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The organization of the plasma–wall interaction remains an urgent problem for long-term operation of a tokamak with an intense thermonuclear fusion reaction. The concept of a lithium cycle and the design of a sectioned divertor for the Demonstration Fusion Neutron Source (DEMO-FNS) tokamak are proposed. The parameters are estimated, and requirements for the components of the lithium cycle are formulated. Technical solutions for the lithium cycle flow rate ≅10 g/s are selected. It is estimated that 0.1-µm liquid lithium layer on the surface of the first wall can protect its solid coating. On the basis of a simple model, it is shown that, at a wall temperature of 200–300°C, a thickness of 0.1 µm can be achieved in ≅1 min. The film can reach quasi-stationary values of 13–15 µm in 3–4 h. Above 340°C, the film does not form because of the increase in the thermal evaporation of lithium. The wall temperature of 700°C of the divertor section with the lithium pool is chosen so that lithium deuteride and lithium tritide do not form in it. They can form in the liquid metal lithium protective layer of the wall at temperatures less than 300°C. In order to significantly reduce the explosion and fire hazard when working with hot liquid lithium, it is proposed to increase the size of the DEMO-FNS divertor section with the lithium pool by 2 to 3 times, which may allow the transition from water to helium coolant. [ABSTRACT FROM AUTHOR]

Building temperature setpoints affect both HVAC energy consumption and occupant comfort. To reduce HVAC energy usage, researchers often investigate how system operations can be optimized under weather and occupancy variability subject to a fixed setpoint that minimizes any possible discomfort. While previous research has explored the selection of dynamic setpoints to minimize HVAC energy consumption based on outdoor temperature, they have often neglected the impact of varying occupancy rates on the setpoints. This paper aims to demystify energy savings derived from fixed and dynamic temperature setpoints under weather and occupancy variability and explores the additional energy savings that can be achieved through dynamic temperature setpoints. An exhaustive HVAC zone temperature setpoint optimizer was developed to determine dynamic setpoints with respect to weather and occupancy (i.e., setpoints that minimize HVAC energy consumption at different occupancy rates based on outdoor weather). U.S. DOE reference building energy models for small, medium, and large office buildings were simulated at 17 climate zones, 4 occupancy rates (25%, 50%, 75%, 100%) and 7 setpoints (19.5°C to 25.5°C at 1°C interval). It was found that, both fixed and dynamic setpoints benefit from the energy reduction of approximately 2-4% from the lower heat generated by the occupants at lower occupancy rates. However, at outdoor temperatures between 5°C and 32°C where occupant heat loads can swing the building between heating, free-running, and cooling modes, dynamic setpoints yield additional 2-10% energy savings, compared to fixed setpoints. [ABSTRACT FROM AUTHOR]

Purpose: Fresh fruits and vegetables (FV) are crucial global food resources, but the presence of heat loads during harvest adversely impacts their shelf life. While freezing technology provides an effective means of removing heat loads, it is an energy-intensive process and may consequently prove too costly for practical business viability. The growing interest in utilizing magnetic field (MF) technology during the freezing of fresh FV enhances the freezing rate and rapidly removes the heat loads of products. Design/methodology/approach: In the present study, pulsed magnetic field (PMF) pretreatment employing specific field strengths (9 T, 14 T and 20 T) was examined as a preliminary step before freezing mango and tomato and compared to the conventional freezing method (untreated) at − 18 °C. Findings: PMF pretreatment prior to freezing demonstrated a noteworthy enhancement in freezing rate by around 10 and 12% when compared with the conventional (untreated) freezing, which exhibited freezing rates of −0.08 °C/min and −1.10 °C/min for mango and tomato, respectively. The PMF pretreatment (at 20 T) provided a higher freezing rate (at p = 0.05) than the conventional freezing method reduced heat loads amounting to 1.1 × 107 J/kg oC and 2.9 × 106 J/kg oC, significantly (at p = 0.05) from mango and tomato, respectively. These reductions in heat loads were approximately more than 5% of the calculated heat loads removed during conventional freezing. Research limitations/implications: Mango and tomato samples were only tested; the results may lack generalizability. Therefore, researchers are encouraged to test for other products for further studies. Practical implications: The paper includes implications for the development of a rapid freezing technique, the development of "pulsed magnetic field" and for eliminating the problem associated with conventional (slow) freezing. Originality/value: The study holds significance for the production of postharvest freezing technology, providing insightful information on the PMF-assisted freezing of cellular foods. [ABSTRACT FROM AUTHOR]

