Solar Radiant Heating Research Articles

Rapid heating rates define the volatile emission and regolith composition of (3200) Phaethon

Asteroid (3200) Phaethon experiences extreme solar radiant heating ( ~ 750 °C) during perihelion (0.14 au), leading to comet-like activity. The regolith composition and mechanism of volatile emission are unknown but key to understanding JAXA’s DESTINY+ mission data (fly-by in 2029) and the fate of near-Sun asteroids more generally. By subjecting CM chondrite fragments to fast, open system, cyclic heating (2-20 °C/min), simulating conditions on Phaethon we demonstrate that rapid heating rates combine with the low permeability, resulting in reactions between volatile gases and decomposing minerals. The retention of S-bearing gas limits the thermal decomposition of Fe-sulphides, allowing these minerals to survive repeated heating cycles. Slow escape of S-bearing gases provides a mechanism for repeated gas release from a thermally processed surface and, therefore the comet-like activity without requiring surface renewal to expose fresh material each perihelion cycle. We predict Phaethon regolith is composed of olivine, Fe-sulphides, Ca-sulphates and hematite.

Energy Assessment and Economic Study of Solar Floor Heating System in Different Climates in Morocco

Abstract Currently, the development of energy production projects in the building sector using alternative energy sources such as solar energy is growing rapidly. This increasing technological progress to achieve the needs of comfort and safety can be considered a major priority, particularly with concerns about energy shortages and current environmental issues threatening not only human well-being but ecosystems as well. The present research aims to provide a comprehensive model for enhancing the energetic performance of rural Moroccan houses, by exploring solar radiant heating systems. The evaluation of the solar floor heating system is carried out by trnsys to evidence the effect of various design parameters on performance indexes of the system concerning six Moroccan cities, which representatively correspond to the Moroccan climatic zoning. The examined analyses cover the effect of the collector area, storage tank volume, and mass flowrate in the solar loop and the building heating loop. Moreover, how the variation of thickness and piping material affect the performances was discussed as well. The major finding of this work is optimizing the system performance gives the possibility to meet adequately the heating load. The energetic analysis shows the system's adaptability to the Moroccan climate, whose solar fraction is around 65% and 87%. For most of the examined sites, it was observed that the demand for auxiliary energy is limited from October to May. The economic investigations revealed that payback periods of the examined system ranged between 7 and 13 years. Besides, the energy and economic outcomes of such systems in Morocco, they are capable to mitigate the huge amount of CO2 emissions as compared to conventional heating systems.

Flying too close to the Sun – The viability of perihelion-induced aqueous alteration on periodic comets

Comets are typically considered to be pristine remnants of the early solar system. However, by definition they evolve significantly over their lifetimes through evaporation, sublimation, degassing and dust release. This occurs once they enter the inner solar system and are heated by the Sun. Some comets (e.g. 1P/Halley, 9P/Tempel and Hale-Bopp) as well as chondritic porous cosmic dust – released from comets – show evidence of minor aqueous alteration resulting in the formation of phyllosilicates, carbonates or other secondary phases (e.g. Cu-sulphides, amphibole and magnetite). These observations suggest that (at least some) comets experienced limited interaction with liquid water under conditions distinct from the alteration histories of hydrated chondritic asteroids (e.g. the CM and CR chondrites).This synthesis paper explores the viability of perihelion-induced heating as a mechanism for the generation of highly localised subsurface liquid water and thus mild aqueous alteration in periodic comets. We draw constraints from experimental laboratory studies, numerical modelling, spacecraft observations and microanalysis studies of cometary micrometeorites. Both temperature and pressure conditions necessary for the generation and short-term (hour-long) survival of liquid water are plausible within the immediate subsurface (<0.5 m depth) of periodic comets with small perihelia (<1.5 A.U.), low surface permeabilities and favourable rotational states (e.g. high obliquities and/or slow rotational periods). We estimate that solar radiant heating may generate liquid water and perform aqueous alteration reactions in 3–9% of periodic comets. An example of an ideal candidate is 2P/Encke which has a small perihelion (0.33 A.U.), a high obliquity and a short orbital period. This comet should therefore be considered a high priority candidate in future spectroscopic studies of comet surfaces. Small quantities of phyllosilicate generated by aqueous alteration may be important in cementing together grains in the subsurface of older dormant comets, thereby explaining observations of unexpectedly high tensile strength in some bodies.Most periodic comets which currently pass close to the Sun are dormant, having experienced surface heating, significant cometary activity and dust release in the past. These bodies may be responsible for the partially hydrated cometary micrometeorites we find at the Earth's surface and their aqueous alteration histories may have been produced by perihelion-induced subsurface heating. This is in contrast to radiogenic and impact heating that operated during the early solar system on asteroids. This study has implications for the alteration history of the active asteroid Phaethon, the target of JAXA's DESTINY+ mission.

