Open Access

ARTICLE

Performance Evaluation of Evacuated Tube Receiver at Various Flow Rates under Baghdad Climate with Nanofluid as Working Fluids

Walaa M. Hashim, Israa S. Ahmed, Ayad K. Khlief^*, Raed A. Jessam, Ameer Abed Jaddoa
Department of Electromechanical Engineering, University of Technology-Iraq, Baghdad, 10066, Iraq[1pc]
* Corresponding Author: Ayad K. Khlief. Email:
(This article belongs to the Special Issue: Advancements in Energy Resources, Processes, Systems, and Materials-(ICSSD2024))

Energy Engineering https://doi.org/10.32604/ee.2025.061630

Received 29 November 2024; Accepted 31 March 2025; Published online 30 April 2025

Abstract

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 m² 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/m² 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.

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Keywords

Evacuated tube solar collector; Al₂O₃-water thermal nanofluid; closed loop pulsating heat pipe; thermal performance

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