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Moderate or Intense Low-oxygen Dilution (MILD) combustion which known as a combustion under highly preheated and diluted condition is a relatively new combustion regime including many differences in comparison with the traditional one. Among many distinguished disparities between combustion modeling of conventional and MILD ones, turbulent-chemistry interaction modeling is an open field of study. Current knowledge on modeling this combustion regime shows that the eddy dissipation concept (EDC) model could be successfully used for modeling of this combustion regime. In this paper, it has been tried to propose some guidelines to modify the semi-empirical constants of the original EDC model for MILD combustion. In this way a parametric study of the EDC model constants for a nonpremixed MILD burner is done in terms of accuracy of prediction while the responses of the model to its constants are focused on the basis of physical arguments. Burner of Dally et al. (JHC) is modeled using the RANS approach in a 2D axisymmetric computational domain for different oxygen levels and fuel jet Reynolds numbers when a reduced detail chemical mechanism of DRM-22 is used to represent the chemical mechanism. Moreover using a well-stirred–reactor analysis and extracting the chemical reactions pathways, discussions are completed. Results show that reducing the C D2 constant which leads to a decrease in time scale and volume fraction constants of the model would improve the performance of the model for MILD condition. Prediction of flame lift-off and minor OH species has been improved by changing default model constants of C τ and C γ to around 0.0893 and 1.0, respectively, especially for lower oxygen levels. Indeed reaction pathway analysis and dimension of reaction zone showed that reducing scales of the defined reactor in the EDC model (i.e. fine structure) to the Kolmogrov or smaller scales might push the reactions inside each structure toward the non-equilibrium condition and enlargement of overall reaction zone and make the EDC model more compatible with MILD combustion characteristics. Reduction in the length and time scales of the fine structure led to improvement in Temperature, OH, and CO profiles inside of MILD region of the JHC burner, although for CO, disagreement is still considerable. Considering error analysis of five checked parameters (i.e. H 2 O, CO 2 , OH, CO, and temperature) at both MILD and conventional regions of the JHC burner may conduct us toward that the defaults setting of the model still works reasonably on the whole when it is used at both regions. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model has been developed to calculate solar cell temperature and module efficiency in opaque mono crystalline silicon (sc-Si) PV module on the basis of degradation rate. The calculated results have been validated by experimental investigations for the opaque PV module. Module efficiency and solar cell temperature of the opaque PV module decrease with increase in degradation rate. In this context, energy matrices are developed and enviroeconomic analysis has been done on the basis of annual energy output of PV modules for different degradation rate. Efficiency and temperature of PV module have been decreasing with an increase in the degradation rate. The energy payback time is found to be 8.80 years and 9.29 years for degradation rate 0.3%/year and 0.9%/year, respectively and unit cost (Rs./kWh) increase with an increase in the degradation rate of PV module. Similarly, the environmental cost reduction is higher for 0.3%/year degradation rate and lower for 0.9%/year degradation rate. [ABSTRACT FROM AUTHOR]

The gravimetric moisture content of peat is the main factor limiting the ignition and spread propagation of smouldering fires. Our aim is to use controlled laboratory experiments to better understand how the spread of smouldering fires is influenced in natural landscape conditions where the moisture content of the top peat layer is not homogeneous. In this paper, we study for the first time the spread of peat fires across a spatial matrix of two moisture contents (dry/wet) in the laboratory. The experiments were undertaken using an open-top insulated box (22 × 18 × 6 cm) filled with milled peat. The peat was ignited at one side of the box initiating smouldering and horizontal spread. Measurements of the peak temperature inside the peat, fire duration and longwave thermal radiation from the burning samples revealed important local changes of the smouldering behaviour in response to sharp gradients in moisture content. Both, peak temperatures and radiation in wetter peat (after the moisture gradient) were sensitive to the drier moisture condition (preceding the moisture gradient). Drier peat conditions before the moisture gradient led to higher temperatures and higher radiation flux from the fire during the first 6 cm of horizontal spread into a wet peat patch. The total spread distance into a wet peat patch was affected by the moisture content gradient. We predicted that in most peat moisture gradients of relevance to natural ecosystems the fire self-extinguishes within the first 10 cm of horizontal spread into a wet peat patch. Spread distances of more than 10 cm are limited to wet peat patches below 160% moisture content (mass of water per mass of dry peat). We found that spatial gradients of moisture content have important local effects on the horizontal spread and should be considered in field and modelling studies. [ABSTRACT FROM AUTHOR]

In this paper we present the methodology for assessing the ionic liquids’ viscosity at six temperature points (25, 35, 45, 50, 60 and 70 [°C]), which utilizes only the in silico approach. The main idea of such assessment is based on the “correction equation” describing the correlation between experimentally measured viscosity and theoretically derived density (calculated with use of molecular mechanics), given at 6 different temperature points. The equation allows for recalculating the viscosity of ILs at 25 °C to determine the viscosity of ILs at other, higher temperature. Since the equation needs the basic viscosity value (at 25 °C) we additionally developed QSPR model that allows predicting it. According to our model, the viscosity of ILs is dependent to the size and branching of the cation and size, shape, symmetry and the vertical electron binding energy of IL’s anion. With those novel tools, it is possible to predict the viscosity of new ionic liquids at different temperatures without the need of experimental measurements. [ABSTRACT FROM AUTHOR]

The influence of temperatures and pressures to the intensity of the Brillouin peaks and the Brillouin shift in gas is analyzed by using the Tenti S6 model. The spontaneous Rayleigh-Brillouin scattering (SRBS) spectra in air with different incident wavelength at different altitudes are simulated for the SRBS lidar applications. A system for detecting the SRBS spectra of gas is also introduced in this paper. The SRBS spectra of N 2 in different pressures at the incident wavelength of 532 nm with the temperature of 300 K and the scattering angle of 90° have been measured, the experiment results are well agreed to the simulations. [ABSTRACT FROM AUTHOR]

This paper deals with the thermal modeling of temperature rise in a pouch lithium-ion battery with LiFePO 4 (also known as LFP) cathode material. The developed model represents the main thermal phenomena in the cell in terms of temperature change. The proposed model is validated with the collected experimental data from a module composed of 11 cells. In the conducted experiments, the different charge and discharge rates of 1/2C, 1C, 2C and 2.5C are applied. It is seen that, the increased discharge rates result in increased temperature on the surface of the battery. When the discharge rate is doubled, from 1C to 2C, cell temperatures have risen by 3.5 times. A simplified model for determining the heat generation is developed and validated with the test results. [ABSTRACT FROM AUTHOR]

