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Alloy phase change materials (PCM) are key materials in latent heat storage systems for solar thermal power generation, however, their application is limited by the high corrosion and oxidation problems of alloys. To reduce the erosion problem of alloy PCM, SiC-based ceramic encapsulated flake graphite (EG) modified Al-Cu28-Si6 alloy was used to successfully prepare composite PCM with high compatibility and oxidation resistance. Adopting static erosion test method, the composite PCM was subjected to 50 thermal cycles (25–1000 °C holding time of 10 h was recorded as 1 cycle). The results showed that SiC-based ceramics have excellent corrosion resistance to composite PCM with 10 wt% EG added, which due to the excellent reticulation and encapsulation of EG. Based on the Young-Laplace equation and the contact angle, the erosion resistance mechanism of silicon carbide ceramic alloys has been revealed. SiC-based ceramic-PCM sensible heat-latent heat composite heat storage material was expected to be used for high-temperature heat storage in solar thermal power generation. [ABSTRACT FROM AUTHOR]

The article describes design of a solar dryer with a heat pump, which is used to increase heat output of the unit twice to solve the problem of using environmentally clean sources of thermal energy for fruit drying. The authors of the research have developed methodology of substantiation of the solar dryer parameters, which is applied to design and justify the optimal technological modes and parameters of the heat carrier in the unit, to describe the heat transfer characteristics of the unit operation, to assess the impact of physical environmental parameters on technological indicators of the process. The novelty described in the article is developed design of a solar dryer with a heat pump and to substantiate its constructive and technological structure. The work supplies scientifically substantiated methodic recommendations on composing and forecasting a parametric series of solar dryers for the conditions of private households and farms, and grounds their design parameters. Designed solar dryer with a heat pump affects solving environmental problems of power engineering due to substitution of the electric and thermal energy by the one obtained from solar energy, and mitigation of social problems by creating new job places needed when producing, installing and exploiting such units. The obtained results can be used for designing and improving technical aspects of fruit drying, to increase technological and energy efficiency of the process. [ABSTRACT FROM AUTHOR]

Solar heating is important for many applications but less attractive for concepts requiring intermittent heating, such as ionic thermoelectric supercapacitors (ITESCs). However, the heating process even at constant solar illumination can be converted to temperature oscillations through water infiltration and evaporation. Here, this process is demonstrated for a carbon nanotube‐cellulose membrane and used to induce temporally varying temperature gradients across an ITESC, which enables continuous operation through repeated charge and discharge cycles. A temperature variation of 10 K can be generated on the top electrode, which leads to a variation in the temperature difference across the ITESC of 7.5 K. Precise control over charge and discharge durations can be achieved by adjusting the volume and interval of the added water. The concept of temporarily adjusting temperatures by evaporative cooling may be extended to create intermittent heating also for other heat sources that are typically constant. [ABSTRACT FROM AUTHOR]

Oscillatory reconnection is a specific type of time-dependent reconnection which involves periodic changes in the magnetic topology of a null point. The mechanism has been reported for a variety of magnetic field strengths and configurations, background temperatures, and densities. All these studies report an oscillation in the current density at the null point, but also report a variety of periods, amplitudes, and overall behaviors. We conduct a parametric study for equilibrium magnetic field strength and initial background temperature, solving two-dimensional resistive magnetohydrodynamic equations around a magnetic X-point. We introduce a parameter space for the ratio of internal to magnetic energy and find self-similar solutions for simulations where this ratio is below 0.1 (which represents a magnetically dominated environment or, equivalently, a low-beta plasma). Self-similarity can be seen in oscillations in the current density at the null (including amplitude and period), ohmic heating, and the temperature generated via reconnection jets. The parameter space of energy ratios also allows us to contextualize previous studies of the oscillatory reconnection mechanism and bring those different studies together into a single unified understanding. [ABSTRACT FROM AUTHOR]

Accurately measuring the actual building performance would be a significant step toward performance contracting. Methods under occupancy have operational advantages but come with additional constraints due to the variability of weather and occupancy conditions, which cannot be overlooked. Especially in recent, well-insulated buildings, since solar gains are a larger contribution to the global heat balance. This work aims to enhance the accuracy of the Heat Transfer Coefficient estimation in an occupied building by taking better account of solar gains in multilinear regression models. The approach adopted here considers solar gains from both the incident solar heat flux through glazing and from the opaque elements of a building by calculating an equivalent outdoor temperature. This model feeds a multilinear regression model whose parameters are estimated by Bayesian inference. Our model for estimating HTC is validated against a set of virtual data from a simulated detached house under different weather conditions. [ABSTRACT FROM AUTHOR]

High-energy electrons carry much of a solar flare's energy. Therefore, understanding changes in electron beam distributions during their propagation is crucial. A key focus of this paper is how the cospatial return current reduces the energy flux carried by these accelerated electrons. We systematically compute this reduction for various beam and plasma parameters relevant to solar flares. Our 1D model accounts for collisions between beam and plasma electrons, return-current electric-field deceleration, thermalization in a warm target approximation, and runaway electron contributions. The results focus on the classical (Spitzer) regime, offering a valuable benchmark for energy flux reduction and its extent. Return-current losses are only negligible for the lowest nonthermal fluxes. We calculate the conditions for return-current losses to become significant and estimate the extent of the modification to the beam's energy flux density. We also calculate two additional conditions that occur for higher injected fluxes: (1) where runaway electrons become significant, and (2) where current-driven instabilities might become significant, requiring a model that self-consistently accounts for them. Condition 2 is relaxed and the energy flux losses are reduced in the presence of runaway electrons. All results are dependent on beam and cospatial plasma parameters. We also examine the importance of the reflection of beam electrons by the return-current electric field. We show that the interpretation of a number of flares needs to be reviewed to account for the effects of return currents. [ABSTRACT FROM AUTHOR]

Chlorophyll in phytoplankton absorbs solar radiation (SR) and affects the thermal structure and dynamics within upwelling regions. However, research on this process across global‐scale coastal upwelling systems is still lacking. Here, we use a coupled ocean‐biogeochemical model to investigate differing responses to chlorophyll‐induced solar absorption between Pacific and Atlantic coastal upwelling regions. Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwelling. In the Pacific, the shading effect of the surface chlorophyll maximum leads to colder subsurface water, which is then upwelled, contributing to cooling. The more stratified upper ocean leads to shallower mixed layer depth, intensifying offshore transport and upwelling. In the Atlantic, the absorption of SR by the subsurface chlorophyll maximum causes warmer and weaker upwelling. The processes described, in turn, trigger positive feedback to ocean biogeochemistry and potentially interact with climate dynamics, underscoring the necessity to incorporate them into Earth system models. Plain Language Summary: Chlorophyll and related pigments in phytoplankton play a key role in absorbing solar radiation and regulating ocean temperatures. In some coastal upwelling regions along the eastern boundaries of oceans, where chlorophyll concentrations are high, studies have suggested that the solar heat absorbed by chlorophyll can influence the temperatures and strength of upwelling. However, there is no study focusing on this process across global coastal upwelling zones. Here, we use computer simulations of ocean and phytoplankton to explore the effects of chlorophyll‐induced solar absorption on upwelling temperatures and strength on a global scale. Our study suggests that this effect varies between Pacific and Atlantic coastal upwelling regions due to their different spatial distributions of chlorophyll: surface chlorophyll in the Pacific warms the water after it has risen to the surface and as it is flowing offshore, while subsurface chlorophyll in the Atlantic warms the water before it rises to the surface. As a result, chlorophyll‐induced solar absorption leads to colder and stronger coastal upwelling in Pacific but warmer and weaker upwelling in Atlantic. Given the limited consideration of this process in previous studies, we emphasize the importance of incorporating it, along with regional differences, into future simulations. Key Points: Chlorophyll‐induced solar absorption leads to colder Pacific coastal upwelling but warmer Atlantic coastal upwellingIn Pacific, chlorophyll‐induced temperature variations intensify ocean stratification and coastal upwelling, in contrast to AtlanticChlorophyll‐induced variations in ocean physics trigger positive feedback, enhancing chlorophyll distributions in coastal upwelling regions [ABSTRACT FROM AUTHOR]

