Solar PV Active and Passive Cooling Technologies - A Review

High temperature and overheating of photovoltaic panels lead to efficiency losses and eventual degradation. For solar PV systems, this is a significant impediment for achieving economic viability. In this study, a novel Window-Integrated Concentrated Photovoltaic (WICPV) system is proposed for window integration. This offers high (50%) transparency and is fabricated and characterised indoors at an irradiance of 1000 Wm−2. Its electrical performance is tested (a) without applied cooling (i.e., under natural ventilation) and (b) with a heat sink to accommodate passive cooling media. The results are compared to study the effects of reduction in operating temperature on system performances. The effectiveness of a sensible cooling medium (water) and two latent heat removal media, phase change materials (or PCMs, RT50 and RT28HC), is investigated. This paper reports the passive temperature regulation of this WICPV at ambient testing conditions. The results demonstrate an increase in electrical power output by (i) 17% (RT28HC), (ii) 19% (RT50), and (iii) 25 % (circulating water) compared with the naturally ventilated system. This shows that PCMs are considerably useful for thermal regulation of the WICPV. Any improvement in efficiencies will be beneficial for increasing electrical energy generation and reducing peak energy demands.

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Experimental Investigation of the Effect of a Combination of Active and Passive Cooling Mechanism on the Thermal Characteristics and Efficiency of Solar PV Module

Inventions ◽

10.3390/inventions6040063 ◽

2021 ◽

Vol 6 (4) ◽

pp. 63

Author(s):

Ephraim Bonah Agyekum ◽

Seepana PraveenKumar ◽

Naseer T. Alwan ◽

Vladimir Ivanovich Velkin ◽

Sergey E. Shcheklein ◽

...

Keyword(s):

Average Power ◽

Thermal Characteristics ◽

Negative Temperature ◽

Passive Cooling ◽

Rear Side ◽

Solar Pv ◽

Electrical Efficiency ◽

Pv Module ◽

Experimental Process ◽

Ultrasonic Humidifier

A photovoltaic (PV) module’s electrical efficiency depends on the operating temperature of the cell. Electrical efficiency reduces with increasing PV module temperature which is one of the drawbacks of this technology. This is due to the negative temperature coefficient of a PV module which decreases its voltage significantly while the current increases slightly. This study combines both active and passive cooling mechanisms to improve the electrical output of a PV module. A heat sink made up of aluminum fins and an ultrasonic humidifier were used to cool the panel. The ultrasonic humidifier was used to generate a humid environment at the rear side of the PV module. The cooling process in the study was able to reduce the temperature of the panel averagely by 14.61 ℃. This reduction led to a 6.8% improvement in the electrical efficiency of the module. The average power of 12.23 W was recorded for the cooled panel against 10.87 W for the referenced module. In terms of water consumption, a total of 1.5 L was approximately consumed during the whole experimental process due to evaporation. In effect, the proposed cooling approach was demonstrated as effective.

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Analytical Modeling and Optimization of a Heat Sink Design for Passive Cooling of Solar PV Panel

Sustainability ◽

10.3390/su13063490 ◽

2021 ◽

Vol 13 (6) ◽

pp. 3490

Author(s):

Fahad AlAmri ◽

Gaydaa AlZohbi ◽

Mohammed AlZahrani ◽

Mohammed Aboulebdah

Keyword(s):

Analytical Model ◽

Conversion Efficiency ◽

Heat Sink ◽

Cooling System ◽

Arid Environment ◽

Solar Panel ◽

Passive Cooling ◽

Solar Pv ◽

Solar Panels ◽

Pv Systems

High temperature is the primary challenge in the development of solar photovoltaic (PV) systems in an arid climate. A rise in temperature diminishes the performance of the PV systems and shortens their lifespan. The goal of this manuscript is to develop an analytical model to predict the temperature of PV panels under a passive cooling system for an arid environment. Taking into consideration the link between solar panel temperature and its conversion efficiency, Kirchhoff’s and Ohm’s laws for a complex circuit were applied to calculate the heat flux in the solar panel system, and hence obtain the temperatures of each layer in the system. Closed-form analytical expressions for temperature, output power, and conversion efficiency of the solar panel were deduced and presented as functions of solar irradiance, ambient temperature, emissivity, wind velocity, tilt angle, and dimensions of fins. Comparison between the results presented in the literature and those predicted by the developed analytical model validated the presented model. Moreover, the length of the fins required for safe thermal operation of solar panels in harsh desert environment were also obtained from analysis. Furthermore, the effect of using such a cooling system on the temperature and efficiency of the solar panels was verified by using the developed model under real conditions in Dammam city during summer and winter seasons. The results showed that the optimized heat sink could raise the solar panel power by 8.7% during summer and by 6.5% during winter.

