Browsing by Author "Casseer, DR"

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item: Conference-Abstract
Assessment of spallart almaras turbulence model for numerical evaluation of ceiling fan performance
Casseer, DR; Ranasinghe, RACP
Ceiling fans are a popular means of providing thermal comfort to occupants in an indoor environment, mainly in tropical countries and it contributes to a significant portion of annual energy consumption throughout the world. It is proven that using ceiling fans in conjunction with air conditioners in an air-conditioned environment can lead to higher thermal comfort at a lower cost of energy which will in turn increase the popularity of the ceiling fans in near future. Understanding the proper flow field around a rotating ceiling fan can lead to design more efficient fan blades, which can lead to significant energy savings. Analyzing these using experimental methods is both a tedious and a costly task. By using numerical methods, this can be achieved at a significant lower cost and effort. For such analyses, CFD methods using RANS equations are widely used for both indoor and outdoor conditions. For this purpose, numerous turbulence models are available, each of which would more accurately predict some cases than others. Therefore, Standard KE, Standard KW, RNG KE and Spalart Allmaras model is evaluated for a case of efficiency assessment of ceiling fans and SA model was found as the most accurate model with just 1.9% NRMSD with experimentally calculated values.
item: Article-Full-text
An assessment on the test setups used for energy labeling of ceiling fans
(Springier, 2021) Casseer, DR; Ranasinghe, C
Ceiling fans are used all over the world as a mean of enhancing indoor thermal comfort. A number of grading programs have been initiated for assessing energy performance of ceiling fans, such as ANSI/AMCA 230, Energy Star, IEC 60879, IS 374 and SLS 1600. The configurations of test setups used for performance evaluations in these standards have significant differences to each other. In this study, the influence of such differences on the calculated performance grade of ceiling fans were investigated and the suitability of each dimension of the test set-up is discussed. Particular emphasis was placed on quantifying the effect of the cylindrical drum used in Energy Star and SLS test methods. For this assessment, extensive three-dimensional numerical simulations and experimental measurements were used. Accordingly, the effect of cylinder height, gap between the fan rotation plane and the cylinder, cylinder diameter and the dimensions of the test chamber were investigated. Results show that, the test cylinder, has no significant impact on the calculated performance grade of the tested ceiling fan (variation is less than 2%), and may be eliminated from the test setup. This justifies the recent decision of AMCA on the removal of test cylinder from the fan test set-up. Further, it was also found that the set up dimensions considered herein is large enough so that the calculated start rating is uneffaced by the surrounding solid walls.