Effect of Nanofluids on PV/T System’s performance.
Abstract
Mounting temperature impedes the conversion efficiency of photovoltaic systems. Studies have shown drastic efficiency escalation of PV modules, if cooled by nanofluids. Ability of nanofluids to supplement the efficiency improvement of PV cells has sought attention of researchers. This chapter presents the magnitude of improved efficiency found by different researchers due to the cooling via nanofluids. The effect of factors (such as, nanoparticle size, nanofluid concentration, flowrate of nanofluid and geometry of channel containing nanofluid) influencing the efficiency of PV systems has been discussed. Collective results of different researchers indicate that the efficiency of the PV/T systems (using nanofluids as coolant) increases with increasing flowrate. Efficiency of these systems increases with increasing concentration of nanofluid up to a certain amount, but as the concentration gets above this certain value, the efficiency tends to decline due to agglomeration/clustering of nanoparticles. Pertaining to the most recent studies, stability of nanoparticles is still the major unresolved issue, hindering the commercial scale application of nanofluids for the cooling of PV panels. Eventually, the environmental and economic advantages of these systems are presented.
Keywords
- PV systems
- Nanofluids
- efficiency
- concentration
- Flowrate
- stability
1. Introduction
Exceeding energy demands and swiftly eliminating conventional energy resources have compelled the researchers to find the alternative means of power generation. To date, only 14% of the world’s power demands are being met via renewable energy means. Sun is the most vital source of energy, almost
There are several methods of PV cooling such as, air cooling (natural air circulation and forced air circulation), water cooling, heat pipe cooling, cooling with Phase Change Materials (PCMs) and cooling via nanofluids [10, 11]. A PV/T system consists of PV module coupled with a heat absorbing unit in which a liquid (water or nanofluid) is circulated to absorb the heat of PV unit to improve the efficiency. The researches show that a PV/T system performs way better than conventional PV systems [12, 13]. Lelea et al. [14] investigated the effect of cooling via
Mixture of solid particles (metallic oxides, metals or carbon nanotubes) of less than 100 nm size at least in one dimension (nanoparticles) disseminated in the liquid fluids like water and polyethylene glycol etcetera (base fluid), is known as nanofluid. Nanofluids can be employed as a coolant as well as optical filters within PV/T systems [15]. PV/T system using nanofluid as coolant can produce far better results than the water cooled system. Al-Waeli et al. [16] conducted an experimental study and they found that cooling of PV module via SiC increased the electrical efficiency by 24.1%, thermal efficiency by 100.19% and overall efficiency by 88.9% as compared to the water-cooled PV/T system. Xu and Kleinstreuer [17] suggested nanofluid based silicon PV/T systems as a useful option for domestic applications as its overall efficiency reached up to 70% (11% electrical efficiency and 59% thermal efficiency).
This chapter reviews the efficiency of PV systems being cooled by various nanofluids. The common ways of cooling PV system via nanofluids are stated in detail along with the parameters influencing the efficiency of the PV/T systems such as irradiance, concentration and flow rate of nanofluid, size of nanoparticles and geometry of micro-channels. Impact of other factors such as the type of nanoparticles and base fluid on the system efficiency are discussed. Eventually, economic and environmental advantages are described.
2. Methods of cooling of PV systems via nanofluids
There are several methods of extracting heat from the PV units via nanofluids. The most common ways are, employing heat collector at the rear end of the panel and using nanofluid as a liquid in spectral splitting filter joined on the front surface of PV module. Sometimes, both methods are used simultaneously in order to increase the efficiency.
2.1. Rear end cooling
In rear-end cooling a thermal collector is coupled at the back end of the PV module to extract the heat. Nanofluid is set to flow through the collector thus taking up the heat of the cells and increasing its own temperature. Nanofluid gets warmed and its heat is further employed for useful purposes. Nanofluid is able to extract major part of the heat energy because of its improved thermophysical properties. The most important thermophysical property is the thermal conductivity. A schematic display of such an arrangement is depicted in the Figure 1.
Energy balance of such PV/T systems is evaluated by the following equation by [19].
Here,
Here,”r” is the packing factor.
Here,
Area of PV to produce a certain amount of electrical power is calculated by the following formula.
Here,
Thermal output energy is found by the following equation.
Here,
Electrical efficiency is found by the following formula.
Here,
Using the aforementioned formulas, the efficiency of a PV/T system is determined.
Radwan et al. [20] examined the cooling effect of
2.2. Optical filter cooling
Extensive work has been carried out on efficiency improvement by using nanofluid flowing through optical filters [21, 22]. Silicon-based Photovoltaic cells can generate electricity by absorbing the part of solar radiation with 400 nm to 1200 nm wavelength. Rest of the solar radiation’s part is either reflected back or absorbed by the PV cells as heat. In optical filter cooling, an optical filter containing nanofluid is held above the front surface of cells to split the spectrum of radiation. Nanofluid-based optical filters separate the part of solar radiation for the PV cells from the radiation part that is more useful for heat generation. There are two kinds of proposed configurations of these systems.
Single Pipe System
Two Pipe System
In single pipe system, there are two sections of pipe; primary section and secondary section. Primary section is set underneath the rear surface of the Photovoltaic module having aluminum sheet in between. Primary section further elongates above the upper surface of PV module. Nanofluid enters from the inlet of primary section, thus, absorbing heat of the module. Heated nanofluid further passes over the PV’s upper surface, in turns filtering the solar radiation. Part of radiation having wavelength equal to silicon bandgap is filtered and rest of the section is absorbed by the nanofluid flowing in the secondary channel which gets out of the secondary pipe at secondary outlet. Air exists between upper surface of PV module and secondary channel section. As the air gets hot, it flows in upward direction and the cool air still remains in contact with PV surface. It is assumed that no convection current is produced in the air. The results indicated, 83% and 80% overall and 76.5% and 74% thermal efficiency for Ag/water and Cu/water nanofluid respectively for above configuration [23]. Schematic diagram of such system is shown in the following Figure 2.