Maintaining a thermally comfortable living and working environment with renewable energy sources is crucial for human health. However, achieving temperature self-regulation in individual textiles without external interventions remains a challenge. Here, we present a dual-modal photonic textile capable of autonomously achieving both low-temperature solar heating and high-temperature radiative cooling under sunlight. This innovative textile is primarily composed of textile fibers that are functionalized with thermochromic microcapsules encapsulated in graphene and barium sulfate coatings, which exhibit approximately 80% visible light optical modulation when integrated into the fabric. We demonstrate that garment and tent (3.5 m × 2.9 m × 1.3 m) fabricated from these textiles can achieve temperature-adaptive, all-weather thermal management, expanding the thermal comfort range by 8.5°C. This research showcases notable potential for applications in fabric-related heat management and highlights the importance of exploring temperature-adaptive solutions for a sustainable and healthy lifestyle. [ABSTRACT FROM AUTHOR]

The utilization of electric energy is rising in the technological world. Solar PV (photovoltaic) cells convert sunlight into electricity, and sunlight radiation also has heat, reducing the panel's efficiency. The heat should control the limited value or otherwise reduce the panel's performance so that heat is moved to the cooling medium, thus maintaining the heat within the functioning limit. The proposed method is explained by the probability of cooling the monocrystalline and polycrystalline structures used as neem oil through an integrated oil container fitted into the unit's backside—the neem oil acts as phase-changing material (PCM). The solar PV rear side neem oil absorbs the heat of the solar PV panel. The neem oil is not filled in the backside tank completely for the reason that the oil needed some breathing gap. The breathing gap of PCM is to enhance the heat-withstand efficiency. The backside neem oil is replaced every 30 min. As an outcome, the front side of solar PV heat is reduced. Neem oil has not polluted the environment and is thus also used to exchange noxious mineral oils. The neem oil moved from the depository tank to the backside of the unit and together into an additional depositor tank, thus being able to be reused. The proposed method is investigated, and functioning comparison occurs in different PV types, such as monocrystalline and polycrystalline modules, with various kinds of edible oil. Thus, the critical outcomes of the monocrystalline and polycrystalline PV panels are to decrease the panel temperature by 2.29% and 4.34%, respectively, and enhance the efficiency of the PV panels by 15.0% and 17.8%, respectively. [ABSTRACT FROM AUTHOR]

Deficiencies in upper ocean vertical mixing parameterizations contribute to tropical upper ocean biases in global coupled general circulation models, affecting their simulated ocean heat uptake and ENSO variability. To better understand these deficiencies, we develop a suite of ocean model experiments including both idealized single column models and realistic global simulations. The vertical mixing parameterizations are first evaluated using large eddy simulations as a baseline to assess uncertainties and evaluate their implied turbulent mixing. Global models are then developed following NOAA/GFDL's 0.25° nominal horizontal grid spacing OM4 (uncoupled) configuration of the MOM6 ocean model, with various modifications that target biases in the original model. We test several enhancements to the existing mixing schemes and evaluate them against observational constraints from Tropical Atmosphere Ocean moorings and Argo floats. In particular, we find that we can improve the diurnal variability of mixing in OM4 via modifications to its surface boundary layer mixing scheme, and can improve the net mixing in the upper thermocline by reducing the background vertical viscosity, allowing for more realistic, less diffuse currents. The improved OM4 model better represents the mixing, leading to improved diurnal deep‐cycle variability, a more realistic time‐mean tropical thermocline structure, and a better Pacific Equatorial Undercurrent. Plain Language Summary: Computational models of the oceanic and atmospheric circulation are critical tools for understanding and projecting changes in the Earth's climate. These models have errors that can arise from many sources, including model formulation or the choices in applying the model. One of the more well known sources of error is the representation of turbulent mixing. In this work we consider specially designed small‐scale models that simulate turbulent mixing, and use their results to improve the representation of turbulence and its induced mixing in large‐scale models. In particular, we investigate how the intensity of mixing varies throughout the day, considering the progression from deep mixing during cooler nighttime surface conditions to shallower mixing in the presence of strong solar heating during the day. We find some modifications to the mixing scheme in the ocean climate model that can improve the model solutions when compared to the real ocean. Key Points: Large eddy simulation results are used to evaluate the diurnal cycle of equatorial turbulent mixing in the OM4 ocean modelReducing vertical viscosity in an ocean model increases shear near the Equatorial Undercurrent (EUC) and can result in increased vertical mixingVertical grid spacing of a few meters helps to resolve shear mixing events within and below the EUC in ocean models [ABSTRACT FROM AUTHOR]

Drying has been widely used to provide a longer shelf life for various agricultural products. The moisture content can be reduced to prevent the spoilage of harvested agricultural products, in order to inhibit the growth of bacteria, yeasts, and molds. Among them, the drying system of solar-assisted air source heat pumps has drawn much attention in recent years, due to excellent energy saving and high dried quality of products. However, solar energy can be badly wasted, when the water tank temperature cannot meet the drying requirement, because of the high drying temperature during the middle and last drying stage. In this study, a solar-assisted multi-heat source heat pump (SMSHP) drying system was proposed to incorporate a watersource evaporator into the existing solar-assisted air source heat pump drying system, in order to improve the economic, and environmental benefit and the utilization rate. The fuzzy analytic hierarchy process was used to develop the optimization model of the SMSHP drying system. The optimization variables were selected as the collector inclination Angle, collector area, water tank volume, heat pump power, water pump flow rate, and airflow rate. The economy, system performance, and energy efficiency were chosen as the optimization objectives of the model. After that, the multi-objective optimization function of the SMSHP drying system was established to obtain a total of 25 groups of optimal combinations after the orthogonal test. Moreover, the simulation model of the SMSHP drying system was developed using the TRNSYS software. The accuracy of the model was verified, according to the experimental platform. Then the 25 groups of optimal combination parameters were introduced into the TRNSYS simulation model of the SMSHP drying system. The optimal parameter group was obtained with the highest system performance. Finally, the optimal and original parameter sets were compared and analyzed to verify the practicability and reliability of the model. The results showed that only 20 groups of 25 optimization parameters met the requirements of the drying process. The relative humidity of the air in the drying room was too high to meet the system requirements in the rest 5 groups. The economy, system performance, and energy efficiency were compared on the 25 groups' optimization. The optimization objective function of the 10th group was the lowest, indicating the optimal objective function. In addition, the TRNSYS simulation also showed that the optimal combination of parameters met the requirement of the drying process. The optimization parameter group 10 was the optimal one. The optimal parameters were obtained: the collector inclination angle was 35 °, the collector area was 40 m², the water tank volume was 1.5 m³, the heat pump power was 10 kW, the water pump flow rate was 2700 kg/h, and the airflow rate was 3500 m³ /h. Compared with the TRNSYS simulation of the original and the optimal parameters, the cost of the SMSHP drying system was reduced by 4.78%, whereas, the system performance and energy saving were improved by 17.08%, and 9.41%, respectively. All indicators were comprehensively improved by 6.27%. The multi-objective optimization of the solar multi-heat source heat pump drying system was carried out using a fuzzy analytic hierarchy process and TRNSYS simulation analysis. The finding has an important guiding significance to improve the performance of solar combined heat pump drying systems. [ABSTRACT FROM AUTHOR]

