Guarantee Rate Research Articles

Variation Characteristics of Actual Evapotranspiration and Uncertainty Analysis of Its Response to Local Climate Change in Arid Inland Region of China

Exploring the variation characteristics of actual evapotranspiration (ETa) and its response to climate change in the arid inland region of China is of great significance for strengthening regional water resources management and maintaining ecological environment security and stability. Taking the Dulan River Basin as the research area, based on the meteorological data from the Wulan Station and hydrological data from the Shanggaba Station from 1981 to 2020, the variation characteristics of ETa at the annual scale were analyzed. The ETa estimation model and joint distribution model of P and potential evapotranspiration (ET0) was constructed based on climate factors, and the uncertainty of ETa response to climate change was explored with the water balance method, multiple linear regression, marginal distribution function, Copula function, and Monte Carlo algorithm. The results showed that the multi-year mean value of ETa in the study area was 261.6 mm, and the interannual process showed an insignificant upward trend, and had no abrupt change during the period. There were two obvious main cycles, which were 19-year periodic changes on the 30-year time scale and 6-year periodic changes on the 9-year time scale. The ETa estimation model based on precipitation (P) and ET0 had good simulation accuracy. The optimal marginal distributions of P and ET0 were Pearson-III (P-III) distribution and Generalized Extreme Value (GEV) distribution, respectively. The Copula joint distribution probability density of P and ET0 was a symmetric saddle-shaped distribution. ETa showed an inverted ‘S’ distribution with the change in joint guarantee rate of P and ET0, ranging from 116.9 mm to 498.6 mm. ETa was an interval range under a certain joint guarantee rate. The research results can provide support for the assessment of ETa, and help to further understand the driving mechanism of climate change on ETa in the arid inland region of China.

Joint guarantee rate index assessment of the contribution of agricultural water-saving measures to river ecological flow in water shortage areas

Reconciling higher ecological water demands and economic purposes with finite freshwater resources remains one of the great management dilemmas. Low water efficiency and large water consumption in agricultural irrigation hinder the protection of river ecological flow in the water shortage areas of Northwest China. By analyzing the surplus and shortage of river ecological protection targets, the intensity guarantee rate index is innovatively proposed to quantitatively evaluate the important contribution of improved water-saving measures for river flow restoration. It compensates for the shortcomings of the duration guarantee rate index in evaluation that may mask ecological problems. Considering ecological baseflow, fish species, and landscape water demand, the ecological flow interval (6.00–12.42 m3/s) was determined. Three scenarios are highlighted for different typical years and irrigation regimes in combination with planting structure adjustment and irrigation water utilization coefficient. In 75 %, 90 %, and 95 % typical years, the maximum total annual water-savings (Scenario 3) are 57.3, 57.1, and 87.2 million m3 (sufficient irrigation); 32.2, 33.9, and 35.5 million m3 (deficit irrigation) respectively. The guarantee degree of river ecological flow under both irrigation regimes increased from the previous 65.6 % to a maximum of 91.7 % and 81.2 %. The increase in the daily guarantee rate and decrease in the intensity guarantee rate under the aforementioned three scenarios indicate a reduction of damage depth and duration of ecological flow. By using a quantitative study, it is pointed out that improving agricultural water-saving is a reasonable and necessary way to protect the river flow.

“Wait” to promote high sighting rates of wildlife in tourism: evidence from a wildlife disturbance experiment

ABSTRACT Ecotourism is often seen as beneficial for both people and nature, but unregulated wildlife tourism can harm wildlife. To improve management practices, we studied rabbit tourism involving Amami rabbits (Pentalagus furnessi) at a Natural World Heritage Site in Japan. The study aimed to determine the sighting rates of wildlife under different car schedules and density scenarios. Using wildlife disturbance experiments and model simulations, we estimated the recovery rate of rabbits after being disturbed by tourists. Our findings revealed that a 20-minute time lag between cars resulted in a 90% recovery rate for the rabbits. Additionally, a regular car schedule increased rabbit sighting rates by approximately 1.85 times compared to random schedules and 2.4 times compared to normal schedules under optimal conditions (maximum density and 50 cars). We also evaluated the profitability of tourism under different rabbit densities and money-back guarantee (MBG) rates. While introducing more cars increased profits, it decreased rabbit sighting rates and increased the likelihood of activating the MBG. In conclusion, our study showed that considering both animal behavior and human interests in developing a tourism management system can balance profitability and minimize the impact of overutilization.