Impact of temperature fluctuation on anaerobic fermentation process of upgrading bioreactor under solar radiant heating

Upgrading bioreactor under solar radiant heating can maintain the anaerobic fermentation process by utilizing absorption and scattering of solar energy in media to improve slurry temperature. Finding the suitable correction factor of temperature fluctuation for calculating kinetic rate of microbial fermentation process can improve simulation accuracy of microbial fermentation process. In present work, a coupled model for simulating the processes of photothermal transmission and anaerobic fermentation was built. Experimental and numerical researches about the anaerobic fermentation process of upgrading bioreactor were made to investigate the effect of temperature fluctuation on the kinetic rate of biochemical reactions. The results show that the temperature fluctuation has big effects on the biochemical reaction rate of each substance in the fermentation process. The n values for calculating heat exchange number BT are discrepant for both different reactants and temperature differences. For instance, when the temperature difference is bigger than 4 K, n = 2 is suitable to the one of cow dung in reactor A, and n = 3 is suitable to the one of pig dung and straw pitch in reactor B. The effect of n values on daily biogas production of straw is bigger than the one of cow dung, since hydrolytic bacteria are more sensitive to temperature fluctuation.

Improved energy utilization efficiency via adding solar radiant heating mode for traditional bioreactor to dispose straw: Experimental and numerical evaluation

Energy utilization efficiency of heating for the operation process of biogas reactor is an important factor limiting its development and popularization. A novel mode of solar radiant heating combined with the conventional heating mode was proposed to reduce the power loss and improve the utilization cycle of heat exchanger. In present work, experimental and numerical researches about the anaerobic fermentation process under two heating modes were made to investigate the effect of temperature fluctuation on non-isothermal fermentation process under solar radiant heating. The results show that the methane production capacity of non-isothermal process under solar radiant heating reduces by up to 14% compared with the constant temperature condition in three seasons; increasing the total solid concentration of bioreactor is helpful for improving the effect of solar radiant heating; the effects of temperature fluctuation coefficient on acid and methane productions are bigger than the one on pH of slurry.

Carbon nanotube heat transfer fluids for solar radiant heating of buildings

Solar-based radiant heating systems represent a sustainable, and relatively low-cost, technology to raise the temperature of the interior thermal mass of our buildings. Through the use of direct absorption solar thermal collectors, the same working fluid which absorbs the solar energy can be used to transfer the energy for storage in the thermal mass of the structure using a network of pipes embedded in concrete floors. This study investigates a promising working fluid which can be used in such systems – one which is based on multi-walled carbon-nanotubes suspended in normal base fluids. A major stumbling block affecting the wide spread use of carbon-nanotube nanofluids is their low dispersion stability at elevated temperatures, which significantly reduces the absorption capabilities of the nanofluids and could lead to clogging of the pumps used to circulate the fluids. In this paper, we report on a scalable UV-ozone (UVO) treatment technique to produce highly stable dispersions for the elevated temperatures experienced by working fluids in radiant heating systems. To probe suitability of UVO treated multi-walled carbon-nanotube (MWCNTs) for solar-assisted radiant heating systems, this paper investigates the effects of exposure time and temperature on stability, optical absorbance properties, the extent of functionalisation, and the photothermal conversion performance of UVO-treated MWCNT nanofluids. No agglomeration or degradation of the MWCNTs was observed at elevated temperatures (up to 150 °C), highlighting the stability of proposed nanofluids.

An assessment of radiative heating as a thermal treatment for invasive snakes in cargo

ABSTRACTThe brown tree snake (Boiga irregularis) is invasive in Guam and presents a continuous threat of accidental export to new islands in outbound cargo. Current attempts to avoid that scenario rely primarily on canine teams to inspect outbound cargo and vehicles. In prior work, we showed that thermal fumigation could effectively elicit snake exit of cargo under conditions when free flow of air streams is feasible, but this method cannot work with tightly packed cargo. Here we show radiative heating can effectively induce snake exit from cargo refuges at temperatures of 44–48 °C; however, we find passive solar heating of cargo to be unreliable in attaining sufficiently high temperatures for cargo sterilization. Although passive solar radiant heating proved unreliable, an active radiant-heating system has promise as a reliable means of treating tightly packed cargo. Times needed for treatment in a closed, controlled setting are sufficiently short that routine application of the method should provide no serious interruption of normal cargo-handling procedures.

