Additional Heat Source Research Articles

Illustration of low-pressure gradient on the MHD flow of viscous fluid over a flat plate: the Homotopy Perturbation Method

The proposed investigation is intended to carry out the salient features of the low-pressure gradient of conducting a viscous fluid flow over a flat plate embedding with a permeable medium. The impact of thermal and solutal buoyancy in conjunction with the additional heat source and the chemical reaction enriches the flow phenomena significantly. The recent need in several industries that depend on the supplied heat source and the solutal reactant optimizes the transport properties. These physical properties are best to be used for the proper shape and size of the product manufactured by the industries. To handle the model, first of all, the governing equations are transformed to ordinary for the suitable choice of transformation rules. Furthermore, an approximate analytical approach i.e. the ‘Homotopy Perturbation Method’ (HPM) is proposed. The illustration of the characteristics of physical parameters blending within the flow phenomena is deliberated through the graph and tables. The important aspects of the outcomes are that the inclusion of buoyant-driven forces encourages the velocity distribution significantly, and in addition to that the additional heat source augments the fluid temperature.

Physical Model of Influence of CaO–FeO–SiO2 Powder Fraction on the Heat Transfer from Torch

Introduction. One of the main ways of heat transfer in metallurgical units is the interaction of the charge with a burning gas torch. The heat is transferred from the torch mainly by radiation. In particular, oxygen converter process under its typical temperature and chemical conditions of oxidation processes is accompanied by combustion reactions with the formation of a torch both in the cavity of the converter (in the so called reaction zone) and above the converter neck as a result of partial post-combustion of exhaust gases leaving the unit.Problem Statement. The processes in metallurgical units are accompanied by significant smoke and dust, which affect the efficiency of heat transfer from the torch of exhaust gases post-combustion to the metal bath that is an additional source of heat in the converter process.Purpose. The purpose of this research is to study the influence of the introduction of solid powder components into the environment around the torch on its heat transfer.Materials and Methods. The research has been carried out on the physical model of a burning torch when CaO-FeO-SiO2 system powders are fed into the torch in air flow. The magnitude of the heat flow density has been estimated on the basis of the registered temperature difference in different parts of the model.Results. It has been established that the feed of air or any solid material at a temperature much lower than the torch temperature has a negative effect on heat transfer from the torch by radiation. However, the total heat flow density is not significantly reduced due to the possible involvement of heated solids in other heat transfer methods. For the CaO-FeO-SiO2 system, the share of silicon dioxide powder as a component with the highest heat capacity has the greatest negative effect on the heat transfer from the torch.Conclusions. The studies based on the physical model have allowed us to qualitatively assess the effect of dustiness of the components of CaO-FeO-SiO2 system of the burning torch environment on its heat transfer and on the contribution of different heat transfer methods from the torch to the total heat flow density in given conditions.

Early-time Ultraviolet Spectroscopy and Optical Follow-up Observations of the Type IIP Supernova 2021yja

We present three epochs of early-time ultraviolet (UV) and optical HST/STIS spectroscopy of the young, nearby Type IIP supernova (SN) 2021yja. We complement the HST data with two earlier epochs of Swift UVOT spectroscopy. The HST and Swift UVOT spectra are consistent with those of other well-studied Type IIP SNe. The UV spectra exhibit rapid cooling at early times, while less dramatic changes are seen in the optical. We also present Lick/KAIT optical photometry up to the late-time tail phase, showing a very long plateau and shallow decline compared with other SNe IIP. Our modeling of the UV spectrum with the TARDIS radiative transfer code produces a good fit for a high-velocity explosion, a low total extinction E(B − V) = 0.07 mag, and a subsolar metallicity. We do not find a significant contribution to the UV flux from an additional heating source, such as interaction with the circumstellar medium, consistent with the observed flat plateau. Furthermore, the velocity width of the Mg ii λ2798 line is comparable to that of the hydrogen Balmer lines, suggesting that the UV emission is confined to a region close to the photosphere.

