Exergetic Analyses of a Particular Absorption Cooling System

2012 ◽  
Vol 326-328 ◽  
pp. 641-646 ◽  
Author(s):  
Nahla Bouaziz ◽  
D. Lounissi ◽  
Lakdar Kairouani ◽  
M. El Ganaoui
Keyword(s):  
Exergy Analysis ◽  
Cooling System ◽  
Working Fluid ◽  
Exergy Destruction ◽  
Mass Energy ◽  
Intermediate Pressure ◽  
Absorption Cooling ◽  
Energy And Exergy ◽  
Absorption Cycle ◽  
Absorption Cooling System

The objective of this work is to present an exergy analysis of a novel absorption configuration using water-ammonia as working fluid. The proposed configuration operates at three pressure levels. The absorber is at an intermediate pressure (Pint). A thermodynamic model based on the mass energy and exergy balances is developed for this purpose. The parameters analyzed are the refrigeration systems performance (COP), the exergy efficiency, the global exergy destruction in the system, the exergy destruction and the irreversibility in different components. The effects of generator, absorber, condenser and evaporator on the performance of the system are examined. Numerical results highlight the great importance of the intermediate pressure on the performance of the system and specially on reducing the operating generator temperature. Consequently, the intermediate pressure is directly responsible on the adaptability of the proposed cooling absorption cycle to low enthalpy sources.

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