In co-melt granulation, collisions occur between the particles to be agglomerated and the binder material. Depending on the stage of granulation, the binder material can be in the solid or liquid phase. The outcome of these collisions controls the dynamics of the granulation process and the fundamental physics of the impacts are of interest. This paper examines the impact of glass beads (model particles) and solid Poly Ethylene Glycol (PEG) flakes on a substrate of PEG as the temperature of the PEG layer is increased from below its melting point to above it. While the layer is in the solid state, the result of the impact can be quantified by the coefficient of restitution. When the layer is in the liquid state, the impact can be quantified by the immersion behaviour. The results obtained show that the coefficient of restitution between either glass beads and PEG flakes and the PEG layer is strongly affected by temperatures. As the PEG layer approaches its melting point, the coefficient of restitution falls to zero. Once the temperature of the PEG layer exceeds the melting point, the impact is characterised by a transient maximum indentation and then rebound to an equilibrium position. These too are strongly dependent on temperature. [ABSTRACT FROM AUTHOR]

A mathematical model to predict creep properties of Ni-based superalloys at intermediate temperature ranges based on microstructure, process and creep condition, and material properties has been developed by modifying and combining previous models. Modifications are made so that as many necessary model parameters as possible, whose values have been obtained from experimental measurement of creep properties, are determined from CALPHAD (CALculation of PHAse Diagrams) thermodynamic calculations. The model can reproduce minimum creep rate, creep rupture time, and time to specific strain for a wide range of Ni-based superalloys, correlating well with experimental data without any further creep experiments. The applicability and limitation of the model as an alloy design tool for new Ni-based superalloys with improved creep properties are discussed in this paper. [ABSTRACT FROM AUTHOR]

Heavy oil reservoirs can be found in many locations around the world, such as Canada, Venezuela, United States and Brazil. When in-situ oil viscosity is prohibitively high to allow recovery by conventional methods, additional techniques are used, such as hot water or steam injection. As water exchanges heat with the surroundings, a temperature gradient is established inside the reservoir, which results in a spatial variation of physical properties, especially viscosity. This leads to different mechanisms for fluid flow and trapping. A typical feature of heavy oil immiscible displacements is early breakthrough due to water fingering, which leads to very poor sweep efficiencies. However, physical experiments and field results have demonstrated that additional mechanisms may play a role in heavy oil immiscible displacements, such as capillary imbibition and oil stripping due to high shear flows. In this paper, a series of numerical experiments are performed to evaluate secondary imbibition at different viscosity ratios and injection rates using a Finite Volume approach to solve the Navier–Stokes equations at the pore-scale, and the Volume of Fluid method to properly capture interfaces. The simulations are performed in a 2-dimensional, water-wet, digital porous medium with complex geometry including dead end pores. The operating conditions and the associated complex topology allow evaluation of the typical pore-scale events in a secondary imbibition process, such as oil ganglion mobilization, break-up and coalescence, micro-fingering due to capillary imbibition and oil stripping in high shear flows. Thus the main production mechanisms observed in a heavy oil immiscible displacement are successfully reproduced. [ABSTRACT FROM AUTHOR]

In this paper, a practical method for designing Organic Rankine Cycle (ORC) power generation system was proposed. The design method was aimed to optimize the cost performance of ORC system and based on experiments and theoretically modeling. In this study, two experimental systems have been built. The first experimental system was used to offer data which were essential to establish the relationships needed to build the semi-empirical model. The second experimental system was employed to validate the model. In the semi-empirical model, objective function was established to quantify the ratio of power output to heat exchangers’ area (preheater, evaporator and condenser’s area), which was used to characterize the cost performance of ORC systems. By combining the experimental data from the first experimental system and theoretical formulas, the objective function was derived with a single variable: evaporation temperature. In the objective function, the optimized evaporation temperature could be obtained by using extremum method. Then other parameters of the ORC system could be also acquired through the model which would allow the ORC system to have good or the best cost performance. [ABSTRACT FROM AUTHOR]

The empirical model proposed by Lee and a fundamental model for the isothermal bainite start temperature ( B s ) are applied in this work to a microalloyed steel undergoing continuous cooling transformation. The fundamental model for B s is based on displacive transformation of bainite. The method proposed in this paper is termed the Bainite Intercept Temperature method (BIT). Using this method it is possible to determine the volume fraction of the phase that forms before bainite, i.e., quasi-polygonal ferrite. BIT analysis is applied to continuous cooling where a two phase microstructure is formed of quasi-polygonal ferrite and mixed bainitic ferrite and bainite/martensite. The estimated intrinsic hardness of the components based on BIT is compared with isothermal transformation results and the hardness is calculated based on the contribution of strengthening mechanisms. [ABSTRACT FROM AUTHOR]

This paper presents a new method to predict the heat transfer coefficient during flow boiling inside horizontal tubes containing twisted tape inserts. The method was developed based on the database presented by Kanizawa et al. This database comprises flow boiling results for horizontal tubes with internal diameters of 12.7 and 15.9 mm, twisted-tape ratios of 3, 4, 9 and 14, mass velocities ranging from 75 to 200 kg m −2  s −1 , heat fluxes of 5 and 10 kW m −2 and saturation temperatures of 5 and 15 °C. The method is flow-pattern based and considers flow boiling, dryout and mist flow regions. The predictive method also takes into account the physical picture of the swirl flow phenomenon by considering swirl flow effects promoted by the twisted tape insert. The proposed method provides satisfactory predictions and captures the main heat transfer trends of the data of Kanizawa et al. and also of independent data from literature. [ABSTRACT FROM AUTHOR]

The present paper deals with the parameter identification of one diode model equivalent circuit of solar cell modules from real data acquired in different temperature conditions. We termed this procedure as an optimization problem and solved it through the FSDE (Free Search Differential Evolution) algorithm as well as a novel IFSDE (Improved FSDE) approach. The IFSDE is compared with other well-known metaheuristics, namely genetic algorithms, harmony search and particle swarm optimization, showing overall better results for the proposed IFSDE approach. In particular, the IFSDE is better in escaping local optima and obtained better results. Identified results are compared with acquired data, what shows the validity of the proposed algorithm. [ABSTRACT FROM AUTHOR]

