Numerical Investigation of Small-Scale Adsorption Cooling System Performance Employing Activated Carbon-Ethanol Pair
Abstract
:1. Introduction
2. Working Principle of Adsorption Cooling System
3. CFD Modeling
3.1. Assumptions
- The adsorbent layer height is equal to the height of the fins.
- The porous media is considered as homogenous.
- Darcy model is adopted for flow through porous media.
- A thermal equilibrium model is assimilated for porous media i.e., the adsorbent and ethanol vapor are at same temperature.
- The variation of the heat of adsorption with the ethanol uptake is not considered, therefore, the average value of the heat of adsorption is used.
3.2. Geometry and Meshing
- -
- Minimum orthogonal quality = 0.9721 where orthogonal quality ranges from 0 to 1 and values close to 0 represents low quality.
- -
- Maximum ortho skew = 0.0279 where ortho skew ranges from 0 to 1 and values close to 1 correspond to low quality.
3.3. Materials and Porous Zone Properties
3.3.1. Materials
3.3.2. Porous Zone Properties
3.4. Boundary Conditions
3.4.1. Pressure Inlet/Wall/Pressure Outlet Conditions
3.4.2. Convection Boundary Conditions
3.5. Governing Equations
3.5.1. Mass Conservation Equation in Porous Media
3.5.2. Momentum Conservation Equation
3.5.3. Energy Conservation Equation
3.5.4. Adsorption Characteristics
3.5.5. Performance Investigation
3.5.6. Mass and Energy Balance Equation
4. Results and Discussion
4.1. Pressure Profile
4.2. Temperature Profiles
4.3. Adsorption Characteristics
4.4. Energy and Mass Balance
4.5. Performance Investigation
5. Conclusions
Author Contributions
Acknowledgments
Conflicts of Interest
Nomenclature
pre-exponential factor (s−1) | |
inertial loss coefficient (m−1) | |
diameter (m) | |
energy (kJ) | |
force vector (N) | |
gravitational acceleration (m·s−2) | |
heat of evaporation (J·kg−1) | |
diffusion time constant (s−1) | |
heterogeneity parameter (-) | |
mass flow rate (kg·s−1) | |
m | mass (kg) |
pressure (Pa) | |
gas constant (kJ·kmol−1·K−1) | |
mass source term (kg·m-3·s−1) | |
uptake (kg·kg−1) | |
thermal energy (J) | |
heat of adsorption (kJ·kg−1) | |
time (s) | |
temperature (K) | |
velocity magnitude (m·s−1) | |
overall velocity vector (m·s−2) | |
Greek | |
permeability (m2) | |
porosity (-) | |
adsorbent’ micropore volume (cm3·g−1) | |
density (kg·m−3) | |
dynamic viscosity (Pa·s) | |
gradient | |
stress tensor | |
Superscripts | |
equilibrium | |
Subscripts | |
apparent, activation | |
ac | activated carbon |
adsorption | |
chill | |
condenser | |
desorption | |
effective | |
g | gas phase |
p | particle |
solid, saturated | |
Acronyms | |
ACS | adsorption cooling system |
CFD | computational fluid dynamics |
NIST | National Institute of Standards and Technology |
SCP | specific cooling power |
COP | coefficient of performance |
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Khanam, M.; Jribi, S.; Miyazaki, T.; Saha, B.B.; Koyama, S. Numerical Investigation of Small-Scale Adsorption Cooling System Performance Employing Activated Carbon-Ethanol Pair. Energies 2018, 11, 1499. https://doi.org/10.3390/en11061499
Khanam M, Jribi S, Miyazaki T, Saha BB, Koyama S. Numerical Investigation of Small-Scale Adsorption Cooling System Performance Employing Activated Carbon-Ethanol Pair. Energies. 2018; 11(6):1499. https://doi.org/10.3390/en11061499
Chicago/Turabian StyleKhanam, Marzia, Skander Jribi, Takahiko Miyazaki, Bidyut Baran Saha, and Shigeru Koyama. 2018. "Numerical Investigation of Small-Scale Adsorption Cooling System Performance Employing Activated Carbon-Ethanol Pair" Energies 11, no. 6: 1499. https://doi.org/10.3390/en11061499