Solar Phase Research Articles

Phase Stability Improvement of a γ-CsPbI3 Perovskite Solar Cell Utilizing a Barium Bis(trifluoromethanesulfonimide) Solution.

The cesium lead iodide (CsPbI3) perovskite solar cell possesses a wide band gap ranging from 1.65 to 1.75 eV, which is suitable for integration into a tandem structure along with a low-band-gap silicon solar cell. Moreover, CsPbI3 has received considerable attention as a potential solution for the prevalent issues of low thermal stability of organic-inorganic perovskite solar cells and phase segregation encountered in conventional mixed halide wide-band-gap perovskite solar cells. Through the implementation of volatile additives, CsPbI3 has demonstrated substantial advancements in efficiency, process temperature, and stability. This study introduces a novel approach for barium (Ba)-doping by spraying an antisolvent containing barium bis(trifluoromethanesulfonimide) during the spin-coating process. By incorporating Ba2+ through this spraying technique, the formation of the delta phase in CsPbI3 is significantly suppressed; thereby, a power conversion efficiency of 18.56% is achieved, and a remarkable 93% of the initial efficiency is maintained after 600 h.

Experimental and numerical study of desalination using solar energy and phase change materials

The present work experimentally desalinate water and model a passive solar desalinator of 0.55 m2 that uses phase change materials (PCM), assessing the effects of storing energy in 4.5 kg of coconut oil or paraffin wax contained in copper tubes, and the mass of water in the container (5.55, 8.25 and 11.0 kg), on the unit performance. The experiments carried out in Santiago de Chile allowed to obtain condensate masses between 3.2 and 4.3 kg/m2 per batch with a temperatures between 23 and 83∘C for the absorber plate and 21–77∘C for the glass. Annual water production ranged from 1120 to 1313 liter/m2, with costs between 0.0165 and 0.0593 $/liter. PCM incorporation had no impact on production as the exposed area is shared between absorber plate and tubes. To better evaluate the effect of the parameters studied, results are presented as the ratio between the mass of condensate and the solar energy received, which gives independence from the solar irradiation variability and allowed to identify a slight superiority in the productivity of condensate using coconut oil. The model developed and coded in MATLAB, including PCM and the effect of self-shading, adequately predicts the mass of condensate and phase temperatures (water, glass and PCM) with a mean root mean square error of 0.03 kg and 1.9∘C respectively. The model is characterized by a low computation time and a high level of prediction for the condensate mass.

Simulations of xenon beam ions emitted from electric thrusters in Earth’s magnetosphere

This study sought to characterize the behavior of exhausted electric thruster xenon ions in the near-Earth magnetospheric environment as functions of various trajectory and particle attributes, neglecting effects of electric fields, plasma waves and particle collisions. This was done via simulation using the AeroTracer program, a software tool which computes ion trajectories within the magnetosphere by applying an adaptive step-size Runge-Kutta technique to the fully relativistic Lorentz equation. Over 3,800 independent simulations were performed, with variables including release position, release energy and direction, ion charge, and orbital phase. Initial release altitude was a major driver in determining whether the ion eventually fell to Earth (“Below Minimum Altitude” or BMA), remained trapped by the simulation’s end (“Maximum Number of Steps” or MNS), or traveled beyond the magnetosphere (“Lost to Space” or LTS). Ions expelled at the highest altitudes investigated - 60,000 km and above - almost invariably were lost to space. Like altitude, increasing inclination and energy were important factors that reduced trapping, affecting the outcome probabilities. Higher charge state produced strong improvement of trapping capability. Effects of orbital phase, day of year and solar cycle phase were also apparent. A transition region was found in the 20,000 km to 60,000 km altitude range, within which the sensitivity of outcomes to parameter variation increased. The ordered sequence MNS> BMA> LTS was found to be consistent with decreasing confinement capability, and it was manifested consistently as parameters were varied.