The use of lithium batteries in the conditions associated with the operation at low temperatures requires studying the effect of temperature factor on battery performance. Using the simulation, and particularly equivalent circuit models method, may be useful at the initial stages of the study. The paper describes the use of lithium battery model with one voltage source, one series resistor, and a single RC block for simulating the LiFePO4 battery operation at low temperatures. The model was validated using experimental data obtained by LiFePO4 battery discharge at different temperatures and showed good accuracy. The simulation results allow estimating the negative effect of low operating temperature on battery parameters and making a conclusion about the need for systems creating optimum operating conditions for batteries working under severe temperature conditions. [ABSTRACT FROM AUTHOR]

This paper presents an advanced mathematical model of a thermoelectric generator that includes the effect of the temperature gradient in the flow direction. The parameters of the exhaust gas from an engine may fluctuate during engine operation; thus, the influence of this fluctuation in the exhaust gas parameters on the optimal thermoelectric performance was considered with the objective of maximizing the total power output through the aid of Fortran. The optimum module areas corresponding to the maximum power output were found to be greatly affected by the flow rate of the exhaust gas but not by the gas temperature. The effect of the fluctuation in exhaust gas parameters on the performance of the corresponding thermoelectric generator at the maximum power output was also studied. A power deviation analysis method was introduced in order to design the optimal TEG module area for a high power output. Based on the results, the optimal design areas were 0.22 m 2 for the co-flow and 0.3 m 2 for the counterflow. The counterflow arrangement is recommended because it maintains a smaller deviation from the peak power output than a co-flow arrangement at their respective optimal design areas if there is sufficient system space. [ABSTRACT FROM AUTHOR]

Theoretical and experimental studies on the nonlinear mechanical properties of lightweight foamed concrete under uniaxial compression are conducted over the temperature range of 223–343 K and the strain rate range of 0.001–118/s in this paper. The experimental results show that the mechanical properties of the materials under uniaxial compression are strongly dependent on the density and temperature, but are weaker on strain rate. Based on the experimental results, the characteristics of density effect and temperature effect are analyzed and a calculation model is developed to describe the nonlinear mechanical behavior of lightweight foamed concrete. The model takes into account the effect of material damage, density and temperature. The experimental verification and the error analysis show that the model is shown to be able to predict the nonlinear deformation behavior of lightweight foamed concrete over a wide range of temperatures and densities. [ABSTRACT FROM AUTHOR]

The increasing interest in studying a Trombe wall with venetian blind (VBTW) has heightened the need for computational tools suitable to predict its thermal behavior. In this paper, a dynamic numerical model of a building with a VBTW was developed. Experiment has been conducted to study the temperature field of the whole building system in cold weather. It was found that the simulation results were in good agreement with the experimental data. The comparisons between the room with the classic Trombe wall and that with the VBTW were made based on the proposed model. The results demonstrated: the optimum time to open air vents of the VBTW was approximately 1.5 h earlier than that of the classic Trombe wall after sunrise; the air average temperature for room with the VBTW was about 5.5 °C higher compared to that with the classic Trombe wall in the daytime; the heat loss of the VBTW was smaller at night. The average predicted mean vote for the three rooms (room with the VBTW, room with the classic Trombe wall and room without Trombe wall) were −1.0, −1.5 and −2.2 in the daytime respectively. In conclusion, a building integrated with the VBTW can not only reduce heating energy needs but also achieve an acceptable condition of comfort in cold weather. [ABSTRACT FROM AUTHOR]

A photovoltaic/thermal (PV/T) system with static miniature solar concentrators can be integrated with building in the similar way to the flat plat PV/T system, however it can not only save lots of the PV materials, but also to some extent obtain a lower heat loss when the temperature is the same as that in the flat plate PV/T system. In this paper, a mathematical model was made to indicate the performances of the static miniature solar concentrating PV/T system. Experiments were also conducted to validate the results of the simulation. A comparison between the simulation and experiment demonstrated that the model was able to obtain the satisfactory simulation outcome to match the experiment outcome. Results showed that the absolute value of the deviation between simulation and experiment on PV electrical efficiencies were about 0.015 and 0.0065 on March 31st and May 13th, and the temperature curves of simulation and experiment were also consistent. In addition, the electrical and thermal performances on four days in different seasons were also simulated and the linear regression analysis on the thermal performance of this solar concentrating PV/T system was expressed to compare with the flat plate PV/T system, which indicated that the static miniature solar concentrating PV/T system has the lower heat loss coefficient and could further expand the use scope of solar energy in buildings. [ABSTRACT FROM AUTHOR]

The temperature and irradiance dependent mathematical model for photovoltaic panel performances estimation is proposed in the paper. The base of the model is the mathematical function of the photovoltaic panel current–voltage curve. The model of the current–voltage curve is based on the sigmoid function with temperature and irradiance dependent parameters. The temperature and irradiance dependencies of the parameters are proposed in the form of analytic functions. The constant parameters are involved in the analytical functions. The constant parameters need to be estimated to get the temperature and irradiance dependent current–voltage curve. The mathematical model contains 12 constant parameters and they are estimated by using the evolutionary algorithm. The optimization problem is defined for this purpose. The optimization problem objective function is based on estimated and extracted (measured) current and voltage values. The current and voltage values are extracted from current–voltage curves given in datasheet of the photovoltaic panels. The new procedure for estimation of open circuit voltage value at any temperature and irradiance is proposed in the model. The performance of the proposed mathematical model is presented for three different photovoltaic panel technologies. The simulation results indicate that the proposed mathematical model is acceptable for estimation of temperature and irradiance dependent current–voltage curve and photovoltaic panel performances within temperature and irradiance ranges. [ABSTRACT FROM AUTHOR]

Accurate evaluation of Joule Thomson Coefficient (JTC) is important for the prediction of flowing temperature profile in a gas producing well. The evaluation of JTC requires the determination of derivative of gas compressibility factor with respect to change in temperature at constant pressure (i.e. (∂Z/∂T)p). This may be determined using an appropriate Equations of States (EOS) for a given gas mixture where compositions details are known. In many cases, the details of gas compositions and its associated properties are not known, especially at the appraisal stage. In this study, a simplified practical method has been developed to predict the JTC. This paper presents details of the mathematical model based on which the proposed method is developed. The terms Z and (∂Z/∂T)p have been predicted for a number of gas mixtures using proposed method, and compared the results with those obtained using Peng–Robinson Equation of State (PR EOS) and HYSYS software to provide the accuracy of this work for evaluation of compressibility factor for gas mixtures. The results showed close agreement between two methods. The model is applied to represent gas field in order to predict the temperature profile for gas production wells. A sample case study has been carried out to investigate the flowing temperature profile along a gas producing well. It is demonstrated that the proposed method can be reliably used for evaluation of well following temperature profile along gas producing wellbores. [ABSTRACT FROM AUTHOR]

