| 1. |
- Behi, Hamidreza, et al.
(författare)
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Enhancement of the Thermal Energy Storage Using Heat-Pipe-Assisted Phase Change Material
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 14:19
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Tidskriftsartikel (refereegranskat)abstract
- Usage of phase change materials' (PCMs) latent heat has been investigated as a promising method for thermal energy storage applications. However, one of the most common disadvantages of using latent heat thermal energy storage (LHTES) is the low thermal conductivity of PCMs. This issue affects the rate of energy storage (charging/discharging) in PCMs. Many researchers have proposed different methods to cope with this problem in thermal energy storage. In this paper, a tubular heat pipe as a super heat conductor to increase the charging/discharging rate was investigated. The temperature of PCM, liquid fraction observations, and charging and discharging rates are reported. Heat pipe effectiveness was defined and used to quantify the relative performance of heat pipe-assisted PCM storage systems. Both experimental and numerical investigations were performed to determine the efficiency of the system in thermal storage enhancement. The proposed system in the charging/discharging process significantly improved the energy transfer between a water bath and the PCM in the working temperature range of 50 & DEG;C to 70 & DEG;C.
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| 2. |
- Ghanbarpour, A., et al.
(författare)
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Evaluation of heat sink performance using PCM and vapor chamber/heat pipe
- 2021
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Ingår i: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 163, s. 698-719
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a numerical study on heat sink thermal performance using phase change materials (PCM) and a vapor chamber for heat source cooling. Heat sink performance in both natural and forced convection heat transfer modes is investigated. The influence of various geometrical parameters such as number, height and thickness of fins for three different modes of conventional heat sink, PCM-based heat sink and heat sink integrated with vapor chamber is studied. Numerical results showed that the number of fins and fin height were more effective than the fin thickness in reducing heat source temperature. Furthermore, in natural convection, the addition of PCM and vapor chamber to the heat sink reduces the heat source temperature by a maximum of 33.1% and 9.5%, respectively, compared to a conventional heat sink. But in forced convection, the use of vapor chamber reduces the heat source temperature by 7.9% while the addition of PCM to the heat sink affects its performance adversely. In fact when fresh air is blown to the heat sink, it provides a higher temperature potential at all the surfaces.
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| 3. |
- Ahangar Zonouzi, S., et al.
(författare)
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Experimental investigation of the flow and heat transfer of magnetic nanofluid in a vertical tube in the presence of magnetic quadrupole field
- 2018
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Ingår i: Experimental Thermal and Fluid Science. - : Elsevier. - 0894-1777 .- 1879-2286. ; 91, s. 155-165
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the effects of applying magnetic field on hydrodynamics and heat transfer of Fe3O4/water magnetic nanofluid flowing inside a vertical tube have been studied experimentally. The applied magnetic field was resulted from quadrupole magnets located at different axial positions along the tube length. The variations of the local heat transfer coefficient and also the pressure drop of the ferrofluid flow along the length of the tube by applying the magnetic quadrupole field have been investigated for different Reynolds numbers. The obtained experimental results show maximum enhancements of 23.4%, 37.9% and 48.9% in the local heat transfer coefficient for the magnetic nanofluid with 2 vol% Fe3O4 in the presence of the quadrupole magnets located at three different axial installation positions for the Reynolds number of 580 and the relative increase in total pressure drop by applying the magnetic field is about 1% for Re = 580. The increase of the heat transfer coefficient is due to the radial magnetic force toward the heated wall generated by magnetic quadrupole field acting over the ferrofluid flowing inside the tube so that the velocity of the ferrofluid in the vicinity of the heated wall is increased. It is also observed that the enhancement of heat transfer coefficient by applying magnetic quadrupole is decreased with increasing the Reynolds number.
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| 4. |
- Ahangar Zonouzi, S., et al.