Building temperature setpoints affect both HVAC energy consumption and occupant comfort. To reduce HVAC energy usage, researchers often investigate how system operations can be optimized under weather and occupancy variability subject to a fixed setpoint that minimizes any possible discomfort. While previous research has explored the selection of dynamic setpoints to minimize HVAC energy consumption based on outdoor temperature, they have often neglected the impact of varying occupancy rates on the setpoints. This paper aims to demystify energy savings derived from fixed and dynamic temperature setpoints under weather and occupancy variability and explores the additional energy savings that can be achieved through dynamic temperature setpoints. An exhaustive HVAC zone temperature setpoint optimizer was developed to determine dynamic setpoints with respect to weather and occupancy (i.e., setpoints that minimize HVAC energy consumption at different occupancy rates based on outdoor weather). U.S. DOE reference building energy models for small, medium, and large office buildings were simulated at 17 climate zones, 4 occupancy rates (25%, 50%, 75%, 100%) and 7 setpoints (19.5°C to 25.5°C at 1°C interval). It was found that, both fixed and dynamic setpoints benefit from the energy reduction of approximately 2-4% from the lower heat generated by the occupants at lower occupancy rates. However, at outdoor temperatures between 5°C and 32°C where occupant heat loads can swing the building between heating, free-running, and cooling modes, dynamic setpoints yield additional 2-10% energy savings, compared to fixed setpoints.

In ITER, disruption-born runaway electrons (REs), unless mitigated, are expected to form a several Mega-Ampere beam that ultimately intercepts the first wall leading to melting of the plasma facing components. Developing a successful mitigation strategy therefore requires modeling that takes into account the coupling between REs and the MHD during the formation and termination of the beam, along with estimates for the wall loads that can be compared to design values. Using the JOREK code, this work aims to provide the latter by presenting a novel model for collisions between REs and the wall and applying it to a beam termination scenario in ITER. To this end, the transport of REs is modeled by tracing particles in the fields calculated by preceding simulations of the disruption event where REs were treated in the fluid picture and self-consistently coupled to the MHD. The resulting heat loads are found to be highly localized in both the poloidal and toroidal directions, with 3D features also playing an important role in the appearance of hot spots. Peak loads were on the order of 10 7 − 10 8 J m 2 . The load distribution was found to only be weakly sensitive to the initial phase space distribution of the REs when decoupled from the fields, while modifying properties of the underlying MHD yielded notable differences in wetted area and peak loads, in particular for cases with higher resistivity. [ABSTRACT FROM AUTHOR]

The design complexity of the new generation of civil aero-engines results in higher demands on engines' components, higher component temperatures, higher heat generation, and, finally, critical thermal management issues. This paper will propose a methodological approach to creating physics-based models for heat loads developed by sources, as well as a systematic sensitivity analysis to identify the effects of design parameters on the thermal behavior of civil aero-engines. The ranges and levels of heat loads generated by heat sources (e.g., accessory gearbox, bearing, pumps, etc.) and the heat absorption capacity of heat sinks (e.g., engine fuel, oil, and air) are discussed systematically. The practical research challenges for thermal management system design and development for the new and next generation of turbofan engines will then be addressed through a sensitivity analysis of the heat load values as well as the heat sink flow rates. The potential solutions for thermal performance enhancements of propulsion systems will be proposed and discussed accordingly. [ABSTRACT FROM AUTHOR]

Knowledge of the emissivity and thermal conductivity of thin metal films used in conjunction with multilayer mirrors for the spectral selection of radiation in the extreme-ultraviolet- and "soft"-X-ray wavelength ranges is necessary in order to correctly calculate the heating of film elements at high heat loads. Heating is associated with absorption in the film of a significant fraction of the incident intensity, and the concept of a high heat load is somewhat arbitrary, since even at an absorbed intensity level on the order of 1 W/cm2 a freestanding film can be heated in vacuum by several hundred degrees. In the first approximation, to estimate the thermal-conductivity coefficient, one could use tabular values for bulk samples of the corresponding metals or use the well-known Wiedemann-Franz law which links the thermal conductivity and the electrical resistivity of the sample; the latter is easier to measure. However, an analysis of the published data indicates significant errors that are possible when using any of these approaches. Therefore, in this work, we measure the thermal conductivity directly by processing the temperature distribution obtained by infrared (IR) pyrometry over a film sample mounted on a heated frame or heated by a flowing electric current. The thermophysical characteristics (thermal conductivity and emissivity) are determined for samples of film absorption filters based on Mo, Al, and Be of submicron thickness (from 100 nm), as well as for films of copper: a metal whose bulk samples have high thermal and electrical conductivity. As expected, significant differences are found between the thermal and electrical properties of the film materials and the properties of the same metals in monolithic samples. [ABSTRACT FROM AUTHOR]

The high magnetic field compact high-temperature superconducting tokamaks are characterized by high energy density, macroscopic instabilities, and high threshold values, which are beneficial to the operation of the device with high parameters, however, this also directly leads to a sharp increase in the heat loads of the divertors. Therefore, in this paper, with reference to the design parameters of SPARC, the TSC is used to simulate the double-null divertor sweeping configuration discharge process of a high magnetic field compact tokamak device (HFCT), and the heat flux distribution on the surface of the target at the time of divertor outer long-leg sweeping in the discharge flat-top stage is obtained, with the peak value of 23.2 MW/m2; both water-cooled monoblock and all-tungsten divertor configurations calculated using ANSYS, which concluded that the tungsten armor thickness d in the all-tungsten divertor configuration should not be greater than 2.5 mm to withstand a peak heat flux of 23.2 MW/m2; on the basis of this configuration, the temperature field of the divertor target is calculated for different sweeping fields and the feasibility of the all-tungsten divertor target model is analyzed. This study can be used as a reference for the design of divertor target in future HFCT. [ABSTRACT FROM AUTHOR]

