Experimental study on influences of cylindrical grooves on thermal efficiency, exergy efficiency and entropy generation of CPU cooled by nanofluids

Author(s):  
Ning Zhao ◽  
Cong Qi ◽  
Tiantian Chen ◽  
Jinghua Tang ◽  
Xin Cui
Author(s):  
Mohammed El Hadi Attia ◽  
Saravanan Kaliyaperumal ◽  
Gunasekar Thangamuthu ◽  
Ilango Rengaraju ◽  
Suman Mann ◽  
...  

Author(s):  
Vijayakumar Rajendran ◽  
Harichandran Ramasubbu ◽  
Karthick Alagar ◽  
Vignesh Kumar Ramalingam

An experimental study has been carried out to enhance a solar air heater’s performance by integrating artificial roughness through baffles on the absorber plate. In this paper, the thermal and energy matrices analysis of a Solar Air Heater (SAH) roughened with V up perforated baffles have been investigated. The effect of various mass flow rates on the SAH was analyzed with and without baffles. Experimental outputs like outlet air temperature, useful energy (heat) gain and thermal efficiency were evaluated to confirm the performance improvement. The baffled absorber plate SAH was found to give the maximum thermal efficiency and useful energy gain of 89.3% and 1321.37 W at a mass flow rate of 0.0346 kg/s, 13% and 12% higher than SAH without baffle. This result showed that the V up-shaped ribs in flow arrangement provide better thermal performance than smooth plate SAH for the parameter investigated. Energy matrices analysis and carbon dioxide mitigation of the SAH system were also analyzed.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Dinc ◽  
Yousef Gharbia

Abstract In this study, exergy efficiency calculations of a turboprop engine were performed together with main performance parameters such as shaft power, specific fuel consumption, fuel flow, thermal efficiency etc., for a range of flight altitude (0–14 km) and flight speeds (0–0.6 Mach). A novel exergy efficiency formula was derived in terms of specific fuel consumption and it is shown that these two parameters are inversely proportional to each other. Moreover, a novel exergy efficiency and thermal efficiency relation was also derived. The relationship showed that these two parameters are linearly proportional to each other. Exergy efficiency of the turboprop engine was found to be in the range of 23–33%. Thermal efficiency of the turboprop engine was found to be around 25–35%. Exergy efficiency is higher at higher speeds and altitude where the specific fuel consumption is lower. Conversely, exergy efficiency of the engine is lower for lower speeds and altitude where the specific fuel consumption is higher.


2014 ◽  
Vol 592-594 ◽  
pp. 1423-1427 ◽  
Author(s):  
G. Kumaresan ◽  
S. Venkatachalapathy ◽  
Indraneel C. Naik

This study aims to investigate the influence of inclination angle and concentration of nanoparticles on the improvement in heat pipe thermal efficiency. Spherical shaped, 40 nm size CuO nanoparticles are used in this study and its physical and thermal chracteristics are investigated. The results are compared with a heat pipe using DI water at horizontal position.The thermal efficiency is improved by increasing the tilt angle and mass of particles dispersed in DI water. The improvement in thermal efficiency obtained are 20.59, 35.92 and 32.57% respectively for 0.5, 1.0 and 1.5 wt% of CuO nanofluids and 60° inclination angle.


2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.


2018 ◽  
Vol 6 (6) ◽  
pp. 161-177
Author(s):  
Abene Abderrahmane ◽  
Mohamed Salah Eddine Seddiki ◽  
Aurora Morocini Mohamed Si Youcef

The use of variable baffle solar panels for drying is the low level of heat exchange with the air in the dynamic vein of the solar panel. This weakness in such systems does not provide optimal performance or high thermal efficiency from their use. There is, however, a very noticeable improvement in heat transfer when the baffles are placed in rows in the ducts. To conduct the experiments, solar energy was simulated, the goal being to improve the relationship between temperature and thermal efficiency of a solar panel air heating plane and to use the system to reduce the time to gently dry the lemon to keep these vitamins. lemon and destinine for a sustainable therapy (the lemon promotes the absorption of calcium and in case of rhumet gill or five also to treat sinusitis, against migraine solair dryness and also for sustainable conservation and also for a sustainable medicine for a sustainable medicine.


2015 ◽  
Vol 813-814 ◽  
pp. 700-706 ◽  
Author(s):  
R. Geetha ◽  
M.M. Vijayalakshmi ◽  
E. Natarajan

The PV/T hybrid system is a combined system consisting of PV panel behind which heat exchanger with fins are embedded. The PV/T system consists of PV panels with a battery bank, inverter etc., and the thermal system consists of a hot water storage tank, pump and differential thermostats. In the present work, the modeling and simulation of a Solar Photovoltaic/Thermal (PV/T) hybrid system is carried out for 5 kWp using TRNSYS for electrical energy and thermal energy for domestic hot water applications. The prominent parameters used for determining the electrical efficiency, thermal efficiency, overall thermal efficiency, electrical thermal efficiency and exergy efficiency are the solar radiation, voltage, current, ambient temperature, mass flow rate of water, area of the PV module etc. The simulated results of the Solar PV/T hybrid system are analyzed for the optimum water flow rate of 25 kg/hr. The electrical efficiency, thermal efficiency, overall thermal efficiency, equivalent thermal efficiency, exergy efficiency are found to be 10%, 34%, 60%, 35% and 13% respectively. The average tank temperature is found to be 50°C.


Entropy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 428 ◽  
Author(s):  
Wang ◽  
Fu

An integrated solar combined cycle (ISCC) with a low temperature waste heat recovery system is proposed in this paper. The combined system consists of a conventional natural gas combined cycle, organic Rankine cycle and solar fields. The performance of an organic Rankine cycle subsystem as well as the overall proposed ISCC system are analyzed using organic working fluids. Besides, parameters including the pump discharge pressure, exhaust gas temperature, thermal and exergy efficiencies, unit cost of exergy for product and annual CO2-savings were considered. Results indicate that Rc318 contributes the highest exhaust gas temperature of 71.2℃, while R113 showed the lowest exhaust gas temperature of 65.89 at 800 W/m2, in the proposed ISCC system. The overall plant thermal efficiency increases rapidly with solar radiation, while the exergy efficiency appears to have a downward trend. R227ea had both the largest thermal efficiency of 58.33% and exergy efficiency of 48.09% at 800W/m2. In addition, for the organic Rankine cycle, the exergy destructions of the evaporator, turbine and condenser decreased with increasing solar radiation. The evaporator contributed the largest exergy destruction followed by the turbine, condenser and pump. Besides, according to the economic analysis, R227ea had the lowest production cost of 19.3 $/GJ.


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