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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]

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.

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]

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.

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]

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]

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]

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.

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]

Cooldown time is one of the major factors in the conduction-cooled superconducting magnet system. Cooldown time means a time cooling a superconducting magnet from room temperature to cryogenic temperature within a stipulated amount of time. The estimation of cooldown time seeks the elapsed time to cool the superconducting magnet by cryocooler during initial cooldown process. This procedure includes the modeling of properties of low temperature superconductor, the dimensions of superconducting magnet, the cryogenic loads, the thermal link between magnet and cryocooler, and the available refrigerating capacity of cryocooler. This method is applied to the conduction-cooled superconducting magnet system developed by ourselves for accuracy confirmation. The effects of magnetic field, size of magnet and thermal link on the initial cooldown are also discussed. [ABSTRACT FROM AUTHOR]

Abstract: A concept for a shaped first wall for ITER is presented. While keeping most features of the 2004 FDR wall (modules segmentation, plasma facing components technologies, plasma facing material), this concept provides protection of the lateral faces of the first wall panels against the intense parallel heat flux coming from the plasma. Excessive beryllium temperatures at the panel edges are avoided during regular operation. The intense heat flux at the top of the vessel is accounted for and protection is provided against the shine thru heat flux. Start-up and ramp down using the wall as a limiter is possible for up to 7.5MW, both inboard and outboard. This is rendered possible by the use of 5MW/m2 technology panels for 40% of the panels. [ABSTRACT FROM AUTHOR]

Abstract: Since the end of 2005 a liquid lithium limiter has been installed on FTU. The liquid lithium is confined by capillarity in a mat of stainless steel or other refractory material and the capillary force counteracts the electromagnetic force. In this paper we review some of the most important results obtained in the experimental campaigns led on FTU. Peaked electron density profiles are spontaneously formed when the density exceeds 1.0×1020 m−3. Despite to the fact that FTU is a fully metallic machine with a TZM toroidal limiter, the only impurity that is present in the plasma is lithium so that very clean plasma are obtained and the beneficial effects are discussed. Heat loads in excess of 5MW/m2 are withstood by the limiter without any damage also because the radiative losses from the evaporated lithium are able to dissipate most of the incoming heat flux. [ABSTRACT FROM AUTHOR]

The cryocooler directly cooled low temperature superconducting magnet is designed, fabricated and tested at the Korea Basic Science Institute (KBSI) for the crystal growth application. The magnet has one solenoidal configuration with a copper former which has a 52 mm room temperature bore. A two-stage 4 K GM cryocooler with 1.5 W refrigeration power is employed to cool the magnet from room temperature to liquid helium temperature. A pair of the binary current lead, a series combination of a normal conductor in the high temperature section and an HTS conductor in the low temperature section, is used for this application. The paper presents the process of design, fabrication and charging test. Also, the performance of the conduction cooled superconducting magnet system is discussed with respect to the supplied current and contact resistance. [ABSTRACT FROM AUTHOR]

The conduction-cooled superconducting magnet with operating current of 180 A is designed, fabricated, and tested for material control application. The superconducting magnet has the effective standard warm bore of 52 mm and the maximum central field of 3 Tesla. Since magnetic field gradient should be larger at the end rather than at the center of the magnet for material control, we developed design method to optimize magnet for this purpose. The safety of the superconducting magnet is evaluated, taking into account the electro-magnetic field, heat and structure, and the superconducting coil is successfully wound by the wet-winding method. The superconducting coil is installed in the cryostat maintaining high vacuum and cooled by a two-stage GM cryocooler. The performance of the conduction-cooled superconducting magnet is discussed with respect to the supplied current, joule heating, and cooling medium. [ABSTRACT FROM AUTHOR]

Abstract: The evaluation of water evaporation from indoor swimming pools is a topic of considerable practical interest, since evaporation may cause the highest energy consumption of the pool plant. A purposely designed experimental apparatus was used to measure the water evaporation rate from a pool scale model inserted into a climatic chamber to control environmental conditions. The experimental data were obtained varying various parameters such as water temperature, air temperature, relative humidity and air velocity. The results were used to propose a prediction model for water evaporation which was compared to other methods found in the literature, showing a good agreement. [Copyright &y& Elsevier]