This paper deals with modeling of the contour evolution of heavy plates in hot rolling. During the rolling process asymmetric rolling conditions, such as temperature gradients or non-homogeneous input thickness profiles, may lead to a non-rectangular plate contour. A continuum mechanics approach is employed to systematically derive the contour evolution of the plate based on the input and output thickness. The mathematical model covering deviations in two dimensions is solved using methods for plane problems in mechanics. A comparison between the simulated contour evolution and measurement data from a real rolling process indicates the good accuracy of the model. Moreover, the model can be executed within one millisecond on a standard computer which stresses its real-time capability. A short analysis of the main reasons for the generation of camber utilizing the proposed model is presented. [ABSTRACT FROM AUTHOR]

In this study, we use an ocean model to explore how vertical mixing influences temperature in the eastern equatorial Pacific Ocean. Our approach is to change the background diffusion coefficient from a constant value κ b to κ b + δ κ ( z ) in various subregions of the tropical Pacific, and then to determine the resulting temperature changes in the near-equilibrium response. In a companion paper (Furue et al., 2015), we consider the impacts of depth-independent κ b anomalies. Here, we examine the impacts of depth-dependent anomalies that are confined above, or centered on, the mid-depth of the pycnocline. During the first year of adjustment, solutions develop a local temperature response that results largely from the one-dimensional balance δ T t = ( δ κ T z ) z = δ κ z T z + δ κ T zz , with a similar equation for salinity. At this stage, δκ generates temperature and salinity anomalies that are either associated with a density change (dynamical anomalies) or without one (spiciness anomalies). Subsequently, dynamical and spiciness anomalies spread to remote regions by wave radiation and advection, respectively. For positive δκ anomalies confined above the mid-pycnocline, δκ z T z tends to produce positive temperature anomalies, which spread to the equator dynamically (by wave radiation) and are still apparent in near-equilibrium solutions. For δκ anomalies confined within the pycnocline (with monopole, dipole, and tripole profiles), the response is dominated by δκ z T z , owing to δκ having a smaller vertical scale than T and to the depth range where δκ is large not overlapping well with that where ∣ T zz ∣ is; the resulting temperature anomalies tend to shift the pycnocline vertically (dipole profile) or to alter its thickness (monopole and tripole profiles). Positive anomalies from all subregions contribute to an increase of near-surface(upper 50 m) temperature in the eastern equatorial Pacific, the amplitude and location of the warming depending on the depth range of the warming band generated within the locally forced subregion. [ABSTRACT FROM AUTHOR]

This paper concerns heat exchange devices with a zigzag configuration containing multi-phase change materials (m-PCMs). A two dimensional mathematical model was established to model the charging behaviour. An experimental system was built to validate the model. The modelling results agree reasonably well with the experimental data for a single PCM, establishing confidence in the model. Extensive modelling was then carried out under different conditions. The results show that the use of m-PCMs intensifies the charging process in comparison with the use of a single PCM. Given other conditions, a larger phase change temperature difference between the m-PCMs gives a more remarkable enhancement of the charging process, and the use of m-PCMs with an unequal mass ratio gives further intensification. The modelling results also show that, for a given input power, an optimal fluid velocity exists for obtaining a high rate of the melting process. [ABSTRACT FROM AUTHOR]

This paper proposes a method to investigate the effects of temperature and strain rate on the forming limit curves (FLCs) by combining a modified Voce constitutive model (Lin-Voce model) with the numerical simulation of Marciniak test. The tensile tests are firstly carried out at different forming temperatures (20, 230 and 290 °C) and strain rates (2.5, 120 and 150 s −1 ) for AA5086 sheet. A modified Voce constitutive model (named Lin-Voce model) is proposed to describe the deformation behavior of AA5086 and its material parameters are identified by inverse analysis technique. Then, the proposed constitutive model is verified by comparing numerical and experimental results obtained by tensile tests and Marciniak test, respectively. Finally, the numerical simulation of Marciniak test is carried out at different temperatures (100, 200 and 300 °C) and strain rates (2.5, 120 and 150 s −1 ), and the effects of temperature and strain rate on the FLCs of AA5086 are investigated and discussed. [ABSTRACT FROM AUTHOR]

This paper examines a mathematical model of the thermal evolution in a specific room of “The City of Refuge”, built in Paris (1933) by Le Corbusier. Although the architect proposed an environmental conditioning system by combining two technological advances: the mur neutralisant – a double-glazed wall with an air cavity that can be heated or cooled – and the respiration exacte – a purified circulating air maintained at constant temperature –, this was never incorporated. This article aims to acquire knowledge of indoor air distribution in the room under study by considering the combination of the mur neutralisant and the respiration exacte . The problem is resolved through a “coupled code”. The first is a two-dimensional model simulating the temperature evolution in the room, while the second is a one-dimensional model used to represent the problem of the mur neutralisant . The numerical model develops the technical issues associated with the implementation of computational fluid dynamics (CFD). The numerical simulations carried out validate the solution of the system proposed. Control of the façade temperature using the active chamber ensures that the operative temperatures obtained for summer and winter fall within the comfort range. The City of Refuge is the clearest precursor of modern active façade systems. [ABSTRACT FROM AUTHOR]

When a number of TEMs (thermoelectric modules) are connected in a series–parallel matrix and under mismatched temperature gradients, the overall maximum output power of the thermoelectric generator (TEG) may be lowered by certain TEMs with relatively smaller temperature difference. It is possible to avoid such a performance decrease by the disconnection of these low temperature TEMs, provided that the critical power point can be accurately determined. In this paper, firstly a rigorous and universal formulation is fully detailed to mathematically determine the conceptions and conditions of the critical power point in the series and parallel TEM arrays. Secondly, experiments of a series–parallel hybrid interconnected TEG are presented to clearly quantify the theoretical analyses. Finally, the hierarchical simulation, based on the SPICE (simulation program with integrated circuit emphasis) platform, is applied to estimate the critical power point. By numerically modeling the nonlinear physical processes of the TEG, the simulation can be used as an enabling technique in any model-based controller to dynamically minimize the mismatch power loss within the TEM matrix of any configuration. In experimental and numerical results, a number of critical power points are disclosed for a 2 × 4 parallel–serial hybrid TEM matrix, where the hot temperature mostly ranges from 120 °C to 60 °C. [ABSTRACT FROM AUTHOR]