Field study of heat pump-assisted hybrid desiccant cooling system for thermal environment control and energy consumption under different load patterns

In modern buildings, indoor humidity must be effectively controlled for thermal comfort and to inhibit the breeding of mold and mildew. To exclude the dependence on additional regeneration heat source for desiccant cooling system, this field study used heat pump-assisted hybrid desiccant cooling (HPDC) systems, which place the evaporator upstream of dehumidification side of the desiccant wheel to perform pre-cooling and pre-dehumidification. The main purpose was to investigate the thermal environment control and energy-saving effects of HPDC systems under different load pattern scenarios; Field studies were conducted in residential buildings, public space, and classrooms. When operating in the first scenario, the electricity consumption of the HPDC system was 37.4% and 14% lower than that of conventional electric heat pumps (EHPs) under different wall thermal-storage conditions. In the second scenario, high dehumidification load led to large adsorption heat, causing indoor temperature to rise continually until the indoor humidity reached the design level. Through the field study in the classroom, the dehumidification mode and cooling mode switching approach can effectively improve indoor temperature control problems and reduce energy consumption by 14% compared to EHP. This field study covers possible application scenarios for HPDC systems, demonstrating the feasibility of replacing conventional air conditioning.

Dynamic heat transfer model of vertical green façades and its co-simulation with a building energy modelling program in hot-summer/warm-winter zones

Cooling demand dominates the energy consumption of buildings in hot-summer/warm-winter zones. Vertical green façades (VGFs) are an effective design strategy to reduce the cooling load in these regions. Many studies have investigated the cooling benefits of VGFs; however, the lack of accurate and low-cost co-simulation methods limits their application as it is difficult for architects and engineers to use them to evaluate the energy consumption of buildings. To address this issue, we developed a dynamic heat transfer (DHT) model for VGFs based on the Beer–Lambert Law and Penman–Monteith Equation. We then proposed a co-simulation approach for VGFs with EnergyPlus by using an additional heat source term and energy management system. We subsequently conducted field measurements to validate the accuracy of the DHT model and the reliability of the co-simulation approach. Finally, we created simulation scenarios in four typical cities in the hot-summer/warm-winter zone of China and analysed the effects of a VGF on the cooling load of an office building. The results indicated that the VGF reduced the room cooling load by 11.7–18.4%. Furthermore, improving the wall insulation only led to a 0.3–8.4% reduction in the room cooling load. Moreover, the cooling load saving rates of rooms with a VGF and well-insulated walls were 6.6–15.8%. Our research is likely to prove useful to future researchers investigating VGFs using DHTs and building designers attempting to effectively incorporate VGFs into architectural plans.

Prevalence of short-lived radioactive isotopes across exoplanetary systems inferred from polluted white dwarfs

ABSTRACT In the Solar system, short-lived radioisotopes, such as 26Al, played a crucial role during the formation of planetary bodies by providing a significant additional source of heat. Notably, this led to early and large-scale melting and iron core formation in planetesimals and their loss of volatile elements, such as hydrogen and carbon. In the context of exoplanetary systems therefore the prevalence of short-lived radioisotopes is key to interpreting the observed bulk volatile budget and atmospheric diversity among low-mass exoplanets. White dwarfs that have accreted planetary material provide a unique means to infer the frequency of iron core formation in extrasolar planetesimals, and hence the ubiquity of planetary systems forming with high short-lived radioisotope abundances. Here, we devise a quantitative method to infer the fraction of planetary systems enriched with short-lived radionuclides upon planetesimal formation from white dwarf data. We argue that the current evidence from white dwarfs point towards a significant fraction of exoplanetesimals having formed an iron core. Although the data may be explained by the accretion of exomoon or Pluto-sized bodies that were able to differentiate due to gravitational potential energy release, our results suggest that the most likely explanation for the prevalence of differentiated material among polluted white dwarfs is that the Solar system is not unusual in being enriched in 26Al. The models presented here suggest a ubiquitous pathway for the enrichment of exoplanetary systems by short-lived radioisotopes, disfavouring short-lived radioisotope enrichment scenarios relying on statistically rare chance encounters with single nearby supernovae, Wolf–Rayet, or AGB stars.