Space Weather Disturbances in Non‐Stormy Times: Occurrence of dB/dt Spikes During Three Solar Cycles

AbstractSpatio‐temporal variations of ionospheric currents cause rapid magnetic field variations at ground level and Geomagnetically Induced Currents (GICs) that can be harmful for human infrastructure. The risk for large excursions in the magnetic field time derivative, “dB/dt spikes”, is known to be high during geomagnetic storms and substorms. However, less is known about the occurrence of spikes during non‐stormy times. We use data from ground‐based globally covering magnetometers (SuperMAG database) from the years 1985–2021. We investigate the spike occurrence (|dB/dt| > 100 nT/min) as a function of magnetic local time (MLT), magnetic latitude (Mlat), and the solar cycle phases during non‐stormy times (−15 nT ≤ SYM‐H < 0). We sort our data into substorm (AL < 200 nT) intervals (“SUB”) and less active intervals between consecutive substorms (“nonSUB”). We find that spikes commonly occur in both SUBs and nonSUBs during non‐stormy times (3–23 spikes/day), covering 18–12 MLT and 65°–80° Mlat. This also implies a risk for infrastructure damage during non‐stormy times, especially when several spikes occur nearby in space and time, possibly causing infrastructure weathering. We find that spikes are more common in the declining phase of the solar cycle, and that the occurrence of SUB spikes propagates from one midnight to one morning hotspot with ∼10 min in MLT for each minute in universal time (UTC). Finally, we discuss causes for the spikes in terms of spatio‐temporal variations of ionospheric currents.

Experimental study on heat transfer and storage of a heating system coupled with solar flat heat pipe and phase change material unit

Using renewable energy, especially solar energy, is essential to achieve a low-carbon society. PCMs suffer from low thermal conductivity, which hinders the efficiency of phase change thermal storage systems. Heat pipes exhibit vastly superior thermal conductivity, making them a promising candidate for enhancing PCM-based systems. To solve the contradiction between building insulation and importing solar energy into buildings in winter, this study proposes a new building heating ceiling system consisting of a flat-plate heat pipe (FHP) coordinated with a phase change material (PCM), and establishes a platform for a heat stockpiling device integrating the FHP and PCM. This research investigates the impact of heating power and bending angle on the heat transfer efficiency of the heat pipe and phase change heat storage system. The experimental findings demonstrate a direct relationship between increasing heating power and the enhancement of the FHP's heat transfer efficiency. When the FHP is bent at a 5° angle and heating power is increased from 20 W to 80 W, to store heat energy into the PCM cavities, the effective thermal conductivity rises significantly, escalating from 7.26 × 104 W/(m·°C) to 15.1 × 104 W/(m·°C), marking a remarkable 108 % rise. Moreover, although increasing the bending angle leads to heightened effective thermal conductivity of the FHP under constant heat input, and the heat transfer in PCM cavities will be weakened within a bending angle of 15°, experimental results demonstrate that the melting time of PCM still decreases with the increase of bending angle; the heat transfer inertia of phase change materials is dominant.

Analysis of GPS-TEC and IRI model over equatorial and EIA stations during solar cycle 24

Total Electron Content (TEC) measurements provided by Global Positioning System (GPS) as well as the International Reference Ionosphere – 2016 model (IRI01-Corr, IRI-2001, and NeQuick) model were compared at two Indian GPS stations: equatorial station Bangalore (12.580N, 77.350 E) and equatorial ionization anomaly (EIA) station Lucknow (26.500N, 80.550 E) during the solar cycle 24 extending from 2007 to 2017. The spectral, regression and statistical analysis displays a double-hump shape with counterclockwise hysteresis within TEC. The solar flux along with the TEC showed erratic as well as sluggish trends throughout the increasing period and flat and rapid throughout the decreasing period of the solar cycle 24. The semiannual and winter anomaly is discovered to be a constant feature throughout the solar cycle. The main idea of the current study is to investigate the performance of IRI01-Corr, IRI-2001, and NeQuick TEC in contrast to GPS TEC data throughout solar cycle 24 at the Indian equatorial and EIA stations. The modeled TEC data exhibit almost complete agreement with the measurement highlighting the same trends in the solar cycle as well as semiannual and seasonal changes. However, there are clear biases between the observed and modeled TECs when local time, seasons, as well as solar activity phases are considered. The main findings of this paper are that the NeQuick model generally underestimates noon-time TEC while the IRI-2001 model overestimates the same. The error in estimating noontime TEC from the IRI model using IRI-2001 as a topside at the EIA station is higher (142 %) than that at the equatorial station (42 %).