Wei An et al. [24] designed a spectral splitting Polypyrrole nanofluid based PV/T system in order to impede thermal losses and escalate the system’s efficiency. Nanofluid used in spectral splitting filter is capable to absorb the part of solar radiations that cannot be utilized by PV cell and converts it into medium temperature thermal energy. The efficiency of PV/T system was found to be 25.2% for nanofluid based spectral splitting filter whereas, its value was 13.3% when there was no filter employed. Hjerrild et al. [25] worked on the cooling of PV system by the help of optical filters, they used Silver as nanoparticle (50 nm diameter) with coating of Silica. The results showed that, base fluid absorbed the ultraviolet part of solar radiation thus decreasing the heat losses whereas, nanoparticles absorbed visible portion of radiation, in turns increasing the overall efficiency of the system. Water showed highest electrical efficiency (85% higher than unfiltered PV) whereas highly diluted nanofluid (
An arrangement in which nanofluids flows in separated channels outperforms the single channel through which the nanofluid is set to flow. In this arrangement a channel is placed underneath the rear surface of PV panel whereas, a separate channel is held above the front surface of the module. Upper channel nanofluid is made to achieve high liquid filter performance whereas the nanofluid flowing beneath the surface achieves higher thermal performance (working as a coolant). This technique achieved 8.5% higher electrical efficiency as compared to the double pass channel in which fluid flows in a single channel [29].
3. Efficiency improvement using nanofluid
Integrating the heat receivers with the conventional PV system is found to elevate both electrical and thermal efficiencies. Several fluids such as water or nanofluids can be used in these receivers to remove heat so as to improve the efficiency of the system. Studies have proved that nanofluid based PV/T system outperforms conventional PV system and water-based PV/T system. Soltani et al. [30] used five different methods for PV cooling (natural cooling, forced air cooling, water cooling,
Gangadevi et al. [35] experimentally examined that the electrical, thermal and overall efficiency of PV module being cooled by Al2O3/water nanofluid got increased by 13%, 45% and 58% respectively as compared to water based and 1 wt% Al2O3 nanofluid based cooling. Mustafa et al. [36] numerically tested the effect of mass flowrate and concentration of nanofluid (TiO2/water) on the efficiency of PV/T system. As per the results, electrical and thermal efficiency of this system is linearly proportional to mass flowrate. Best results are obtained at low concentration of nanofluid.
Electrical, thermal and overall efficiencies of the various PV/T systems working with different nanofluids is expressed in the Table 1.
Authors | Nanoparticle | Base Fluid | Concentra-tion | Flowrate | Module Type, Irradiation (W/m2) | Ambien Temp | Module Temp | Electrical Efficiency | Thermal Efficiency | Overall Efficiency | |
---|---|---|---|---|---|---|---|---|---|---|---|
Energy | Exergy | ||||||||||
A | SiC | Deionized Water | 3 wt% | — | — | — | — | 100.19% Increase compared to Water Cooled PV System | 24.1% increase compared to Water Cooled PV System | 88.9% increase compared to conven-tional PV | — |
No Cooling | — | — | — | 845.42, Monocry-stalline | — | — | — | — | 10.90% | ||
— | Deionized Water | — | — | — | — | — | — | 12.23% | |||
ZnO | Deionized Water | — | — | 10°C Reduction compared to conventional PV | — | — | — | 12.29% | |||
— | PCM + Deionized water | — | — | 6°C Reduction compared to conventional PV | — | — | — | 13.17% | |||
PCM + ZnO | Deionized Water | — | — | — | — | — | — | 13.42% | |||
— | Water | — | — | Silicon Crystalline PV Module | — | — | — | — | 3.051% increase compared to natural cooling | — | |
Fe3O4 | Water | 0.5 wt.% | — | — | — | — | 3.13% increase compared to natural cooling | — | |||
SiO2 | Water | 0.5 wt.% | — | — | — | — | 3.35% increase compared to natural cooling | — | |||
— | — | — | — | 1000, Monocry-stalline | — | 79.1 °C | 8% | — | — | — | |
Al2O3 | Water | 0.30wt.% | 0.2 L/s | 42.2 °C | 12.10% | 34.40% | — | — | |||
— | Water | — | 5000 ml/min | 750, Monocrystalline | — | 16.58% Decrease compare to conventional PV | .61% Increase compared to conventional PV | — | — | — | |
Ti2O3 | Water-polyethylene glycol | 0.1 wt% | 5000 ml/min | 22.9%% Decrease compare to conventional PV | 0.82% Increase compared to conventional PV | — | — | — | |||
ALOOH-XH2O | Water | 0.01 wt.% | 300 ml/min | 1000 Monocry-stalline | 25°C | Decrease from 62°C to 32.5°C | 27.12% Increase compared to conventional PV | — | — | — | |
No Cooling | — | — | — | 855, Monocrystalline | 33°C | — | — | — | 11%, | 11.53% | |
— | Deionized Water | — | 30L/h | — | 8.2% Increase compared to conventional PV | 35.60% | 47.20% | 13.54% | |||
SiO2 | Water | 1 wt% | — | — | 9.01% Increase compared to conventional PV | — | 49.80% | 13.85% | |||
SiO2 | Water | 3 wt.% | — | — | 9.75% Increase compared to conventional PV | — | 52.40% | 14.02% | |||
TiO2 | Deionized Water | 0.2 wt.% | 30 kg/h | 917 Monocrystalline | 33.4 °C | 11.48°C Reduction as compared to Conventional PV | 6.54% Increase compared to conventional PV | — | — | — | |
ZnO | 0.2 wt.% | 30 kg/h | 11.85°C Reduction as compared to Conventional PV | 6.46% Increase compared to conventional PV | — | — | — | ||||
Al2O3 | 0.2 wt.% | 30 kg/h | 11.03°C Reduction as compared to Conventional PV | 6.36% Increase compared to conventional PV | — | — | — | ||||