Effects of an Arctic under‐ice bloom on solar radiant heating of the water column

AbstractThe deposition of solar energy in the upper Arctic Ocean depends, among other things, on the composition of the water column. During the N‐ICE2015 expedition, a drift in the Arctic pack ice north of Svalbard, an under‐ice phytoplankton bloom was encountered in May 2015. This bloom led to significant changes in the inherent optical properties (IOPs) of the upper ocean. Mean values of total water absorption in the upper 20 m of the water column were up to 4 times higher during the bloom than prior to it. The total water attenuation coefficient increased by a factor of up to around 7. Radiative transfer modeling, with measured IOPs as input, has been performed with a coupled atmosphere‐ice‐ocean model. Simulations are used to investigate the change in depth‐dependent solar heating of the ocean after the onset of the bloom, for wavelengths in the region 350–700 nm. Effects of clouds, sea ice cover, solar zenith angle, as well as the average cosine for scattering of the ocean inclusions are evaluated. An increase in energy absorption in the upper 10 m of about 36% is found under 25 cm ice with 2 cm snow, for bloom conditions relative to prebloom conditions, which may have implications for ice melt and growth in spring. Thicker clouds and lower sun reduce the irradiance available, but lead to an increase in relative absorption.

Surface and volumetric ablation behaviors of SiFRP composites at high heating rates for thermal protection applications

An irreversible ablation process of a silica fiber reinforced polymer (SiFRP) composite under various thermal conditions was investigated using a numerical and experimental study. Both an oxyacetylene torch and a solar radiant heating facility were developed and used to simulate the rapid heating process. A theoretical model was proposed to predict the surface ablation behavior of SiFRP composites when only steady-state ablation is considered. The accuracy of the model was evaluated by comparing calculated and experimental surface ablation recession rate and wall temperature for a silica/phenolic composite. The effect of variable thermal and transport properties on ablation behavior was analyzed. Furthermore, a model for predicting the volumetric ablation behavior was presented. The heat transfer, generation of decomposition gases and their subsequent diffusion process in the internal material were simulated. This study would provide a fundamental understanding for the design of high temperature thermal protection system.

A New Hybrid Bathroom System Based on Energy Saving Concept

Based on the characteristics of hot water supply in bathroom, this article proposes a new hybrid energy hot water supply system. The programmable logic controller(PLC) as the master controller was adopted in this system, which could automatically detect and storage main thermal physical of the system, such as temperature, water level, solar radiation intensity, power consumption and so on. The active thermal utilization technology of solar energy, air-source heat pump technology, solar energy intensive natural ventilation technology and low temperature hot water floor radiant heating technology were organically integrated in this system, which has the advantages of energy conservation and environment protection, high automation, safe and reliable operation, etc. At the same time, it can make good use of electric power cost between on-peak and off-peak, and promote the optimal allocation of power resources and reduce the cost, which can achieve the goal of intelligent control and energy saving.

Effect of sea‐ice melt on inherent optical properties and vertical distribution of solar radiant heating in Arctic surface waters

AbstractThe inherent optical properties (IOPs) of Polar Waters (PW) exiting the Arctic Ocean in the East Greenland Current (EGC) and of the inflowing Atlantic waters (AW) in the West Spitsbergen Current (WSC) were studied in late summer when surface freshening due to sea‐ice melt was widespread. The absorption and attenuation coefficients in PW were significantly higher than previous observations from the western Arctic. High concentrations of colored dissolved organic matter (CDOM) resulted in 50–60% more heat deposition in the upper meters relative to clearest natural waters. This demonstrates the influence of terrigenous organic material inputs on the optical properties of waters in the Eurasian basin. Sea‐ice melt in CDOM‐rich PW decreased CDOM absorption, but an increase in scattering nearly compensated for lower absorption, and total attenuation was nearly identical in the sea‐ice meltwater layer. This suggests a source of scattering material associated with sea‐ice melt, relative to the PW. In the AW, melting sea‐ice forms a stratified surface layer with lower absorption and attenuation, than well‐mixed AW waters in late summer. It is likely that phytoplankton in the surface layer influenced by sea‐ice melt are nutrient limited. The presence of a more transparent surface layer changes the vertical radiant heat absorption profile to greater depths in late summer both in EGC and WSC waters, shifting accumulation of solar heat to greater depths and thus this heat is not directly available for ice melt during periods of stratification.

