https://orcid.org/0000-0002-8404-4961
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ABSTRACT
Recently, an increase in the demand for evacuated tube solar water heaters has been observed in Iraq due to their acceptable thermal efficiency, which reduces the dependence on electrical energy to heat water for domestic uses. The efficiency of the evacuated tube increases with the amount of received solar radiation. Therefore, in the present work, the evacuated tube has been installed at the center of the parabola cylinder to focus more sunlight on its surface. Since the sun has a relative movement concerning the earth, which is variable from one season to another, and during the day from sunrise to sunset, heating water with an evacuated tube solar water heater (ETSWH) has fluctuating temperatures. An effective technique for increasing the efficiency of a solar water heating system is solar tracking technology, which exploits solar radiation continuously during the day. The LDRs were utilized as sensors, and a 12 V linear actuator have been used to guide the position of the modified trough solar water heater (MTSWH). A microcontroller board (Arduino Uno) implements the program code (software part). The MTSWH was experimentally tested, and the results showed that installing a single-phase open thermosyphon evacuated tube at the focus of the parabolic cylinder (MTSWH) increased the thermal efficiency by 16.5%. Moreover, the implementation of solar tracking system led to an increase in the outlet water temperature by 32% and ensured a continuous supply of water throughout the day at high temperatures compared to the conventional trough solar water heater (CTSWH). This study revealed that the MTSWH performance results showed good agreement with previous studies.
Nomenclatures
| Abbreviation | = | Items |
| ETSWH | = | Evacuated tube solar water heater |
| MTSWH | = | Modified trough solar water heater |
| CTSWH | = | Conventional trough solar water heater |
| PTC | = | Parabolic center solar collector |
| θ_rim | = | Edge angle |
| GC | = | Absorber tube |
| OTET | = | Open thermosyphon evacuated tube |
| PWM | = | Pulse Width Modulation |
| TD | = | Typical deviation |
| T.E | = | Typical error |
| AAT | = | Ambient air temperature |
| SRI | = | Solar radiation intensity |
| WS | = | Wind speed |
| T | = | Temperature |
| Qu | = | Useful energy |
| m ̇ | = | Mass flux |
| Cp | = | Heat capacity of the water |
| LDR | = | light-dependent resistor |
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
Milia H. Majeed
Milia H. Majeed, PhD student, Ural Federal University (UrFU), Russia. Master’s in Electronics and Nanoelectronics Engineering from Ural Federal University (UrFU), Russia, 2021.
Naseer T. Alwan
Naseer T. Alwan obtained his PhD in Renewable Energy Engineering from Ural Federal University, Russia. Currently working at the Northern Technical University, Iraq.
Sajjad A. Salih
Sajjad A. Salih, PhD student, Ural Federal University (UrFU), Russia. Master in mechanical power engineering from Warsaw University of Technology, Poland 2017.
Baseem A. Aljashaami
Baseem A. Aljashaami, PhD student, Ural Federal University (UrFU), Russia. Master in Building Services, Hydro, and Environmental Engineering from Warsaw University of Technology, Poland, 2017.
S. E. Shcheklein
S. E. Shcheklein, Professor, Ural Federal University, Russia; B.N. Yeltsin, Department of Nuclear Power Plants and Renewable Energy. Head of the Department.
Vladimir I. Velkin
Vladimir I. Velkin, professor of the Ural Federal University, Department of nuclear power plants and renewable energy sources, Russia