(författare)
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Experimental study of the subcooled flow boiling heat transfer of magnetic nanofluid in a vertical tube under magnetic field
- 2020
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Ingår i: Journal of thermal analysis and calorimetry (Print). - : Springer. - 1388-6150 .- 1588-2926. ; 140:6, s. 2805-2816
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the subcooled boiling heat transfer of a Fe3O4/water magnetic nanofluid flowing through a vertical tube has been investigated experimentally in the presence and absence of a magnetic field. The magnetic field has been generated by quadrupole magnets. The subcooled boiling heat transfer coefficient and the boiling curves of the ferrofluid flow under the action of the magnetic field have been compared with those in the absence of magnetic field. The results showed that magnetic actuation contributes to have higher heat fluxes at the same wall superheat in comparison with heat fluxes achieved in the no magnetic field case. Therefore, the local subcooled boiling heat transfer coefficients are increased by the magnetic field. The maximum measured enhancement in local subcooled boiling heat transfer coefficient along the length of the tube by applying magnetic field is 46.58% at applied heat flux of 77,000 W m−2 and mass flux of 270 kg m−2 s−1. Furthermore, the enhancement of local heat transfer coefficient by applying magnetic field decreases as the applied heat flux in the subcooled boiling region is increased.
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| 5. |
- Badran, Bassam E., et al.
(författare)
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Theoretical Study of a Multilevel Heat Pump for Multi-Source Heating
- 2021
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Ingår i: 6Th Iir Conference On Thermophysical Properties And Transfer Processes Of Refrigerants (Tptpr2021). - : INT INST REFRIGERATION. ; , s. 243-250
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Konferensbidrag (refereegranskat)abstract
- Industry and other sectors are currently looking for solutions to decarbonize their processes, including heating, which is mainly based on fossil fuel boilers. Heat pumps can provide heating with higher performance based on their high coefficient of performance (COP). This work considers a multilevel heat pump (MTHP) for multi-source heating, based on a three-stage cascade in which excess heat in the condenser is used for external flows, that can be connected in series or parallel. Several available low GWP refrigerants have been considered, and a multi-parameter selection analysis has been carried out. For low, medium, and high-temperature stages, R1243zf, R-1224yd(Z), and R-1233zd(E) are the best refrigerants, respectively, selected. This system is able to operate between 0 and 160 degrees C, with three heating levels at 60, 110, 160 degrees C (31.75, 21.59, and 29.92 kW, respectively) at a COP of 2.181. The total cooling capacity of the system is 45.08 kW and the total heating capacity is 83.26 kW. The MTHP concept can provide a significant carbon footprint reduction compared to natural gas boilers used in European countries.
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| 6. |
- Behi, H., et al.
(författare)
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A new concept of thermal management system in Li-ion battery using air cooling and heat pipe for electric vehicles
- 2020
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Ingår i: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 174
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the concept of a hybrid thermal management system (TMS), including air cooling and heat pipe for electric vehicles (EVs). Mathematical and thermal models are described to predict the thermal behavior of a battery module consisting of 24 cylindrical cells. Details of various thermal management techniques, especially natural air cooling and forced-air cooling TMS are discussed and compared. Moreover, several optimizations comprising the effect of cell spacing, air velocity, different ambient temperatures, and adding a heat pipe with copper sheets (HPCS) are proposed. The mathematical models are solved by COMSOL Multiphysics®, the commercial computational fluid dynamics (CFD) software. The simulation results are validated against experimental data indicating that the proposed cooling method is robust to optimize the TMS with HPCS, which provides guidelines for further design optimization for similar systems. Results indicate that the maximum module temperature for the cooling strategy using forced-air cooling, heat pipe, and HPCS reaches 42.4 °C, 37.5 °C, and 37.1 °C which can reduce the module temperature compared with natural air cooling by up to 34.5%, 42.1%, and 42.7% respectively. Furthermore, there is 39.2%, 66.5%, and 73.4% improvement in the temperature uniformity of the battery module for forced-air cooling, heat pipe, and HPCS respectively.
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| 7. |
- Behi, Hamidreza, et al.
(författare)
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Heat pipe air-cooled thermal management system for lithium-ion batteries : High power applications
- 2021
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 183
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Tidskriftsartikel (refereegranskat)abstract
- Thermal management of lithium-ion (Li-ion) batteries in Electrical Vehicles (EVs) is important due to extreme heat generation during fast charging/discharging. In the current study, a sandwiched configuration of the heat pipes cooling system (SHCS) is suggested for the high current discharging of lithium-titanate (LTO) battery cell. The temperature of the LTO cell is experimentally evaluated in the 8C discharging rate by different cooling strategies. Results indicate that the maximum cell temperature in natural convection reaches 56.8 degrees C. In addition, maximum cell temperature embedded with SCHS for the cooling strategy using natural convection, forced convection for SHCS, and forced convection for cell and SHCS reach 49 degrees C, 38.8 degrees C, and 37.8 degrees C which can reduce the cell temperature by up to 13.7%, 31.6%, and 33.4% respectively. A computational fluid dynamic (CFD) model using COMSOL Multiphysics (R) is developed and comprehensively validated with experimental results. This model is then employed to investigate the thermal performance of the SHCS under different transient boundary conditions.
