Numerical analysis on the load reduction of a pipe-embedded window with different water temperatures and structures under different climates

When performing consecutive sets of a resistance exercise, maintaining performance within a specified repetition range has been shown to be essential for achieving muscular adaptations conducive to different training goals. However, maintaining repetition performance can be difficult when using shorter rest intervals between sets (i.e., < or = 1 min), which may require load reductions. Therefore, the purpose of the current study was to compare repetition performance when keeping the load constant or reducing the load by different percentages during a lower-body workout. Ten repetition maximum (10RM) loads were established for the back squat, leg curl, and leg extension exercises. Subjects performed 4 workouts under the following load conditions: (a) constant load for all sets, (b) 5% load reduction after each set, (c) 10% load reduction after each set, and (d) 15% load reduction after each set. Pairwise comparisons indicated that, when averaged across sets, significantly fewer repetitions were accomplished for the back squat and leg curl within the constant condition vs. the 15% condition (p < 0.05). Conversely, for the leg extension, there were no significant differences in the repetitions accomplished between conditions (p > 0.05). Pairwise comparisons also indicated that, when averaged across exercises, significantly fewer repetitions were accomplished for set 3 within the constant, 5%, and 10% conditions vs. the 15% condition (p < 0.05). In summary, the back squat and leg curl required 15% load reductions per set to maintain repetition performance. Conversely, load reductions were not necessary for the leg extension.

The rate of wheel load reduction used for assessment the safety degree of wheels due to wheel load reduction caused by the heavy and suspended the derailment, Which is one of the important indexes about the Vehicle running safety assessment. The paper presents a forecasting method about the rate of wheel load reduction based on NARX neural network, Which use NARX neural network to realize accurate modeling of rail irregularities to the rate of wheel load reduction. The experimental results show that NARX neural network can realize the accurate prediction of the rate of wheel load reduction, and show the effectiveness of the proposed method.

The high temperature isolation valve (HTIV) is a key component to assure the safety of a high temperature gas cooled reactor connected with a hydrogen production system for protections of radioactive material release from the reactor to the hydrogen production system as well as of combustible gas ingress to the reactor at the accident of fracture of an intermediate heat exchanger and the chemical reactor. However, the HTIV has not been made for practical use in the helium condition over 900°C yet. The conceptual structure design of an angle type HTIV was carried out. A seat made of Hasteloy-XR is welded inside a valve box. Internal thermal insulation is employed around the seat and a liner because the high temperature helium gas flows inside the valve. The inner diameter of the top of seat was set 445 mm based on fabrication experiences of valve makers. A draft overall structure was proposed based on the diameter of the seat. The numerical analysis was carried out to estimate the temperature distribution and stress of metallic components by using a three-dimensional finite element method code. Numerical results showed that the temperature of the seat was simply decreased from the top around 900°C to the root, and the thermal stress locally increased at the root of the seat, which was connected with the valve box. The stress was lowered below the allowable limit 120 MPa by decreasing the thickness of the connecting part and increasing the temperature of the valve box to around 350°C. The stress also increased at the top of the seat. Creep analysis revealed that the intactness of the HTIV is kept after the assumed operation cycles of the plant life as well as at the depressurization accident.

Analyzing building loads and energy-efficient retrofits is crucial for effective energy management and sustainable development. Strengthening the identification and analysis of factors that impact energy consumption is informative for devising appropriate measures. In order to address the current limitations in analyzing building energy consumption, the present study proposes a combination of the arc elasticity analysis method with CO2 storage technology. By introducing sensitivity and arc mean elasticity indices, the cooling and heating loads of building energy consumption can be analyzed. Subsequently, a CO2 refrigeration system and compression process can be designed to optimize the storage of CO2 and facilitate its role in energy conservation and reduction of energy consumption. Thus, the research aims to fulfill the potential of CO2 in promoting energy efficiency and reducing consumption. The study utilized software simulation and experimental analysis to examine the impact of the proposed method. The findings revealed a positive correlation between the heat transfer coefficient and the building's annual heat load. In addition, the maximum data variation of the building's cold load was a mere 0.05 per cent, and the relative discrepancy between the software simulation and the actual load values was less than 10 per cent. The exterior building's total cold load value showed a difference of more than 25 per cent when cooled with CO2 intervention compared to the non-intervention result. Furthermore, the building's maximum load reduction reached 3.4 per cent when uniformly varying the thickness of the insulation layer from 40 mm to 100 mm. The proposed method demonstrates a positive impact on building energy sensitivity analysis. Its energy loss design for various parts of the building could offer useful references for practical engineering designs.