Asymmetric modulation of solar activity on tropical cyclone frequency over the western North Pacific and the possible mechanism

The impacts of solar activity on the tropical Pacific climate have been widely reported. However, few studies focus on the effects of solar activity on the tropical cyclone (TC). Based on the observational and reanalysis data for 1979–2020, this study investigated the solar modulation of TC frequency over the western North Pacific in different solar cycle phases. Results suggest that the regressions of TC frequency to solar activity are asymmetric in the high- and low-solar activity years (HS and LS). Specifically, the intensified solar activity could markedly induce more TCs in HS; however, no significant modulation can be found in LS. Further exploration reveals a possible air–sea coupled mechanism for this interesting phenomenon. The relatively cloud-free area in the western North Pacific could receive more incoming solar radiation at the surface in HS than in LS. This increased regional surface net solar radiation in HS could produce a stronger surface upward latent heat flux and, thus, greater evaporation. Along with that, the local upward motion is dramatically enhanced over the TC source. Then, for compensation, the regional sea level pressure is reduced, and the low-level winds become cyclonic over the TC origin. All of these solar-caused regional atmospheric anomalies in HS contribute to more TC generations. The key to this possible mechanism is the increased regional solar forcing at the ocean surface that is amplified by regionally enhanced upward latent heat flux and evaporation.

Three-dimensional inversion of corona structure and simulation of solar wind parameters based on the photospheric magnetic field deduced from the Global Oscillation Network Group

In this research, the Potential Field Source Surface–Wang–Sheeley–Arge (PFSS–WSA) solar wind model is used. This model consists of the Potential Field Source Surface (PFSS) coronal magnetic field extrapolation module and the Wang–Sheeley–Arge (WSA) solar wind velocity module. PFSS is implemented by the POT3D package deployed on Tianhe 1A supercomputer system. In order to obtain the three–dimensional (3D) distribution of the coronal magnetic field at different source surface radii (Rss), the model utilizes the Global Oscillation Network Group (GONG) photospheric magnetic field profiles for two Carrington rotations (CRs), CR2069 (in 2008) and CR2217 (in 2019), as the input data, with the source surface at Rss = 2Rs, Rss = 2.5Rs and Rss = 3Rs, respectively. Then the solar wind velocity, the coronal magnetic field expansion factor, and the minimum angular distance of the open magnetic field lines from the coronal hole boundary are estimated within the WSA module. The simulated solar wind speed is compared with the value for the corona extrapolated from the data observed near 1 AU, through the calculations of the mean square error (MSE), root mean square error (RMSE) and correlation coefficient (CC). Here we extrapolate the solar wind velocity at 1 AU back to the source surface via the Parker spiral. By comparing the evaluation metrics of the three source surface heights, we concluded that the solar source surface should be properly decreased with respect to Rss = 2.5Rs during the low solar activity phase of solar cycle 23.

Influence of different rotational speeds of inner and outer tubes on phase change heat storage: An optimization study

The implementation of the solar phase change heat storage evaporation heat pump system with a latent heat energy storage system has shown promising potential in enhancing solar heating and facilitating the efficient utilization of solar energy. Nevertheless, the utilization of a heat storage medium phase change material with low thermal conductivity in the latent heat energy storage system has hindered its broad-scale application. This present study focuses on a triplex-tube latent heat energy storage unit with N-eicosane serving as the phase change material. A subzone rotation strategy has been developed to improve the melting properties of the unit, and a numerical model of the energy storage unit has been constructed and authenticated. The Taguchi method has been utilized to examine the effect of inner tube speed, outer tube speed, and fin/wall material on melting properties, and the interaction between control variables has been scrutinized. The research findings indicate that the optimized structure, according to the Taguchi method, significantly shortens the melting time by 26.22%, and increases the average rate of temperature response and average heat storage rate by 22.98% and 32.39%, respectively. It should be noted, however, that there is a certain decrease in the total heat absorption during the melting period. By examining the internal dynamic temperature/velocity response, this study displays that the augmentation of the rotation speed in the zone improves the overall convective intensity and heat transfer performance in the unit.

Optical Imaging Polarimetry of Comet 21P/Giacobini–Zinner during Its 2018 Apparition

We conducted polarimetric observations of comet 21P/Giacobini–Zinner in the optical wavelength region using the polarimetric imager PICO equipped with the 50 cm telescope for Public Outreach at the Mitaka Campus of the National Astronomical Observatory of Japan on UT 2018 September 16, at a solar phase angle of 77° for the comet. We used Gunn’s i′-band filter to cover the wavelength region where sunlight reflected by dust grains dominates cometary spectra. The intensity map of comet 21P/Giacobini–Zinner showed an elongated coma structure along the east–west direction. The linear polarization degree map was almost uniform and showed no evidence of jet or arc structures in the inner coma. The linear polarization degree was 22% in the coma, which is consistent with other optical polarization observations of 21P/Giacobini–Zinner for this and previous apparitions reported in the literature. The measured polarization angles (179°) were nearly perpendicular to the position angle of the scattering plane of 271°. There is no evidence of significant changes in the dust properties (composition, porosity, and size distribution) in the comet from its 1985 to 2018 apparitions. The spectral gradient of the linear polarization degree for the comet was nearly flat in the wavelength range of ∼510–830 nm at a solar phase angle of ∼77° during the 2018 apparition.