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| 8. |
- Behi, Hamidreza, et al.
(författare)
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Investigation of PCM-assisted heat pipe for electronic cooling
- 2017
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 127, s. 1132-1142
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Tidskriftsartikel (refereegranskat)abstract
- Today, higher-power computer chips are available, but they generate too much heat that irreparably damages inside components. In this paper, a horizontal phase change material (PCM)-assisted heat pipe system for electronic cooling was introduced as a potential solution to this problem. A computational fluid dynamic model was developed and validated to assist the investigation. A surface temperature profile along the heat pipe was used to validate the CFD model. The liquid fraction and temperature distribution of PCM were reported during the charging process at different input powers. It was found that the PCM-assisted heat pipe provided up to 86.7% of the required cooling load in the working power range of 50-80 W. Contribution of PCM was calculated to be 11.7% of the provided cooling load and preventing heat dissipation.
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| 9. |
- Behi, Hamidreza, et al.
(författare)
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Thermal management analysis using heat pipe in the high current discharging of lithium-ion battery in electric vehicles
- 2020
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Ingår i: Journal of Energy Storage. - : Elsevier Ltd. - 2352-152X .- 2352-1538. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Thermal management system (TMS) for commonly used lithium-ion (Li-ion) batteries is an essential requirement in electric vehicle operation due to the excessive heat generation of these batteries during fast charging/discharging. In the current study, a thermal model of lithium-titanate (LTO) cell and three cooling strategies comprising natural air cooling, forced fluid cooling, and a flat heat pipe-assisted method is proposed experimentally. A new thermal analysis of the single battery cell is conducted to identify the most critical zone of the cell in terms of heat generation. This analysis allowed us to maximize heat dissipation with only one heat pipe mounted on the vital region. For further evaluation of the proposed strategies, a computational fluid dynamic (CFD) model is built in COMSOL Multiphysics® and validated with surface temperature profile along the heat pipe and cell. For real applications, a numerical optimization computation is also conducted in the module level to investigate the cooling capacity of the liquid cooling system and liquid cooling system embedded heat pipe (LCHP). The results show that the single heat pipe provided up to 29.1% of the required cooling load in the 8C discharging rate. Moreover, in the module level, the liquid cooling system and LCHP show better performance compared with natural air cooling while reducing the module temperature by 29.9% and 32.6%, respectively.
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| 10. |
- Behi, Mohammadreza, et al.
(författare)
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Evaluation of a novel solar driven sorption cooling/heating system integrated with PCM storage compartment
- 2018
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 164, s. 449-464
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Tidskriftsartikel (refereegranskat)abstract
- Recently the interest in solar thermal cooling has been growing for Air Conditioning (AC) applications. This paper presents an applied experimental and numerical evaluation of a novel triple-state sorption solar cooling module. The performance of a LiCl-H2O based sorption module (SM) for cooling/heating system with integration of an external energy storage has been evaluated. The dynamic behavior of the SM, which can be driven by solar energy, is presented. Two PCM assisted configurations of the SM have been studied herein; (i) PCM assisted sorption module for cooling applications (ii) PCM assisted sorption module for heating applications. Initially, an experimental investigation was carried out to evaluate the charging/discharging process of the SM without external energy storage. Secondly, the initial experimental configuration was modeled with a PCM integrated storage compartment. The PCM storage compartment was connected to the Condenser/Evaporator (C/E) of the SM. The temporal history of the sorption module's C/E and PCM storage, the cyclic and average performance in terms of cooling/heating capacity, cooling/heating COP, and the total efficiency were experimentally and numerically investigated. Furthermore, PCM charging/discharging power rate and solidification/melting process of the PCM in the integrated storage compartment to the SM were predicted by the model.
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