The design complexity of the new generation of civil aero-engines results in higher demands on engines’ components, higher component temperatures, higher heat generation, and, finally, critical thermal management issues. This paper will propose a methodological approach to creating physics-based models for heat loads developed by sources, as well as a systematic sensitivity analysis to identify the effects of design parameters on the thermal behavior of civil aero-engines. The ranges and levels of heat loads generated by heat sources (e.g., accessory gearbox, bearing, pumps, etc.) and the heat absorption capacity of heat sinks (e.g., engine fuel, oil, and air) are discussed systematically. The practical research challenges for thermal management system design and development for the new and next generation of turbofan engines will then be addressed through a sensitivity analysis of the heat load values as well as the heat sink flow rates. The potential solutions for thermal performance enhancements of propulsion systems will be proposed and discussed accordingly.

The operation process of marine diesel engines when using fuel with a sulfur content of no more than 0.1 % was chosen as the object of the study. Similar types of fuel are characterized by a lower auto-ignition temperature and higher calorific value. During combustion, this leads to an increase in the rate of fuel combustion and the degree of pressure increase during combustion, precisely because of this, the dynamic loads on the parts of the cylinder-piston group and diesel engine bearings increase. Also, this (due to the increase in temperature at the end of combustion) creates conditions for an increase in the concentration of nitrogen oxides in diesel exhaust gases. This (namely, the change in dynamic and thermal loads that occur during the use of fuels with a reduced sulfur content in marine diesel engines) leads to the occurrence of emergency situations. As a method of managing the risk of such emergency situations, the reconfiguration of the high-pressure fuel equipment, namely the change of the advance angles of the fuel supply, is proposed. The research was carried out on a vessel intended for the transportation of containers and on which a marine diesel engine 8K80ME-8.2-TII MAN-Diesel & Turbo was installed as the main engine. Combustion pressure, the degree of pressure increase during combustion, the temperature of exhaust gases, and the concentration of nitrogen oxides in exhaust gases were chosen as the indicators for evaluating the use and implementation of the proposed method. It has been experimentally proven that this results in an increase in the environmental sustainability of diesel operation by 3.61–10.97 %, an increase in thermal stability – up to 2.54 %, and an increase in dynamic stability – up to 4.82 %. This is due to the shift of the self-ignition and combustion process towards expansion and the corresponding decrease in pressure and temperature at the end of combustion. The most favorable use of this method is on modern diesel engines that have an electronic fuel injection control system, so they do not require mechanical reconfiguration of fuel pumps. Taking this into account, the method based on the change of fuel advance angles is defined as the one that provides management of the risk factors of emergency situations when using low-sulfur fuel in marine diesel engines. [ABSTRACT FROM AUTHOR]

An 0D model is proposed that makes it possible to estimate the limiting stationary heat loads to the targets covered with liquid lithium (LL) layer, taking into account the effects of vapor shielding by sputtered and evaporated LL and hydrogen recycling. Several models of cooled target substrates are considered in which the LL layer facing the plasma is placed. For the considered substrate models, a parametric analysis of the tolerable stationary heat loads to the target on the substrate thickness, the effective cooling energy per particle of sputtered lithium, and the lithium prompt redeposition factor was carried out. It is shown that, at a small substrate thickness, the choice of the substrate model has a significant impact on the tolerable heat loads. It is also shown that even at unrealistically large values of the effective cooling energy, the dissipation of lithium remains modest. This means that in regimes with a high power coming from the core plasma to the edge, the injection of an additional radiator is required. Finally, it is shown that one of the most effective ways to increase the tolerable stationary heat loads would be to reduce the thickness of the target substrate.

Human global anthropogenic influence forces the developers of household refrigeration equipment to reconsider their attitude towards absorption refrigeration devices (ARD). The working body of ARD consists of natural components – water-ammonia solution (WAS) with the addition of inert gas (hydrogen, helium or their mixture) and is absolutely environmentally safe – it has zero values of ozone-depleting potential and the potential of the "greenhouse" effect. Absorption refrigeration devices have a number of such unique qualities, such as: silence, high reliability and long service life, absence of vibration, magnetic and electric fields during operation; the possibility of using several sources of energy in one device – both electric and alternative; the possibility of working with low-quality energy sources, in particular, electric energy, in the range of network voltage 160...240 V. At the same time, ARDs have higher energy consumption compared to similar compression models. In this work, an attempt is made to analyze the energy characteristics in a wide range of regime parameters using the thermodynamic parameters of real ARDs obtained by various researchers. The developed method of thermodynamic calculation of a typical absorption refrigeration device, which is based on the results of experimental studies of typical real models, allows variant calculations for a wide range of operating parameters. It is shown that a decrease in the average evaporation temperature leads to an increase in heat loads on the ARD elements, i.e. freezers always have large weight and size characteristics, compared to refrigerating chambers of medium cold. The limitation of the maximum boiling temperature in the ARD generator was found, which is determined by the corrosion resistance of the wall material. It has been shown that ARDs of tropical design with a working pressure of 30 bar in the system require high energy consumption, compared to similar models for a temperate climate. [ABSTRACT FROM AUTHOR]