This paper presents a solar chimney that acts as a heat accumulator. It is based on its alternating charging (melting of the phase change material—PCM) and discharging (solidification), which helps to save energy and ensures stable operation of the solar chimney. In this paper, special attention has been paid to the heat dissipation process (solidification of the PCM). The theoretical model of solidification has been solved in an original way. This paper presents a new simple theoretical model for the solidification of the PCM on a flat plate and presents the results of numerical tests. The theoretical model presents a method for determining the heat transfer coefficient at the solidification front of the PCM. In addition, the heat transfer coefficient from the flowing air to the outer surface of the solidifying front plate was determined experimentally in an original way. The heat transfer coefficient values resulting from the experiments may be employed in order to calculate the heat transfer coefficient for air flowing through the slot of the collector in the solar chimney. The calculated value of the heat transfer coefficient was 18.55 W/m²K. [ABSTRACT FROM AUTHOR]

This study addresses the challenge of optimizing flat-plate solar collector design, traditionally reliant on trial-and-error and simplified engineering design methods. We propose using physics-informed neural networks (PINNs) to predict optimal design conditions in a range of data that not only characterized the highlands of Ecuador but also similar geographical locations. The model integrates three interconnected neural networks to predict global collector efficiency by considering atmospheric, geometric, and physical variables, including overall loss coefficient, efficiency factors, outlet fluid temperature, and useful heat gain. The PINNs model surpasses traditional simplified thermodynamic equations employed in engineering design by effectively integrating thermodynamic principles with data-driven insights, offering more accurate modeling of nonlinear phenomena. This approach enhances the precision of solar collector performance predictions, making it particularly valuable for optimizing designs in Ecuador's highlands and similar regions with unique climatic conditions. The ANN predicted a collector overall loss coefficient of 5.199 W/(m2·K), closely matching the thermodynamic model's 5.189 W/(m2·K), with similar accuracy in collector useful energy gain (722.85 W) and global collector efficiency (33.68%). Although the PINNs model showed minor discrepancies in certain parameters, it outperformed traditional methods in capturing the complex, nonlinear behavior of the data set, especially in predicting outlet fluid temperature (55.05 °C vs. 67.22 °C). [ABSTRACT FROM AUTHOR]

Context: The coat is the first defense layer protecting animals from direct sunlight, influencing radiant-heat absorption and loss. Dark coat colour may increase animal heat impact because of higher absorption of solar radiation. Aims: We investigated the impact of pigmentation intensity on the heads of animals and their thermal responses to solar radiation. Furthermore, we compared the thermal responses between dark and light brown-coloured animals, to determine whether the duration of sun and shade exposure (3 h each) is sufficient to differentiate the heat gain and losses between the two groups. Methods: The effect of coat colour on rectal and surface temperatures in Boer goats, classified according to their head pigmentation pattern as dark (DB, N = 11) or light brown (LB, N = 11), exposed to sun and shade, was evaluated. The animals' body and head surface temperatures were measured the same day before, during, and after sun exposure by using infrared thermography. Individual thermographic images were analysed by body regions (rump, leg, neck) and head areas (eye, ear, upper and lower part of the head, and the muzzle). Key results: During solar radiation, all measured variables increased. In the shade, the rump, leg, and neck surfaces remained elevated, whereas the head area cooled down faster, with the highest temperature changes measured for the ear of about 10%. Most surface cooling occurred within 30 min after returning to the shade. Coat colour groups differed only in higher overall muzzle temperature of DB than that of LB goats (P = 0.048). Correlations between rectal and surface temperatures were low to medium, ranging from −0.02 (eye) to 0.31 (muzzle). Conclusions: The head area is suggested as the important thermal window for heat dissipation and selective brain cooling. Light brown-headed animals were more efficient in eliminating the heat gained from solar radiation when returned to shade. Implications: The colouration of the animal's head may play an important role for its heat tolerance. As an easy-to-recognise characteristic, coat colour can serve as a selection trait for local goat populations. In view of global warming, selection for lighter coat colour in domestic ruminants may also become important even under temperate climates. Coat colour plays an important role in heat tolerance of livestock, because dark coat colour may increase animal heat stress as a result of higher absorption of solar radiation. We focused on the influence of head pigmentation of Boer goats and found light brown-headed animals to be more efficient in eliminating the solar heat gained during outdoor grazing when returned to the shade. In view of global warming, breeding for light coat colour in domestic ruminants could alleviate heat stress. [ABSTRACT FROM AUTHOR]

Accurate air temperatures underpin environmental research. Most professional meteorological air temperature measurements still expose thermometers within traditional, naturally ventilated screens. Their representation of true air temperature depends on screen airflow, and therefore local winds. Accuracies of daily maximum (Tmax) and minimum (Tmin) air temperatures are assessed by comparison between a naturally ventilated large conventional screen and a co‐located aspirated reference screen. In over 1200 days' data, the naturally ventilated Tmin and Tmax both showed small (median < 0.06°C) cold bias, but, in 1% of cases, warm Tmax bias and cold Tmin bias >|1°C|. The Tmin cold bias is associated with calm clear nights, and the Tmax warm bias events with calm winter days at low sun angles, allowing solar heating of the screen. The prevalence of poor natural ventilation, potentially affecting Tmin and Tmax, is estimated across European sites. Poor ventilation occurred at Tmin for 12% of values, and at Tmax for 4%. Climatological averaging will reduce these effects, but, without corroborating wind data, statistical changes in Tmin or Tmax, including identifying "Tropical Nights" (Tmin > 20°C) or occurrences of winter extremes, may have limited value. Wider adoption of aspirated thermometer screens, with an initial overlap period, will largely eliminate these effects. [ABSTRACT FROM AUTHOR]

In addition to solar water heating and transformers, these applications of research include heat exchangers and braking fluids, as well as acoustics and microelectronics. The mathematical model of Poiseuille hybrid nanofluid flow through a microchannel is considered with differing thermal conductivity and viscosity parameters. This mathematical model has mainly been developed to cater to the diversity of the hybrid nanofluid properties, which contains oxide and metal nanoparticles, for example, Cu and Al2O3 immersed in water (H2O) and Ethylene glycol (EG) as the base liquid. The substructure for hybrid nanofluid abides by the mixture of 20% water while the rest is filled with EG. Moreover, the perception of entropy is analyzed. The dimensional form of the current problem is deformed into a non-dimensional form using the appropriate choice of similarity transformation. Thence, the Runge–Kutta-Fehlberg method is being used to treat the numerical solution for the problem. The graphs spectacle the entropy, Bejan numbers, and physical behavior of the contributing factors to the flow phenomena. The numerical results of the rate coefficients for these parameters are shown in the table below. Furthermore, a comparison analysis is conducted to confirm the current result with prior work demonstrating a higher degree of concordance. [ABSTRACT FROM AUTHOR]