ОЦЕНКА ВОЗМОЖНОСТИ СОЛНЕЧНОГО ТЕПЛОСНАБЖЕНИЯ С ИСПОЛЬЗОВАНИЕМ ВОЗДУШНОГО ТЕПЛОВОГО НАСОСА

Solar energy is one of the sources of renewable energy. However, during the cold season in Russia, the use of solar energy is difficult due to low outdoor air temperatures. The purpose of this article is to analyze the possibility of energy saving when using solar energy for the heating system of an individual residential building in Vladivostok. The latitude of the city is 43 °, but the estimated temperature for the design of heating is -22 ° C. This greatly complicates the use of solar heat. The possibility of accumulation of low-potential heat in a specially equipped outhouse (greenhouse) for conversion by a thermal air-water pump is analyzed in order to use it for heating needs in the future. Two constructions are considered as the finishing material of the extension: a two-layer polycarbonate with an air layer and an energy-saving double-glazed window. The calculation shows that in the coldest month is January, the potential of solar thermal energy is 14 %–37 % of the required heat demand, depending on the material used in the construction of the extension. In March and April, excess heat is generated. It can be used for hot water supply needs. Thus, for an individual residential building, the use of solar heat accumulated in a greenhouse extension is relevant as an additional source of heat for the heating system.

Experimental Investigation on Productivity Enhancement of a Solar Still Modified with the Evacuated Tube Heat Pipe using Paraffin Wax

The current work involves experimental investigation on a conventional solar still to improve the productivity of fresh water by introducing the evacuated tube thermosyphon heat pipe. The evacuated tube thermosyphon acts as additional heat source to the solar still. The paraffin wax was utilized as latent heat storing medium, filled between the evacuated glass tube and thermosyphon heat pipe to escalate the fresh water productivity during off-sunshine hours. Two identical solar stills, one with three evacuated tube thermosyphon and another without it, were constructed and tested simultaneously. The solar radiation intensity, volume of fresh water produced, and temperature at various points such as basin water, glass cover, ambient and evaporator and condenser section of the heat pipe were measured. The utilization of evacuated tube heat pipe as an additional heat source increases heat input by 84.5%. The increase in heat input upsurges the gathering of fresh water by more than three times when compared to the conventional solar still. Accumulative fresh water productivity from the modified solar still was 215.7% higher than fresh water productivity from the conventional solar still. The modified solar still was capable to yield fresh water during no sunshine hours of evening as an effect of utilization of phase change material. The study suggests that direct coupling of the evacuated heat pipe to the solar still performs well in terms of fresh water yield and the same can be employed for household purpose.

Ultra-pure hydrogen production via ammonia decomposition in a catalytic membrane reactor

In this work two alternatives are presented for increasing the purity of hydrogen produced in a membrane reactor for ammonia decomposition. It is experimentally demonstrated that either increasing the thickness of the membrane selective layer or using a small purification unit in the permeate of the membranes, ultra-pure hydrogen can be produced. Specifically, the results show that increasing the membrane thickness above 6 μm ultra-pure hydrogen can be obtained at pressures below 5 bar. A cheaper solution, however, consists in the use of an adsorption bed downstream the membrane reactor. In this way, ultra-pure hydrogen can be achieved with higher reactor pressures, lower temperatures and thinner membranes, which result in lower reactor costs. A possible process diagram is also reported showing that the regeneration of the adsorption bed can be done by exploiting the heat available in the system and thus introducing no additional heat sources.