Observations of the Earth climate for the last 100−150 years have revealed that the atmospheric air temperature in the ground level shows quite a rapid growth. Megalopolises and other settlements behave as large sources producing thermal pollution of the Earth air basin. Transport facilities, heated buildings, and heat and electric networks release a significant amount of energy, which accumulates in the air medium of cities and then dissipates into the surrounding space. The most rapid change in the air temperature has been noted for the last 50 years. The greatest increase of the outdoor air temperature, e.g., in St. Petersburg, is observed in the cold period of the year. It has been determined that the average air temperature in the cold period of the year (from October to April) has increased by 1.51°С, whereas the average air temperature increased by 0.72°С for the same interval of time but in the warm period of the year (from May to September), i.e., half as much as in the cold period. It has been found from studies of regulatory and reference documents that the standard climatic data specified in them lag significantly from the currently occurring climate changes. The article presents an analysis of the outdoor air temperatures in St. Petersburg for the period from 1992 to 2021 and an assessment of air temperatures in the coldest day and the coldest 5-day spell with reliabilities of 0.92 and 0.98 and also the absolute minimal air temperature for the considered 30-year interval of time. It is pointed out that the actual climatic indicators derived from statistical processing of daily data arrays are by 3–4°С higher than those specified in the relevant standards. As a result, when buildings are designed for the standard conditions specified by the existing regulations, the contractual loads turn out to be overestimated essentially in comparison with the actual ones, which is revealed in designing the configurations of settlement heat-supply systems. The consideration of actual climatic indicators opens up the possibility to decrease the contractual heat loads of consumers on a sound basis and, as a consequence, to achieve thermal energy saving without degrading the heat-supply quality. [ABSTRACT FROM AUTHOR]

The three-dimensional (3D) edge Monte Carlo transport code EMC3-EIRENE has been employed to study edge plasma and impurity transport with toroidally localized argon seeding using the Chinese fusion engineering testing reactor (CFETR) X-divertor configuration. The argon impurity seeded at different poloidal locations was investigated to evaluate the varied profile of the main plasma in the scrape-off layer (SOL) and on the divertor targets, which showed a strong dependence on the poloidal position of argon gas puffing. The argon impurity seeded in the upstream SOL regions can result in a toroidally asymmetric distribution of electron density and temperature, while a toroidally symmetric distribution was obtained for argon seeded in the strike point regions. The deposition pattern of electron density and temperature showed several lobe-like and island-like structures on the 3D divertor targets of CFETR with upstream argon injection, whereas a perturbed profile was achieved for argon seeding in the strike point regions. In order to verify the toroidal asymmetry of heat load distribution, the argon impurity seeded at different poloidal locations was investigated to estimate its influence on the toroidal heat load on divertor plates. The argon injected in the strike point regions gave rise to a toroidal asymmetry of heat load distribution on divertor targets, while a toroidal symmetry of heat load distribution was observed for argon injected in upstream SOL locations.

Large-eddy simulations (LES) were performed to study the turbulent flow in a channel of height H with a staggered array of pin fins with diameter D = H/2 as a function of heating loads that are relevant to the cooling of turbine blades and vanes. The following three heating loads were investigated—wall-to-coolant temperatures of Tw/Tc = 1.01, 2.0, and 4.0—where the Reynolds number at the channel inlet was 10,000 and the back pressure at the channel outlet was 1 bar. For the LES, two different subgrid-scale models—the dynamic kinetic energy model (DKEM) and the wall-adapting local eddy-viscosity model (WALE)—were examined and compared. This study was validated by comparing with data from direct numerical simulation and experimental measurements. The results obtained show high heating loads to create wall jets next to all heated surfaces that significantly alter the structure of the turbulent flow. Results generated on effects of heat loads on the mean and fluctuating components of velocity and temperature, turbulent kinetic energy, the anisotropy of the Reynolds stresses, and velocity-temperature correlations can be used to improve existing RANS models. [ABSTRACT FROM AUTHOR]

Two-thirds of the final energy consumption of the EU residential sector goes towards space heating of buildings, yet a huge portion of the population still suffers from energy poverty. Identifying optimum heating strategies of current buildings would be a solution to this crisis, which is the main aim of the developed algorithm in this research. The algorithm incorporates a modified version of the simple hourly method from the ISO 13790 standard to determine the hourly heating load and indoor temperatures of buildings based on any heating strategy. Flexibility in the input of building and weather data make this tool versatile with practicality towards building users and policymakers. With this algorithm, a case study to evaluate three commonly used domestic heating strategies has been established for nine different residential buildings in typical cold winter conditions in Germany. Most EU households heat their buildings either continuously throughout the day at fixed temperatures, sporadically at fixed times or at peak loads during the evening. The continuous heating strategy is rated the best consuming minimal energy with consistent temperatures and optimal thermal comfort ranges. The sporadic and peak load heating strategies provide fluctuating indoor temperatures with high standard deviations of up to 8.70°C while consuming a similar cumulative energy to the continuous heating strategy. Additionally, both these aforementioned strategies augment energy poverty and promote indoor mould formation on the building envelope caused by water vapor condensation. Consequently, this algorithm can be applicable to any building type of any region. [ABSTRACT FROM AUTHOR]