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Impact of roof shading on building energy performance in warm & humid climatic places of India

iCRBE Procedia ◽

10.32438/icrbe.202037 ◽

2020 ◽

pp. 50-64

Author(s):

Kuladeep Kumar Sadevi ◽

Avlokita Agrawal

Keyword(s):

Energy Consumption ◽

Energy Conservation ◽

Energy Performance ◽

General Assumption ◽

Climatic Conditions ◽

Building Envelope ◽

Passive Cooling ◽

Base Case ◽

U Value ◽

The Impact

With the rise in awareness of energy efficient buildings and adoption of mandatory energy conservation codes across the globe, significant change is being observed in the way the buildings are designed. With the launch of Energy Conservation Building Code (ECBC) in India, climate responsive designs and passive cooling techniques are being explored increasingly in building designs. Of all the building envelope components, roof surface has been identified as the most significant with respect to the heat gain due to the incident solar radiation on buildings, especially in tropical climatic conditions. Since ECBC specifies stringent U-Values for roof assembly, use of insulating materials is becoming popular. Along with insulation, the shading of the roof is also observed to be an important strategy for improving thermal performance of the building, especially in Warm and humid climatic conditions. This study intends to assess the impact of roof shading on building’s energy performance in comparison to that of exposed roof with insulation. A typical office building with specific geometry and schedules has been identified as base case model for this study. This building is simulated using energy modelling software ‘Design Builder’ with base case parameters as prescribed in ECBC. Further, the same building has been simulated parametrically adjusting the amount of roof insulation and roof shading simultaneously. The overall energy consumption and the envelope performance of the top floor are extracted for analysis. The results indicate that the roof shading is an effective passive cooling strategy for both naturally ventilated and air conditioned buildings in Warm and humid climates of India. It is also observed that a fully shaded roof outperforms the insulated roof as per ECBC prescription. Provision of shading over roof reduces the annual energy consumption of building in case of both insulated and uninsulated roofs. However, the impact is higher for uninsulated roofs (U-Value of 3.933 W/m2K), being 4.18% as compared to 0.59% for insulated roofs (U-Value of 0.33 W/m2K).While the general assumption is that roof insulation helps in reducing the energy consumption in tropical buildings, it is observed to be the other way when insulation is provided with roof shading. It is due to restricted heat loss during night.

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A tes

Indonesian Journal of Energy ◽

10.33116/ije.v1i3.27 ◽

2018 ◽

Vol 1 (3) ◽

Author(s):

IJE Manager

Keyword(s):

Energy Supply ◽

Fossil Fuels ◽

Geographical Location ◽

Weather Conditions ◽

Past Century ◽

Solar Pv ◽

Pv Systems ◽

Trade Offs ◽

A Site ◽

Selection Methodology

In the past century, fossil fuels have dominated energy supply in Indonesia. However, concerns over emissions are likely to change the future energy supply. As people become more conscious of environmental issues, alternatives for energy are sought to reduce the environmental impacts. These include renewable energy (RE) sources such as solar photovoltaic (PV) systems. However, most RE sources like solar PV are not available continuously since they depend on weather conditions, in addition to geographical location. Bali has a stable and long sunny day with 12 hours of daylight throughout the year and an average insolation of 5.3 kWh/m2 per day. This study looks at the potential for on-grid solar PV to decarbonize energy in Bali. A site selection methodology using GIS is applied to measure solar PV potential. Firstly, the study investigates the boundaries related to environmental acceptability and economic objectives for land use in Bali. Secondly, the potential of solar energy is estimated by defining the suitable areas, given the technical assumptions of solar PV. Finally, the study extends the analysis to calculate the reduction in emissions when the calculated potential is installed. Some technical factors, such as tilting solar, and intermittency throughout the day, are outside the scope of this study. Based on this model, Bali has an annual electricity potential for 32-53 TWh from solar PV using amorphous thin-film silicon as the cheapest option. This potential amount to three times the electricity supply for the island in 2024 which is estimated at 10 TWh. Bali has an excessive potential to support its own electricity demand with renewables, however, some limitations exist with some trade-offs to realize the idea. These results aim to build a developmental vision of solar PV systems in Bali based on available land and the region’s irradiation.

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