Matching analysis between the heating/cooling capacity of PVT heat pumps and the heating/cooling demand of residential buildings across various regions in China

PVT-HP (Photovoltaic-Thermal Heat Pump) is a novel type of energy saving technology. Existing researches on PVT-HP technology focuses only on its operating performance under some specific conditions, ignoring the matching of its energy supply capacity with the energy demand of buildings, which is very important for its engineering design and application. In this paper, the matching relationship between the heating/cooling capacity of the PVT-HP system and the heating/cooling demand of residential buildings in major cities of China has been analyzed. To achieve this goal, a novel prediction model used to calculate the heating/cooling performance of the PVT-HP system has been proposed. And the daily heating guarantee rate and daily cooling guarantee rate have been put forward to evaluate the matching relationship. Based on the evaluation indexes, the applicable matching relationship between the installed capacity of the PVT-HP system and the heating/cooling area of residential buildings has been analyzed. The result of case study shows that for the selected cities of Shenyang, Beijing and Wuhan, the heating/cooling area of residential building for PVT-HP system with installed capacity of 1hp should not exceed 17m2, 31m2 and 25m2, respectively. Further matching analysis of major cities in China shows that the PVT-HP system is more suitable for application in hot summer and cold winter zones of China, in where the suggested heating/cooling area for the PVT-HP system with installed capacity of one horse power is within the range of 30m2 to 37m2.

Method of Calculating Outdoor PM2.5 Concentration in Fresh Air Systems Based on Population Density Distribution Regions

With the gradual increase in population density, population migration poses unprecedented challenges to urban environments and their capacity. The fresh air system effectively ensures fresh air in indoor environments. An important parameter affecting the selection of a fresh air filtration system is calculating particulate matter at a concentration of less than 2.5 μm (PM2.5). The PM2.5 concentration values of 31 cities in China from 2017 to 2020 were selected for analysis in this study. Based on mathematical induction and population density zoning, a new method that combines population density zoning is proposed, and the recommended constant K values for different regions are analyzed. The definition of K refers to the ratio of the outdoor design concentration value of PM2.5 to the annual average at different guarantee rates. The air filters for fresh air systems in five typical cities (Harbin, Beijing, Urumqi, Xi’an, Guangzhou) are also used as examples. The K values and selection differences under different recommendation methods are compared and analyzed. Under population migration and urbanization scenarios, the results indicate that the recommended K of the seven major regions method was optimal. Under these conditions, the recommended K values for five typical cities under strict and normal conditions differ from their average K values by 0.07 and 0.04, respectively. This method can accurately select fresh air filtration systems under different population densities; however, population density is related to factors such as policies and the economy and must be updated and revised regularly. On the whole, it provides reference values for the selection of PM2.5 design concentrations in fresh air systems under population distribution differentiation.

Multi-objective optimal allocation of water resources in Shule River Basin of Northwest China based on climate change scenarios

The optimal allocation of water resources is crucial for addressing regional water scarcity, adapting to climate change, and promoting sustainable development. This study focused on the Shule River Basin and considered three climate scenarios (SSP1–2.6, SSP2–4.5, SSP5–8.5), which is combinations of Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs). A water resources optimal allocation model including water supply and demand prediction, multi-objective optimization, decision-making and analysis on optimal water allocation schemes was constructed. This model aims to analyze the optimal allocation of water resources in the Shule River Basin over three planning years (2025, 2030, 2035), considering guarantee rates of 50 % and 75 % under various climate scenarios. The obtained results indicate that: (1) An increasing trend in water demand in the planning year. For instance, under the SSP1–2.6 scenario, the basin's water demand is projected to reach 1.920×10^9 m3, 2.037×10^9 m3, and 2.103×10^9 m3 in 2025, 2030, and 2035, respectively. (2) The total water supply with a guarantee rate of 50 % (75 %) in the planning years is projected to be 1.939 (1.483)×10^9, 1.957(1.502) ×10^9, and 1.974 (1.519) ×10^9 m3, respectively. (3) In the three scenarios of SSP1–2.6, SSP2–4.5, and SSP5–8.5, the water demand for domestic and ecology is met in each planning year. There is a slight water shortage in the industrial sector, with a shortage rate ranging from 0 % to 13.41 %. The agricultural sector experiences the highest water shortage, with a rate of 1.93–44.77 %. (4) The water supply structure of each optimal allocation scheme of water resources was optimized. The economic benefits mainly depend on the industrial and ecological sectors. These findings offer valuable insights for optimizing the distribution of regional water resources in response to changing climatic conditions.