In the first divertor campaign in Wendelstein 7-X (W7-X), unexpected significant heat loads were observed at particular plasma-facing components (e.g. baffle tiles and middle divertor part) which were not designed to receive high heat flux. In a prior investigation, it was concluded that the previous diffusive field line tracing (DFLT) model used for divertor design in W7-X cannot reproduce these loads, due to the missing physics in simulating the heat transport in the shaded flux tubes. To tackle this issue, two new efficient codes (DFLT_rev and EMC3-Lite) are introduced and validated against various experimental heat distributions in different magnetic configurations. The new tungsten baffle tiles have been designed with these codes and mounted in the machine, aiming for mitigated heat loads in the upcoming campaign.

The official Spherical Tokamak for Energy Production mission aims to demonstrate the ability to generate net electricity from fusion with the STEP Prototype Power plant. One of the key technological and engineering challenges in fusion power plants is managing the loads on the first wall within acceptable limits. Therefore, the conceptual design development of the STEP Prototype Power plant needs to be based on load estimates derived using legitimate plasma physics assumptions through dynamic and flexible tools. The current design foresees the STEP main chamber first wall to withstand steady-state heat loads of up to ∼ 1 MW/m 2 , excluding critical regions expected to receive higher heat loads such as the baffle regions approaching the divertors. These critical areas will require ad hoc assessments and will be designed with the presence of limiters. This article focuses on the models and methodology adopted for designing the 2-D poloidal contour of the STEP first wall, based on the anticipated charged particle and radiation heat loads during normal operation. Firstly, the models adopted for calculating the charged particle and radiation heat loads are introduced. The first model is validated through benchmarking against the particle tracing code SMARDDA, while the second model is verified by comparing it with data from the MAST-U experiment. Secondly, the model used to design the 2-D first wall contour according to the heat loads is explained. We acknowledge that this preliminary design stage assumes certain simplifications, notably an axisymmetric geometry, for computational efficiency and clarity in presentation. It is understood that subsequent design phases will address the complexities of real-world engineering, including non-axisymmetric effects, transient plasma scenarios, and the impact of disruptions on the first wall design. Finally, an automatic procedure based on these models is presented for defining the 2-D poloidal contour of the STEP first wall to minimize heat loads, taking into account the need to radiate most of the alpha-particle and auxiliary heating power. By providing an overview of the models, methodology, and an automatic procedure, this paper contributes to the design process of the STEP first wall, addressing the engineering challenges associated with fusion power plant development. • Proposes a methodological approach for designing the initial first wall contour of the STEP Prototype Power plant. • Addresses significant engineering challenges associated with managing heat loads on the first wall in fusion power plants. • Introduces models and methodology for predicting heat loads resulting from charged particles and radiation. • Develops an automatic procedure for defining the 2D poloidal contour of the STEP first wall to minimize heat loads. • Contributes to the ongoing design process of the STEP first wall and addresses engineering challenges in fusion power plant development. [ABSTRACT FROM AUTHOR]

Type I Edge Localized Modes (ELMs) occur naturally in H-mode plasmas, the operational regime envisaged for ITER, and lead to high temporal heat load peaks on plasma-facing components that might induce surface melting and deteriorated material properties due to recrystallization. ELM mitigation techniques are being developed that either attempt to fully suppress the ELM, e.g. using resonant magnetic perturbations (RMP), or to trigger the ELM at higher frequencies, intending to reduce its energy content and hence the heat load peak.In this paper, the effect of the increased ELM frequency achieved by ELM mitigation techniques on the ITER tungsten divertor monoblock thermal and recrystallization behavior is numerically analyzed by solving the unsteady heat conduction equation when repeatedly exposing the monoblock to ELM-like heat loads under ITER baseline burning plasma operating conditions. The impinging heat load is based on a set of empirical relations readily found in literature and the recrystallization fraction is computed using an empirical data fit which is based on the non-isothermal JMAK equation as function of temperature and time. Uncertainties such as the statistical spread on empirical relations and the unknown inter-ELM heat load, as well as the effect of the ELM frequency, are quantified by a parameter scan.Adopting the recently developed concept of a ‘recrystallization budget’ to determine the allowed monoblock heat loads [G. De Temmerman et al., PPCF 60 (2018) 0044018], it was found that ELM frequencies between 25 – 50 Hz are allowed for inter-ELM heat loads between 9 – 6 MW m−2, respectively, when assuming that the scaling for the peak ELM target energy density in [T. Eich et al., NME 12 (2017) 84-90] holds. This provides a new limit for ELM mitigation strategies in ITER.

