The influence of snow deposits on thermal efficiency of vacuum tube collectors

Abstract

Global warming promotes the acceleration forces all countries to reduce fossil energy sources and increase renewable energy sources with the development of environmentally friendly resource-saving technologies. The vast territory of Russia is permafrost or has seasonally frozen soils. The use of renewable energy sources, especially solar energy sources, is especially important for such territories.The article presents the experimental results of the operating modes of a pilot industrial solar hot water supply system with two vacuum tube collectors after snow pollution or icing of pipe surfaces. This technique is used to measure the hourly values of thermal energy from the conversion of solar radiation by collectors with polluted and cleaned collector surfaces on a sunny day after snowfall or icing. The average hourly value of solar insolation (with contaminated surfaces and after their cleaning) is obtained by integrating the meter recordings on the incident heat flux from the sun (by 600 values each) at an interval of 6 seconds. It is found that when the collector pipe surface is iced, the decrease in the thermal energy supply is maximum and amounts to 36.96 %. In other cases it varies from 8.51 to 13.47 %.