For certain temperate climate types, cooling towers have the potential to produce high temperature chilled water, which when used in conjunction with radiant and displacement cooling technologies, have prompted interest in this concept as a potential approach for the conditioning of buildings. The feasibility of the proposed system depends largely, on achieving low approach water temperatures within an appropriately designed cooling tower, at acceptable levels of energy performance. Using a validated mathematical model, the current paper examines the performance of such a cooling tower for four different temperate climate conditions. The current assessment shows for building water return temperature of 22 °C, for temperate climates that are considered warm and humid, the limitations on cooling tower operation are when ambient conditions exceed 25 °C and 75% RH. Two strategies were investigated to allow the smallest practicable approach to the wet bulb temperature to be achieved: (i) increasing the tower air flowrate, (ii) decreasing the tower water flowrate. For a temperate climate that is warm and humid, operating the cooling tower with an approach of 1.0 K was found to be not practicable for all encountered weather conditions, but use of a 2.0 K approach was found to be practicable for all conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Relative humidity has a performance enhancing effect above frosting conditions. • The effect of relative humidity on performance is after a limit value. • Outdoor temperature rise highly improves performance. • Higher capacity air conditioners performs better performance in colder climates. • Deriving the COP change rate correlation with temperature and relative humidity. The paper investigates the performance effect of outdoor temperature and relative humidity on ASHP performance above frosting conditions, with the developed mathematical model. The model results are validated with the experimental data available in literature, of four ASHPs in the 2.7 kW−5.8 kW capacity range. 4 kW capacity ASHP is taken as reference. Constant heating (CH), constant work (CW) and variable heating (VH) modes are determined as operating modes. The model results reveal that relative humidity is a performance enhancing factor above frosting conditions. In VH mode, which is the most realistic operating mode for residences, raise in outdoor temperature from 7 °C to 14 °C increases the COP value by 30%, and raise in the relative humidity from 0.6 to 1.0 provides an additional 5% COP increase. In CH and CW modes, the contribution of relative humidity to performance increases with temperature, up to 10.7% and 6.4%, respectively. Correlations giving the COP change rate with respect to ambient temperature and relative humidity are derived with higher than 0.9839 R2 values for dry and humid conditions of the CH, CW and VH operating modes. These correlations can be useful for researchers who intends to analyze ASHP performance based on ambient conditions. [ABSTRACT FROM AUTHOR]

High energy dissipation systems with friction such as disc brakes require high and constant coefficient of friction. Its value, however, depends beside the materials of the contacting components, on the sliding velocity, contact pressure, temperature, etc. Generally the relationship of these parameters is nonlinear. In this paper an axisymmetric FE contact model was developed to study an influence of the coefficient of friction on the braking time, braking distance, maximum temperature of sliding components of a disc brake and the evolution of the sliding velocity. Computations were carried out based on the equation of motion and the boundary-value heat conduction problem of friction. The main purpose of the study was to compare the transient temperature fields of the pad and the disc, braking time, and braking distance at constant and temperature-dependent coefficient of friction. Dependencies of the coefficient of friction on the temperature and the contact pressure were adopted from experimental measurements and implemented to the FE model of a brake. Temperature and wear evolutions were presented and relevant correlations were discussed. [ABSTRACT FROM AUTHOR]

The assessment of paving and compaction temperatures effect on Hot Mix Asphalt (HMA) properties has been the subject of various researches. The present study aims to build upon these researches, by investigating the effectiveness and practicality of infrared thermography (IRT) as an emerging technology to assess HMA paving and compaction. For this purpose a field experiment was performed using a thermographic system to investigate the impact of the temperature in a paving project where two different types of HMA were used. The recorded mat surface temperatures are used effectively for the identification of temperature differentials, as well the detection of pavement defects. In addition, density-growth curves are developed for the specific mixtures and compaction pattern being used. IRT data is further analyzed for the development of simple HMA cooling models, providing a quick and efficient means to estimate the compaction time. More details and discussion are outlined in the paper. [ABSTRACT FROM AUTHOR]

Highlights: [•] Time warp invariant echo state network is used to construct I–V model of a PV array. [•] I–V model is obtained by irradiance, temperature of each solar cell. [•] The model in the paper considers partially shading and parameters uncertainties. [Copyright &y& Elsevier]

A numerical time-dependent model of an active magnetic regenerator (AMR) was developed for cooling in the kilowatt range. Earlier numerical models have been mostly developed for cooling power in the 0.4 kW range. In contrast, this paper reports the applicability of magnetic refrigeration to the 50 kW range. A packed bed active magnetic regenerator was modelled and the influence of parameters such as geometry and operating parameters were studied for different geometries. The pressure drop for AMR bed length and particle diameter was also studied. High cooling power and coefficient of performance (COP) were achieved by optimization of the diameter of the magnetocaloric powder particles and operating frequency. The optimum operating conditions of the AMR for a cooling capacity of 50 kW was determined for a temperature span of 15 K. The predicted coefficient of performance (COP) was found to be ~6, making it an attractive alternative to vapour compression systems. [ABSTRACT FROM AUTHOR]

Abstract: Environmental temperature has an enormous influence on large machine tools with regards to thermal deformation, which is different from the effect on ordinary-sized machine tools. The thermal deformation has hysteresis effects due to environmental temperature, and the hysteresis time fluctuates with seasonal weather. This paper focused on the hysteresis nonlinear characteristic, analyzing the thermal effect caused by external heat sources. Fourier synthesis, time series analysis and the Newton cooling law were combined to build a time-varying analytical model between environmental temperature and the corresponding thermal error for a large machine tool. A multiple linear regression model based on the least squares principle was used to model the internal heat source effects simultaneously. The two models were united to make up a synthetic thermal error prediction model called the environmental temperature consideration prediction model (ETCP model). A series of experiments were performed using a large gantry type machine tool to verify the accuracy and efficiency of the predicted model under random environments, random times and random machining conditions throughout an entire year. The proposed model showed high robustness and universality, with over 85% thermal error, with up to 0.2mm was predicted. The mathematical model was easily integrated into the NC system and could greatly reduce the thermal error of large machine tools under ordinary workshop conditions, especially for long-period cycle machining. [Copyright &y& Elsevier]