Boehmite (ALOOH-xH2O) | Water | 0.1 wt.% | 200 ml/min | — | — | 21.6°C Reduction compared to without cooling | 21.87% Increase compared to without cooling | — | — | — | |
No cooling | — | — | — | Monocrystalline | –– – | — | 11.31% | — | — | — | |
— | Water | — | 0.02 kg/s | — | 12.42% | 18.43% | — | — | |||
CuTiO2 | Water | 0.2 wt.% | 0.02 kg/s | — | 12.87% | 19.50% | — | — | |||
— | Water | — | 0.167 kg/s | 1000 Polycrystalline | 30 °C | Decreased from 87–57°C | 11.40% | — | — | — | |
SiC | Water | 1 wt.% | 0.167 kg/s | Decreased from 87–41°C | 12.75% | 85% | 97.75% | — | |||
TiO2 | Water | 1 wt.% | 0.167 kg/s | Decreased from 87–45°C | 12.30% | — | — | — | |||
SiO2 | Water | 1 wt.% | 0.167 kg/s | Decreased from 87–50 °C | 11.80% | — | — | — | |||
Al2O3 | Water | 10 wt% | 30 kg/h | Monocrystalline | — | — | 6.23% Increase compared to pure water | — | — | — | |
TiO2 | Water | 10 wt% | 30 kg/h | — | — | 6.02% Increase compared to pure water | — | — | — | ||
ZnO | Water | 10 wt.% | 30 kg/h | — | — | 6.88% Increase compared to pure water | — | — | — | ||
SiO2 | Water | 10 wt.% | 30 kg/h | — | — | 5.77% Increase compared to pure water | — | — | — | ||
— | Deionized Water | — | 0.026 kg/s | Polycrystalline PV Module | — | — | 8.5% Increase compared with conventional PV system | — | — | — | |
Silver with 1 vol.% potassium oleate surfactant | Deionized Water | 0.5 vol.% | 0.026 kg/s | — | — | 0.9% Increase compared to water cooled system | — | — | — | ||
No Cooling | — | — | — | 917 Monocrystalline | 34.42°C | — | 12.73% | — | 12.73% | 10.29% | |
— | Water | 0.2 ey% | 30 kg/h | 11% decrease compared to conventional PV | 13.41% | 34.12% | 47.53% | 11.56% | |||
ZnO | Water | 0.2 wt% | 30 kg/h | 11.85% decrease compared to conventional PV | 13.59% | 46.05% | 59.64% | 12.17% | |||
TiO2 | Water | 0.2 wt% | 30 kg/h | 11.48% Decrease compared to conventional PV | 13.63% | 44.34% | 57.97% | 11.93% | |||
Al2O3 | Water | 0.2 wt% | 30 kg/h | 11.03% Decrease compared to conventional PV | 13.44% | 36.66% | 50.10% | 11.88% | |||
No Cooling | — | — | — | — | — | — | 8.98% | — | — | — | |
— | Water | — | 0.01 kg/s | Without Glazing | — | — | 8.77% | 19.36% | — | — | |
— | — | 0.01 kg/s | With Glazing | — | — | 6.40% | 21% | — | |||
CuO | Water | 0.05% | 0.01 kg/s | Without Glazing | — | — | 7.62% | 28.22% | — | — | |
Water | 0.05% | 0.01 kg/s | With Glazing | — | — | 6.18% | 30.43% | — | — | ||
— | — | — | — | — | 25°C | 68.3°C | 7.11% | — | — | — | |
— | Water | — | 0.175 kg/s | — | 45.22°C | 9.92% | 35.40% | — | — | ||
— | PCM + Water | — | 0.175 kg/s | — | 42.22°C | 12.32% | 50.50% | — | — | ||
PCM + SiC | Water | — | 0.175 kg/s | — | 39.52°C | 13.70% | 72% | — | — | ||
No Cooling | — | — | — | — | — | 46.9 | 10.04% | — | — | — | |
— | Water | — | — | — | 25.47 | 11.20% | — | — | — | ||
Al2O3 | 0.4 wt.% | — | — | 22.67 | 12.06% | — | — | — | |||
No Cooling | — | — | — | 48.49 | 12.57% | — | — | — | |||
— | — | — | — | 24.93 | 11.39% | — | — | — | |||
CuO | 0.6 wt.% | — | — | 22.13 | 10.23% | — | — | — |
Efficiency enhancement of PVT systems being cooled by the nanofluids is due to the enhanced thermal conductivity of the nanofluids. Increase in thermal conductivity is dependent on concentration, size and type of the nanoparticle [4].
4. Factors affecting efficiency of nanofluid-based PV/T systems
Various factors such as the concentration of nanofluid, flowrate of nanofluid, size of the nanoparticle, geometry of microchannel, type of base fluid and irradiance influence the efficiency of nanofluid-based PV/T system. Effects of these factors are discussed in the subsequent sections.
4.1. Irradiance
Increase in irradiance cause the module temperature to escalate as more heat reaches the surface. Khanjari et al. [2] investigated environmental parameters that affect the efficiency of a PV/T system cooled by nanofluids (
4.2. Concentration
Researchers have found contradictory results when it comes to concentration enhancement of nanofluids. Manikandan and Rajan [39] harnessed sand for the cooling of PV/T system in order to enhance the efficiency. They tested 0.5, 1 and 2 vol% concentration and the collection efficiency ratio for these concentrations was found to be 3.6%, 11.2% and 26.9% whereas the solar collection efficiency increased by 9% and 16.5% for 0.5% and 2% respectively. Sardarabadi and Fard [40] also examined that increasing the mass fraction of nanoparticles from 0.05 to 10 wt%, the thermal performance of the system increased by four times. Wei An. [24] examined the effect of nanofluid concentration in spectral splitting filter based PV/T system. They observed that increasing the concentration of the nanofluid increased the nanofluid temperature and system’s electrical efficiency, but the thermal efficiency gets decreased in this way.
The maximum overall efficiency of the system was found to be 75.93% and 80.58% when the ferrofluid concentration was increased from 1 wt% to 3 wt% respectively [37]. Khanjari et al. [41] observed that increasing volumetric concentration of the nanoparticle (from 1–5%) increased the heat transfer coefficient and thus the overall efficiency (from 1.33% to 11.54% for silver and 0.72% to 4.26% for alumina). Radwan et al. [20] observed efficiency escalation with increasing concentration. But some researchers witnessed contradictory results. Karami and Rahimi [34] examined that increasing concentration of nanoparticles reduces the efficiency because of agglomeration or clustering of the suspended particles. Abd-Allah, [42] found best results at 0.1 wt% amongst (0.01, 0.1, 0.5 wt%).