The Study on the Energy Saving of Wall Mounted Solar Capillary Low-Temperature Hot Water Radiant Heating System

Through the comparative study of solar capillary low-temperature hot water radiant heating system with air source heat pump system has found that solar energy heat collecting efficiency has a great relationship with the collector temperature for the given system. To reduce the temperature of solar heat collector circulating water can greatly improve the heat collecting efficiency of the heat collector .With the increase of temperature of the water in the heat collector, heat collecting efficiency decrease rate changes linearly. Increasing water storage can improve the heat collecting efficiency, for this heat collecting system, the optimum collector temperature is 32 °C. In this study, COP reached 5 when the low temperature solar hot water capillary system mode is being used, and this result is nearly 5 times higher than that of the air source heat pump mode . Using the low temperature solar water heating capillary system, 27.35 kwh / (m2 ·heating season) of electricity can be saved compared with the amount of electricity consumed by air source heat pump. According to the price of current Beijing city , the estimated period of investment payback is 4.8 years .

The Heating Coefficient Experimental Analysis of Solar Water-Assisted Low Temperature Air Source Heat Pump System

In winter,Many families use air source heat pump because of the low evaporation temperature of the system, resulting in lower heating efficiency of system. To solve this problem, the low temperature solar assisted hot water was added to the project which is on the basis of air source heat pump, and the system has been tested. After analysis of the collection efficiency of solar collectors at low temperatures and comparative analysis of the temperature cycle, pressure, energy consumption of the low-temperature solar-assisted systems and air source heat pump system, the optimal collector temperature and law of heat pump refrigerant cycle changes of the system were obtained. Theoretically, comparative analysis of low temperature air source heat pumps and solar hot water secondary air source heat pump compression ratio and COP. It gives the key parameters affecting the compression ratio and COP, pointing out ways to improve the heat pump COP. Finally, a key measure to improve the thermal performance of the unit system is proposed, to provide a reference for future practical applications and research. Foreword Air source heat pump in ambient air contains rich low grade solar potential as a source of heat, it has inexhaustible characteristics [1] . The main reason for restricting the use of air source heat pump in northern area of our country is when the outdoor air temperature is low in winter, the outdoor coil frost severe heating efficiency air source heat pump is greatly reduced. Martinez suggested experimental study on the application of solar radiant floor heating systems , solar water temperature is 50-60°C, low efficiency, especially when overcast snow lower system efficiency [2] .In view of the outdoor coil frosting problem, direct expansion solar assisted heat pump water heater system using the proposed by Li Yuwu, from a certain extent alleviated the problem of heat in winter for coil winter fros, improving the heating coefficient and improved the operating characteristics of the unit. However, this system requires the direct absorption of heat in air tube, and the specific heat of air is small, difficult to heat storage, illumination by solar radiation impact, unstable system operation [3]. Based on the above issues, for the low-level office building , the new rural residential , this study presents low temperature solar auxiliary air source heat pump system , the device uses low-temperature solar hot water heat pump system as low , both full use of solar energy , but also eliminates the original system frost problems and improve the efficiency of solar collectors and heat set to improve the evaporation temperature of the evaporator , thereby increasing the compression ratio of the heat pump unit .

Thermal decomposition behavior of silica‐phenolic composite exposed to one‐sided radiant heating

When polymer‐matrix composite reaches sufficiently high temperature, pyrolysis reactions of the polymer matrix occur. The thermal decomposition behavior of silica‐phenolic composite was investigated using solar radiant heating experiment with one‐sided heat flux. Thermogravimetric studies and combined thermal analysis techniques were performed to characterize the thermal decomposition kinetics of phenolic resin. Simultaneously a thermal response model was used to calculate the through‐thickness temperature distribution. The calculated time‐dependent temperature profile at different material depths were compared with the experimental results measured at the same location. The silica‐phenolic composite exhibited an excellent thermal insulation during thermal exposure. The postheating specimen was sectioned in millimeter segments to determine the density profile. On the basis of the density profile, the transition from char layer to pyrolysis zone to virgin material was estimated. Finally, the material morphology was analyzed for silica‐phenolic composite after thermal exposure. POLYM. COMPOS., 36:1557–1564, 2015. © 2014 Society of Plastics Engineers

Building Energy Conservation Technology Based on Solar Energy Utilization

This paper analyzed the application of the solar house and solar radiant floor heating in building energy conservation. It also introduced the situation of the solar energy utilization in foreign countries.