To accurately evaluate the load reduction effect and influence mechanism of power grid centralized maintenance measures, this study takes Sichuan Province's centralized maintenance practice in 2025 as the research object. It integrates operational data from the power load management system and meteorological monitoring data, and applies the Linear Mixed-Effects Model (LMEM) to quantitatively test the statistical significance of the measure effects. Additionally, it conducts an in-depth analysis of the mechanisms by which user type (detailed in accordance with the National Economic Industry Classification GB/T4754 — 2017), location, and daily maximum temperature affect load reduction.The study finds that:Centralized maintenance measures achieve significant load reduction; user industry type and location are key factors driving response differences, with the impact of location being particularly prominent; the impact of daily maximum temperature is not significant. Industry and regional characteristics can effectively explain the heterogeneous characteristics of individual users. This study not only provides empirical evidence for the refined management of demand response but also offers methodological references for the effect evaluation and optimization of similar demand-side management measures in power grids.

The Forecasting of the Single-row Reciprocating Expander Temperature Fields

ABSTRACTThe paper introduced the concept of a multilevel microgrid (MG), which starts at the building level and creates an MG at this level. The development process of MG in China was described in detail for the first time, including the key issues and the research direction. The prediction error and uncertainty analysis of wind power, photovoltaic power generation, load, and controllable generator components are given, respectively. The uncertainty distribution model is helpful to construct the objective function of minimizing the operating cost of MG. First, an hypothetical apartment building’s suitability for installation of solar panels, wind turbines, and solar thermal devices in Shanghai was analyzed, including the principles and characteristics of their electrical generation and energy collection. Compared to the analysis of a single building, the results are more comprehensive for simulating the loading of different buildings in a variety of situations. The mathematical model of peak load shaving in an MG was constructed, and the interior-point method was used to solve it. By simulation analysis, the variation of load curve and related parameters before and after peak load shaving was obtained. First, the average loading of an office building with and without the MG was compared, and the reduction rate in peak loading of a building was used to analyze whether there was additional storage and found the change rule. A neighborhood with the additional MG technologies and additional storage units is better than other existing literature in showing the effectiveness of peak- load reduction.

Energy consumption for air conditioning purposes accounts for 60-80% of electricity used in Qatar. As District Cooling Plants (DCPs) has a potential to reduce energy consumption and CO2 emissions, Qatar and GCC are continuously shifting paradigm towards adoption of DC plants to satisfy the rapidly growing demand in all sectors. However, DC plants usually rely on wet cooling towers for disposing the excess heat to the ambient. Hence the efficiency of DCPs is significantly influenced by the cooling tower effectiveness in heat disposal, which is dominated by latent heat or evaporation of water in a counter atmospheric current air stream. Operation district cooling plants (DCPs) under extremely high humidity in summer represents one of the major thermodynamic limitations in terms of maintain the outlet water temperature of cooling towers (i.e. chiller's condenser cooling water) as low as possible to guarantee higher efficiency of DCPs. The cooling tower efficiency degrades considerably at higher relative humidity of air, which approaches saturation limits in summer, where the cooling demand is high. The ambient wet-bulb (WB) temperature is a limiting factor for the capacity of cooling towers (CT), which determines the inlet cooling water temperature to the chiller's condenser (outlet water temperature from the CT). Due to prevailing weather conditions in Qatar and GCC, this temperature is designed based on 31 °C WB temperature in summer, which result in a 34 °C inlet condenser cooling water temperature. This represents a thermodynamic limitation to reduce the energy consumption of chillers, which lies under the focus of this study. Desiccant cooling is an environmentally attractive alternative to conventional mechanical air-conditioning, especially for air dehumidification purposes. It does not require ozone depleting refrigerants and it can be run off low temperature solar heat or waste heat. The electrical coefficient of performance of desiccant cooling can be above 20, making it over 6 times more efficient than conventional air cooled vapor compression system. This project seeks to develop new processes to reduce air humidity and WB temperature by around 6 °C prior to entering the CT to break the above mentioned thermodynamic limitation. Air dehumidification takes place using liquid to air membrane (3-fluid LAMEEs) for further dehumidification of air. A hybrid solar PV-Thermal system is used for regeneration of both desiccant systems. Lumped and numerical analysis has been conducted using COMSOL Multiphysics software to predict the outlet air temperature and humidity for 3-fluid LAMEEs when used for air cooling and dehumidifying. Results of the numerical and lumped analysis showed that the 3-fluid LAMEE alone can effectively decrease the humidity content of ambient air by up to 40%, while the outlet air temperature can be reduced by 6 °C. Accordingly, the inlet cooling water temperature to the chiller's condenser (outlet water temperature from the CT) can be reduced to 27-28 C, which provides a potential saving of around 25% in energy consumption of the Chiller in district cooling plants.