Both composition and temperature play a crucial role in determining the NO radiative cooling in lower thermosphere as observed by TIMED/SABER. In this work, we present a detailed investigation of seasonal variation in thermospheric NO radiative cooling. We have carried forward the investigation of Li et al. (2018) regarding the variations in local nighttime peak NO radiative cooling and its altitude during solar maximum and solar minimum conditions. By analyzing latitudinal changes over quiet times for each month in year 2018, it is evident that both the investigated parameters exhibit summer-winter variability. The qualitative contribution of different species (i.e., NO, and O), and temperatures in determining the vertical profile of NO radiative cooling for different latitudes is investigated by utilizing the NRLMSISE-00 estimated parameters, and SNOE observed NO density. The temperature, NO density, and compositional variations due to asymmetrical solar heating and associated summer-to-winter circulation in both the hemispheres during solar minimum conditions seem to be the dominating factor in controlling the NO radiative cooling during different seasons. The altitudes at which maximum cooling by NO occurs exhibits an inverse correlation with the amount of radiative cooling. The region of enhanced NO densities (polar and summer hemispheric low-mid latitude regions) have larger NO radiative cooling with lower peak altitudes in comparison to other regions (equatorial to winter hemispheric low-mid latitude regions), where NO radiative cooling is low with higher peak altitude values. [ABSTRACT FROM AUTHOR]

Characterizing the exchange of water between the Martian atmosphere and the (sub)surface is a major challenge for understanding the mechanisms that regulate the water cycle. Here we present a new data set of water ice detected on the Martian surface with the Thermal Emission Imaging System (THEMIS). The detection is based on the correlation between bright blue‐white patterns in visible images and a temperature measured in the infrared that is too warm to be associated with CO2 ${\mathrm{CO}}_{2}$ ice and interpreted instead as water ice. Using this method, we detect ice down to 21.4°S, 48.4°N, on pole‐facing slopes at mid‐latitudes, and on any surface orientation poleward of 45° latitude. Water ice observed with THEMIS is most likely seasonal rather than diurnal. Our data set is consistent with near‐infrared frost detections and predictions by the Mars Planetary Climate Model. Water frost average temperature is 170 K, and the maximum temperature measured is 243 K, lower than the water ice melting point. Melting of pure water ice on the surface is unlikely due to cooling by latent heat during its sublimation. However, 243 THEMIS images show frosts that are hot enough to form brines if salts are present on the surface. The water vapor pressure at the surface, calculated from the ice temperature, indicates a dry atmosphere in early spring, during the recession of the CO2 ${\text{CO}}_{2}$ ice cap. The large amount of water vapor released by the sublimation of warm frost cannot stabilize subsurface ice at mid‐latitudes. Plain Language Summary: During spring, parts of the Martian surface at mid and high latitudes are covered by a thin, bright layer of frost. Some of these ice deposits are made of CO2 ${\text{CO}}_{2}$ ice, but some frosts have a temperature that is too warm to be CO2 ${\text{CO}}_{2}$ frosts and are thus constituted of water ice that forms in winter and sublimes in spring. We conducted a spatial and temporal mapping of these ice deposits using the camera THEMIS onboard the Mars Odyssey orbiter to better characterize the exchange of volatiles between the Martian atmosphere and the surface. Water ice is preferentially detected on pole‐facing slopes rather than flat surfaces below 45° latitude and all types of surfaces at higher latitudes. In late spring, water ice cannot melt despite solar heating because it cools down with the release of latent heat. On the other hand, these ice deposits are warm enough to form brines if salt crystals are present at the surface. When the frost sublimes, it serves as a source of water vapor that can diffuse into the ground and recondense to stabilize the permafrost below the surface. However, this effect is not sufficient to stabilize subsurface ice at low latitudes. Key Points: Seasonal water frosts on Mars are identified with coincident visible and temperature data obtained with THEMIS poleward of 48°N and 21°SWater frosts remain too cold to melt as pure ice. However, the warmest frost deposits observed may co‐exist with brinesWarm water frost, which releases a large amount of water vapor when it sublimates, cannot stabilize the low‐latitude subsurface ice [ABSTRACT FROM AUTHOR]

Recent analyses show the importance of methane shortwave absorption, which many climate models lack. In particular, Allen et al. (2023) used idealized climate model simulations to show that methane shortwave absorption mutes up to 30 % of the surface warming and 60 % of the precipitation increase associated with its longwave radiative effects. Here, we explicitly quantify the radiative and climate impacts due to shortwave absorption of the present-day methane perturbation. Our results corroborate the hypothesis that present-day methane shortwave absorption mutes the warming effects of longwave absorption. For example, the global mean cooling in response to the present-day methane shortwave absorption is -0.10±0.07 K, which offsets 28 % (7 %–55 %) of the surface warming associated with present-day methane longwave radiative effects. The precipitation increase associated with the longwave radiative effects of the present-day methane perturbation (0.012±0.006 mm d -1) is also muted by shortwave absorption but not significantly so (-0.008±0.009 mm d -1). The unique responses to methane shortwave absorption are related to its negative top-of-the-atmosphere effective radiative forcing but positive atmospheric heating and in part to methane's distinctive vertical atmospheric solar heating profile. We also find that the present-day methane shortwave radiative effects, relative to its longwave radiative effects, are about 5 times larger than those under idealized carbon dioxide perturbations. Additional analyses show consistent but non-significant differences between the longwave versus shortwave radiative effects for both methane and carbon dioxide, including a stronger (negative) climate feedback when shortwave radiative effects are included (particularly for methane). We conclude by reiterating that methane remains a potent greenhouse gas. [ABSTRACT FROM AUTHOR]

Performance of Photovoltaic-double skin facade (Photovoltaic-DSF) system in summer has been critical. Owing to high solar ingress, cooling requirement of a building significantly increases. Photovoltaic-DSF system provides a shield and controls the heat gain through fenestration in the interior spaces. In the present article, mathematical correlations are developed for energy characterization of forced-ventilated Photovoltaic-DSF system in India's hot summer zone i.e. Jaipur. The Photovoltaic-DSF system has been installed and monitored for Jaipur's summer months (May to July). L25 Orthogonal array of design parameters (air cavity thickness, air velocity, and PV panel's transparency) and their respective levels have been developed using Taguchi design to perform experiments. Based on experimental results, multiple linear regression has been used to forecast solar heat gain coefficient, PVs electrical power and daylighting illuminance indoors as function of design factors. The statistical significance of mathematical relationships is sorted by variance analysis, which is found to be in good accord with field measurements (R² > 0.90). The proposed correlations are pragmatic in designing Photovoltaic-DSF systems for hot summer conditions. The Photovoltaic-DSF system with 30% transmittance and air velocity of 5 metres per second in 200 mm air cavity thickness achieved maximum energy performance in hot summers. [ABSTRACT FROM AUTHOR]

The mechanism of convective cell initiation and regeneration in the Bandung Basin ( 107. 35 ∘ E - 107. 95 ∘ E ; 6. 75 ∘ S - 7. 25 ∘ S ), Indonesia, is investigated using a Weather Research and Forecasting model. Based on the Cumulative Distribution Function and Regeneration Index, model simulations were conducted using case studies in February–March 2019. Upslope wind flows to the mountain peak in north and south of the basin due to solar heating, carrying water vapor from the bottom of the basin. Therefore, low-level convergence is formed due to the convergence of winds from the bottom of the basin and from outside the basin. The low-level convergence causes the developing updraft, makes atmosphere unstable, and generates convective initiation. The convective system will be developed in the mountains region, produced precipitation, and formed cold pools on the surface. The cold pool will fall down the slopes and convective activity from the mountains will continue to the bottom of the basin. The convective system's outflow causes the cold pool to move in the west–east direction. The cold pool will collide with warmer air from the opposite direction, resulting in an updraft at the cold pool leading edge, and convection will be re-initiated (convective regeneration) in the Bandung Basin, with the new convective system tending to move eastward. [ABSTRACT FROM AUTHOR]