This paper investigates the feasibility of a microalgae derived hydrogen process at a pilot scale. For that, a general transient mathematical model for managing microalgae derived hydrogen production, with temperature dependence of the cultivation medium is developed. The tool allows for the determination of the resulting whole system temperature, and mass fractions distribution. The simplified physical model combines principles of classical thermodynamics, mass, species and heat transfer, resulting in a system of differential equations which are discretized in space using a three-dimensional cell-centered finite volume scheme, namely a volume element model (VEM). A Michaelis–Menten type expression is proposed for modeling the rate of H2 production with dependence on O2 inhibition. Tridimensional simulations are performed in order to determine the mass fractions distributions inside a compact photobioreactor (PBR), under different operating conditions. A relatively coarse mesh was used (6048 volume elements) to obtain converged results for a large compact PBR computational domain (2 m × 5 m × 8 m). The largest computational time required for obtaining results was 560 s, i.e., less than 10 min. The numerical results for microalgal growth are validated by direct comparison to experimental measurements. Hydrogen production simulations are conducted to demonstrate PBR intermittent operation (aerobic and anaerobic stages) feasibility and adequate species evolution trends in an indirect biophotolysis approach. Therefore, after experimental validation for a particular H2 production system, it is reasonable to state that the model could be used as an efficient tool for PBR systems thermal design, control and optimization for maximum H2 production. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we propose a model to study the phenomenon of phase separation during lava flow. Lava is considered as a mixture of two incompressible fluids with different density, in that the mass density of the mixture is determined by the concentrations of the two constituents. We consider as state variables the order parameter, describing the difference in concentration of the fluids, the velocity of the mixture and the absolute temperature. We assume that the order parameter satisfies a Cahn–Hilliard equation, where the chemical potential depends on the velocity and we model lava as a Bingham fluid whose apparent viscosity and yield stress increase exponentially as temperature decreases, according to experimental data. The heat equation provides the evolution equation for temperature. We prove that this model is consistent with the principles of thermodynamics. [Copyright &y& Elsevier]

Abstract: The aim of this paper consists in defining optimal conditions of controlled and selective gold leaching contained in copper–gold slag, by wet chlorination. Studies were conducted on three types of copper–gold slag, resulting as by-products from pyrometallurgical processing of non-ferrous raw materials. Due to high levels of copper in slag, an oxidative pre-treatment is necessary to separate gold from accompanying elements and also for copper recovery. After nitric acid pre-treatment, nearly 87% of Cu was readily extracted, and lead and silver contents in all three types of solid samples have been reduced by 91.34% and 96.29%, respectively. Selective leaching of the solid phase resulting after HNO3 pre-treatment was done by wet chlorination, using nascent chlorine (Cl2) as the leaching agent, with the presence of hydrochloric acid (HCl). The chlorine was obtained “in situ” by the reaction of sodium hypochlorite (NaOCl, 5% Cl2) and HCl. In this study, the effect of nitric acid pre-treatment, redox potential (Eh) given by sodium hypochlorite (NaOCl) consumption, hydrochloric acid concentration, temperature and leaching time have been studied. The potential required for a rapid leaching rate and for avoiding the reduction of gold is 950mV (vs AgCl/Ag(KCl sat)). The 5% NaOCl consumption required for gold leaching from pre-treated samples was lower than NaOCl consumption necessary for original sample leaching. The highest gold extraction yield (98%) was obtained after 6h at ambient temperature, solid/liquid ratio (w/v) 1:2 and 4M HCl. In order to explain experimental results a mathematical model of the simultaneous gold, copper, lead and silver dissolution has been developed. It considers at particle level, the competition between surface reaction and the diffusion of the active species by a gel coating that covers the dissolving particle. [Copyright &y& Elsevier]

Isothermal compression tests of Ti17 titanium alloy with the initial lamellar-type microstructure at the deformation temperatures and strain rate ranges of 780–860°C and 0.001–10.0s−1, respectively, were conducted on a Gleeble-1500 thermo-mechanical simulator. The flow stresses of all different conditions were obtained. The typical flow curves presented that softening at all the deformation conditions, even at low strain rate (0.001s−1), which have been considered that the flow softening results from lamellar globularization at low strain rates and adiabatic shear bands at high strain rates. According to orthogonal experiment and variance analysis on the significance of strain, strain rate, deformation temperature as well as interaction between strain rate and deformation temperature to the flow stress, the effect of interaction between strain rate and deformation temperature can be neglected in comparison with other factor. Thus, with consideration of strain, strain rate, and deformation temperature, a multivariate nonlinear regression model was established to predict the flow stress in isothermal compression of Ti17 titanium alloy in this paper. Predicted and experimental results show that the developed constitutive equation enables to predict the flow stress accurately throughout the entire domain of temperature and strain rate, excepting at high strain rate (10s−1), deformation temperature 780°C for Ti17 titanium alloy. [ABSTRACT FROM AUTHOR]

In a previous study, we proposed a dual-function microporous layer (MPL) to improve the cold-start capability of polymer electrolyte fuel cells (PEFCs). The conceptual MPL design is to use an ionomer-based binder with low Pt loading, thereby allowing the MPL to provide additional volume for ice storage during cold-start PEFC operations. Although the benefit of using a dual-function MPL was numerically elucidated in our previous study, the question regarding the use of this new MPL under normal PEFC operation remains to be addressed. In this paper, we extend our discussion to the effects of a dual-function MPL under subzero to normal operating temperatures. The three-dimensional (3D) cold-start PEFC model developed in our previous study is modified for transient PEFC simulations to consider a wide range of operating temperatures from −20 °C to 80 °C. Simulation results show a negligible performance drop at the normal PEFC temperature of 80 °C, because of the presence of the dual-function MPL in a PEFC membrane electrode assembly. In addition, water back flow from the cathode to anode is reduced on using the dual-function MPL, owing to the additional water uptake driven by its ionomer content. This study clearly demonstrates that this dual-function MPL technology may be applied to automotive PEFC stack development without sacrificing fabrication cost and cell performance during normal PEFC operations. [ABSTRACT FROM AUTHOR]

Abstract: The current paper explores experimentally and numerically obtained mechanical responses of the Nakazima-type sheet forming for the magnesium alloys ZE10 and AZ31 at elevated temperature (200°C). The results from the experiments revealed sufficient ductility allowing sheet forming processes at the prescribed test temperature. The material's anisotropy recorded in previous experiments was confirmed. Differences in the mechanical response between the two materials in terms of strain paths during the forming experiments were quantified. The corresponding numerical responses were obtained employing a suitable constitutive model taking into account the characteristic anisotropy in deformation. In addition, for predicting limit conditions of the forming process, the localization criterion by Marciniak and Kuczynski was adopted. The constitutive model together with the localization criterion was implemented in a finite element framework based on a fully implicit time integration scheme. The reasonably good agreement between the responses of the model and the respective experiments indicated the predictive capabilities of the implemented model for the considered magnesium alloys. [Copyright &y& Elsevier]

