Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 30836
An Experimental Study on Evacuated Tube Solar Collector for Heating of Air in India

Authors: Avadhesh Yadav, V.K. Bajpai


A solar powered air heating system using one ended evacuated tubes is experimentally investigated. A solar air heater containing forty evacuated tubes is used for heating purpose. The collector surface area is about 4.44 m2. The length and outer diameters of the outer glass tube and absorber tube are 1500, 47 and 37 mm, respectively. In this experimental setup, we have a header (heat exchanger) of square shape (190 mm x 190 mm). The length of header is 1500 mm. The header consists of a hollow pipe in the center whose diameter is 60 mm through which the air is made to flow. The experimental setup contains approximately 108 liters of water. Water is working as heat collecting medium which collects the solar heat falling on the tubes. This heat is delivered to the air flowing through the header pipe. This heat flow is due to natural convection and conduction. The outlet air temperature depends upon several factors along with air flow rate and solar radiation intensity. The study has been done for both up-flow and down-flow of air in header in similar weather conditions, at different flow rates. In the present investigations the study has been made to find the effect of intensity of solar radiations and flow rate of air on the out let temperature of the air with time and which flow is more efficient. The obtained results show that the system is highly effective for the heating in this region. Moreover, it has been observed that system is highly efficient for the particular flow rate of air. It was also observed that downflow configuration is more effective than up-flow condition at all flow rates due to lesser losses in down-flow. The results show that temperature differences of upper head and lower head, both of water and surface of pipes on the respective ends is lower in down-flow.

Keywords: air flow direction, Evacuated tube solar collector, solar air heating, solar thermal utilization

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 4755


[1] R Perez et al. (1995), 'Calculating solar radiation received by tubular solar-energy collectors', Solar Engineering; I: 699-704.
[2] L Qin (1999), 'Evaluation of evacuated tubular solar-collectors for large SDHW systems and combined space-heating systems', Proceedings of northsun99, Edmonton, Alberta, Canada.
[3] S Lart (2000), 'Development of a thermal performance test for an Integrated collector-storage solar water heating system', PhD Thesis, pp university of Wales Cardiff.
[4] G.L. Morrison et al. (2001), 'Water in glass evacuated tube solar water heaters', proceedings of ISES solar world congress, Adelaide, Australia, pp 545-550
[5] G.L. Morrison (2004), 'Water-in-glass evacuated tube solar water heaters', Solar Energy Vol. 76, pp 135-140.
[6] L.J. Shah (2004), 'Vertical evacuated tubular-collectors utilizing solar radiation from all directions', Applied Energy Vol. 78, pp 371-395.
[7] G.L. Morrison (2005), 'Measurement and simulation of flow rate in a water-in-glass evacuated tube solar water heater', Solar Energy Vol. 78, pp 257-267.
[8] Indra Budihardjo (2007), 'Natural convection flow through Water-in¬glass evacuated tube solar collectors', Solar Energy Vol. 81, pp 1460¬1472.
[9] Louise Jivan Shah (2007), 'Theoretical flow investigations of an all glass evacuated tubular collector', Solar Energy Vol. 81, pp 822-828.
[10] Yong Kim (2007), 'Thermal performance comparisons of the glass evacuated tube solar collector with shapes of absorber tube', Renewable Energy Vol. 32, pp 772-795.
[11] X.R. Zhang(2008), 'An Experimental study on evacuated tube solar collector using supercritical CO2, Applied Thermal Engineering Vol. 28, pp 1225-1233
[12] I. Budihardjo (2009), 'Performance of Water-in-glass evacuated tube solar water heaters', Solar Energy Vol. 83, pp 49-56.
[13] Liangdong Ma (2010), 'Thermal performance analysis of the glass evacuated tube solar collector with U-tube', Building and Environment Vol. 45, pp 1959-1967.