A Study on the Construction and Evaluation of the Water Resource Reutilization System for Farmland Diversion and Drainage

Water is an essential resource for both rural and agricultural areas; it can be wisely distributed and used in the field to protect daily life, production, the natural environment, and the safety and stability of regional drainage and flood control systems. Our research selected a typical plains rural river network area with agriculture as the main industry to investigate the most effective method of farmland diversion and drainage. We comprehensively planned and transformed the water system flow, water conservation engineering, and the ecological environment in the irrigation area through the reutilization system. The reutilization system’s operation and scheduling design is implemented for four specific periods: the water replenishment cycle, agricultural irrigation, agricultural drainage and the rainy period of the flood season. The research period ranges from 2020 to 2023 after the completion of the system. We used monitoring, the recording of hydraulic equipment parameters and data collection to evaluate the balance of water supply and demand in the study area. At the same time, we have tracked and evaluated the four aspects of water quality enhancement, water conservation and flood control, and agricultural irrigation. The results show that the total agricultural water consumption decreased by 2.9%, and the amount of water saved increased by 9.6%. The current segment creates the rivers’ embankment standards. With a 92% irrigation guarantee rate, the current section forms and the embankment standards of the rivers satisfy the design storage volume and the flood level of one in twenty years. The water quality of all the rivers in the area has decreased by 5~10% compared to the average concentration prior to establishment. This study verifies the comprehensive effect and the suitability of the system by comparing the before and after effects, and provides a scientific basis for the method of efficient recycling and utilization of water resources in the rural plains river network area; we also propose the guidance of increasing the digital twin control and long-term operation mechanism to ensure the long-term stable operation of the technology.

Effect of Water Tank Size and Supply on Greenhouse-Grown Kidney Beans Irrigated by Rainwater in Cold and Arid Regions of North China

In response to water scarcity in the Bashang area of northwest Hebei Province, a cold and arid region in north China, and to address the diminishing groundwater levels caused by pumping irrigation, this study investigated the impact of rainwater tank size and water supply on kidney beans production in greenhouses under various precipitation scenarios to determine the production potential and development strategies for regional precipitation resources. Under the background of average annual precipitation, kidney bean yield increased with increasing reservoir volume and shorter irrigation cycles. Under a 4-day irrigation cycle, the water demand satisfaction rate of kidney beans reached 100% water demand when the rainwater tank size was 15.7 m3. Against the wide variation in multi-year regional precipitation from 1992 to 2023, the annual effect of rainwater harvest was simulated using precipitation data collected 20 years with an 80% precipitation guarantee rate. The average minimum yield reduction rate obtained was 9.4%, and the corresponding minimum rainwater tank size was 29.5 m3. By superimposing the rainwater harvested in the shed and nonshed areas, the volume of the reservoir without yield reduction could be reduced to 20.0 m3. The sum of discharged and inventory water was much greater than the water scarcity in each water supply situation. Simulating and analyzing the effect of the relationship between rainwater tank size and water supply on rainwater harvesting in regional farmland by year provides important data affecting the construction of regional rainwater storage facilities and water supply efficiency. To achieve a high, stable yield of kidney beans grown in a greenhouse with shed film and shed area rainwater harvesting in north China, 2.6 m3 supplementary groundwater irrigation is still needed during the annual growing season.

A control strategy considering buildings’ thermal characteristics to mitigate heat supply-demand mismatches in district heating systems

In district heating systems (DHS), periodic heat supply-demand mismatches (HSDM) exacerbate issues such as thermal imbalance and hydraulic instability. To mitigate these issues, this paper proposes a supply water temperature correction strategy for heating stations that considers building's thermal characteristics. Firstly, buildings are classified into energy-saving levels based on comprehensive thermal characteristic Bc and heat load index. Secondly, simulation models are developed for buildings with different thermal characteristics, and response of indoor temperature to supply-demand mismatch rates was analyzed. Then, after determining the regulation sequence and supply water temperature of heating stations, a balanced control strategy is formulated for HSDM conditions. Finally, the proposed strategy was applied to a practical combined heat and power system (CHPS) in severe cold regions. The results showed that the studied heating stations were classified into 4 types. After regulation of both insufficient and excessive heating conditions, the indoor temperature guarantee rate increased by over 20 %; the ranges of thermal imbalance degree and hydraulic imbalance degree were reduced by more than 0.09 and 0.22, respectively; the SD of supply water pressure and supply-return pressure difference were reduced by over 0.17 and 0.11, respectively. The strategy provides a reference for global balanced control of DHS under similar HSDM conditions.