It is shown that the conditions of ideal heat exchange, according to which at the given heat load and overall heat transfer coefficient the entropy production in the system attains its lower boundary, can be realized in a set of countercurrent heat exchangers on coordinated selection of temperatures and heat capacities of flows. The parameters of flows and the distribution of heat transfer coefficients and heat loads between two-flow heat exchangers for the Newtonian kinetics have been determined. The value of the minimal dissipation and the profile of the distribution of the overall heat transfer coefficient for the case where the temperature profile of one of the flows is fixed have been obtained. [ABSTRACT FROM AUTHOR]

During the operation of the integrated energy system (IES), the dynamic behaviour of heat loads can affect the optimal operation strategy. This study proposes a novel optimal day-ahead operation method of user-level IES considering the dynamic behaviour of heat loads. Firstly, based on the energy hub, the model of heat loads with dynamic behaviour is added into IES. The dynamic behaviour is embodied by water temperature which can be represented by differential equations. Then, the optimal day-ahead operation model aimed at minimising the energy purchase cost is proposed. Piecewise linearisation is utilised to simplify the temperature constraints which can transform the initial non-convex and non-linear optimisation into a linear programming problem. Finally, case studies are carried out on a practical case, and the results indicate that with the consideration of dynamic behaviour of heat loads, the energy purchase cost can be reduced by 5.6%.

This study proposes a novel optimal day-ahead operation method for the user-level integrated energy system (IES), which can take into account the dynamic behaviour of heat loads and customers' heat satisfaction. First, based on the energy hub, the dynamic model of heat loads is added into IES. Additionally, the customers' heat satisfaction model is constructed by the variance of water temperature and punishment coefficient. Then, the optimal day-ahead operation model aimed at minimising the total cost is proposed. Constraints of energy purchase, operation of energy converters, loads, temperature and the variation of temperature are all contained. Piecewise linearisation and a standard modelling method are utilised to simplify the initial non-convex and non-linear problem to a quadratic programming problem. Finally, case studies are carried out on a practical calculation example. Results indicate that the total cost can be reduced by 5.6% when considering the dynamic behaviour of heat loads. Also, customers' heat satisfaction exerts a remarkable influence on the total cost.

The current design for the ITER Low Field Side Reflectometer (LFSR) diagnostic system contains six circular waveguides that function as both launch and receive antennas. The front end of LFSR system, interfacing with the plasma facing DFW and its supporting diagnostic shielding Modules (DSM), is integrated into Equatorial Port Plug 11(EPP#11). In-vessel LFSR configuration is mainly divided into two sections, i.e. Front Antenna Unit (FAU) and in-vessel Transmission Line (TL) components. During plasma normal operation, the 14 MeV neutrons from D-T fusion reactions penetrate into the port plug and LFSR components. Neutronics code ATTILA is used for assessing the volumetric heating of in-vessel components. The maximum normal heat load due to radiation and the charge exchange from plasma is 0.35 MW/m2, which has to be applied on those surfaces affected by a viewing factor consistent with the aperture surface position and orientation. The front antenna unit (FAU) needs the active cooling to handle the radiant and nuclear heating from the plasma. Due to the specific viewing aperture layout at the front-end of in-vessel LFSR, the cooling channel design is challenging. The thermal-hydraulic iterations are performed to achieve the desirable temperature distribution of the water cooled front antenna units. Finally, the progressive ratcheting effects of the FAU subjected to cyclic thermal loading are examined by the preliminary non-linear elastic-plastic analysis. [ABSTRACT FROM AUTHOR]

A crucial component for any Neutral Beam Injection system is the beam duct, which connects the beam sources to the fusion reactor. There are two types of losses in the duct: geometrical losses due to scraping of the beam on beamline components, and reionisation losses due to interaction of the beam with background gas. A suite of modeling tools has been created to get insight in the magnitude of the losses and power deposition on beamline components: a molecular flow code taking into account the full 3D geometry to calculate background gas densities, FEM calculations in ANSYS to calculate magnetic fields, particle tracking through the magnetic field while interacting with the background gas via a Monte-Carlo scheme to calculate beam losses and resulting power loads. To illustrate the potential of the suite of models, the NBI beamline 2 of the ASDEX Upgrade tokamak is studied, which recently underwent an upgrade of the box exit scraper. Gas densities and magnetic fields are calculated and compared with measurements. Calculated heat loads are benchmarked with the calorimetry on the residual ion dumps. Power deposition in the duct is calculated before and after the installation of the new NBI box exit scraper to assess the impact of this upgrade. [ABSTRACT FROM AUTHOR]

A method and an algorithm to solve the problem on reproduction, with maximum possible accuracy, of heat loads on the surface of the spacecraft in a thermal vacuum chamber with the aid of the radiating system incorporating thermal shields and halogen incandescent lamps have been presented. In simulation experiments conducted for the characteristic heat loading of the spacecraft surface, the possibility to substantially improve the accuracy of solution of the problem by combining the thermal shields and the incandescent lamps into a single radiating system has been demonstrated. [ABSTRACT FROM AUTHOR]

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The influence of the CO2 concentration in a local air zone in naturally ventilated residential houses on the residents’ behaviour was numerically investigated. A numerical two-dimensional CFD model of the indoor zone based on experiments performed by the authors was used. Different resident locations in the fluid domain and different inlet velocities imposed by wind were considered in simulations. The overall thermal comfort and IAQ indices were also calculated. The investigations results show that in contrast to the overall air quality, the local CO2 was strongly dependent upon the resident location, fresh air inlet velocity and ventilation system type.

