Experimental Comparison of Flat Plate and Evacuated Tube Solar Thermal Collectors for Domestic Hot Water Preparation in 
Education Facilities

Moldovan, Macedon; Vişa, Ion; Burduhos, Bogdan

doi:10.13044/j.sdewes.d7.0285

Cited by 8 publications

(4 citation statements)

References 20 publications

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“…As noted above, this study is unique in the sense that it is based on executing four complete solar system installations as a laboratory, which allows the performance of four complete solar thermal systems to be measured simultaneously under identical climatic conditions. Although the performance of these technologies according to irradiation availability has been extensively studied by different authors [38,39], those analyses have been performed in a simulation environment. Local studies have also previously been performed [25], but only with ETC technology.…”

Section: Discussionmentioning

confidence: 99%

Residential Solar Thermal Performance Considering Self-Shading Incidence between Tubes in Evacuated Tube and Flat Plate Collectors

et al. 2021

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The performance of solar thermal technology under high-altitude equatorial climatic and solar path conditions has not been determined. Evacuated tube solar collectors are more efficient than flat plate collectors in cold and cloudy regions; however, due to their dependence on orientation, the irradiation incidence between the tubes of these collectors can be blocked. In this study, the performance of these types of collectors was analyzed to determine the implications of their orientation under these specific climate conditions. Four solar thermal systems were installed: two of the systems used evacuated tube collectors, and two used flat plate collectors. Each collector was connected to storage and discharge points to simulate residential consumption when observing the real performance of the four systems in terms of irradiation availability. The evacuated tube collectors were more efficient and reduced the backup energy requirement by up to 20.6% more on average than the flat plate collectors. In addition, the performance of the evacuated tube collectors increased by up to 9.8% when the tubes were arranged parallel to the solar path, compared to when they were arranged perpendicular to the solar path, verifying that the blockage effect is an important parameter to consider for evacuated tube technology. The main novelty of this research is the comparison of these two technologies under different orientations, with perpendicular and parallel dispositions toward the solar path, in a high-altitude equatorial location where solar collectors are not typically oriented in any particular orientation. To the best of our knowledge, this is the first complete analysis of real systems deployed under these conditions.

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Section: Discussionmentioning

confidence: 99%

Residential Solar Thermal Performance Considering Self-Shading Incidence between Tubes in Evacuated Tube and Flat Plate Collectors

et al. 2021

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“…The solar thermal collectors are installed on the rooftop of a nearby building at a tilt angle of 42 • yearly optimized to maximize the thermal energy output during the periods with activity in the campus. This solar thermal system was designed to provide domestic hot water mainly for the locker rooms of a nearby Sport Hall [29].…”

Section: Case Studymentioning

confidence: 99%

Yearly Electrical Energy Assessment of a Photovoltaic Platform/Geothermal Heat Pump Prosumer

2021

Self Cite

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Romania introduced in 2018 an amendment to the national law 220/2008 by including the Prosumer concept that allows investors in grid-connected photovoltaic systems with a capacity up to 27 kWp to receive a feed in tariff for the electricity delivered to the grid representing approximatively one third of the price paid when the electricity is consumed from the grid. Thus, the challenge is to use as much as possible the photovoltaic power when it is produced. A methodology is developed to evaluate how much of the electrical energy output of a grid-connected photovoltaic platform is used by a geothermal heat pump for space heating in a building. A numerical simulation is performed in Trnsys17 based on locally measured meteorological parameters over a period of one entire year. A case study is presented for which the characteristics of the building, of the heat pump system and of the photovoltaic system are described and integrated into the transient simulation environment. The numerical results are comparatively presented and discussed along with experimental data for sunny days in cold season. For the analysed case study, the self-consumption is 16%, significantly lower than the yearly coverage degree of 70%. Further research can be done to increase the self-consumption.

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“…Evacuated Tube Solar Collectors (ETSCs) are primarily beneficial and functional in different climate conditions, including moderate and cold climate temperature values. Using ETSC offers considerable practicality, more workability, and significant thermal energy storage than a flat plate collector, as the vacuum is used in ETSC to mitigate the thermal energy losses and heat transfer between the collector and the ambient [10]. Nevertheless, using ETSC in freezing climates with highly low-temperature values would lower their performance due to the significant difference between the ambiance and the hot water stored.…”

Section: Introductionmentioning

confidence: 99%

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

Yasir Al-Abayechi,

Yaser Alaiwi,

Zainab Al-Khafaji

2024

ARNHT

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This research is carried out to investigate and examine the critical benefits and significant contributions of integrating nanoparticles into the ETSC system to enhance the thermal efficiency, thermal performance, temperature out, and energy storage of the ETSC. The Simcenter STAR-CCM+ 2022.1 software package implemented numerical analysis and thermal simulations. Further, a comparative analysis is conducted on two case studies to validate the critical role and contributions of employing the aluminum oxide nanomaterial in the solar collector system to enhance its thermal efficiency and improve its thermal performance and heat transfer, including (1) conventional ETSC and (2) ETSC with Al2O3. According to the numerical analysis and comparative study findings, the results of this research revealed that employing and adding the aluminum oxide nanomaterial into the ETSC system had contributed to several beneficial impacts and significant advantages. In addition, using Al2O3 achieved enhancements in the thermal efficiency, increases in the outlet collector’s temperature, improvements in the rate of heat flux of the pipes, the tube inside the collector, heat transfer of the hot water storage tank, and a rise in the temperature gradient the hot water temperature increased from (between 44.3 and 74.8 ºC) to (between 49.6-80.3 ºC). Besides, the velocity of the water flow inside the solar collector in the second case in which the aluminum oxide nanoparticles are used was higher due to the absorption of further solar radiation and thermal energy, which resulted in a considerable increase in the kinetic energy of water molecules from 0.01 to 0.07 m/s. Also, it was found that the velocity directions and profile were slightly more turbulent in the second case than the conventional solar collector due to more thermal energy absorbed and stored in the ETSC from solar radiation.

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Experimental Comparison of Flat Plate and Evacuated Tube Solar Thermal Collectors for Domestic Hot Water Preparation in Education Facilities

Cited by 8 publications

References 20 publications

Residential Solar Thermal Performance Considering Self-Shading Incidence between Tubes in Evacuated Tube and Flat Plate Collectors

Residential Solar Thermal Performance Considering Self-Shading Incidence between Tubes in Evacuated Tube and Flat Plate Collectors

Yearly Electrical Energy Assessment of a Photovoltaic Platform/Geothermal Heat Pump Prosumer

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

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