Cieslinski et al. [43] found no impact of nanoparticle concentration on the performance of the PV/T system. They observed that 1 wt% of
In order to obtain best results, there is always a need to determine the optimum concentration of nanoparticles in base fluid instead of using high volume fraction of nanofluid [43, 44]. However, instead of increasing the concentration of the same kind of nanoparticle, blending a different kind of nanoparticles can help improve the efficiency of PV module in a more efficient way [45].
4.3. Flowrate
Sathieshkumar et al. [46] concluded that both electrical and thermal efficiency of the PV/T system increases with increasing flow rate but after a certain flowrate magnitude the efficiencies of the system start to decline. Overall energy efficiency is found to be higher in turbulent regime whereas overall exergy efficiency is higher in laminar regime [47]. Mustafa et al. [36] numerically tested the effect of mass flowrate and concentration of nanofluid (TiO2/water) on the efficiency of PV/T system. As per the results, the electrical and thermal efficiency of this system was found to be linearly proportional to mass flowrate.
Hasan et al. [48] observed that increasing the mass flowrate increased the cell efficiency linearly. As the mass flowrate increased from 0 to 1.666 kg/s the electrical efficiency of the cell increased from 8% to 16.5% at
PV/T system in laminar regime outperforms turbulent regime. More PV efficiency can be achieved in turbulent regime but it requires higher pumping power thus making the overall system efficiency lesser [15]. Although heat transfer in case of higher Reynolds numbers is seemed to increase because of greater Brownian motion of particles but too high a Reynolds number requires higher pumping power which eventually reduces the overall performance of the microchannels containing nanofluids [49]. Xu and Kleinstreur [50] concluded that increased concentration elevates the system efficiency when cooled by Al2 O3/water nanofluid. Higher inlet Reynolds number yields higher cell efficiency but too high a Reynolds number is not favorable. Low inlet temperature of nanofluid is capable to produce pronounced cooling effect. Height of channel containing nanofluid is also of much consideration, slight variation in channel height varies the required pumping power and significant change in entropy generation rate.
4.4. Nanoparticle size
Due to the smaller size, nanoparticles have large surface area which is attributed to higher heat transfer rates. Nanoparticles have high thermal conductivity, but heat capacity is low. Nanoparticles are stable in the base fluid at high temperatures and they do not agglomerate in the water as well [51]. Energy and exergy efficiency of the system can be increased by increasing the size of the nanoparticle in the turbulent regime but in laminar regime the case is opposite. Yazdanifard et al. [15] interestingly found no effect of particle size on the efficiency. They used Titanium dioxide nanofluid and Aluminum oxide nanofluid for the cooling purpose but no significant efficiency alteration was observed. Whereas, Al-Shamani et al. [4] observed that heat transfer of the nanofluid decreased with a decrease in size of the nanoparticle. Therefore, there is still a need for further experimentation to conclusively narrate the effects of nanoparticle size on the efficiency of the solar systems.
4.5. Base fluid
Not only the type of nanoparticle affects the performance of the PV/T system but the type of base fluid is also of same significance while predicting the performance of the system. Using base fluids such as ethylene-glycol, polyethylene glycol, cetyltrimethylammonium bromide water mixtures instead of water can considerably elevate the cell efficiency [15]. Addition of surfactant and selection of suitable pH of nanofluid can display pronounced effects [44]. Rajeb et al. [52] examined both numerically and experimentally the effect of variation in concentration (0.1, 0.2 and 0.4 wt%), type of nanoparticle (Al2O3 and Cu) and type of base fluid (water and ethylene glycol) on the efficiency of PV/T system being cooled by nanofluid. They observed that increasing the concentration of nanofluid increased the efficiency of the system. The system best performed when water was used as base fluid as compared to ethylene glycol base fluid. According to the drawn results, maximum electrical and thermal efficiency was found to be 13.55% and 77% respectively for Cu/water nanofluid based PV/T system, at 0.4 wt%. Whereas, they found 13.54% electrical and 60% thermal efficiency for Cu/ethylene glycol based PV/T system, at 0.4 wt%. Conclusively, Cu/water nanofluid based system outperformed Al2O3/water based system in terms of electrical and thermal efficiency. Hosseinzadeh et al. [53] found that a PV system being cooled by water only, performed better than the systems cooled by either ethylene glycol only and water-ethylene glycol (50% water and 50% ethylene glycol).
4.6. Nanoparticle type
Maadi et al. [54] stated that for metalloids the viscosity of the nanofluids gets increased and the specific heat capacity is decreased, which is not favorable. This is because, at a given mass fraction the volume of the metalloid nanofluids is increased due to high density. Hasan et al. [48] observed that cooling the PVT by impinging SiC, TiO2, SiO2 nanofluids and pure water improved the maximum power output by 62.5%, 57%, 55% and 50% as compared to the conventional PV module. Al-Shamani et al. [55] tested SiO2, TiO2 and SiC based nanofluid for the cooling purpose to analyze the efficiency betterment. Following the experimental results, SiC/water nanofluid outperformed rest of the nanofluids. At 1000 W/m2 irradiance and 0.170 kg/s mass flowrate, SiC/water nanofluid based PV/T system showed 13.529% electrical efficiency whereas, TiO2/water and SiO2/water nanofluid based PV/T systems depicted 10.978% and 10.302% electrical efficiency respectively. PV/T system utilizing water solely for cooling, approached 9.608% electrical efficiency.
Kolahan et al. [56] examined the entropy generation in PV/T system due to the addition of nanoparticles both numerically and experimentally. They used
Extensive experimentation has been conducted to examine the effect of magnetic on the performance of nanofluids [66, 67, 68, 69, 70]. If the Ferro-nanoparticle is used in the system, employing alternating magnetic field around the channels can improve the efficiency of the system. Experimental results also depicted that the alternating magnetic field improved the system performance whereas, the constant field did not produce significant efficiency enhancement when compared with the no field condition. The system efficiency was found to be 71.91% when there was no field applied, whereas, the efficiency went up to 73.58% in the presence of alternating magnetic field (50 Hz) in case of 1 wt% and
4.7. Channel geometry
Narrow channels offer higher enhancement in the heat transfer coefficient whereas the wide channels depict instabilities in lateral heat transfer. Roughness in the pipes also affects the magnitude of heat transfer. Pipes with greater roughness magnitude offer greater heat transfer due to the increased contact surface. In order to achieve higher performance, the temperature distribution inside the channel should be held uniform, the temperature should be kept low and the pressure drop should also be as minimum as possible [49]. Considering the Table 3, helical channel performs best because of greater surface contact of nanofluid with the rear surface of PV unit.