Reduction in on-off operations of an air source heat pump with active thermal storage and demand response: An experimental case study

To investigate the retention efficiency and mechanism of nitrogen of Vegetative filter strips (VFSs) in the Danjiangkou Reservoir area, simulated runoff discharging experiments were carried out in a new-established Bermuda VFS. The results showed that the Bermuda VFS reduced 73.1-86.1 % of surface runoff through infiltration. The outflow rate of runoff increased first and then became stable with time. The concentration reduction rates (CRRs) and load reduction rates (LRRs) of NH3-N increased initially and then decreased with the increase of inflow concentration. The average CRRs and LRRs of NH3-N in three treatments ranged 66.1-90.3 % and 90.0-96.7 %, respectively. The concentration reduction of NH3-N was primarily achieved by soil adsorption. The optimal inflow concentration of NH3-N for the optimum CRR was between 0.65 and 3.52 mg/dm3. The CRRs and LRRs of NO3-N fluctuated between 6.8-14.0 % and 72.0-77.9 % in three treatments. The concentration reduction of NO3-N was primarily achieved by plant uptake and soil microbe assimilation. The optimal inflow concentration of NO3-N for optimum CRR exceeded 6.78 mg/dm3. The CRRs and LRRs of TN increased with the increase of inflow concentrations. The average CRRs in the low, moderate and high treatments reached 9.7, 14.8 and 27.4 %, respectively, and the average LRRs reached 72.1, 74.3 and 81.2 %, respectively. The optimal inflow concentration of TN for optimum CRR exceeded 10.21 mg/dm3. The study showed that Bermuda grass can retain nitrogen in runoff efficiently and should be promoted around the Danjiangkou reservoir.

Thermal performance of a flat-plate heat-pipe collector array

Shading devices are essential for reducing solar radiation and cooling loads in buildings located in tropical climates. In the Jakarta region, the highest solar factor is observed on west- and east-facing facades, followed by north- and south-facing orientations. National building policy in Indonesia encourages facades to face north–south to reduce solar heat gain. This study explores horizontal static and dynamic shading devices on north-facing facades and evaluates their impact on cooling load reduction and daylight performance. The methodology includes calculating and simulating energy use intensity (EUI) using EnergyPlus and conducting illuminance analysis using Radiance and Grasshopper. Key parameters considered in the shading design include sun position, illuminance levels, and EUI. The results show that static shading devices with a fixed tilt angle of 20° and a depth of 1.2 m reduce the cooling load by 15.82% while ensuring that at least 30% of the workspace floor area receives an average illuminance of 300 lux throughout the year. Meanwhile, dynamic shading devices with adjustable tilt angles ranging from 10° to 40°, following the sun’s position, reduce the cooling load by 15.75%–18.83%. This configuration consistently ensures that at least 30% of the workspace floor area achieves 300 lux of illuminance each month. These findings provide a practical reference for the design of north-facing shading devices in tropical climates, balancing thermal performance and daylight availability.

In order to study the influencing factors of energy consumption of water-loop heat pump system, the optimal loop-water temperature strategy is proposed. The multi-variable building load is transformed into circulating water energy only related to water temperature. From Carnot cycle to think of the optimal loop-water temperature strategy, the original water temperature control method is changed. This paper shows that there is a unique circulating water temperature, which can minimize the overall energy consumption under certain building load conditions.

The paper presents the possibility of applying the internal systems of thermal insulation of heated rooms with design guidelines. It discusses the problems of the inner insulation effect, the re-use and new aesthetics on comfort room thermo-humidistat.

This study evaluates three listed farmhouses in Ørland Municipality which are going to be relocated and rehabilitated according to current Norwegian standards and requirements. Accordingly, the study assesses possible challenges and solutions regarding energy upgrading and restoration while preserving their historic features and cultural heritage. The study suggests solutions for the energy rehabilitation of the three farmhouses based on a literature review, hygrothermal simulations and energy simulations. These solutions include thermal post-insulation of external walls and above the framework of joists against the cold attics with mineral wool, vacuum insulation panels (VIP), and aerogel blankets. Additionally, fenestration renovation options and the potential for implementation of building integrated photovoltaics (BIPV) are reviewed. Lastly, simulations of multiple energy-saving measures for each of the farmhouses have been conducted.A new foundation due to the relocation, together with post-insulation of the cold attic are found to be feasible measures considering the preservation of architectural appearance and authenticity. Regarding the external walls, post-insulating externally is preferable for the farmhouses considering moisture issues and interior space savings. However, it is important to consider any possible loss of cultural heritage value. Alternatively, internal thermal insulation with aerogel blankets may be a feasible solution due to its high thermal resistance applying small thicknesses. The results show that in some cases, enhancing old original windows with a secondary glazing is an equally good solution compared to a total replacement of the windows, and is recommended for cultural preservation. Implementation of BIPV contributed to meet the net energy demand requirement. Nevertheless, it is recommended that the chosen BIPV systems resemble an accepted roofing material from the regulatory requirements, e.g., slates, to accommodate the building’s architectural aesthetics and authenticity.This study provides insight and recommendations for the rehabilitation of three listed traditional farmhouses in Trøndelag County, addressing energy efficiency while preserving their cultural significance. The findings show that it is possible to achieve today’s energy requirements when rehabilitating listed heritage buildings. Results from energy simulations show that a reduction in net energy demand between 55 % and 75% is possible, while it is essential to note that each building is unique, and a case-by-case approach is needed. Nevertheless, the findings can be applicable for a general energy upgrading of heritage buildings.