Seasonal Variation of the F2-Layer Critical Frequency and Comparison with the IRI-2016 Model during Two Extremes of Solar Activity Phase of Solar Cycle 22

Abstract: Introduction: The variation of the ionosphere is mostly studied using the critical frequency of the F2-layer (foF2) whose values can also be predicted by an ionospheric model. The widely used model for predicting ionospheric parameters is the International Reference Ionosphere (IRI). Aim: This paper aims to demonstrate how well the current International Reference Ionosphere (IRI-2016) model performs in predicting the critical frequency of the F2-layer (foF2) over two equatorial stations during two extremes of solar activity phase of solar cycle 22.. Methods: The hourly foF2 experimental data collected during the Maximum Phase of Solar Activity MPSA year (1989) and Minimum Phase of Solar Activity MnPSA year (1986) at Ougadougou (Geomagnetic Latitude 0.59 oN, Geomagnetic Longitude 71.46 oE) in the African longitudinal sector and Manila (Geomagnetic Latitude 3.4 oN, Geomagnetic Longitude 191.1 oE) in the Asia longitudinal sector as well as the predicted foF2 data by the IRI-2016 model were used in this study. Sunspot data from Zurich was utilized as a measure of solar activity phase. The foF2 data were grouped into four seasons before analysis began. Comparing the seasonal means of the experimental foF2 data and the IRI-2016 modeled foF2, it was possible to determine how closely the model matched the experimental data at the different seasons and longitudinal sectors Results: The results showed that the IRI-2016 model overestimate and underestimate the observed foF2 at different periods of the day during the equinox and solstice seasons. Observation showed that the highest positive and negative percentage deviations were observed mostly during the post-midnight hours. Observation also showed that Seasonal mean values of the IRI-2016 model of both options showed remarkable improvement at this two stations since their values have little difference from the observed foF2 values. Conclusion: The discrepancy (underestimation and overestimation) in the IRI-2016 model is found larger during MPSA year than during MnPSA year. The URSI option performs better than the CCIR option since its predicted values are much closer to the observed values. Both options of the model perform better in the Asian longitudinal sector than the African longitudinal sector.

Long-term forcing of the Sun’s coronal field, open flux, and cosmic ray modulation potential during grand minima, maxima, and regular activity phases by the solar dynamo mechanism

ABSTRACT Magnetic fields generated in the Sun’s interior by the dynamo mechanism drive solar activity over a range of time-scales. Direct sunspot observations exist for a few centuries; reconstructed variations based on cosmogenic isotopes in the solar open flux and cosmic ray flux exist over thousands of years. While such reconstructions indicate the presence of extreme solar activity fluctuations in the past, causal links between millennia scale dynamo activity, consequent coronal field, solar wind, open flux and cosmic ray flux variations remain elusive; a lack of coronal field observations compounds this issue. By utilizing a stochastically forced solar dynamo model and potential field source surface extrapolation, we perform long-term simulations to illuminate how dynamo generated magnetic fields govern the structure of the solar corona and the state of the heliosphere – as indicated by variations in the open flux and cosmic ray modulation potential. We establish differences in the nature of the large-scale structuring of the solar corona during grand maximum, minimum, and regular solar activity phases and simulate how the open flux and cosmic ray modulation potential vary across these different phases of activity. We demonstrate that the power spectrum of simulated and observationally reconstructed solar open flux time series are consistent with each other. Our study provides the theoretical foundation for interpreting long-term solar cycle variations inferred from cosmogenic isotope based reconstructions and establishes causality between solar internal variations to the forcing of the state of the heliosphere.