Intensity | Cooling Fluid | Electrical Efficiency | Thermal Efficiency |
---|---|---|---|
200 | SiC-Water | 16.90% | 8% |
1000 | SiC-Water | 10.90% | 48% |
200 | CuO-Water | 16% | 6% |
1000 | CuO-Water | 10% | 41% |
200 | Al2O3-Water | 13.50% | 6% |
1000 | Al2O3-Water | 9.80% | 41% |
200 | Water | 11.90% | 4% |
1000 | Water | 8.40% | 31% |
Researcher | Nanoparticle | Base fluid | Concen-tration | Flowrate | Channel Geometry | Effect on Temperature | Effect on Electrical Efficiency |
---|---|---|---|---|---|---|---|
Karami and Rahimi [34] | Boehmite | Water | 0.01 wt% | 300 ml/min | Straight | Decreased from 62°C to 32.5°C for flowrate 0–300 ml/min | 27.12% increase compared to Conventional PV System |
Karami and Rahimi, [57] | Boehmite | Water | 0.1 wt% | 200 ml/min | Straight | 18.33°C Temperature Reduction | 20.57% increase compared to conventional PV System |
Boehmite | Water | 0.1 wt% | 200 ml/min | Helical | 24.22°C Temperature Reduction | 37.67% increase compared to Conventional PV System |
4.8. Circulation method
When cooling the PV module via nanofluid, the circulation method is also of much importance. If the circulation is done via passive method, the increasing intensity of light would cause a reduction in electrical efficiency and enhancement in thermal efficiency because natural convection is not that efficient. Thus, active convection cooling should be employed to obtain optimum results. Whereas, the elevation in thermal efficiency is due to the availability of enough time for the cooling fluid to exchange heat. However, the overall efficiency of the system gets increased if the cooling is employed. Pumping of nanofluid can further improve the efficiency compared to the passive cooling [38].
5. Advantages of nanofluid-based cooling
5.1. Environmental benefits
Fossil fuel based power plants emit tons of noxious gases that detriment the environment. Since the solar power plants are emission free, production of electricity via this method can eliminate the emission of 16,974,57 tons of CO2 [58]. Hassani et al. [26] evaluated that nanofluid based PV/T systems can omit the emission of 448 kg
5.2. Economic benefits
PV/T system can provide an economical solution for industrial and domestic power demands. Studies indicate a significant reduction in energy consumption produced from conventional resources due to the use of such system [23, 59]. Taylor et al. [60] also narrated that a solar thermal based power plant of 100 MW capacity can save about $3.5 million per annum if the nanofluid receiver is incorporated with it. Nanofluids need a smaller area for heat transfer thus making the PV system compact and reducing the costs [51]. The economic analysis depicted that the cost of energy produced by nanofluid based PV/T system is 82% less than the current prices in Saudi Arabia [33]. Nanofluid system is predicted to takes only 2 years for pay-back [26]. Sardarabadi et al. [61] evaluated that size reduction by 21, 32,33 and 34 from energy viewpoint and 5,6,7 and 6 from exergy viewpoint for PVT/water, PVT/TiO2, PVT/ZnO and PVT/Al2O3 respectively. By size reduction we mean the amount of material saved for the same required energy and exergy outputs at the same conditions.
6. Conclusion
Cooling of PV module by nanofluids significantly enhances electrical efficiency and thermal energy. Cooling causes the heat removal which in turns halts the development of thermal stresses, making the PV modules to last long and operate more efficiently. Employing nanofluids impedes entropy generation as well. Efficiency of this system escalates with increasing concentration of nanofluid up to a certain limit but as the concentration exceeds this optimum limit, efficiency tends to decline because of the clustering and agglomeration of nanoparticles. Increasing flowrate of nanofluid increases the efficiency but as the flow gets into turbulent regime the instability issues arise and this also requires higher pumping power, in turns reducing overall system’s efficiency. Using helical microchannel can increase the heat transfer and thus overall efficiency gets elevated. Using surfactant in the nanofluid can also surge the system’s performance. Some of the measures that can refine the performance of these systems include,
Glazing can drastically improve the nanofluid based PV/T system’s performance [46, 47].
Simultaneously using optical filters over the surface and thermal collector at the rear end can also elevate performance.
Applying alternating magnetic field around the flow channel can supplement the performance of system if the Ferro-nanoparticles are being used.
The unresolved challenges being faced by the researchers while using nanofluids include instability, agglomeration, high pumping power, and erosions. Stability improvement is the most important need of the hour in order to further proceed towards commercial use of nanofluids, as no perfect method of preparation and processing of stable nanofluid has been determined up-to-date.
References
- 1.
Sargunanathan S, Elango A, Mohideen ST. Performance Enhancement of Solar Photovoltaic Cells Using Effective Cooling Methods: A Review. Renewable and Sustainable Energy Reviews. Vol. 642016 Oct 31. pp. 382-393. DOI: 10.1016/j.rser.2016.06.024 - 2.
Khanjari Y, Kasaeian AB, Pourfayaz F. Evaluating the environmental parameters affecting the performance of photovoltaic thermal system using nanofluid. Applied Thermal Engineering. 2017 Mar 25; 115 :178-187. DOI: 10.1016/j.applthermaleng.2016.12.104 - 3.
Gangadevi R, Agarwal S, Roy S. A novel hybrid solar system using nanofluid. Int. J. Engineering Research And Technology. 2013; 6 (6):747-752 - 4.
Al-Shamani AN, Yazdi MH, Alghoul MA, Abed AM, Ruslan MH, Mat S, Sopian K. Nanofluids for improved efficiency in cooling solar collectors–a review. Renewable and Sustainable Energy Reviews. 2014 Oct 31; 38 :348-367. DOI: 10.1016/j.rser.2014.05.041 - 5.