The use of solar heat as energy input for the synthesis of some types of nanomaterials with great demand provides an alternative to the utilization of energy from the grid or other sources, which often come from fossil fuels. Thus, it can be seen as a valid approach to green chemistry. In this work, the synthesis of zinc oxide (ZnO) through a wet chemical method, using low‐temperature solar heat is investigated. The concept of compound parabolic concentrator was employed to construct a solar collector which also served as a synthesis reactor. Solar radiation was concentrated on the outer surface of a tubular receiver, while the synthesis reaction occurred inside. The natural fluctuations of solar radiation caused the synthesis temperature to vary between 50 and 70°C. Three solar syntheses were done at these conditions. For comparison, three other syntheses were done at 50, 60, and 70°C of constant temperature, in an electric hot plate, under controlled laboratory conditions and using electricity from the grid. Crystalline clusters of nanoflakes with sizes between 40.4 and 55.7 nm of pure ZnO were obtained using solar heat, remarkably similar in shape and size to those made in the laboratory at 50°C. However, a slightly lower bandgap energy of 3.27 eV was attained. The band gap energies of the ZnO grown at 50, 60, and 70°C were 3.28, 3.31, and 3.29 eV, respectively. In the ultraviolet range, nearly 90% of absorbance was observed for all the ZnO manufactured, regardless of the synthesis temperature. Therefore, these results may help demonstrate that it is feasible to produce high‐quality ZnO with low‐temperature solar heat, establishing a new green approach for the synthesis of nanomaterials. [ABSTRACT FROM AUTHOR]

Passive radiative cooling is a zero‐energy technology vital for mitigating the energy crisis. However, achieving intelligent thermal management across varying weather conditions (day/night and summer/winter) while maintaining sustainability is a significant challenge. Here, a recyclable biomass film engineered for adaptive, year‐round energy conservation is introduced. This film utilizes porous acetyl cellulose (AC) as a cooling‐side matrix, enabling efficient radiative cooling during hot days (8.5 °C reduction) and minimizing overcooling on cold nights (only 2.5 °C reduction). This performance is facilitated by high solar reflectance (96.3%) and broad‐spectrum infrared emission (95.4%), optimizing atmospheric thermal regulation. The reverse side, coated with carbon black (CB), demonstrates superior solar heating (20.9 °C increase), allowing for effortless switching between cooling and heating by flipping the film. Further, the film employs a solvent‐responsive ethyl cellulose (EC) adhesion, ensuring durability, complete recycling, and reuse. With ultraviolet (UV) resistance, self‐cleaning, and durability, coupled with intelligent thermal management, this work provides new ideas for advanced radiative heat management materials, enabling adaptive control during both daytime/nighttime and summer/winter. [ABSTRACT FROM AUTHOR]

Photochromic smart windows have drawn increasing attention as an approach to improve building energy efficiency and enhance indoor daylight comfort. However, existing photochromic smart windows still block sunlight from entering the room on sunny winter days, causing additional energy consumption for heating. Herein, a dual‐mode smart window is designed with decoupled photo and thermal functions by combining colorless Fe‐doped WO3 photochromic film with window rotation. Based on this, selective heating and cooling of the room between winter and summer is achieved while maintaining the daylight comfort benefits during all seasons. As a proof of concept, the smart window reduces the temperature of a model house by up to 7.9 °C in summer mode, while in winter mode the temperature is only reduced by 0.7 °C. The proposed seasonally adaptive dual‐mode smart window obtains by window rotation overcomes the limitations of conventional photochromic smart windows, which not only achieves better energy efficiency but also retains improved daylight comfort. Furthermore, it demonstrates that the heat absorbed by the smart window can be harnessed to produce electricity through the integration of thermoelectric modules within the glazing, which enhances its impact on reducing energy consumption. [ABSTRACT FROM AUTHOR]

About one-third of world energy production is destined to the industrial sector, with process heat accounting for about 70% of this demand; almost half of this quota is required by endothermic processes operating at temperatures above 400 °C. Concentrated solar thermal technology, thanks to cost-effective high-temperature thermal energy storage solutions, can respond to the renewable thermal energy needs of the industrial sector, thus supporting the decarbonization of hard-to-abate processes. Particularly, parabolic trough technology using binary molten salts as heat transfer fluid and storage medium, operating up to 550 °C, could potentially supply a large part of the high-temperature process heat required by the industry. In this work, four industrial processes, representative of the Italian industrial context, that are well suited for integration with molten salt concentrators are presented and discussed, conceiving for each considered process a specific coupling solution with the solar plant, sizing the solar field and the thermal storage unit, and computing the cost of the process heat and its variation with the storage capacity. Considering cost data from the literature associated with the pre-COVID-19 era, an LCOH comprising the range 5–10 c€/kWhth was obtained for all the cases studied, while taking into account more updated cost data, the calculated LCOH varies from 7 to 13 c€/kWhth. [ABSTRACT FROM AUTHOR]

This article is devoted to increasing the efficiency of ecological solar panels with their combination with the house's roof. A solar panel construction that combines both the solar collector and the building cover is considered. This work investigates the efficiency of solar panels depending on the type of coating, heat-carrying medium mass flow rate, tube diameter, and the distance between the tubes. Among the coatings, Grafplast PDA roofing material is the most effective. Prandelli/Tuborama tubes with a diameter of 16 mm are recommended. The diameter of the tubes significantly affects the efficiency of the solar panel only at low intensity of solar radiation. [ABSTRACT FROM AUTHOR]

Marine low-level clouds are key to the Earth's energy budget due to their expansive coverage over global oceans and their high reflectance of incoming solar radiation. Their responses to anthropogenic aerosol perturbations remain the largest source of uncertainty in estimating the anthropogenic radiative forcing of climate. A major challenge is the quantification of the cloud water response to aerosol perturbations. In particular, the presence of feedbacks through microphysical, dynamical, and thermodynamical pathways at various spatial and temporal scales could augment or weaken the response. Central to this problem is the temporal evolution in cloud adjustment, governed by entangled feedback mechanisms. We apply an innovative conditional Monte Carlo subsampling approach to a large ensemble of diurnal large-eddy simulation of non-precipitating marine stratocumulus to study the role of solar heating in governing the evolution in the relationship between droplet number and cloud water. We find a persistent negative trend in this relationship at night, confirming that the role of microphysically enhanced cloud-top entrainment. After sunrise, the evolution in this relationship appears buffered and converges to ∼-0.2 in the late afternoon. This buffering effect is attributed to a strong dependence of cloud-layer shortwave absorption on cloud liquid water path. These diurnal cycle characteristics further demonstrate a tight connection between cloud brightening potential and the relationship between cloud water and droplet number at sunrise, which has implications for the impact of the timing of advertent aerosol perturbations. [ABSTRACT FROM AUTHOR]

The mismatch between solar radiation resources and building heating demand on a seasonal scale makes cross-seasonal heat storage a crucial technology, especially for plateau areas. Utilizing phase change materials with high energy density and stable heat output effectively improves energy storage efficiency. This study integrates cascaded phase change with a cross-seasonal heat storage system aimed at achieving low-carbon heating. The simulation analyzes heat distribution and temperature changes from the heat storage system to the heating terminal. The results indicate that although the solar collectors operate for 26.3% of the total heat storage and heating period, the cumulative heat stored is 45.4% higher than the total heating load. Heat transferred by the cross-seasonal heat storage system accounts for up to 61.2% of the total heating load. Therefore, the system reduces fuel consumption by 77.6% compared to conventional fossil fuel heating systems. Moreover, radiant floor heating terminals, with a wide range of operating temperatures, match well with cascaded phase change heat storage and can reduce operation time by 19.5% and heat demand by 5.2% compared to conventional radiators. In addition to demonstrating the feasibility of applying cascaded phase change technology in cross-seasonal heat storage heating, this study reveals the lifecycle sustainability due to the shortened heat storage period. The configuration, parameters, and simulation results provide a reference basis for system application and design. [ABSTRACT FROM AUTHOR]