Abstract: Forschungszentrum Karlsruhe (FZK) is developing the cryopumps for the ITER Neutral Beam Injectors (NBI). The system is characterized by high gas flows against which the cryopumping system must maintain the required pressures down to 10−3 Pa in the beam line vessel. During detailed investigations of the gas dynamics in the neutral beam system it showed up that in the close geometry of the beam line design a cryopump with a gas capture probability of 30% is needed to cover the low pressures. This cannot be achieved by a classical cryopump design using a chevron baffle because it is limited to gas capture probabilities below 24%. Therefore, a novel cryopump has been developed which is characterised by a gas capture probability of 33%. The engineering design of the pump takes into account that it will be operated under the conditions of the ITER cryosupply. Under these conditions the heat load to the low temperature circuits of the new cryopump design is only 20% higher than for the classical cryopump which is in regard of the 50% higher pumping speed a very good improvement of the entire efficiency. The new cryopump design is now the reference design for the ITER Heating NBI. Two cryopumps will be integrated in the beam line vessel, each of them about 8m long and 2.75m high resulting in an overall pumping speed for hydrogen (H2) of 5000m3 s−1. This paper describes the vacuum conditions of the ITER Heating NBI and summarizes the pumping properties of the cryosorption pump as well as to the investigations on the heat loads to the cryogenic circuits. [Copyright &y& Elsevier]

A closed-loop cooling concept for 21 T Fourier transform ion cyclotron resonance (FT-ICR) superconducting magnets is presented. In the magnet system, low temperature superconducting coils are immersed in a subcooled 1.8 K bath, which is connected to the saturated helium reservoir through the weight load relief valve. Saturated liquid helium is refrigerated by a Joule-Thomson (JT) heat exchanger and flows through the JT valve, isenthalpically dropping its pressure to approximately 1.6 kPa, corresponding to a saturation temperature of 1.8 K. Helium gas exhausted from JT pump is liquefied by a two-stage cryocooler located after the vapor purify system. In the present paper, the amount of heat budget is determined and the structural design of cryostat is carried out by the relevant analyses. The position of a cryocooler in the magnet system is investigated, taking into account the requirement of magnetic field for normal performance. Helium liquefaction system, a key component of the closed-loop cooling system, is fabricated and tested in order to demonstrate the feasibility of our new cryogenic cooling for high field magnets. [ABSTRACT FROM AUTHOR]

The development of the semi-retractable current leads for a 21 T Fourier Transform Ion Cyclotron Resonance (FT-ICR) superconducting magnet system is presented. The semi-retractable current leads are composed of a normal metal element, conducting the current from room temperature to intermediate temperature, and an HTS element, conducting the current down to liquid helium temperature. An HTS element is partly immersed in liquid helium and the joint between the normal metal and HTS element is continuously refrigerated by a cryocooler. After magnet energization the metal element is disengaged from the HTS element without breaking vacuum to the insulating vacuum space. In the paper, the optimized dimensions of the leads are presented in order to minimize the thermal heat load when carrying operational current with some margin. The intermediate block with a lockable set point and the insulating vacuum system are fabricated and the adaptability and reliability are tested during engage and disengage performance. The effects of vacuum level and performance cycle on the electrical contact resistance in a lockable set are also investigated. [ABSTRACT FROM AUTHOR]

A new concept of current leads for a 21 T Fourier Transform Ion Cyclotron Resonance (FT-ICR) superconducting magnet system is presented. The binary current lead, a series combination of a normal conductor in the high-temperature section and an HTS conductor in the low-temperature section, is employed. The HTS section is partly immersed in liquid helium and the joint between the normal metal and HTS conductor is cooled by the contact with a cryocooler. After excitation, the normal metal conductor section is thermally disengaged from the HTS section without disturbance to the insulating vacuum space and without requiring complete removal of the current leads. The present paper describes the so-called semi-retractable current leads for a 21 T FT-1CR magnet system application. The optimized dimensions of the leads are presented in order to minimize the thermal heat load when carrying operational current with some margin. [ABSTRACT FROM AUTHOR]

The energy consumption in an apartment building in Copenhagen supplied by district heating has been monitored from November 2000 to June 2002. During the period heat cost allocators were installed on the radiators and the set point for domestic hot water was raised in order to prevent the Legionella Disease. Results from the space heating system and the loading circuit for production of domestic hot water are discussed with respect to heat loads, cooling of the district heating water and the efficiency of the pump and the heat exchangers. The Public Service Obligation for utility companies in Denmark to help their customers to save energy calls for tools to analyse the energy consumption and the efficiency of the system. The possibility to use three-dimensional plots to analyse the thermodynamic performance is discussed as one option. [Copyright &y& Elsevier]