Oruc ME, Desai AV, Kenis PJ, Nuzzo RG. Comprehensive energy analysis of a photovoltaic thermal water electrolyzer. Applied Energy. 2016 Feb 15; 164 :294-302. DOI: 10.1016/j.apenergy.2015.11.078 - 6.
Bashir MA, Ali HM, Ali M, Siddiqui AM. An experimental investigation of performance of photovoltaic modules in Pakistan. Thermal Science. 2013; 19 :134 - 7.
Ali HM, Mahmood M, Bashir MA, Ali M, Siddiqui AM. Outdoor testing of photovoltaic modules during summer in Taxila, Pakistan. Thermal Science. 2016; 20 (1):165-173. DOI: 10.2298/TSCI131216025A - 8.
Bashir MA, Ali HM, Amber KP, Bashir MW, Hassan AL, Imran S, Sajid M. Performance investigation of photovoltaic modules by back surface water cooling. Thermal Science. 2017; 21 (2):290 - 9.
Ali M, Ali H.M, Moazzam W, Saeed M.B: Performance enhancement of PV cells through micro-channel cooling. WEENTECH Proceedings in Energy GCESD 2015 24th–26th February 2015 Technology Park, Coventry University Coventry, United Kingdom. 2015 Feb; 24 :211. DOI: 10.3934/energy.2015.4.699 - 10.
Shukla A, Kant K, Sharma A, Biwole PH. Cooling methodologies of photovoltaic module for enhancing electrical efficiency: A review. Solar Energy Materials and Solar Cells. 2017 Feb 28; 160 :275-286. DOI: 10.1016/j.solmat.2016.10.047 - 11.
Sathe TM, Dhoble AS. A review on recent advancements in photovoltaic thermal techniques. Renewable and Sustainable Energy Reviews. 2017 Sep 30; 76 :645-672. DOI: 10.1016/j.rser.2017.03.075 - 12.
Michael JJ, Iniyan S, Goic R. Flat plate solar photovoltaic–thermal (PV/T) systems: A reference guide. Renewable and Sustainable Energy Reviews. 2015 Nov 30; 51 :62-88. DOI: 10.1016/j.rser.2015.06.022 - 13.
Al-Waeli AH, Sopian K, Kazem HA, Chaichan MT. Photovoltaic thermal PV/T systems: A review. International Journal of Computation and Applied Sciences IJOCAAS. 2017; 2 (2) - 14.
Lelea D, Calinoiu D.G, Trif-Tordai G, Cioabla A.E, Laza I, Popescu F: The hybrid nanofluid/microchannel cooling solution for concentrated photovoltaic cells. In AIP Conference Proceedings 2015 Feb 17 (Vol. 1646, No. 1, pp. 122-128). AIP. DOI. 10.1063/1.4908592 - 15.
Yazdanifard F, Ameri M, Ebrahimnia-Bajestan E. Performance of nanofluid-based photovoltaic/thermal systems: A review. Renewable and Sustainable Energy Reviews. 2017 Sep 30; 76 :323-352. DOI: 10.1016/j.rser.2017.03.025 - 16.
Al-Waeli AH, Sopian K, Chaichan MT, Kazem HA, Hasan HA, Al-Shamani AN. An experimental investigation of SiC nanofluid as a base-fluid for a photovoltaic thermal PV/T system. Energy Conversion and Management. 2017 Jun 15; 142 :547-558. DOI: 10.1016/j.enconman.2017.03.076 - 17.
Xu Z, Kleinstreuer C. Concentration photovoltaic–thermal energy co-generation system using nanofluids for cooling and heating. Energy Conversion and Management. 2014 Nov 30; 87 :504-512. DOI: 10.1016/j.enconman.2014.07.047 - 18.
Yousefi T, Veysi F, Shojaeizadeh E, Zinadini S. An experimental investigation on the effect of Al2O3–H2O nanofluid on the efficiency of flat-plate solar collectors. Renewable Energy. 2012 Mar 31; 39 (1):293-298. DOI: 10.1016/j.renene.2011.08.056 - 19.
Sardarabadi M, Passandideh-Fard M, Maghrebi MJ, Ghazikhani M. Experimental study of using both ZnO/water nanofluid and phase change material (PCM) in photovoltaic thermal systems. Solar Energy Materials and Solar Cells. 2017 Mar 31; 161 :62-69. DOI: 10.1016/j.solmat.2016.11.032 - 20.
Radwan A, Ahmed M, Ookawara S. Performance enhancement of concentrated photovoltaic systems using a microchannel heat sink with nanofluids. Energy Conversion and Management. 2016 Jul 1; 119 :289-303. DOI: 10.1016/j.enconman.2016.04.045 - 21.
Taylor RA, Otanicar T, Rosengarten G. Nanofluid-based optical filter optimization for PV/T systems. Light: Science & Applications. 2012 Oct 1; 1 (10):e34 - 22.
Crisostomo F, Hjerrild N, Mesgari S, Li Q, Taylor RA. A hybrid PV/T collector using spectrally selective absorbing nanofluids. Applied Energy. 2017 May 1; 193 :1-4. DOI: 10.1016/j.apenergy.2017.02.028 - 23.
Mittal T, Saroha S, Bhalla V, Khullar V, Tyagi H, Taylor RA, Otanicar T.P: Numerical study of solar photovoltaic/thermal (PV/T) hybrid collector using nanofluids. ASME Paper No. MNHMT2013-22090. 2013 Dec 11 - 24.
An W, Zhang J, Zhu T, Gao N. Investigation on a spectral splitting photovoltaic/thermal hybrid system based on polypyrrole nanofluid: Preliminary test. Renewable Energy. 2016 Feb 29; 86 :633-642. DOI: 10.1016/j.renene.2015.08.080 - 25.
Hjerrild NE, Mesgari S, Crisostomo F, Scott JA, Amal R, Taylor RA. Hybrid PV/T enhancement using selectively absorbing Ag–SiO2/carbon nanofluids. Solar Energy Materials and Solar Cells. 2016 Apr 30; 147 :281-287. DOI: 10.1016/j.solmat.2015.12.010 - 26.
Hassani S, Saidur R, Mekhilef S, Taylor RA. Environmental and exergy benefit of nanofluid-based hybrid PV/T systems. Energy Conversion and Management. 2016 Sep 1; 123 :431-444. DOI: 10.1016/j.enconman.2016.06.061 - 27.