The problem of coronal heating is one of the fundamental problems of solar physics. At present, it is again attracting great interest due to the appearance of a large amount of observational data of high spatial and temporal resolution. These data made it possible to diagnose plasma parameters from observations of waves and oscillations in coronal magnetic structures and, moreover, to introduce analytical constraints on the coronal heating function. In this paper, we propose an approach allowing us to impose constraints on the heating function based on data on the gravitational stratification of the solar atmosphere. The developed algorithm is applied to the altitude profiles of temperature and density in several regions of the solar corona obtained from direct modeling of EUV radiation from the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA). Assuming that the heating function is a power function of temperature and density, we determine the domain of power-index constraints allowing us to realize the observed altitude profiles. The obtained results are combined with the conditions of stability for the entropy and magnetoacoustic modes, to narrow the region of possible parameters further. [ABSTRACT FROM AUTHOR]

In present research the impact of insulation on the discharge process of phase change material (PCM) and a comparison of the thermal performance of a solar cooker using two distinct types of heat transfer fluid (HTF) were experimentally investigated. The aim of this study is to select best performing HTF at the thermal performance point of view. In this experiment a solar cooker with an integrated PCM thermal storage unit was connected through connecting pipes to an evacuated tube solar collector. Separately, water and SigmaTherm-K were used as HTF to evaluate the thermal performance of a solar cooker. Acetanilide of commercial grade was utilized as thermal storage material in the solar cooker. Both charging and discharging of PCM were studied with insulation and without insulation. It was discovered that the temperature attained with PCM in an insulated cooker is 16.5°C and 19.3°C higher than without PCM using water and SigmaTherm-K as HTF respectively. It was concluded that using PCM with the SigmaTherm-K increased the amount of average energy by 29.11% compared to water. The temperature attained by water as cooking load increased from 22°C to 77°C and from 20.1°C to 86.2°C using water and SigmaTherm-K as a HTF respectively. [ABSTRACT FROM AUTHOR]

Due to its significance and effect on interior spaces, photovoltaic Trombe walls are regarded as sustainable technologies. This is because they use solar energy to heat the building and give thermic comfort without requiring the use of cooling equipment to reduce power consumption. not to mention supplying the structure with electricity. To investigate how operational conditions and climatic change affect PV/TW, two empirical models--one with DC fans and the other without--were developed. The two models were compared with each other. To demonstrate their impact on system competency, operating conditions for both dusty and non-dusty days have been examined. When DC fans are used on a dust-free day, the system's electrical and thermal competence is 10.2 percent and 17.6 percent, respectively. The system's electrical and thermal competence levels were 8.4 percent and 40.1 percent, respectively, on a day when there was no dust and when the DC fans were not operating. The system that had fans had a higher thermic and electrical efficiency than the other two systems, with values of 11.9 percent and 6.6 percent, respectively, on the dusty days. The system's thermic and electrical efficiency were 34.1 percent and 3.5 percent, respectively, without fans. This suggests that dusty days have an impact on the experimental system's electrical and thermic efficiency. [ABSTRACT FROM AUTHOR]

Thermal systems for solar air heating have been widely used in both industrial and residential contexts, and are essential for converting and recovering solar energy. Thermal performance in solar air heaters (SAHs) can be improved through the repetitive application of artificial roughness to the surfaces. This research work includes a numerical evaluation of SAH performance with artificial rough surfaces made up of combined transverse trapezoidal ribs and chamfered grooves. The ANSYS Fluent software version 2023 R1 was used to simulate SAH with varying relative roughness pitch (P/e=7.14−35.71), relative roughness heights (e/Dh=.021−.042), and Reynolds number (Re=6000−18000). The RNG k−ϵ model was chosen to forecast an enhancement in Nusselt number (Nu), friction factor (f), and thermohydraulic performance factor (TPF) for the proposed roughness. Out of multiple roughness parameters analyzed, it was determined that the compound turbulator with P/e=10.71 and e/Dh=.042, were the most effective. The TPF for this scenario was determined to be 2.12 at Re=6000. Finally, a numerical based empirical correlations for Nu and f in terms of Re, P/e, and e/Dh were developed. [ABSTRACT FROM AUTHOR]

The climatological characteristics and mechanisms of diurnal variation in summer precipitation over the Tibetan Plateau and its adjacent basins (i.e., the Tarim Basin, Ganges Basin, and Sichuan Basin) are investigated using observational/reanalysis data and a high-resolution dataset from convection-permitting regional climate downscaling. The results indicate that the diurnal variations of precipitation are nearly out of phase between the central Tibetan Plateau and the surrounding basins. Precipitation in the main body of the plateau preferentially occurs in the afternoon-evening hours, primarily attributed to daytime solar heating induced enhancement of local convective instability and large-scale moisture convergence. In contrast, precipitation in the surrounding basins favors the midnight-early-morning period. The diurnal oscillation of the mountain-plain solenoid circulation, which is resultant from the elevated daytime solar heating and nighttime longwave radiative cooling along the topographical slope, is identified as a crucial mechanism governing the diurnal precipitation pattern in all the basins. Additional factors contributing to the midnight-early-morning precipitation include the nocturnal strengthening of the low-level southwest monsoon flow for the Ganges and Sichuan Basins, as well as propagating convection originating from the eastern plateau and leading to a diurnal phase lag in the Sichuan Basin. These results further enhance our knowledge and understanding of the complex diurnal precipitation cycle and associated physical processes over the Tibetan Plateau and nearby regions. [ABSTRACT FROM AUTHOR]

This study investigates the usage of photovoltaic (PV) and thermal collectors separately to assist a heat pump for supplying domestic hot water (DHW). Usage of PV and thermal collectors together to assist a heat pump and experimentally validated simulation of an air source heat pump can be considered as novelty of this study. Firstly, experimental tests were performed in a climatic room to validate the developed simulation model. Four experimental parameters, namely the coefficient of performance of the air source heat pump, average tank temperature, and heat pump inlet and outlet temperatures have been used for the validation and the highest obtained deviation was 4.5%. Simulations were carried out by adding thermal collectors and photovoltaic panels in different combinations, with a maximum of three collectors to assist the heat pump that provides DHW. For scenarios with one and two solar components (PV or thermal), applying only thermal collectors was more efficient and economical for both with a payback of 3.9 years and 4.3 years, respectively. For the scenario with three solar components, although the system supported by one thermal and two photovoltaic collectors was the most efficient option, the system supported by three photovoltaic collectors was the most economical scenario with a payback period of 4.6 years. The study found that combining thermal and photovoltaic collectors can significantly reduce energy consumption for DHW. [ABSTRACT FROM AUTHOR]

