The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

J. Ryan - One of the best experts on this subject based on the ideXlab platform.

Shamsoddin Ghiami - One of the best experts on this subject based on the ideXlab platform.

  • comparative study based on energy and exergy analyses of a baffled solar air heater with latent storage collector
    Applied Thermal Engineering, 2017
    Co-Authors: Amir Ghiami, Shamsoddin Ghiami
    Abstract:

    Abstract In this empirical study, exergy and energy investigation of a novel solar air heater (SAH) was undertaken in presence of the paraffin wax slab as the Phase-Change-Material (PCM). Characteristics of the system was scrutinized in presence and absence of baffle on the absorber plate. In the experimental study, two types of baffle-equipped and an unequipped absorber plate were inspected in presence of PCM unit and their exergy and efficiency were compared. For the baffled absorber plates, the baffles are made of galvanized plates and are arranged in sequential or staggered manner. At three different air mass flow rates of 0.017 Kg / s , 0.014 Kg / s and 0.009 Kg / s , inlet, PCM and outlet temperature were measured and compared. Exploiting the 1st and 2nd Thermodynamics Laws, the exergy and energy efficiencies were calculated. This study’s outcome approved that, at different air mass flow rates, the baffle-equipped SAH obtained the highest efficiencies while the unequipped one has the lowest. It has been found out that, at the mass flow rate of 0.017 Kg / s , the maximum energy efficiency was attained for sequence-arranged baffle-equipped SAH (26.78%), while unequipped SAH had the least energy efficiency (14.30%) at the same mass flow rate. The exergy efficiencies varied between 4.86 - 20.47 % for all cases of study.

  • comparative study based on energy and exergy analyses of a baffled solar air heater with latent storage collector
    Applied Thermal Engineering, 2017
    Co-Authors: Amir Ghiami, Shamsoddin Ghiami
    Abstract:

    Abstract In this empirical study, exergy and energy investigation of a novel solar air heater (SAH) was undertaken in presence of the paraffin wax slab as the Phase-Change-Material (PCM). Characteristics of the system was scrutinized in presence and absence of baffle on the absorber plate. In the experimental study, two types of baffle-equipped and an unequipped absorber plate were inspected in presence of PCM unit and their exergy and efficiency were compared. For the baffled absorber plates, the baffles are made of galvanized plates and are arranged in sequential or staggered manner. At three different air mass flow rates of 0.017 Kg / s , 0.014 Kg / s and 0.009 Kg / s , inlet, PCM and outlet temperature were measured and compared. Exploiting the 1st and 2nd Thermodynamics Laws, the exergy and energy efficiencies were calculated. This study’s outcome approved that, at different air mass flow rates, the baffle-equipped SAH obtained the highest efficiencies while the unequipped one has the lowest. It has been found out that, at the mass flow rate of 0.017 Kg / s , the maximum energy efficiency was attained for sequence-arranged baffle-equipped SAH (26.78%), while unequipped SAH had the least energy efficiency (14.30%) at the same mass flow rate. The exergy efficiencies varied between 4.86 - 20.47 % for all cases of study.

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

Amir Ghiami - One of the best experts on this subject based on the ideXlab platform.

  • comparative study based on energy and exergy analyses of a baffled solar air heater with latent storage collector
    Applied Thermal Engineering, 2017
    Co-Authors: Amir Ghiami, Shamsoddin Ghiami
    Abstract:

    Abstract In this empirical study, exergy and energy investigation of a novel solar air heater (SAH) was undertaken in presence of the paraffin wax slab as the Phase-Change-Material (PCM). Characteristics of the system was scrutinized in presence and absence of baffle on the absorber plate. In the experimental study, two types of baffle-equipped and an unequipped absorber plate were inspected in presence of PCM unit and their exergy and efficiency were compared. For the baffled absorber plates, the baffles are made of galvanized plates and are arranged in sequential or staggered manner. At three different air mass flow rates of 0.017 Kg / s , 0.014 Kg / s and 0.009 Kg / s , inlet, PCM and outlet temperature were measured and compared. Exploiting the 1st and 2nd Thermodynamics Laws, the exergy and energy efficiencies were calculated. This study’s outcome approved that, at different air mass flow rates, the baffle-equipped SAH obtained the highest efficiencies while the unequipped one has the lowest. It has been found out that, at the mass flow rate of 0.017 Kg / s , the maximum energy efficiency was attained for sequence-arranged baffle-equipped SAH (26.78%), while unequipped SAH had the least energy efficiency (14.30%) at the same mass flow rate. The exergy efficiencies varied between 4.86 - 20.47 % for all cases of study.