Abstract: The pulse tube engine represents the thermodynamic inversion of the pulse tube refrigerator used in cryogenic cooling applications. It has a high potential to be used as a prime mover for the conversion of low grade waste heat into mechanical or electrical energy. This paper describes an analytical analysis of the pulse tube engine based on a zero-dimensional model. During compression and expansion, the engine components are considered as isothermal with characteristic temperatures. At the piston's dead centers, a thermal relaxation model is used to switch between these temperatures. Analytical relations for the pV–work developed by the pulse tube engine and its efficiency are derived. The irreversible nature of the pulse tube engine is studied by calculating the entropy production in the components. Furthermore, the thermodynamic cycle is investigated analytically under variation of design features and operating conditions. The results are compared to prior numerical studies. The minimal temperature ratio above which the engine provides a work output is derived analytically and compared to experimental observations. Fundamental characteristics and application limitations of the pulse tube engine are disclosed. An upper limit for the efficiency of the pulse tube engine is derived theoretically and confirmed experimentally as well as through numerically calculations. [Copyright &y& Elsevier]

Abstract: A universal relationship between the partial molar entropy of electrons in a conductor and the absolute thermoelectric power of the conductor was previously established using macroscopic thermodynamics. This relationship may depend on temperature but not on the type of material. Building on this, a recent comment published in this journal, as well as some earlier work, has argued that the partial molar entropy of electrons in a conductor is essentially equivalent to the absolute thermoelectric power of the metal. The argument was based on the thermodynamic and transport properties of a free electron Fermi gas. To further validate the relationship the present paper extends this approach to a jellium model of electronic structure. If the proposed equivalence between partial molar entropy and absolute thermoelectric power is valid it opens the way for an experimental thermodynamic method to measure quantities that have previously been considered un-measurable, such as partial molar entropies of ions in solution and electric fields in homogeneous conductors placed in a temperature gradient. It also relates to questions about the completeness of current thermodynamic theory and the possibility of a new principle or law of thermodynamics. [Copyright &y& Elsevier]

Abstract: The experimental study of the oxidation of cyclohexane has been performed in a jet-stirred reactor at temperatures ranging from 500 to 1100K (low- and intermediate temperature zones including the negative temperature-coefficient area), at a residence time of 2s and for dilute mixtures with equivalence ratios of 0.5, 1, and 2. Experiments were carried out at quasi-atmospheric pressure (1.07bar). The fuel and reaction product mole fractions were measured using online gas chromatography. A total of 34 reaction products have been detected and quantified in this study. Typical reaction products formed in the low-temperature oxidation of cyclohexane include cyclic ethers (1,2-epoxycyclohexane and 1,4-epoxycyclohexane), 5-hexenal (formed from the rapid decomposition of 1,3-epoxycyclohexane), cyclohexanone, and cyclohexene, as well as benzene and phenol. Cyclohexane displays high low-temperature reactivity with well-marked negative temperature-coefficient (NTC) behavior at equivalence ratios 0.5 and 1. The fuel-rich system (ϕ =2) is much less reactive in the same region and exhibits no NTC. To the best of our knowledge, this is the first jet-stirred reactor study to report NTC in cyclohexane oxidation. Laminar burning velocities were also measured by the heated burner method at initial gas temperatures of 298, 358, and 398K and at 1atm. The laminar burning velocity values peak at ϕ =1.1 and are measured as 40 and 63.1cm/s for Ti =298 and 398K, respectively. An updated detailed chemical kinetic model including low-temperature pathways was used to simulate the present (jet-stirred reactor and laminar burning velocity) and literature experimental (laminar burning velocity, rapid compression machine, and shock tube ignition delay times) data. Reasonable agreement is observed with most of the products observed in our reactor, as well as the literature experimental data considered in this paper. [Copyright &y& Elsevier]

While electronic noses have been around for over 30 years, little effort has been devoted to the development of transferable calibration models, which are models that can be applied to multiple equivalent devices without adjustment. The majority of published results limit itself to data sets gathered with a single device. This lack of insight in transferable models hampers large scale implementations of eNose-based applications as individual calibration of a multitude of devices for a specific application area is generally unrealistic due to the requirement of actual samples to be measured. For simple gases this may be do-able, but in the case of more complex samples such as biological patient material it is logistically impossible. In this paper we show the influence of the deviation of the sensor temperature on the measurement reproducibility and by inference on the transferability of calibration models. We introduce the total inertia (φ 2) as a measure for the heterogeneity within the measured data. The total inertia is an objective measure known from linear algebra, where it is used to calculate the correspondence between matrices. We use 5 micro-hotplate metal-oxide sensors from the same wafer, with an inter-sensor heater temperature difference of approximately 15°C in combination with 2 substances, n-butyl-acetate and hexane. This research demonstrates the increase in heterogeneity of the measured response values in relation to a temperature shift. A shift of 15°C at the sensor surface causes an increase of heterogeneity that is 10–15 times higher than the increase in heterogeneity caused by inter-sensor responses to the substances when operated at exactly the same temperature. Some mixtures of substances will be separable by pattern recognition under virtually any condition, and strict temperature control will neither improve nor deteriorate results. However the significant contribution of temperature deviation toward data heterogeneity renders it plausible that optimized temperature control, and by inference lower data heterogeneity, is a prerequisite for transferability of a calibration model. This holds true when applied to metal-oxide sensors and for mixtures containing substances showing a fair degree of similarity. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents an overview of the finite element (FE) analyses on the trim coils (TCs) and tests performed at IPP, and focuses on some specific aspects of the TC assembly. Global FE models (GM) of two types of TCs predicted the coil deformations and reaction forces on the supports. Dead weight, temperature rise during operation up to 80°C, electromagnetic loads of 19 field configurations, and outer vessel (OV) deformations have been taken into account. In addition, local models were created for the critical winding pack (WP) regions as well as for each support clamp, and were analyzed with boundary conditions determined by the GM. The detailed WP sub-models were developed to verify the insulation strength against local stresses. The simulations were supported by various mechanical tests under static and cyclic loads. Aim of these experiments was to determine the time dependent behavior of the silicone rubber pads which are used as interfaces between TC and supports, and to check and optimize the assembly tools as well as procedures for the TCs and their supports. [Copyright &y& Elsevier]

