The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform

Mohamed Tawfik - One of the best experts on this subject based on the ideXlab platform.

  • Efficiency Factors of solar Collectors of parallel plates for water
    Solar Energy, 2013
    Co-Authors: G. Góngora-gallardo, Antonio Colmenar-santos, Manuel Castro, Mohamed Tawfik
    Abstract:

    Abstract In this paper, we derived the Collector Efficiency Factor, F ′, of two solar Collectors of parallel plates for water, which is based on the Efficiency Factors of air heaters. This solar Collectors were built in the past but without considering their Efficiency Factors. The Efficiency Factors: F and F ′, correspond to the basic model of Hottel–Whiller–Bliss (widely adopted in the literature) and they are useful for simulating the behavior of solar Collectors. Finally we assess the theoretical potential of parallel plates Collectors; in this case, the parallel plates Collector “absorbent cover”, is more efficient than the conventional one, assuming an application of a thermosyphon system with laminar velocity.

B.n. Prasad - One of the best experts on this subject based on the ideXlab platform.

  • Thermal performance characterstics of artificially roughened and boosted solar air heaters
    2014
    Co-Authors: B.n. Prasad, G.n. Sah
    Abstract:

    This paper represents the results on data collected under actual outdoor conditions for artificially roughened and smooth solar air heaters with and without booster mirrors. The results show that the effect of boosting of solar radiation is appreciable and consequently, the thermal Efficiency of the roughened Collectors with booster mirrors increases further over the roughened ones without any further increase in the pressure drop over that in the roughened ones. The values of the Collector heat removal Factor and Collector Efficiency Factor of

  • Thermal performance of artificially roughened solar air heaters
    Solar Energy, 2013
    Co-Authors: B.n. Prasad
    Abstract:

    Artificially roughened solar air heaters have been analysed (Prasad and Saini, 1988) for fully developed turbulent flow and found to perform better both quantitatively and qualitatively compared to the smooth ones under the same operating conditions. Optimal thermo-hydraulic performance of such solar air heaters has been analysed (Prasad and Saini, 1991) and investigated (Prasad and Verma, 2000) for the maximum heat transfer and minimum pressure drop. This paper represents the experimental results on heat transfer and thereby thermal performance of artificially roughened solar air heaters for fully developed turbulent flow data collected under actual outdoor conditions. Such solar air heaters have been found to give considerably high value of Collector heat removal Factor (FR), Collector Efficiency Factor (F′) and thermal Efficiency (ηth) as compared to the corresponding values of those of smooth Collectors. In the range of the operating parameters investigated, the ratio of the respective values of the parameters FR, F′ and ηth for the roughened Collectors to the smooth Collectors have been found to be 1.786, 1.806 and 1.842 respectively.

G. Góngora-gallardo - One of the best experts on this subject based on the ideXlab platform.

  • Efficiency Factors of solar Collectors of parallel plates for water
    Solar Energy, 2013
    Co-Authors: G. Góngora-gallardo, Antonio Colmenar-santos, Manuel Castro, Mohamed Tawfik
    Abstract:

    Abstract In this paper, we derived the Collector Efficiency Factor, F ′, of two solar Collectors of parallel plates for water, which is based on the Efficiency Factors of air heaters. This solar Collectors were built in the past but without considering their Efficiency Factors. The Efficiency Factors: F and F ′, correspond to the basic model of Hottel–Whiller–Bliss (widely adopted in the literature) and they are useful for simulating the behavior of solar Collectors. Finally we assess the theoretical potential of parallel plates Collectors; in this case, the parallel plates Collector “absorbent cover”, is more efficient than the conventional one, assuming an application of a thermosyphon system with laminar velocity.

Pedro M. L. P. Magalhães - One of the best experts on this subject based on the ideXlab platform.

  • Extension of the Perers model for photovoltaic-thermal (PV-T) Collectors
    Solar Energy, 2018
    Co-Authors: Pedro M. L. P. Magalhães
    Abstract:

    Abstract Solar thermal Collectors including hybrid photovoltaic-thermal (PV-T) Collectors can be certified in accordance with the ISO 9806 standard for an assessment of their reliability and thermal performance. The ISO 9806 standard relies on the Perers model for the latter though the model does not differentiate between hybrid (fluid circulation and electricity generation) and non-hybrid (no electricity generation) operation of PV-T Collectors. The present communication proposes an extension of the Perers model explicitly accounting for the effective absorption Factor reduction caused by electricity generation in PV-T Collectors under maximum power point (MPP) operation, and discusses its suitability for parameter estimation via multi-linear regression (MLR). The solution devised assumes a linear MPP cell Efficiency temperature dependence and employs the Collector Efficiency Factor construct on which the original Perers model already implicitly relies, thus avoiding the need to measure additional quantities while remaining compatible with MLR. In doing so, more detailed thermal performance modelling of PV-T Collectors is possible than with the standard Perers model, with minimal additional effort and while retaining the original’s modularity. The extended model’s added relevance is nonetheless predicted to be positively correlated with the thermal and electrical performance levels and the cell Efficiency temperature dependence.

Prabha Chand - One of the best experts on this subject based on the ideXlab platform.

  • Thermal and thermohydraulic performance of wavy finned absorber solar air heater
    Solar Energy, 2016
    Co-Authors: Abhishek Priyam, Prabha Chand
    Abstract:

    Abstract In the present paper, the performance analysis of finned absorber solar air heater has been investigated analytically. The fluid channel is formed by two transversely positioned wavy fins attached on the absorber plate with bottom side thermally insulated and the top surface of absorber subjected to uniform heat flux. The expression for Collector Efficiency Factor of such Collector has been developed. Effects of mass flow rates and fin spacings on the thermal performance have been presented and the results are compared with plain solar air heater. Further, the thermohydraulic performance parameter called ‘effective Efficiency’ has been employed and presented to express the net useful thermal energy gain, taking into account the equivalent thermal energy required to produce the work energy necessary to overcome the additional friction or hydraulic losses as a result of extended surfaces on the absorber plate. The mathematical model provides reasonable predictions of the performance of wavy fin solar air heater and it can be useful in designing such types of solar air heater.

  • The effect of Collector aspect ratio and fin density on the thermal performance of rectangular finned absorber solar air heaters
    2012 IEEE Third International Conference on Sustainable Energy Technologies (ICSET), 2012
    Co-Authors: Prabha Chand, S P Sharma
    Abstract:

    The effect of Collector aspect ratio on the thermal performance of solar air heater with plain fins on the absorber plate has been investigated theoretically. With constant Collector area, the effect of various parameter such as air temperature rise, Efficiency, Collector Efficiency Factor, Collector heat removal Factor and fin density on aspect ratio have also been investigated. It is seen that either increasing the Collector aspect ratio or increasing the fin density will improve the thermal performance.