Saroha S, Mittal T, Modi PJ, Bhalla V, Khullar V, Tyagi H, Taylor RA, Otanicar TP. Theoretical analysis and testing of nanofluids-based solar photovoltaic/thermal hybrid collector. Journal of Heat Transfer. 2015 Sep 1; 137 (9):091015 - 28.
Jin J, Jing D. A novel liquid optical filter based on magnetic electrolyte nanofluids for hybrid photovoltaic/thermal solar collector application. Solar Energy. 2017 Oct 1; 155 :51-61. DOI: 10.1016/j.solener.2017.06.030 - 29.
Hassani S, Taylor RA, Mekhilef S, Saidur R. A cascade nanofluid-based PV/T system with optimized optical and thermal properties. Energy. 2016 Oct 1; 112 :963-975. DOI: 10.1016/j.energy.2016.06.142 - 30.
Soltani S, Kasaeian A, Sarrafha H, Wen D. An experimental investigation of a hybrid photovoltaic/thermoelectric system with nanofluid application. Solar Energy. 2017 Oct 1; 155 :1033-1043. DOI: 10.1016/j.solener.2017.06.069 - 31.
Hussien HA, Noman AH, Abdulmunem AR. Indoor investigation for improving the hybrid photovoltaic/thermal system performance using nanofluid (Al2O3-water). Eng Tech J. 2015; 33 (4):889-901 - 32.
Hussien HA, Hasanuzzaman M, Noman AH, Abdulmunem AR. Enhance photovoltaic/thermal system performance by using nanofluid. 2014 - 33.
Ebaid MS, Ghrair AM, Al-Busoul M. Experimental investigation of cooling photovoltaic (PV) panels using (TiO2) nanofluid in water-polyethylene glycol mixture and (Al2O3) nanofluid in water-cetyltrimethylammonium bromide mixture. Energy Conversion and Management. 2018 Jan 1; 155 :324-343. DOI: 10.1016/j.enconman.2017.10.074 - 34.
Karami N, Rahimi M. Heat transfer enhancement in a hybrid microchannel-photovoltaic cell using Boehmite nanofluid. International Communications in Heat and Mass Transfer. 2014 Jul 31; 55 :45-52. DOI: 10.1016/j.icheatmasstransfer.2014.04.009 - 35.
Gangadevi R, Vinayagam BK, Senthilraja S. Experimental investigations of hybrid PV/spiral flow thermal collector system performance using Al2O3/water nanofluid. In IOP Conference Series: Materials Science and Engineering 2017 May (Vol. 197, No. 1, p. 012041). IOP Publishing. DOI: 10.1088/1757-899X/197/1/012041 - 36.
Mustafa W, Othman MY, Fudholi A. Numerical investigation for performance study of photovoltaic thermal Nanofluid system. International Journal of Applied Engineering Research. 2017; 12 (24):14596-14602 - 37.
Ghadiri M, Sardarabadi M, Pasandideh-fard M, Moghadam AJ. Experimental investigation of a PVT system performance using nano ferrofluids. Energy Conversion and Management. 2015 Oct 31; 103 :468-476. DOI: 10.1016/j.enconman.2015.06.077 - 38.
Al-Waeli AH, Chaichan MT, Kazem HA, Sopian K. Comparative study to use nano-(Al2O3, CuO, and SiC) with water to enhance photovoltaic thermal PV/T collectors. Energy Conversion and Management. 2017 Sep 15; 148 :963-973. DOI: 10.1016/j.enconman.2017.06.072 - 39.
Manikandan S, Rajan KS. Sand-propylene glycol-water nanofluids for improved solar energy collection. Energy. 2016 Oct 15; 113 :917-929. DOI: 10.1016/j.energy.2016.07.120 - 40.
Sardarabadi M, Passandideh-Fard M. Experimental and numerical study of metal-oxides/water nanofluids as coolant in photovoltaic thermal systems (PVT). Solar Energy Materials and Solar Cells. 2016 Dec 31; 157 :533-542. DOI: 10.1016/j.solmat.2016.07.008 - 41.
Khanjari Y, Pourfayaz F, Kasaeian AB. Numerical investigation on using of nanofluid in a water-cooled photovoltaic thermal system. Energy Conversion and Management. 2016 Aug 15; 122 :263-278. DOI: 10.1016/j.enconman.2016.05.083 - 42.
Abd-Allah SR, Abdellatif OE, El-Kady ES. Performance of cooling photovoltaic cells using Nanofluids - 43.
Cieśliński J, Dawidowicz B, Krzyżak J. Performance of the PVT solar collector operated with water–Al2O3 nanofluid. Polska Energetyka Słoneczna. 2016 (1-4):5-8 - 44.
Mahian O, Kianifar A, Kalogirou SA, Pop I, Wongwises S. A review of the applications of nanofluids in solar energy. International Journal of Heat and Mass Transfer. 2013 Feb 28; 57 (2):582-594. DOI: 10.1016/j.ijheatmasstransfer.2012.10.037 - 45.
Chen M, He Y, Huang J, Zhu J. Synthesis and solar photo-thermal conversion of au, ag, and au-ag blended plasmonic nanoparticles. Energy Conversion and Management. 2016 Nov 1; 127 :293-300. DOI: 10.1016/j.enconman.2016.09.015 - 46.
Sathieshkumar N, Sureshkumar LN, Balamurugan R. Performance analysis of hybrid solar photovoltaic thermal collector with nanoparticles. Inten. Journal of Current Research in Engineering and Technology. 2017 - 47.
Yazdanifard F, Ebrahimnia-Bajestan E, Ameri M. Investigating the performance of a water-based photovoltaic/thermal (PV/T) collector in laminar and turbulent flow regime. Renewable Energy. 2016 Dec 31; 99 :295-306. DOI: 10.1016/j.renene.2016.07.004 - 48.
Hasan HA, Sopian K, Jaaz AH, Al-Shamani AN. Experimental investigation of jet array nanofluids impingement in photovoltaic/thermal collector. Solar Energy. 2017 Mar 1; 144 :321-334. DOI: 10.1016/j.solener.2017.01.036 - 49.
