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Experimental and numerical study of unsteady non‐periodic wall heat transfer under step, ramp and cosine temperature perturbations
Author(s) -
Antonopoulos K. A.,
Democritou F.
Publication year - 1994
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4440180602
Subject(s) - mechanics , heat transfer , transient (computer programming) , thermal , airflow , trigonometric functions , boundary value problem , convective heat transfer , convection , computer simulation , heat transfer coefficient , materials science , thermodynamics , physics , mathematics , computer science , mathematical analysis , geometry , operating system
An experimental and numerical study of the transient non‐periodic wall heat transfer problem is presented. A computer‐controlled indoor/outdoor environment simulation system produces any desired variation of the air temperature, thus allowing measurement of the dynamic thermal behaviour of any test wall under the desired boundary conditions. Measurements of the temperature field within the wall, of the heat flow and of the convection coefficients at the wall surfaces are performed during step, ramp and cosine perturbations of the outdoor air temperature. The measurements are in very good agreement with the numerical predictions obtained by a developed finite difference solution procedure. The results showed that in building heat transfer applications, for example in air conditioning, the usual assumption of periodic outdoor conditions may lead to considerable errors in case of a significant temporary deviation of the temperature from periodicity.