Latest Mesoproterozoic (ca. 1.2–1.1 Ga) amphibolite-facies metamorphism from the Dete-Kamativi Inlier, NW Zimbabwe: Implications for a Rodinia-related intracratonic orogen in Southern Africa

The Magondi Belt has been regarded as a Paleoproterozoic orogen formed by the collision of the Zimbabwe Craton and an unknown continental block. The Dete-Kamativi Inlier (DKI) located approximately 200 km west-southwest of the main Magondi Belt has been regarded as an extension of the belt. Here, we report new geochronological data for pelitic schists and a felsic orthogneiss from the DKI using monazites (CHIME method) and zircons (LA-ICP-MS analysis), and discuss the tectonic evolution of the region. Zircons from a felsic orthogneiss in the Kamativi area yielded magmatic and metamorphic ages of 2279 ± 25 Ma and 2020 ± 28 Ma, respectively. Similar Paleoproterozoic ages of ca. 2.1–1.8 Ga were also obtained from subhedral and rounded monazite grains in the pelitic schists. In contrast, irregular-shaped monazite intergrown with biotite in a different pelitic schist gave three latest Mesoproterozoic isochron ages of 1196 ± 37 Ma, 1143 ± 32 Ma, and 1070 ± 25 Ma, suggesting a long-lived (>120 million years) thermal event with several monazite-growing stages. Consistent isochron ages of 1062 ± 41 Ma and 1061 ± 26 Ma were obtained from monazites in the felsic orthogneiss and metapelite samples from an adjacent region. The application of phase equilibrium modeling for the peak mineral assemblage in the garnet-andalusite-biotite-cordierite-bearing pelitic schist with 1196–1070 Ma metamorphic ages indicated a peak P–T condition of 520–600 °C and 1.5–2.5 kbar, suggesting low-pressure amphibolite-facies metamorphism. The condition is lower than that obtained from the hornblende-plagioclase geothermometry of amphibolites (>700 °C) from the southwest part of the DKI, which probably corresponds to an earlier (ca. 2.0 Ga) high-grade metamorphic condition. The youngest thermal event, 994–982 Ma, from monazite rim in a mylonitic orthogneiss might correspond to the timing of later deformation. The latest Mesoproterozoic (1.2–1.1 Ga) amphibolite-facies metamorphism was likely associated with an intracratonic orogeny related to the activity of broadly coeval orogenic events, such as the Namaqua-Natal orogenic belt related to the amalgamation of the Rodinia supercontinent. Regional magmatic activity of the Umkondo large igneous province at 1112–1108 Ma could have also been an additional heat source.

RESEARCH OF METHODS FOR MEASURING THE PHYSICAL PARAMETERS OF THE FLUE GAS POSTCOMBUSTION TORCH IN OXYGEN CONVERTER

The oxygen-converter process is accompanied by the release of a significant amount of off-gases, that under the conditions of postcombustion form a torch over the neck of the converter. It is an additional source of heat in the converter. Change the torch nature corresponds the peculiarities of the heat blowing. However, it is difficult to register and analyze the torch due to the significant temperature above the neck of the unit and the large amount of dust released during the blowing. And, if small particles of dust can considerably heat up in real conditions of the converter and strengthen indicators of a torch, much bigger particles can interfere with it. It was conducted a physical modeling on a single gas torch of 250-300 mm particles of different chemical composition (corresponding to the oxygen-converter process) influence on the possibility to register the physical characteristics of the postcombustion torch: heat transfer, luminosity (brightness) and electrical characteristics. Visually, it was established that the direct supply of non-oxidizing solid particles to the burning torch turns the burning flame in yellow or yellow-orange color and the flame increases in size due to incomplete combustion of the fuel mixture compared to pure combustion (without dust). This manifestation is characteristic of particles of oxides of silicon, calcium and magnesium and iron (III) oxide. Particles that can be oxidized by contact with a burning torch, in addition to increasing the visible part, cause a significant increase in the visual brightness of the flame.

Classification of Heat Evolution Terms in Li-Ion Batteries Regarding the OCV Hysteresis in a Li- and Mn-Rich NCM Cathode Material in Comparison to NCA

