Water spray cooling technique applied on a photovoltaic panel: The performance response
Introduction
Photovoltaic (PV) technology [1] is widely used today in different applications [2], [3], [4] but due to relatively high initial investments and low overall efficiency, the number of installed capacities is lower than expected. The second major problem of the commercial PV technology is its cleaning issue, i.e. dust impact and other particles accumulated on the front PV panel surface that can significantly reduce the amount of delivered electricity (in some cases reduction can go up to 30%). The previously mentioned issues (facts) can be overbridged through the improvement of existing market available technologies or through development of novel PV technologies. One possible option is to provide an increase in panel electrical efficiency along with solving its cleaning issue and aiming to develop feasible cooling techniques for the PV panel.
Even though novel PV technologies are currently under research and more efficient PV technologies are bound to be discovered (it is just matter of time), their expected market price will probably be too high for current market capabilities, so a wider market implementation can be questionable long term. A second possible option, besides the development of novel PV technologies, is to modify and upgrade existing available PV technologies.
It is well known that electrical efficiency in PV systems can be improved if panel temperature is reduced. This problem has been thoroughly studied in past years through the development of different cooling techniques. For the current market available PV technologies, electrical efficiency degradation is due to the rise of panel temperature which ranges from 0.25%/ °C up to 0.5%/° (depending from the specific PV technology used), so possible electrical efficiency improvement can be obtained with a proper cooling technique and keeping in mind that each cooling technique should have proven feasibility.
The objective of this paper was to develop an experimental setup and to investigate a water spray cooling technique, implemented simultaneously on the front and back side of a PV panel as well as other different water spray cooling circumstances to ensure gained result comparison and to offer an optimal cooling solution (regime). The proposed water spray cooling technique can potentially increase PV panel performance due to an evaporation and self-cleaning effect, which is also a great benefit in terms of improved feasibility in the long run.
Section snippets
Brief overview of the previous research findings regarding PV cooling techniques
The previous research work focused on different designs and experimental validation in cooling strategies for PV panels, to investigate their influence on overall efficiency and also to investigate specific energy losses in PV systems [5], [6]. In the majority of the proposed cooling techniques, water was used as a coolant and cooling was implemented on the front or backside of the PV panel. For example, in [7] authors investigated the effect of evaporative cooling implemented on PV panels and
The system configuration description
According to Fig. 1, an experimental configuration was assembled from a flat PV monocrystalline module of 50 W nominal maximal power with an effective surface of 0.31 m2. The examined panel’s general characteristic is specified in Table 1. The panel was equipped with a system of nozzles mounted on the PV panel front and rear sides to ensure proper water spray distribution on both sides of the PV panel.
The panel was fixed under a specific angle of 17° (to obtain the highest electricity output for
General circumstances
The panel was tested on a geographical location with a Mediterranean climate (city of Split situated on the coastal side of Croatia) on a typical clear summer day where average temperatures of the surrounding air ranged from 27 °C and up to 30 °C. Measurements were provided from 11 am to 14 pm (period of highest solar irradiation levels during June). During the series of measurements, irradiation ranged from 810 W/m2 to 850 W/m2, in the already mentioned period of highest solar irradiation (specific
Conclusions
In this paper, a water spray cooling technique was proposed and experimentally tested on a monocrystalline photovoltaic panel for different cooling circumstances (regimes). The best cooling option turned out to be simultaneous cooling of front and backside PV panel surfaces. The gained experimental results (i.e. performance response) are summarized and briefly presented in Table 4, depending from different cooling regimes in the circumstances of highest solar irradiation levels.
In Table 4, we
References (38)
Solar power generation by PV (photovoltaic) technology: a review
Energy
(2013)- et al.
Photovoltaic modules and their applications: a review on thermal modelling
Appl Energy
(2011) - et al.
Experimental study on a hybrid energy system with small-and medium-scale applications for mild climates
Energy
(2014) - et al.
Energy efficiency evaluation of a hybrid energy system for building applications in a Mediterranean climate and its feasibility aspect
Energy
(2015) Effects of evaporative cooling on efficiency of photovoltaic modules
Energy Convers Manage
(2014)- et al.
Performance evaluation of a PV (photovoltaic) module by back surface water cooling for hot climatic conditions
Energy
(2013) - et al.
Performance analysis of water cooled concentrated photovoltaic (CPV) system
Renew Sustain Energy Rev
(2012) - et al.
Enhancing the performance of photovoltaic panels by water cooling
Ain Shams Eng J
(2013) Increased electrical yield via water flow over the front of photovoltaic panels
Sol Energy Mater Sol Cells
(2004)- et al.
Energy and thermo-fluid-dynamics evaluations of photovoltaic panels cooled by water and air
Sol Energy
(2014)
Using a wind driven ventilator to enhance a photovoltaic cell power generation
Energy Build
An active cooling system for photovoltaic modules
Appl Energy
Improved PV/T solar collectors with heat extraction by forced or natural air circulation
Renewable Energy
Global analysis of photovoltaic energy output enhanced by phase change material cooling
Appl Energy
Submerged photovoltaic solar panel: SP2
Renewable Energy
Experimental study on a hybrid photovoltaic/heat pumps system
Appl Therm Eng
Experimental investigation on the photovoltaic-thermal solar heat pump air conditioning system on water-heating mode
Exp Thermal Fluid Sci
Experimental study of a photovoltaic solar-assisted heat-pump/heat-pipe system
Appl Therm Eng
Solar hybrid air-conditioning system for high temperature cooling in subtropical city
Renewable Energy
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