Reduction In Cell Temperature Research Articles

Year-round experimental analysis of a water-based PVT-PCM hybrid system: Comprehensive 4E assessments

In this year-long study conducted in Cairo, Egypt, an innovative water-based photovoltaic-thermal (PVT) system coupled with phase change material (PCM) was evaluated for its ability to enhance building energy efficiency. The system utilizes 22 copper capsules filled with RT35 paraffin wax and a water-cooling duct to ensure optimal electricity generation and heat storage. The proposed system underwent detailed 4E (energy, exergy, economic, and environmental) assessments to compare its performance against traditional uncooled PV panels. The results indicated significant improvements: a reduction in cell temperature by up to 8.3 °C, an increase in electrical efficiency by 4.0–13.3%, and a boost in power output by 4.1–15.9%. Overall, the system demonstrated efficiencies between 27.23 and 67.33%, along with an exergy efficiency peak at 74.64% in July, substantially outperforming the uncooled panel. Economically, the PVT-PCM system achieved a 1.58-year payback period, and carbon emissions were reduced by 32%, highlighting its viability and environmental benefits. The potential of the PVT-PCM system to advance sustainable building energy management was strengthened by this study, providing a significant step forward in integrating renewable energy within architectural designs.

Temperature Reduction as Operando Performance Recovery Procedure for Polymer Electrolyte Membrane Fuel Cells

To efficiently mitigate the reversible performance degradation of polymer electrolyte membrane fuel cells, it is crucial to thoroughly understand recovery effects. In this work, the effect of operando performance recovery by temperature reduction is evaluated. The results reveal that operando reduction in cell temperature from 80 °C to 45 °C yields a performance recovery of 60–70% in the current density range below 1 A cm−2 in a shorter time (1.5 h versus 10.5 h), as opposed to a known and more complex non-operando recovery procedure. Notably, the absolute recovered voltage is directly proportional to the total amount of liquid water produced during the temperature reduction. Thus, the recovery effect is likely attributed to a reorganization/rearrangement of the ionomer due to water condensation. Reduction in the charge transfer and mass transfer resistance is observed after the temperature reduction by electrochemical impedance spectroscopy (EIS) measurement. During non-operando temperature reduction (i.e., open circuit voltage (OCV) hold during recovery instead of load cycling) an even higher recovery efficiency of >80% was achieved.

INVESTIGATION OF HYBRID PHOTOVOLTAIC /THERMAL SOLAR SYSTEM PERFORMANCE UNDER IRAQ'S CLIMATE CONDITIONS

The research investigates the use of fins fastened to a solar panel's rear surface for passive cooling. The research compared solar modules with air cooling against modules with connected fins acting as a heat sink. The comparison was based on the former. The research studies the cooling of modules with fins using two different types of air: ventilation air and still air. By comparing the heat transmission by photovoltaic panels with and without fins, the research sought to analyses the effects of the environment and solar radiation on the performance of solar cells. The inquiry was done hypothetically. According to the findings, using fins for cooling reduced cell temperature and improved electrical and thermal efficiency. The estimated performance values of the PVT solar cell obtained by using the COMSOL program and the experimental measurements carried out during the daytime were reasonably in accord. The biggest reduction in cell temperature is (3.7ºC at noon), while the greatest increases in electrical and thermal efficiency are (16.54% and 58.3%, respectively). There is good agreement between experimental and numerical results.

Performance investigation of a hybrid PV/T collector with a novel trapezoidal fluid channel

The photovoltaic-thermal collector (PV/T) is an innovative technology that combines PV cells and solar thermal collectors into a co-generation unit, enabling full-spectrum solar utilization. This research proposes and examines a hybrid PV/T system with novel trapezoidal fluid channels embedded in graphite, arranged in a parallel S-shaped structure under outdoor conditions of Beijing. Parametric discussions and daily performance analysis are conducted to assess its effectiveness and stability. A daily average of 12.7 °C reduction in cell temperature compared to PV modules results in a relative 5.20 % improvement in electrical output under the intensity of solar radiation is 597 W/m2. Similarly, the peak temperature of the water tank reaches 56.9 °C, and thermal efficiency is enhanced by 7.86 % over conventional sheet-tube PV/T collectors. For further optimization, a constrained adaptive particle swarm optimization algorithm (EPF-APSO) is constructed based on the experimental data, implementing a variable water flow rate (VWV) strategy. Compared to a constant water flow rate (CWV), the overall energy collected varies from 2.755 to 2.828 kWh per day, potentially reducing pump energy consumption by 17.93 %. The contribution of this paper provides references on structural and operational parameters optimization of PV/T collectors applying machine learning algorithms for better comprehensive efficiency.

