Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.T...Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.This paper aims to present the results of experimental investigations on the thermal performance of heat pipe-type evacuated solar collectors.The experimented system consists of 15 tubes,providing the hot nanofluid to 100-L storage in a closed flow loop.The solar collector with a gross area of 2.1 m^(2)is part of the solar hot water test system located in Baghdad-Iraq.Al2O3 nanofluid at 0.5%volume concentration in water as working fluid was used in three flow rates of 3.3,6.6,and 10 L/min over two months,March and April.The experimental results indicated that maximum solar irradiation was 1070 and 1270 W/m^(2)in March and April,respectively.The maximum daily average of rate heat gain 11,270 and 12,040 W was recorded in March and April,respectively.In terms of the best operational flow rate,the system performs better at 3.3 L/min nanofluid flow rate.For the considered study period,the average monthly maximum energy efficiencies of the solar collector in March and April were 86%and 80%,respectively.展开更多
基金The University of Technology,specifically the Department of Electromechanical Engineering,provided invaluable assistance during the experimental work,for which the authors are quite grateful.
文摘Achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge since the absorption peaks of common metal particles are usually located in the visible part of the radiation spectrum.This paper aims to present the results of experimental investigations on the thermal performance of heat pipe-type evacuated solar collectors.The experimented system consists of 15 tubes,providing the hot nanofluid to 100-L storage in a closed flow loop.The solar collector with a gross area of 2.1 m^(2)is part of the solar hot water test system located in Baghdad-Iraq.Al2O3 nanofluid at 0.5%volume concentration in water as working fluid was used in three flow rates of 3.3,6.6,and 10 L/min over two months,March and April.The experimental results indicated that maximum solar irradiation was 1070 and 1270 W/m^(2)in March and April,respectively.The maximum daily average of rate heat gain 11,270 and 12,040 W was recorded in March and April,respectively.In terms of the best operational flow rate,the system performs better at 3.3 L/min nanofluid flow rate.For the considered study period,the average monthly maximum energy efficiencies of the solar collector in March and April were 86%and 80%,respectively.
