Experimental analysis of thermal performance of flat plate and evacuated tube solar collectors in stationary standard and daily conditions
- Dipartimento di Fisica Tecnica, Universita degli Studi di Padova, Via Venezia 1, 35131 Padova (Italy)
New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is measured following the standard and it is compared with the input/output curves measured for the whole day. The first purpose of the present work is the comparison of results in steady-state and quasi-dynamic test methods both for flat plate and evacuated tube collectors. Besides this, the objective is to characterize and to compare the daily energy performance of these two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is plotted against the daily incident solar radiation. Test runs have been performed in several conditions to reproduce different conventional uses (hot water, space heating, solar cooling). Results are also presented in terms of daily efficiency versus daily average reduced temperature difference: this allows to represent the comparative characteristics of the two collectors when operating under variable conditions, especially with wide range of incidence angles. (author)
- OSTI ID:
- 21337881
- Journal Information:
- Solar Energy, Vol. 84, Issue 8; Other Information: Elsevier Ltd. All rights reserved; ISSN 0038-092X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
EVACUATED TUBE COLLECTORS
FLAT PLATE COLLECTORS
COMPARATIVE EVALUATIONS
EFFICIENCY
PERFORMANCE
STANDARDS
DIAGRAMS
HOT WATER
SOLAR WATER HEATING
SOLAR SPACE HEATING
STEADY-STATE CONDITIONS
INCIDENCE ANGLE
DAILY VARIATIONS
COMPOUND PARABOLIC CONCENTRATORS
SOLAR AIR CONDITIONING
Quasi-dynamic method
Daily efficiency