PV thermal regulation and water harvesting hybrid system using evaporative cooling of silica gel layer

A proposed system for a passive cooling technique of photovoltaic (PV) via desorption cooling and water harvesting using a silica gel layer is investigated numerically. The harvested water is discussed, and the performance of the desorption-cooled PV is compared with the naturally cooled PV cell. The silica gel layer provides the water needed for evaporative cooling, so the proposed system can be used where water does not exist. The system model is presented, solved using MATLAB, and validated. The impact of the ambient conditions (ambient temperature and relative humidity), solar intensity, and silica gel layer thickness on the PV performance and silica gel uptake are presented for constant conditions and transient input weather conditions. The findings show a considerable reduction in the cell temperature and an enhancement in the cell efficiency. Also, The harvested water quantities are obtained at different operating conditions and layer thicknesses. At constant input conditions, a maximum reduction in the average PV cell temperature of 16.18 °C and an efficiency enhancement of 8.76% are achieved using a silica gel layer of 1 cm thickness. In addition, the maximum harvested water is reported as 1.238 kg/m2 for 2 cm layer thickness. For transient input weather conditions, the same performance enhancement with a reduced daily average cell temperature of 7 °C and an efficiency enhancement of 4.8% is achieved at the different silica gel layer thicknesses during 13 hr of simulation. Also, the maximum harvested water is reported as 2.35 kg/m2 for 3 cm thickness. Increasing the silica gel layer thickness influences the cell performance adversely under constant operating conditions, while this effect vanishes for actual transient input weather conditions. In contrast, increasing the thickness layer can increase the harvested water, which depends on the incident flux.

Performance analysis of the solar photovoltaic thermal system using phase change material

This study presents the experimental analysis of photovoltaic thermal system and calculations for percentage electrical efficiency gained and thermal energy. Photovoltaic cells are sensitive to temperature and its performances decrease with increasing temperature. To increase the performance of the photovoltaic panel, a phase change material cum water heating arrangement is attached to the photovoltaic panel. To reduce the cell temperature, paraffin wax (phase change material) is used in the experiment as a heat storage medium. A copper tube is attached to the containment box filled with phase change material. Water is heated through paraffin wax when it flows through the copper tube. The photovoltaic thermal system has a dual benefit over photovoltaic system i.e. it improves electrical efficiency and produces thermal energy simultaneously. It was concluded from the experimental work that percentage of electrical efficiency gained from the photovoltaic thermal system is 1.12% in comparison with polycrystalline silicon photovoltaic panel of model DDS50M at ambient temperature. The maximum reduction in cell temperature and the average thermal energy produced is 8.5°C and 25.45 J/min respectively.

Numerical investigation on the effect of different parameters in enhancing heat transfer performance of photovoltaic thermal systems

Abstract Photovoltaic thermal (PV/T) collectors that supply both electricity and heat are growingly becoming popular in household and other applications. However, efficient heat removal from backside of PV module is still a challenge that hampers its electrical as well as thermal performance. In the present research, an absorber-plate less thermal collector has been introduced and mathematical model of such a PV/T system has been developed, which is employed in COMSOL Multiphysics® software to simulate the heat transfer phenomenon in the system. Effect of different flow parameters on heat transfer and PV/T performance is thus studied numerically in the developed simulation model. Also, the effect of irradiation level and depth of the flow channel has been examined on the thermal as well as electrical performance of the module. Results reveal that PV/T electrical and thermal efficiency increase with both of Reynolds and Prandtl number. Heat transfer rate is observed to increase as high as 25.5% with increasing Reynolds number. A maximum reduction in cell temperature of 10.2 °C is obtained by increasing the channel depth. Elimination of absorber plate from thermal collector simplified the design reducing its weight and cost as well.

Performance enhancement of concentrated photovoltaic systems using a microchannel heat sink with nanofluids

A new cooling technique for low concentrated photovoltaic–thermal (LCPV/T) systems is developed using a microchannel heat sink with nanofluids. In this study, Aluminum Oxide (Al2O3)–water and Silicon Carbide (SiC)–water nanofluids with different volume fractions are used as cooling mediums. The influence of cooling mass flow rate and nanoparticles volume fractions on the performance of LCPV/T system is investigated at different values of concentration ratio. A comprehensive model is developed which includes a thermal model for the photovoltaic layers, coupled with thermo-fluid dynamics of two-phase flow model of the microchannel heat sink. The model is numerically simulated to estimate the performance parameters such as the solar cell temperature and the electrical and thermal efficiency. Results indicate that a significant reduction in solar cell temperature is attained particularly at the high concentration ratio by using nanofluids compared to using water. Using SiC–water nanofluid achieves a relatively higher reduction in cell temperature than Al2O3–water nanofluid. By increasing the volume fraction of nanoparticles, both SiC–water and Al2O3–water nanofluids accomplish a major reduction of cell temperature. As a result, the use of nanofluids achieves higher solar cell electrical efficiency, particularly at lower Reynolds number (Re) and higher concentration ratio, than the use of water. The influence of nanofluids on thermal efficiency varies according to the concentration ratio. Furthermore, friction power increases with the increase in both Reynolds number and nanoparticle volume fraction. By increasing the volume fraction of the nanoparticle, the net electrical power increases at high concentration ratio while the thermal power decreases. The results of this study indicate that the use of nanofluids is effective cooling technique, particularly at high solar concentration ratios where the solar cell temperature reduces to 38°C, and electrical efficiency improves up to 19%.