Hot-spot generation is critical to the performance and lifespan of photovoltaic (PV) modules; however, the underlying mechanisms of hot-spot formation have not been fully elucidated. This work conducted a localized shading test on a PV module, measured the micro-electrical characteristics and temperature distributions of both the shaded and unshaded cells, calculated the heat-source power densities, and then predicted the occurrence and locations of hot and cold spots via numerical simulations. It was found that, under an irradiance of 750 W/m2, when one cell in a PV module is shaded by 1/2, the unshaded area within the shaded cell exhibited a hot spot, with the temperature reaching up to 77.66 °C, approximately 22.5 °C higher than the surrounding cells. The intrinsic mechanism for the occurrence of the hot spot is that, compared with the unshaded cells, the unshaded portion of the shaded cell can generate an extra significantly large Joule heat power density, about 1079.62 W/m2. The reason for generating such a large Joule heat power density is that this portion is in a reverse-bias state with a high current density flowing through it, according to our measurements. In contrast, the shaded portion forms a cold spot, about 7.5 °C cooler than the surrounding cells. This is because the shaded portion can only generate a Joule heat power density of about 46.98 W/m2 due to the small reverse-bias current density flowing through it and fails to absorb heat from solar irradiance, which is about 645 W/m2. Moreover, this work demonstrates that the hot-spot temperature initially rises and then decreases with increasing shading ratio, with the highest temperatures and the most pronounced temperature changes occurring around a shading ratio of 1/2. The presented method can be also used to evaluate the performance and reliability of various other PV modules under local shading conditions. [ABSTRACT FROM AUTHOR]

This research paper examines how multi-angled façade systems improve and optimise energy performance compared to a flat façade and meet sustainability targets for lower energy use to align with UN SDGs 3, 11, 12, and 13. The multi-angled façade system does not tilt up and down. Instead, it employs two different window orientations on a vertical axis (left and right). The large portion orients more to the north to allow more daylight to penetrate inside the room, and the small part is oriented more to the south to provide passive solar heating. The investigations in this research paper were carried out using version 4.8 of the IDA ICE software, and the researchers evaluated the energy consumption, the energy action through the façade, and the building's inside operative temperature. The results of this paper present the simulation findings for primary energy consumption in different scenarios. For example, the researchers explain that one can save 6.3 kWh/(m2·year) when using a multi-angled façade system compared to a flat façade. This is in addition to improving the thermal indoor climate that results from using the façades. The conclusions of the research show that the façade with multiple angles maximises using daylight and optimises solar power, thus avoiding overheating issues. [ABSTRACT FROM AUTHOR]

Self-shading building form has a significant influence on indoor solar gains and energy performance. This paper presented a methodology for quantifying self-shading building forms, which categorized them into three types: inclined, cantilevered, and hybrid (inclined and cantilevered). The prediction model for the quantitative indexes and solar heat gains through windows was established through regression analysis, while the influence of proposed self-shading building forms on energy performance in different climatic regions of China was evaluated and compared. Results suggest that energy-saving potential of the cantilevered type is the highest, followed by the hybrid type. Compared to the south orientation, energy-saving potentials for east and west orientations are more pronounced. As building location changes from south to north, energy-saving potential is increasingly influenced by orientation. The proposed self-shading building forms have a maximum energy-saving potential of 14%, 23%, and 22% for Jinan, Shanghai, and Guangzhou respectively. Finally, corresponding design strategies were suggested to provide guidance and assistance for designers. [ABSTRACT FROM AUTHOR]

The coronal heating problem is considered one of the most puzzling problems in solar physics. It is based on the question of why the corona temperature reaches a temperature of over 2 × 10 6 K whereas the temperature of the surface of the sun has about 10 3 - 10 4 K. Since the corona is far away from the source of heat, it is realistic that the outer surface should be cooler. Solar physicists and astrophysicists have tried for several decades to solve this puzzle by supplying heat to the corona, despite several advances in MHD theory, computational and numerical simulations. Although these candidates' sources of energy hold a number of drawbacks, the problem is still open. A motivating approach has been proposed by Walsh which consists of supplying a time-dependent sinusoidal heating function to the heat to preserve the loop at coronal temperature. Yet, the loop temperature at ∼ 2 × 10 6 K is preserved and cools only if a critical frequency is exceeded. In this study, it was found that the MHD formulation of the Walsh approach in fractal dimensions may offer a potential solution to the problem. In particular, oscillations of the temperature in the space-fractal dimension close to unity relax quicker than those with smaller values. For time-fractal dimensions much smaller than unity, the temperature enters a state of steady state oscillations after a long time. Our analyses also reveal irregularities in the propagation of temperature over a long period of time. For low frequency and space-fractal dimensions close to unity and low time-fractal dimensions, the temperature enters a cycle of an oscillating phase by rising and falling gradually. It is probable that the loop will stay hot after a series of cycles, and extended periods of no heating are not possible for small frequencies. Additional features related to the propagation of the magnetic field in low-Reynolds numbers are discussed. [ABSTRACT FROM AUTHOR]

Solar-assisted Photovoltaic-Membrane Distillation (PMD) is a passive tool to cool and distillate salty water. A theoretical study was conducted in the current work using the COMSOL Multiphysics version 5.6 to develop the CFD model of the PMD. The meteorological data of Baghdad-Iraq was obtained using Meteonorm software V8.0.3.Effects of membrane thickness, space between evaporation and condensation layer, height of fins, number of fins, and inlet water temperature on cell temperature and water productivity were investigated. Thickness of 100 µm exhibited a minimum temperature polarization and maximum membrane coefficient. Space thickness of 2.5 mm exhibited a temperature difference of 4°C between evaporation and condensation layers. Integrating the PMD system into solar panel reduced the cell surface temperature by 7oC. Adding a heat sink of 5 fins with a fin height of 2 cm resulted in a maximum cell temperature of 50 oC and yielded water at point 0.615 kg/h.m2 rate. [ABSTRACT FROM AUTHOR]

This study undertakes the comparative layout study of a V-grooved solar air heater (SAH) with a view to show the optimum design layout for the air heater. Several studies have been conducted on comparing isolated V-groove SAH with other designs of SAH. However, from literature there have not been studies on the comparative layout pattern of V-groove SAHs. It was equally, observed from literature that design layouts of V-groove systems are mainly parallel in nature. Thus, there is a knowledge gap on studies focusing on the layout pattern of Vgrooved systems. Thus, the paper seeks to address this with the research question as "What is the optimum layout for a V-groove solar air heater?" In comparison to active mode of solar air heating, the heat energy analysis of passive solar air heaters, has not been widely studied. Hence, the study is limited to natural convection systems. The study focuses on comparative analysis/evaluation of two basic layout of V-grooved solar air heater- parallel and perpendicular air flow design layouts. The outcome of the work has revealed that the systems can easily be adapted to low temperature applications. From the study, it is deduced that even though the Parallel designed layout of V-groove SAH showed a better efficiency when compared to the Perpendicular designed layout of V-groove SAH that both of them are statistically the same at 5% probanility level using the completely randomized design (CRD) statistical method. The layout pattern does not necessarily mean better output in operation. However when compared to similar works done using the same dimensions for flat plate designs that there is an appreciable improvement in the efficiency of operation. [ABSTRACT FROM AUTHOR]

The growing use of glass in architecture has driven research into reducing its energy consumption. Thermochromic (TC) glass technology shows promise for enhancing building energy efficiency by regulating solar heat dynamically. Although TC glass helps reduce heat radiation, additional solutions like Low-E or vacuum glass are needed to control heat convection and conduction. Low-E glass, while effective in lowering heat transfer, may increase surface temperature. Thermo-sensitive hydrogels, known for their light-scattering properties at high temperatures, have been explored to complement TC glass. However, their stability at elevated temperatures remains a challenge, especially for applications requiring durability under varying weather conditions. This study proposes enhancing the adhesion between hydrogel and glass by introducing silica–oxygen bonds. As a result, TC glass demonstrates stable performance over 100 cycles within temperature ranges from 85 °C to 30 °C in summer and 40 °C to −20 °C in winter. Furthermore, by incorporating ethylene glycol, the freezing point of TC glass is reduced to −26 °C, rendering it suitable for use in colder regions. The implementation of TC glass effectively addresses the dual requirements of summer shading and winter heating in areas with both cold winters and hot summers, significantly reducing building energy consumption. This study contributes substantially to developing advanced intelligent building materials, paving the way for more sustainable architectural designs. [ABSTRACT FROM AUTHOR]