  • comparative study based on energy and exergy analyses of a baffled solar air heater with latent storage collector
    Applied Thermal Engineering, 2017
    Co-Authors: Amir Ghiami, Shamsoddin Ghiami
    Abstract:

    Abstract In this empirical study, exergy and energy investigation of a novel solar air heater (SAH) was undertaken in presence of the paraffin wax slab as the Phase-Change-Material (PCM). Characteristics of the system was scrutinized in presence and absence of baffle on the absorber plate. In the experimental study, two types of baffle-equipped and an unequipped absorber plate were inspected in presence of PCM unit and their exergy and efficiency were compared. For the baffled absorber plates, the baffles are made of galvanized plates and are arranged in sequential or staggered manner. At three different air mass flow rates of 0.017 Kg / s , 0.014 Kg / s and 0.009 Kg / s , inlet, PCM and outlet temperature were measured and compared. Exploiting the 1st and 2nd Thermodynamics Laws, the exergy and energy efficiencies were calculated. This study’s outcome approved that, at different air mass flow rates, the baffle-equipped SAH obtained the highest efficiencies while the unequipped one has the lowest. It has been found out that, at the mass flow rate of 0.017 Kg / s , the maximum energy efficiency was attained for sequence-arranged baffle-equipped SAH (26.78%), while unequipped SAH had the least energy efficiency (14.30%) at the same mass flow rate. The exergy efficiencies varied between 4.86 - 20.47 % for all cases of study.

Robert S. Whitney - One of the best experts on this subject based on the ideXlab platform.

  • Non-Markovian quantum Thermodynamics: Laws and fluctuation theorems
    Physical Review B, 2018
    Co-Authors: Robert S. Whitney
    Abstract:

    This work brings together Keldysh non-equilibrium quantum theory and Thermodynamics, by showing that a real-time diagrammatic technique is an equivalent of stochastic Thermodynamics for non-Markovian quantum machines (heat engines, refrigerators, etc). Symmetries are found between quantum trajectories and their time-reverses on the Keldysh contour, for any interacting quantum system coupled to ideal reservoirs of electrons, phonons or photons. These lead to quantum fluctuation theorems the same as the well-known classical ones (Jarzynski and Crooks equalities, integral fluctuation theorem, etc), whether the system's dynamics are Markovian or not. Some of these are also shown to hold for non-factorizable initial states. The sequential tunnelling approximation and the cotunnelling approximation are both shown to respect the symmetries that ensure the fluctuation theorems. For all initial states, energy conservation ensures that the first law of Thermodynamics holds on average, while the above symmetries ensures that the second law of Thermodynamics holds on average, even if fluctuations violate it.

  • Non-Markovian quantum Thermodynamics: Laws and fluctuation theorems
    Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2018
    Co-Authors: Robert S. Whitney
    Abstract:

    This work brings together Thermodynamics and nonequilibrium quantum theory, by showing that a real-time diagrammatic technique on the Keldysh contour is an equivalent of stochastic Thermodynamics for non-Markovian quantum machines (heat engines, refrigerators, etc.). Symmetries are found between quantum trajectories and their time reverses on the Keldysh contour, for any interacting quantum system coupled to ideal reservoirs of electrons, phonons, or photons. These lead to quantum fluctuation theorems the same as the well-known classical ones (Jarzynski and Crooks equalities, integral fluctuation theorem, etc.), whether the system's dynamics are Markovian or not. Some of these are also shown to hold for nonfactorizable initial states. The sequential tunneling approximation and the cotunneling approximation are both shown to respect the symmetries that ensure the fluctuation theorems. For all initial states, energy conservation ensures that the first law of Thermodynamics holds on average, while the above symmetries ensure that the second law of Thermodynamics holds on average, even if fluctuations violate it.