Evacuated Solar Tube Performance Enhancement Evaluation

khaled ali alkhaledi, Kenneth H. Means, Salaheddine Bendak, Allison Arnold, James Jones

Abstract


In our fast-growing and expanding world, securing a reliable energy supply to power our societies has become essential in order to continue forward as well as preserve the natural resources around us. Developing renewable energy, such as that acquired from solar collectors, can help provide people with reliable and safe source of power worldwide. Evacuated solar tubes are a clean, economical, and efficient method of heating water. They are robust and durable in their construction and therefore are able to be successfully implemented across many geographical regions and various climates. The goal of this paper is the evaluation of enhancements made towards the output efficiency of evacuated solar tubes for water heating with the addition of solar reflectors behind the tubes in various geometric arrangements. The strategy implemented was to analyze several measurable variables through each test configuration conducted in order to determine the thermal performance of the each test. Thus an apparatus was constructed, and four different configurations were tested at varying distances: Flat background, 45o V-shaped background, 60o V-shaped background, and a half circle background. After analyzing the data collected and determining the positives and negatives of each configuration, it was found that all cases where reflectors were implemented led to increases in the amount of energy absorbed by the solar tubes. Furthermore, all test configurations showed an increases in both the efficiency and amount of heat generated.  The saving in power consumption for the 60°V-Shape tubes at 15.25 cm was significant, therefore; it was concluded that the -shape configuration is the most beneficial.


Keywords


Evacuated solar tubes; reflectors; solar energy; solar azimuth; heat

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