We investigate the heat release of Li- and Mn-rich NCM (LMR-NCM) and NCA half-cells during cycling at different C-rates and quantify the individual contributions to the overall heat flow using a combination of isothermal micro-calorimetry and electrochemical methods. The paper focuses in particular on the open-circuit voltage (OCV) hysteresis of the LMR-NCM material, which results in a significant reduction in energy round-trip efficiency (≈90% for LMR-NCM/Li cells vs ≈99% for NCA/Li cells at C/10) and therefore in an additional source of heat that has to be considered for the thermal management of the cell. The total heat release of the LMR-NCM/Li cells is found to be nine times higher than that of the corresponding NCA/Li cells (at C/10). In the case of the LMR-NCM cathode, the heat due to OCV hysteresis is responsible for up to 55% of the total energy loss. Using the applied approach, the OCV hysteresis heat is separated into its share during charge and discharge and is furthermore presented as a function of SOC. Additional sources of heat, such as reversible entropic heat, parasitic effects, and measurement limitations, are discussed in terms of their contribution to the overall energy balance of the two cell chemistries.

Sustainable heating system by infrared radiators

Maintaining the optimum temperature in the living quarters is the key to a comfortable stay. Due to the lack of a central heating system or in the event of its insufficiency, they resort to the installation of additional heat sources. There is a wide range of devices on the market with different operating principles, hence the difficulty of which is better - a convector or infrared heater. A comparative analysis of devices will help you make the right choice. Asking the question of which is better a convection heater or an infrared heater, one must decide on its role in heating the house. It is better to use them as additional equipment with an existing heating system. One of the effective sources of additional heating are infrared radiators. Its principle of operation is based on infrared radiation, which provides a quick and qualitative increase in temperature in any part of your apartment. Today, more and more people prefer infrared radiators. From the usual electric convector, they differ in that they heat not the air in the room, but hard surfaces (floors, walls) and objects, and these, in turn, leak heat into the surrounding space. So, the entire room is heated up unnoticeably.

On electron temperature rise in divertor relevant recombining plasma along magnetic field line

The rise of electron temperature along the magnetic field line was clearly observed in divertor relevant recombining plasma, even though there was no additional electron heating source. Electron temperature obtained at recombination front was approximately 0.5 eV, whereas it increased up to greater than 1 eV at downstream of recombination front. Although this temperature rise is likely common in detached or recombining plasmas, the mechanism has not been understood yet. This report provides a reasonable interpretation of temperature rise along the magnetic field line, for the first time: depletion of low energy electrons due to volumetric recombination leads to deformation of electron energy distribution, resulting in an apparent increase in electron temperature. Our experiment supports this interpretation in that the experimentally observed electron temperature showed good agreement with calculated effective electron temperature.

Nano gold coupled black titania composites with enhanced surface plasma properties for efficient photocatalytic alkyne reduction

A nanocomposite design is proven for achieving efficient, selective, and robust alkyne semi-hydrogenation through photocatalytic process, which avoids the use of additional heat sources and traditional toxic Pb additives. The gold nanoparticles (Au NPs) coupled crystalline-core@amorphous-shell structured and wide-spectrum-responsive black titania (BT) with enhanced surface plasma properties holds the key to attaining high activity and selectivity. The hot electron injection from conductive BT to the surface of plasmonic Au NPs stimulated by solar light activates the alkynes and directly participates in the selective conversion to overcome the energy barriers. The engineered Au/BT gives a record turnover frequency of 1012 h−1 and excellent stability for phenylacetylene semi-hydrogenation under solar light irradiation and shows broad scope toward selective hydrogenation of alkynes containing various substituent groups of –CH3, –OH, and –Cl. The kinetic isotope effects and in situ infrared spectroscopy analysis for structure-activity relationship and reaction mechanism of phenylacetylene reduction were also demonstrated.

Matching-design for inverter air-source heat pump system based on heating load characteristics of civil buildings

Although the inverter air-source heat pump (IASHP) and composite systems have a characteristic of energy conversion, the design of IASHP and the application of IASHP assisted with additional heat sources are absent based on the relationship between the demand side and supply side. Therefore, this paper proposes a heating load decomposition method to design IASHP with an auxiliary heat source system to offer users heating in severe cold regions. Specifically, the heating load decomposition method divides the heating load of the civil building into three regions by seeking heating energy balance points. It can get an optimal heating energy balance point with the best HSPF and an optimal design heating energy balance point with the best evaluating parameter. On these grounds, we produce an IASHP prototype. The experimental results confirm the superiority of the heating load decomposition method. Compared to the traditional design method, it improves by 6.5%-12.6% of heating capacity and 2.3%-17.4% of COP of IASHP porotype. Besides, the heating performance of IASHP assisted with an electric heating system selected by an optimal heating energy balance point is better than that of an independent IASHP heating system. In contrast, electric heating only pays 6.7% of the heating capacity of the IASHP unit operated at −27.0 °C of ambient temperature.