The modular stellarator Wendelstein 7-X in Greifswald (Germany) was successfully taken into operation in 2015. In the next experimental campaign in 2017, divertor plasmas are planned up to 80 MJ input power limited by the largely uncooled first wall. In 2020, long pulse plasmas are foreseen once the water cooled first wall has been completed. In long pulses, bootstrap currents gradually develop in the plasma, which causes a shift of the strike lines onto the relatively poorly cooled edge of the divertor. To prevent overloading of these edges, a so-called scraper element can be positioned in front of the divertor, intersecting those strike lines that would otherwise hit the divertor edges. As a result, these edges are protected but as a drawback the pumping efficiency of neutrals is also reduced. To assess the impact, two uncooled scraper elements will be installed in the mid-break of the next campaign, one at the top of module 5 and one at the bottom of module 3. The divertor and scraper elements are monitored with Langmuir probes, neutral gas manometers, thermocouples and IR and VIS cameras viewing the plasma facing surface. This paper describes the integration of the uncooled scraper elements and their diagnostics in Wendelstein 7-X. A dedicated low power plasma scenario was developed to evaluate the uncooled scraper element, allowing for reduced heat loads and design simplifications. It is demonstrated that the diagnostics are still capable of measuring the impact of the scraper element. An easily accessible socket to plug in the cables of the diagnostics integrated in the scraper was designed and installed up front to allow for a fast and simple installation of the scraper element in the short mid-break. [ABSTRACT FROM AUTHOR]

District heating networks play an important role in the heating and cooling sector, serving up to 60% of the citizens in some countries. The availability of a thermal network supplying multiple users allows producing heat from different sources and multiple technologies. The possibility of relying on different solutions allows the system manager to optimize the heat generation by choosing the best unit for each operation condition. This choice is based on a deep knowledge of heat load profiles, that are related to users’ behavior, network performances and control logics. This paper provides an analysis of a DH system operation over ten heating seasons, with the aim of highlighting the main characteristics of the heat load variations and finding the fundamental drivers for heat load prediction. Although the system has seen a significant development throughout the years, the specific energy consumption has been found to be comparable on the whole duration of the analysis. Two main patterns are highlighted, based on the different operation settings along the hours of the day and the outdoor temperature as the main weather driver for building's heat demand. [ABSTRACT FROM AUTHOR]

The paper describes a technique for manufacturing of sub-micron metal membranes based on magnetron deposition of multilayer structures. Tensile stress, biaxial elastic modulus and mechanical strength of 25–50 nm thick multilayer Mo/ZrSi 2 membranes were measured, and the behavior of these parameters before and after vacuum heating of samples at the level of heat loads up to 1 W/cm 2 was studied. The elastic properties were obtained from measurements of deformation dependence of the round membranes on the applied pressure differential. A rapid increase in tensile stress of a 25 nm thick Mo/ZrSi 2 film was observed at a uniform heat load of 0.25 W/cm 2 which was probably caused by desorption of water molecules from the membrane surface. [ABSTRACT FROM AUTHOR]

Information about the temperature of plasma-facing components is important for a reliable tokamak operation. A temperature monitoring system using Fiber Bragg Grating (FBG) sensors is foreseen for the new tokamak COMPASS Upgrade, which is currently starting its construction. This diagnostic can be a valuable complement to IR thermography, thermocouples, and Langmuir probe divertor diagnostics. The system will be optimized to estimate the steady-state and transient heat loads, such as runaway electrons, on the divertor and limiters. In this contribution, current progress in the design of the FBG sensors for the COMPASS-U initial open divertor and guard limiters is presented. The heat flux on the plasma-facing components is modeled for diverted and first phase circular plasma scenarios by the PFCFlux code. The subsequent heating and the mechanical strain in the components dedicated for the placement of the sensors is simulated by the finite element analysis software ANSYS. Using these results, the optimal placement and configuration of the sensors are determined with respect to the anticipated maximum temperature and gradients. • Calorimetry diagnostic is being developed for the COMPASS-U tokamak first wall. • This diagnostic will utilize novel Fiber Bragg Grating temperature sensors. • It will be installed in the inner and outer guard limiters and initial open divertor. • Deposited energy and heat flux profile can be determined from these measurements. [ABSTRACT FROM AUTHOR]

On behalf of the European Commission, a ‘critical raw materials’ list has been created, including rare materials susceptible of special location and exploitation thereby their importance in the stability of global economy development and current life quality. This fact, confers primary importance to Geophysics and new ore bodies operation as using of existing reserves in order to be able to supply current requirements of global production. One of the most important effects at underground environment is higher host-rock temperature triggered by geothermal gradient. In addition of this thermal loads, diesel fluxes are also important, as well as air humidity and drift ventilation. Thermal loads analysis for dimensioning cooling systems is strongly influenced by the high thermal inertia of host-rock in underground mines, which involves the appearance of long-term transient processes during the setting up.