Abstract: A Lorentz force flowmeter is a device used for contactless measurements of the flow rate in liquid metals at high temperatures. Application of this device in practice requires a calibration procedure. In this paper, numerical modeling is used to calibrate this flowmeter in different flow conditions. Laminar and turbulent flow effects on the calibration curve are analyzed for liquid aluminum flow in closed and open channels. The flow damping caused by the Lorentz forces is also analyzed for laminar and turbulent flows. Numerical computations including flow are compared to the simplified case of a solid conductor moving at constant rate. The computations performed for laminar flows in open and closed channels, show significant flow effects on the Lorentz forces as comparing to the case of solid body computations. In the case of high Reynolds number turbulent flows in closed and open channels, the results are very close to solid body computations. In conclusion, the flow effects are important for the calibration procedure only for laminar flows. At high Reynolds numbers, the complex numerical models used for computing the calibration curves can be replaced by simple solid body computations. [Copyright &y& Elsevier]

Abstract: We present herein the first of two parts in the development and validation of a chemically and physically consistent mathematical model of a commercial dual-layer (SCR+PGM) monolithic NH3 slip converter (ASC). The overall project followed a systematic approach of growing complexity, and its results emphasize the beneficial features of a dual-layer configuration with the SCR catalyst on top of the PGM component. Specifically, we report in this paper NH3/O2/NO NO2 steady-state and transient kinetic runs performed over the PGM component of the dual-layer NH3 slip catalyst. The PGM component was tested in a representative temperature range (150–550°C) in the form of precursor washcoat powders at high space velocities in order to gain kinetic information. From these data an original global PGM kinetic model was developed, which fully accounts for the effects of temperature and of NO2/NO x feed ratio (0–1) on NH3 oxidation. The model considers NO2 inhibition on NO oxidation, as well as a novel NO2 inhibition effect on the NH3 oxidation reactions. Comparative NH3/O2/NO NO2 steady-state runs were performed also over two combinations of SCR+PGM powders (sequential double-bed and mechanical mixture). The N2 selectivity was greater over the mechanical mixture, as in this configuration the unselective NH3 oxidation products (NO x ) formed over the PGM catalyst had a chance to further react selectively with NH3 over the SCR catalyst. Such a positive interaction between the PGM and the SCR catalytic chemistries was satisfactorily predicted by a model involving the simple superposition of the PGM and SCR kinetics. In the following part of the project the herein developed PGM kinetics, together with consistent SCR kinetics, will be incorporated in a novel dual-layer monolith catalyst model and validated against both lab-scale and engine test bench data collected over dual-layer ASC systems. [Copyright &y& Elsevier]

Abstract: In this paper, we present a phenomenological mathematical model for describing the features of the brine channels in sea ice. The differential system is composed of the Ginzburg–Landau and Cahn–Hilliard equations, in addition to the heat equation, that controls the ice–liquid phase transition by the temperature and hence the establishment of brine channels. The compatibility of this system with the thermodynamic laws and a maximum theorem is proved. [Copyright &y& Elsevier]

Abstract: In this paper, systematic experimental investigation on the heat flux distribution inside the furnace of a 300MW CFB boiler was presented. Detailed experimental setup and measurement techniques were presented and a finite element method approach was applied to determine the heat flux. The heat flux profile on the rear wall along the horizontal direction shows a significant imbalance at different boiler loads. As a result of the non-uniform layout of the heating surfaces, which is the essential reason, as well as the imbalance and deviation of the temperature field, solid suspension density and solid flow rate, the central section of the furnace possesses higher heat flux distribution compared to the side sections. The heat flux is also found to increase with the increasing boiler load and decrease as the height increases. Heat flux near the roof, where the solid suspension density is rather small, is found to decrease remarkably revealing less heat absorption in this area. In addition, an empirical model of heat transfer coefficient is revised using the average data at different boiler loads. A mechanism heat transfer model based on the membrane water-wall configuration is proposed and validated with the heat flux profile obtained from the measurement. The model provides good accuracy for correlating 85% of the data within ±10%. [Copyright &y& Elsevier]

Abstract: In this paper, the development of the tandem reciprocating room-temperature active magnetic regenerative refrigerator and the numerical simulation for the effect of the dead volume are presented. The dead volume effect is analyzed by establishing a one-dimensional time-dependent model for the active magnetic regenerator (AMR). The cooling power at the mass flow rate of 5 g s−1 water and a temperature span of 20 K is reduced from 4 W to 2 W when the length of the dead volume (D DV = 12 mm) is increased from 15 mm to 30 mm. The numerical results indicate that the minimization of dead volume facilitates the improvement of the AMR performance. In particular, the components and the parameters of AMR system are demonstrated. The printed circuit heat exchangers (PCHEs) are employed as the warm end heat exchangers in order to minimize the dead volume of the system. The experimental apparatus includes two active magnetic regenerators containing 186 g of Gd spheres. The maximum no-load temperature span of 26.8 K and a maximum cooling power of 33 W at a zero temperature span were obtained with the frequency of 0.5 Hz under the maximum field of 1.4 T. [Copyright &y& Elsevier]

Abstract: In this paper, the operating feasibility of a single-stage metal based hydride heat pump (SS-MHHP) working on the principle of crossed van't Hoff line concept is presented. The performance of the system is predicted by solving the unsteady, two-dimensional mathematical model in an annular cylindrical configuration employing two different hydride alloy pairs, namely, V0.846Ti0.104Fe0.05/Fe0.9Mn0.1Ti and V0.855Ti0.095Fe0.05/MmNi4.7Al0.3 (regeneration alloy/refrigeration alloy). The influences of heat source (T H ) and refrigeration (T C ) temperatures on the amount of hydrogen transferred between the paired reactors, coefficient of performance (COP) and specific cooling power (SCP) of the crossed van't Hoff SS-MHHP system are studied. Within the selected ranges of operating temperatures, the COP of the crossed van't Hoff SS-MHHP is about 60% higher than the conventional single-stage MHHP. The optimum operating temperatures of V0.846Ti0.104Fe0.05/Fe0.9Mn0.1Ti and V0.855Ti0.095Fe0.05/MmNi4.7Al0.3 combinations are found to be 373/303/291 K and 400/303/283 K (heat source/heat sink/refrigeration temperatures), respectively. At the optimum operating temperatures, the COP and SCP of the V0.846Ti0.104Fe0.05/Fe0.9Mn0.1Ti and V0.855Ti0.095Fe0.05/MmNi4.7Al0.3 combinations are 0.89 and 30.8 W/kg of total mass and 0.86 and 30.3 W/kg of total mass, respectively. [Copyright &y& Elsevier]