On the thermal performance of naturally ventilated room with straw insulation retrofitted envelope for different climatic zones of India

The heat insulating potential of straw, an agricultural residue, used as part of the envelope of unconditioned buildings is the focus of the current work. Using a CFD software with experimentally validated boundary conditions, transient thermal analysis is performed on a 3-D model room of dimensions 3 m × 3 m × 2.5 m with vents and heat source representing a naturally ventilated indoor space. The thermal performances of a reference uninsulated concrete envelope and a straw insulation-based envelope are compared in terms of quantitative parameters such as indoor air temperature, decrement factor, and time lag as well as a qualitative discussion on the need for occupant adaptation, namely closing or opening of inlet vent and requirement of additional heating. The assessment and subsequent recommendation of straw insulation utilization is done for representative summer and winter days of the five different climatic zones of India. A maximum reduction of up to 3.5 °C in the peak indoor air temperature is achievable with inlet temporarily closed when straw insulation is included in the envelope in summer conditions. In winter conditions of cold climatic zone, with inlet always closed, use of straw insulation leads to the lessening of additional active heat source requirement by as much as 600 W for the considered model room. Further, the effects of increased straw insulation thickness, removal of heat source, varying inlet air velocity, and changing the position of the straw insulation to the outside are also analyzed for the extreme warm and cold conditions.

Peristaltic flow of electrically conducting nanofluid under the action of Joule and radiative heat within an asymmetric microchannel

The proposed mathematical model is based upon the peristaltic flow of an electrical conducting nanofluid within an asymmetric microchannel. The flow takes place under the action of dissipative heat energy due to the occurrence of the magnetic field that is basically known as Joule heating and radiative heat proposed as thermal radiation along with the additional heat source. Moreover, the impact of upper/lower wall zeta potential and the expression for the electric potential is presented using the Poisson Boltzmann equation and Debey length approximation. The well-known numerical practice is used for distorted governing equations with appropriate boundary conditions. Further, computation of the pressure gradient is obtained for the associated physical parameters. The graphical illustration shows the characteristics of the pertinent parameters on the flow problem and the tabular result represents the simulated values for the rate coefficients. In the significant examination, the study reveals that the mobility parameter due to the occurrence of the electric field vis-à-vis time parameter encourages the velocity distribution within the center of the channel furthermore significant retardation occurs near the wall region.

Analysis of terraforming on mars using nuclear power for the beginning of space colonization

As a historic challenge for humans, Martian colonization has been initiated by nuclear energy. A moving nuclear power plant could be imaginable known as a nuclear reactor rover. The design of the nuclear reactor rover has been performed where the important matter is how to make the caterpillar move the reactor and its facilities. Hence the slider length and contact point are proposed. The normalized heat transfer is analyzed by slide length and contact point where they are normalized as 1.0 and 10.0, respectively. Although the slider length of the caterpillar is proportional to heat transfer, the contact point shows the adverse values. Longer slider length and less contact point could be the optimized heat production system by the caterpillar which is the additional heat source except the other nuclear reactor. Any other planet could be considered as a potential human colony using the nuclear terraforming technology.

Numerical simulation of the gas flow with radiation and heat transfer

In this article we focus on the heating of the solid body placed in the vicinity of the intense heat source. We simulate the heat transfer caused by the direct contact with surrounding heated gas. Furthermore it is necessary to take into account the heat transfer caused by the radiation, which radically affects the resulting heat flux. We work with the non-stationary viscous compressible fluid flow with additional heat sources, described by the RANS equations. The heat radiation is simulated using other supplemented equations. The heat transfer equations are solved inside the considered body.