Dark matter is a type of matter hypothesized in astronomy and cosmology to account for a large part of the mass that appears to be missing from the universe. China Dark matter EXperiment (CDEX) is a direct detection system of dark matter. A cryogenic system for CDEX-10 has been designed and constructed. This note describes the cryogenic system of the CDEX-10, theoretical predictions of the heat loads to the cryostat, and measured heat loads at operation. The cryostat is an argon cooled bath type cryostat. Two pulse tube refrigerators are used for argon liquefying. The dark matter detecting needs a very quiet condition, so a special thermal shield is designed to reduce the radiation heat leakage. [ABSTRACT FROM AUTHOR]

The rising climatic concerns force the conventional power system to minimise the gas emissions. Microgrid integrating with renewable energy plays a key role in utilising power systems in a more environment friendly way. Compared with single renewable energy system, the microgrid with multi‐energy systems is more attractive in practice. The schedule problem is considered to schedule wind power, combined heating and power generation (CHP), battery, and power grid in order to satisfy the electricity load and heat loads in the microgrid with the minimal cost in real time. Owing to the stochastic nature of wind power generation, it is a challenge to solve the multi‐energy scheduling problem when using the obtained real‐time information. In this study, the joint scheduling of the microgrid with multi‐energy systems is formulated as a rolling horizon Markov decision process (MDP). Moreover, then the rollout algorithm is applied to solve the problem in order to deal with the large state and decision space of MDP, which is caused by the increase of the number of CHPs. The feasible base policy needed in the rollout algorithm is constructed using a greedy algorithm. Numerical results demonstrate that the algorithm can achieve the requirement of real‐time scheduling effectively. [ABSTRACT FROM AUTHOR]

The ICE-E model is a user-friendly tool that allows cold store operators to predict the energy consumption of their stores as heat loads vary due to changes in ambient conditions and store usage patterns. Weather data and construction and usage details are used to predict heat load and refrigeration COP on an hourly basis over a whole year. The model was validated against the industry standard CoolPack model and the features of the models were compared. The ICE-E model is better suited to non-technical cold store users who may not know details such as U -values, air change rates, respiration rates, condensing and evaporating temperatures, and it has additional features such as the ability to change efficiencies of lights and fans. It can help users to identify which cold store features and operating parameters have the greatest impact on energy consumption, and assess the scope for measures aimed at reducing it. [ABSTRACT FROM AUTHOR]

Summer in the Persian Gulf region presents physiological challenges for Australian sheep that are part of the live export supply chain coming from the Australian winter. Many feedlots throughout the Gulf have very high numbers of animals during June to August in order to cater for the increased demand for religious festivals. From an animal welfare perspective it is important to understand the necessary requirements of feed and water trough allowances, and the amount of pen space required, to cope with exposure to these types of climatic conditions. This study addresses parameters that are pertinent to the wellbeing of animals arriving in the Persian Gulf all year round. Three experiments were conducted in a feedlot in the Persian Gulf between March 2010 and February 2012, totalling 44 replicate pens each with 60 or 100 sheep. The applied treatments covered animal densities, feed-bunk lengths and water trough lengths. Weights, carcass attributes and health status were the key recorded variables. Weight change results showed superior performance for animal densities of ≥1.2 m 2 /head during hot conditions (24-h average temperatures greater than 33 °C, or a diurnal range of around 29–37 °C). However the space allowance for animals can be decreased, with no demonstrated detrimental effect, to 0.6 m 2 /head under milder conditions. A feed-bunk length of ≥5 cm/head is needed, as 2 cm/head showed significantly poorer animal performance. When feeding at 90% ad libitum 10 cm/head was optimal, however under a maintenance feeding regime (1 kg/head/day) 5 cm/head was adequate. A minimum water trough allowance of 1 cm/head is required. However, this experiment was conducted during milder conditions, and it may well be expected that larger water trough lengths would be needed in hotter conditions. Carcass weights were determined mainly by weights at feedlot entry and subsequent weight gains, while dressing percentage was not significantly affected by any of the applied treatments. There was no demonstrated effect of any of the treatments on the number of animals that died, or were classified as unwell. However, across all the treatments, these animals lost significantly more weight than the healthy animals, so the above recommendations, which are aimed at maintaining weight, should also be applicable for good animal health and welfare. Therefore, best practice guidelines for managing Australian sheep in Persian Gulf feedlots in the hottest months (June–August) which present the greatest environmental and physical challenge is to allow feed-bunk length 5 cm/head on a maintenance-feeding program and 10 cm/head for 90% ad libitum feeding, and the space allowance per animal should be ≥1.2 m 2 /head. Water trough allocation should be at least 1 cm/head with provision for more in the summer when water intake potentially doubles. [ABSTRACT FROM AUTHOR]