Mid‐Latitude Double H‐Spikes: Their Properties and Signatures in Different Geomagnetic Indices

AbstractProper assessment of geomagnetic disturbances is a key aspect of space weather as technology is often impacted by space weather activity without previous warnings or proper forecasts. Double H‐spikes are a form of longitudinal asymmetry observed at midlatitudes. They are geomagnetic disturbances occurring simultaneously on the dayside and nightside as a negative/positive H‐spike, which go unnoticed through common geomagnetic indices. This work presents the results of a systematic search for double H‐spikes occurred over a 23‐year period and analyzes characteristics of the double H‐spikes such as the occurrence dependence on the solar cycle, season, intensity and phase of the geomagnetic storm. Our outcomes indicate that double H‐spikes are a global phenomenon closely related with the substorm phenomenon and the ground magnetic disturbances observed at mid‐latitude are remote effects of field‐aligned currents (FACs). FACs would be the part of the substorm current wedge developed from the expansion onset of intense substorms whose effects have wide longitudinal extend as they are observed on the dayside and the nightside. Also mid‐latitude global SYM and ASY indices are affected by FACs during those periods. Time derivatives of the SuperMAG SMR12 and SMR00 sector indices allow us to conclude that double H‐spikes, as short‐time high‐intensity magnetic disturbances, pose a potential risk to damage ground‐technological systems at midlatitudes.

Physical properties of NEOs derived from their phase curves

ABSTRACT The observation of Near Earth objects (NEOs) allows us to study the physical properties of the smallest size bodies of our Solar System and help impose constraints on their origin and evolution. The solar phase curve is a very important tool to derive diverse physical properties of a small body so that we set up an observational campaign to derive the phase curve parameters (H, G1, G2) for a large number of NEOs. We present here the obtained phase curves for 12 NEOs, along with the rotation period for two of them and the V–R colour for four. The data was acquired mainly at the Astronomical Observatory of Sertão de Itaparica (Brazil), with some NEOs also observed at the Osservatorio di Campo Imperatore (Italy). Considering all the objects observed throughout our campaign we analysed a homogeneous dataset of 30 NEOs along with data acquired by ATLAS (Asteroid Terrestrial-impact Last Alert System telescopes survey) for MB asteroids. The behavior in the phase space G1-G2 of 21,865 MBA and 103 NEOs was analysed, separating the objects in intervals of albedos and sizes. From the large MB data set we found evidence that the distribution in the G1-G2 phase space has strong dependence not only on the albedo but also on the object’s size. This is particularly true for the smaller objects. The main result being that, on the contrary to what occurs with the MB larger objects, we are unable to estimate the albedo of a NEO from its phase curve parameters.

Proton Flux Variations During Solar Energetic Particle Events, Minimum and Maximum Solar Activity, and Splitting of the Proton Belt in the South Atlantic Anomaly

AbstractThe analysis of the proton flux variations observed by the Energetic Particle Telescope (EPT) at energies >9.5 MeV from the launch of PROBA‐V satellite on 7 May 2013 up to October 2022 shows an anti‐correlation between the proton fluxes and the solar phase. At solar minimum, the fluxes are higher at low L corresponding to the northern border of the South Atlantic Anomaly (SAA). This solar cycle modulation of the inner belt is mainly due to losses by increased atmospheric interactions during solar maximum. Strong Solar Energetic Particle (SEP) events, like in January 2014, June 2015, and September 2017, inject energetic protons at high latitudes, but not in the inner belt where protons are trapped at long term at low L. Nevertheless, big geomagnetic storms, including those following SEP a few days after, can cause losses of protons at the outer border of the proton belt, due to magnetic field perturbations. A double peak in the proton belt is observed during long period of measurements only for the EPT channel of 9.5–13 MeV. The narrow gap between the two peaks in the inner belt is located around L = 2. This resembles to a splitting of the proton belt, separating the SAA into two different parts, North and South. The high‐resolution measurements of PROBA‐V/EPT allow the observation of small‐scale structures that brings new elements to the understanding of the different source and loss mechanisms acting on the proton radiation belt at LEO.

Integration of phase change thermal storage system with vertical solar Chimney In Greenhouse

The performance stability of the system can be improved by incorporating a solar chimney with a phase-change material (PCM). It is recommended that instead of using the traditional multi-curved trough air collectors for solar greenhouses, a solar phase change thermal storage wall construction system with vertical air channels be employed. Solar thermal utilization of the rear wall. In order to verify feasibility of the construction system, a multi-curved trough air collector test system for solar greenhouse and a phase-change heat storage wall test system with vertical air channels were built respectively. The air velocity in the heater, the air flow parameters (air velocity, air channel spacing, air flow direction) in the sensible heat storage wall layer in the solar greenhouse, etc. The study’s findings indicate that the collector performs at its peak level of total heat absorption when its air velocity is between 1.4 and 1.8 m/s, and that heat absorption rises as solar radiation intensity rises. The suggested system design orientation offers an efficient way to raise the thermal performance of the system with the least amount of work and expense for practical applications.