Research of Solar Assistant Floor Radiant Heating in Freezing Region

Base on theory, experiment system was established to research the feasibility of using solar energy to heating in freezing region. Through one heating period to verify that solar assistant floor radiant heating was feasible and it can save energy, initial cost can be payback in 4 years.

The Study of the Solar Energy Heating System in the Cold Region

This article researched on solar radiant floor heating system between theory and experiment cold region. The experiment is basis on home water heater as the main source of solar radiant floor heating system, solar collector area of 1.8m2, water capacity 0.208m3, heating load of 110w/m2. In addition to the electric coil consumed energy for prevent freezing damage of out door pipes. The entire system is any other consumption. Test results between techno-economic analysis and calculation show that: a total test system saved energy 2262230.22 per year, the system payback period is 3.4 years.

Vibration Control of Composite Spacecraft Booms Subjected to Solar Heating

In this paper, piezoelectric feedback control of vibration and instability of spacecraft booms modeled as circular thin-walled cross-section beams and subjected to solar radiant heating is investigated. Having in view that composite material systems are likely to play a great role in the design of these devices, the beam constituent materials encompass non-classical effects such as anisotropy and transverse shear. In addition, in order to induce beneficial elastic couplings, a special ply-angle distribution achieved via the usual helically wounding fiber-reinforced technology, the so called filament winding, is implemented. The dynamic governing equations including the temperature effects and the related boundary conditions are obtained via the application of Hamilton's principle. Toward the end of controlling the oscillations and prevent the occurrence of the thermal dynamic instability, a feedback control capability based on the use of the piezoelectric induced strain actuation is implemented. The performance of its implementation considered in conjunction with that of the structural tailoring are highlighted and pertinent conclusions are derived.

THERMALLY INDUCED BENDING VIBRATION OF COMPOSITE SPACECRAFT BOOMS SUBJECTED TO SOLAR HEATING

Thermally induced bending vibration of spacecraft booms modeled as circular thin-walled beams of closed cross section and subjected to thermal radiation is investigated. One assumes that the boom is built up of composite material systems, and in this context, the constituent materials of the beam include nonclassical effects such as anisotropy and transverse shear. In addition, in order to induce beneficial elasticcouplings, a special ply-angle distribution achieved via the usual helically wounding fiber-reinforced technology is implemented. Both the dynamic governing equations involving the temperature effects and the related boundary conditions are obtained via the application of the extended Hamilton principle. The case of the spacecraft boom equipped with a concentrated mass at its free end, fixed at the other end, and exposed to solar radiant heating is studied from both the induced-vibration and stability points of view. The numerical simulations display deflection time history of bending displacements as a function of the fiber orientation of the composite materials, damping factor, and angle of incidence of heat radiation. The obtained results are likely to fill a gap in the specialized literature and to play a good role toward a better understanding of the factors that contribute not only to the occurrence of the thermal flutter instability, but also to its avoidance.

Heat, mass and momentum transfer of a water film flowing down a tilted plate exposed to solar irradiation

This paper has investigated the heat, mass and momentum transfer of a water film falling over a tilted plate with solar radiant heating and water evaporation. A cluster of physical models which include conduction, convection with flow turbulence, diffusion, radiation and phase change was developed for predicting the characteristics of heat, mass and momentum transfer. A fully implicit control-volume finite-difference procedure was used to solve the coupling equations. The effects of various parameters on heat, mass and momentum transport were investigated. The results revealed that the gradients of temperature and the mass fraction of water vapor in the gas layer, and the wind velocity played a key role in the heat and mass transfer along the gas-water interface. The water film Reynolds number related to the film thickness and the plate tilt angle markedly exerted an influence on the eddy viscosity and the turbulent Prandtl number of the water film. The ambient atmospheric temperature only dramatically affected the interfacial sensible heat transfer. The magnitude of solar incident flux had intense influence on the water film temperature but not on the interfacial heat and mass transfers.