The management of organic waste through anaerobic digestion is an alternative to energy recovery. This research focused on evaluating the production of biogas with different inoculums. For this purpose, two types of systems were implemented—one used a heating system controlled by an STC-1000 thermostat, while the other used a solar heating system under a polycarbonate parabolic trough. The experiment was carried out at laboratory level with 3 L PET bottle biodigesters and the biogas produced was collected with the water displacement technique in 3 L bottles, calibrated every 50 mL, over 43 days. Inoculums of the following manure concentrations were used: water (1:5, 1:2, 1:3) mixed with Caesalpinia spinosa meal and molasses. The results determined that the thermostat-controlled heating system generated 69.6 mL/day of biogas while the other system produced 610.9 mL/day. On the other hand, the T1 treatment with a manure:water ratio of 1:5 and molasses and Caesalpinia spinosa meal inoculums in both systems had a higher average biogas volume. In terms of methane (CH₄), the highest value of 76.9% was obtained through the T1 treatment under the controlled heating system. This allows the production of biogas with a high concentration of methane, which in future applications can be utilized for residential or industrial purposes, promoting economic, social and environmental development. Since the main challenge in the production of biogas is to reduce the digestion time, which is influenced by the temperature of the site, two types of inoculums with a low cost and easy access were used. [ABSTRACT FROM AUTHOR]

The energy consumption of residential buildings plays a crucial role in overall energy consumption and environmental sustainability. This paper aims to conduct an energy analysis of a residential house located in China, with a focus on comparing the accuracy of the model, identifying areas for improvement, and proposing energy-efficient solutions. Four sets of temperature sensors were placed to monitor the ambient temperature at which the building is located and the indoor temperature of the residential building during a heating season. The energy consumption of keeping the building running at a low temperature was recorded and compared with the simulation results to verify the accuracy of the model. The monitoring results give the weekly average temperature of each zone on each floor, and the door and window positions, room layouts, and orientations are discussed to analyze the thermal response of the building. In addition, the effect of the heat transfer coefficient of the exterior walls, the heat transfer coefficient of the roof, and the solar heat gain coefficient (SHGC) of the exterior windows on the heating energy consumption of the building are further analyzed through simulations. The results show that, after adding a certain thickness of insulation to the exterior walls and roofs of a building, increasing the thickness of the insulation layer produces little extra energy saving. The use of building windows with high SHGC can effectively reduce building heating energy consumption. [ABSTRACT FROM AUTHOR]

The diurnal cycling of the surface mixing/mixed layer (ML) depth, air‐sea heat flux, and vertical profiles of the temperature and turbulent kinetic energy dissipation rate in the tropical central South China Sea was observed in summer (June 2017) and winter (January 2018). In the daytime, solar heating warmed and stabilized the ML, and the thickness of the ML can be well characterized by the Zilitinkevich scale as noted in previous studies. By contrast, in the nighttime the ML was deepened by convective turbulence generated by surface cooling. Guided by these observations, we have derived a simple scaling for the nighttime deepening of the ML by simplifying the classic Kraus‐Turner type model. We show that the variation of the ML depth can be scaled by a function of the wind speed, air‐sea heat flux and the temporal variation of the sea surface temperature, all of which are observable variables at the sea surface. It is found that the scaling works well in reproducing observed variations of the ML depth from hydrographic data. As such, this study advances our understanding of the response of the upper ocean to atmospheric forcing and provides a simple way for predicting the ML depth with solely surface observations. Plain Language Summary: The mixed layer (ML) is the well‐mixed region of the upper ocean, which is mainly influenced by air‐sea interactions (e.g., wind forcing and buoyancy fluxes). The ML deepening/shoaling processes is critically important for physical, chemical, and biological oceanography. The diurnal variation of the ML depth is caused by daytime heating and nighttime cooling. In the daytime, the surface water gains heat (buoyancy), and then a shallow stable ML (with a thickness of several meters) is formed by the stirring of wind. In the nighttime, by contrast, the surface water loses heat (buoyancy) making the shallow ML unstable, and then the thickness of ML will develop to tens of meters. In this study, we propose a new method to estimate the diurnal variation of the ML depth with wind speed, air‐sea heat flux, and sea surface temperature, all of which are observable variables at the sea surface. Our method well characterizes the observed ML depth throughout the diurnal cycle, making it possible to approximate the upper ocean structure without underwater data. Key Points: Diurnal cycling of stratification and turbulence is ubiquitous in the tropical upper ocean, even in winterA new scaling of the diurnal mixing/mixed layer depth in terms of sea surface variables (wind speed, air‐sea heat flux, and sea surface temperature) is proposed and testedIt provides a simple way to predict the diurnal mixing/mixed depth with solely surface observations [ABSTRACT FROM AUTHOR]

After leaving the Sun’s corona, the solar wind continues to accelerate and cools, but more slowly than expected for a freely expanding adiabatic gas. Alfvén waves are perturbations of the interplanetary magnetic field that transport energy. We use in situ measurements from the Parker Solar Probe and Solar Orbiter spacecraft to investigate a stream of solar wind as it traverses the inner heliosphere. The observations show heating and acceleration of the plasma between the outer edge of the corona and near the orbit of Venus, along with the presence of large-amplitude Alfvén waves. We calculate that the damping and mechanical work performed by the Alfvén waves are sufficient to power the heating and acceleration of the fast solar wind in the inner heliosphere. [ABSTRACT FROM AUTHOR]

The inverse temperature layer (ITL) beneath water‐atmosphere interface within which temperature increases with depth has been observed from measurement of water temperature profile at an inland lake. Strong solar radiation combined with moderate wind‐driven near‐surface turbulence leads to the formation of a pronounced diurnal cycle of the ITL predicted by a physical heat transfer model. The ITL only forms during daytime when solar radiation intensity exceeds a threshold while consistently occurs during nighttime. The largest depth of the ITL is comparable to the e‐fold penetration depth of solar radiation during daytime and at least one order of magnitude deeper during nighttime. The dynamics of the ITL depth variation simulated by a physical model forced by observed water surface solar radiation and temperature is confirmed by the observed water temperature profile in the lake. Plain Language Summary: An idealized one‐dimensional heat transfer equation reveals the physical mechanisms of water temperature increasing with depth beneath the water‐atmosphere interface known as inverse temperature layer (ITL). Solar radiation is the dominant forcing of water temperature profile while wind‐driven turbulent mixing is a critical process determining whether the ITL forms. The limited depth of the ITL poses a constraint on the rate of heat transfer from the water body into the atmosphere. The dynamics of the ITL plays an important role in the water and energy cycle of large water bodies such as lakes and oceans. Key Points: The formation of inverse temperature layer (ITL) is driven by strong solar radiation and moderate wind‐driven turbulenceThe ITL depth has pronounced diurnal cycle shallower during daytime than during nighttimeA physical model using observed solar radiation and water surface temperature captures the ITL dynamics [ABSTRACT FROM AUTHOR]