Hassan I, Phutthavong P, Abdelgawad M. Microchannel heat sinks: An overview of the state-of-the-art. Microscale thermophysical engineering. 2004 Jan 1; 8 (3):183-205. DOI: 10.1080/10893950490477338 - 50.
Xu Z, Kleinstreuer C. Computational analysis of nanofluid cooling of high concentration photovoltaic cells. Journal of Thermal Science and Engineering Applications. 2014 Sep 1; 6 (3):031009 - 51.
Elsheikh AH, Sharshir SW, Mostafa ME, Essa FA, Ali MK. Applications of nanofluids in solar energy: A review of recent advances. Renewable and Sustainable Energy Reviews. 2017 Nov 2. DOI: 10.1016/j.rser.2017.10.108 - 52.
Rejeb O, Sardarabadi M, Ménézo C, Passandideh-Fard M, Dhaou MH, Jemni A. Numerical and model validation of uncovered nanofluid sheet and tube type photovoltaic thermal solar system. Energy Conversion and Management. 2016 Feb 15; 110 :367-377. DOI: 10.1016/j.enconman.2015.11.063 - 53.
Hosseinzadeh M, Kazemian A, Sardarabadi M, Passandideh-Fard M. Experimental investigation of using water and ethylene glycol as coolants in a photovoltaic thermal system. Energy Conversion and Management. 2017; 17 :12-20 - 54.
Maadi S, Kolahan A, Passandideh Fard M, Sardarabadi M. Effects of Nanofluids thermo-physical properties on the heat transfer and 1st law of thermodynamic in a serpentine PVT system. In17th Conference On Fluid Dynamics, fd2017 2017 Aug 27 - 55.
Al-Shamani AN, Sopian K, Mat S, Hasan HA, Abed AM, Ruslan MH. Experimental studies of rectangular tube absorber photovoltaic thermal collector with various types of nanofluids under the tropical climate conditions. Energy Conversion and Management. 2016 Sep 15; 124 :528-542. DOI: 10.1016/j.enconman.2016.07.052 - 56.
Kolahan A, Maadi S, Passandideh Fard M, Sardarabadi M. Numerical and experimental investigations on the effect of adding nanoparticles on entropy generation in PVT systems. In17th Conference On Fluid Dynamics, fd2017 2017 Aug 27 - 57.
Karami N, Rahimi M. Heat transfer enhancement in a PV cell using Boehmite nanofluid. Energy Conversion and Management. 2014 Oct 31; 86 :275-285. DOI: 10.1016/j.enconman.2014.05.037 - 58.
Lari MO, Sahin AZ. Design, performance and economic analysis of a nanofluid-based photovoltaic/thermal system for residential applications. Energy Conversion and Management. 2017 Oct 1; 149 :467-484. DOI: 10.1016/j.enconman.2017.07.045 - 59.
Vokas G, Christandonis N, Skittides F. Hybrid photovoltaic–thermal systems for domestic heating and cooling—A theoretical approach. Solar Energy. 2006 May 31; 80 (5):607-615. DOI: 10.1016/j.solener.2005.03.011 - 60.
Taylor RA, Phelan PE, Otanicar TP, Walker CA, Nguyen M, Trimble S, Prasher R. Applicability of nanofluids in high flux solar collectors. Journal of Renewable and Sustainable Energy. 2011 Mar; 3 (2):023104 - 61.
Sardarabadi M, Hosseinzadeh M, Kazemian A, Passandideh-Fard M. Experimental investigation of the effects of using metal-oxides/water nanofluids on a photovoltaic thermal system (PVT) from energy and exergy viewpoints. Energy. 2017 Nov 1; 138 :682-695. DOI: 10.1016/j.energy.2017.07.046 - 62.
Michael JJ, Iniyan S. Performance analysis of a copper sheet laminated photovoltaic thermal collector using copper oxide–water nanofluid. Solar Energy. 2015 Sep 30; 119 :439-451. DOI: 10.1016/j.solener.2015.06.028 - 63.
Al-Waeli AH, Sopian K, Chaichan MT, Kazem HA, Ibrahim A, Mat S, Ruslan MH. Evaluation of the nanofluid and nano-PCM based photovoltaic thermal (PVT) system: An experimental study. Energy Conversion and Management. 2017 Nov 1; 151 :693-708. DOI: 10.1016/j.enconman.2017.09.032 - 64.
Sardarabadi M, Passandideh-Fard M, Heris SZ. Experimental investigation of the effects of silica/water nanofluid on PV/T (photovoltaic thermal units). Energy. 2014 Mar 1; 66 :264-272. DOI: 10.1016/j.energy.2014.01.102 - 65.
Hamdan MA, Kardasi KK. Improvement of photovoltaic panel efficiency using nanofluid. Int. J. of Thermal & Environmental Engineering. 2017; 14 (2):143-151. DOI: 10.5383/ijtee.14.02.008 - 66.
Sheikholeslami M, Shehzad SA. Numerical analysis of Fe3O4–H2O nanofluid flow in permeable media under the effect of external magnetic source. International Journal of Heat and Mass Transfer. 2018 Mar 31; 118 :182-192. DOI: 10.1016/j.ijheatmasstransfer.2017.10.113 - 67.
Sheikholeslami M. CuO-water nanofluid flow due to magnetic field inside a porous media considering Brownian motion. Journal of Molecular Liquids. 2018 Jan 1; 249 :921-929. DOI: 10.1016/j.molliq.2017.11.118 - 68.
Sheikholeslami M. Numerical simulation of magnetic nanofluid natural convection in porous media. Physics Letters A. 2017 Feb 5; 381 (5):494-503. DOI: 10.1016/j.physleta.2016.11.042 - 69.
Sheikholeslami M. Numerical investigation for CuO-H2O nanofluid flow in a porous channel with magnetic field using mesoscopic method. Journal of Molecular Liquids. 2018 Jan 1; 249 :739-746. DOI: 10.1016/j.molliq.2017.11.069 - 70.
Sheikholeslami M, Rokni HB. Simulation of nanofluid heat transfer in presence of magnetic field: A review. International Journal of Heat and Mass Transfer. 2017 Dec 31; 115 :1203-1233. DOI: 10.1016/j.ijheatmasstransfer.2017.08.108