Multicolor and multi-spot observations of Starlink’s Visorsat

Abstract This study provides the results of simultaneous multicolor observations for the first Visorsat (STARLINK-1436) and the ordinary Starlink satellite (STARLINK-1113) in the U, B, V, g′, r, i, RC, IC, $z$, J, H, and Ks bands to quantitatively investigate the extent to which Visorsat reduces its reflected light. Our results are as follows: (1) in most cases, Visorsat is fainter than STARLINK-1113, and the sunshade on Visorsat therefore contributes to the reduction of the reflected sunlight; (2) the magnitude at 550 km altitude (normalized magnitude) of both satellites often reaches the naked-eye limiting magnitude (<6.0); (3) from a blackbody radiation model of the reflected flux, the peak of the reflected components of both satellites is around the $z$ band; and (4) the albedo of the near-infrared range is larger than that of the optical range. Under the assumption that Visorsat and STARLINK-1113 have the same reflectivity, we estimate the covering factor, Cf, of the sunshade on Visorsat, using the blackbody radiation model: the covering factor ranges from 0.18 ≤ Cf ≤ 0.92. From the multivariable analysis of the solar phase angle (Sun–target–observer), the normalized magnitude, and the covering factor, the phase angle versus covering factor distribution presents a moderate anti-correlation between them, suggesting that the magnitudes of Visorsat depend not only on the phase angle but also on the orientation of the sunshade along our line of sight. However, the impact on astronomical observations from Visorsat-designed satellites remains serious. Thus, new countermeasures are necessary for the Starlink satellites to further reduce reflected sunlight.

Investigation of X-band and Ka-band amplitude scintillation based on measurement data collected during ESA’s BepiColombo superior solar conjunction campaign

Solar phase scintillation and solar amplitude scintillation are fundamentally important in deep space mission operations for designing a communication system capable of transmitting signals when the signal path is close to the Sun. The ESA’s BepiColombo measurement data were analyzed in a previous paper in terms of the power spectral density of the solar phase scintillation, also with a comparison with Woo’s solar phase scintillation theory, when X-band and Ka-band signals propagate close to the Sun with a small Sun-Earth-Probe (SEP) angle during the superior solar conjunction campaign in March 2021 in its cruise phase to Mercury. In this paper the solar amplitude scintillation is analyzed both by calculating the power spectral density and the scintillation index. The results of scintillation index, derived from these measurement data, fit the NASA JPL’s scintillation index model.

Koudougou Station TEC’s Variability Seasonal Anomalies Analysis During Fluctuating Events Over Solar Cycle 24

This paper deals with the analysis of anomalies on variations of total electron content (TEC) during fluctuating geomagnetic events through solar cycle 24 at Koudougou station (lat 12°15'N; long:-2°20'E). Study of anomalies was done by comparing the variations of TEC during solstice and equinox seasons and variations of TEC at equinoxes to those at solstices. Comparison was made taking into account solar cycle phases and seasons influences. Equinoctial asymmetry is recorded at ascending and maximum phases. Winter anomaly is observed all night (0000 LT-04 00 LT and 2000 LT-2300 LT) at solar maximum and at all times during the ascending phase, except around 0600 LT and 1800 LT. Semi-annual asymmetry is observed during all phases of solar cycle 24 during fluctuating events.

Photothermal and thermoelectric performance of PCMs doped with nanoparticles and metal foam

Combination of solar thermal power generation and Phase Change Materials (PCMs) helps solve the disadvantages of solar instability. In order to improve the photothermal performance of PCMs, PCMs doped with high thermal conductivity metal foam and nanoparticles were applied. The influence of nanoparticle mass fractions (ω = 0%, 0.5%, 0.8%, 1.0%), pore densities of metal foam (PPI = 5, 10, 15), light intensities (I = 600–1000 mw/cm2) was discussed. Results showed that an increase in pore densities of metal foam is beneficial to improving the thermal conductivity and increasing the temperature difference, the metal foam PPI = 15 can bring a maximum temperature rise of 7.9%, and can increase the temperature difference growth rate by 24.82%. The addition of nanoparticles increases the maximum voltage and power by up to 8.53% and 8.0%, respectively. This research has certain reference and guiding value for the application of thermoelectric power generation.