Decentralized intelligent multi-party competitive aggregation framework for electricity prosumers

Electricity management systems are experiencing significant challenges due to the increased penetration of distributed energy resources. Electricity flows in distribution networks are transforming from unidirectional to bi-directional form. Consumers are transitioning to prosumers with different characteristics, where they take more active roles in electricity generation and consumption. Aggregators are vital financial intermediary agents in the power system transitions, as they could aggregate energy profiles of prosumers. The market competition between aggregators and interactions between prosumers and aggregators are complex and dynamic, which requires a holistic framework to model the market competition. This paper proposes an intelligent aggregation framework with edge computing, enabling decentralized competition for multiple aggregators and prosumers, which can be solved with a graph-based consensus algorithm. This study mathematically proves the proposed algorithm's convergence guarantee and convergence rate. In addition, the proposed framework is applied to an open-source dataset to demonstrate its applicability. Lastly, a benchmark analysis is conducted to show that the proposed algorithm has better communication complexity than the benchmark algorithms.

Configuration method for medium-deep ground source heat pump system considering renewable energy consumption and smart grid interaction

Medium-deep ground source heat pump (GSHP) systems have the advantages of low carbon, high heat exchange intensity, good thermal storage capacity, and intermittent operation characteristics, which are conducive to renewable energy consumption and grid demand response. The source-side parameters affect the configuration of underground borehole engineering, heat pump units, and other equipment. However, current research mainly focuses on the underground heat exchanger modeling, underground heat exchange, and system operation control, while there are few studies on multi-factor ground source-side parameter design and optimal configuration. In this study, the indicator analyzing the unsteady features and thermal balance state of medium-deep geothermal resources was introduced, and the source-side water temperatures were optimized based on the dynamic characteristics of the geothermal and building sides. A simulation configuration methodology for the source-side flow rate and storage capacity was developed considering the electricity prices, life-cycle cost (LCC), and grid interaction. The optimization of the ground source-side design temperature, flow rate, and capacity parameters of residential and office building heating scenarios were analyzed in northern China, respectively. The results showed that the borehole inlet and outlet temperature can be designed to 5.5 °C/17.5 °C under the annual sustainable state, and the optimal flowrate can be set to 65.77 m3/h, to achieve the lowest cost and highest heating season guarantee rate for the residential scenario. For the office building with optimal system and storage capacity, the average annual LCC is 192,000 yuan/year, with the cumulative peak shaving of 55.8 %, and an increase of 103.3MWh renewable electricity consumption.

Experimental and simulation study on the performance of a solar assisted multi-source heat pump drying system in Zhengzhou area

Zhengzhou of Henan province is an important agricultural production base. To improve the performance of the combined drying system and promote the development of agricultural products in Zhengzhou area, a solar assisted multi-source heat pump (SMSHP) drying system was proposed based on a traditional solar assisted air source heat pump (SASHP) drying system. The simulation models were developed for the air source heat pump (ASHP), SASHP, and SMSHP drying system respectively. The coefficient of performance, energy consumption and specific moisture extraction rate of the drying systems under different seasons were analyzed. Moreover, to validate the simulation models, an experimental platform of the combined drying system was designed and set up, and the experimental tests were carried out on the ASHP, SASHP, and SMSHP drying system. The simulation results revealed that the SMSHP drying system had lower energy consumption, higher coefficient of performance and specific moisture extraction rate than that of the SASHP drying system. The most significant performance enhancement was observed in spring, where the SMSHP system demonstrated a 22.69 % increase in coefficient of performance, a 19.2 % increase in specific moisture extraction rate, and a 16.11 % decrease in energy consumption compared to the SASHP drying system. Comparing with the experimental data, the simulation model errors of the energy consumption, coefficient of performance, and specific moisture extraction rate of the SMSHP drying system were 3.19 %, 0.28 %, and 2.27 %, respectively. Therefore, the accuracy of the simulation results was confirmed. To better calculate the heat provided by the solar collection system, the concept of the tank heating guarantee rate was first introduced, and it was found to be more scientific than the solar energy guarantee rate. At last, The economic and environmental benefit of the drying systems were analyzed during the life cycle, and the SMSHP drying system exhibited better comprehensive performance than the SASHP drying system. This paper provides valuable insights into the comprehensive utilization of solar energy and the control logic of solar assisted air source heat pump combined drying system under different seasons.

Operating characteristics of photovoltaic/thermal–ground source heat pump system in cold regions

To investigate the operating performance of photovoltaic thermal integrated heat pumps in terms of the effects of the control strategy and the component parameters, this paper considers an office building in Zhengzhou city as the research object. A photovoltaic/thermal integrated ground source heat pump system model is established using TRNSYS software. Using this model, a system is developed with four operating modes based on temperature differences and seasonal control. The soil temperature, the unit energy consumption, and the solar energy guarantee rate are used as indicators to study the soil’s thermal balance and the energy consumption characteristics of the model system in the four operating modes. The effects of the control strategy design and the photovoltaic/thermal collector area on the system performance are analyzed, and the annual cost method is used to evaluate the system’s economy. The research results indicate that the tank heating mode’s closing temperature increased from 47 °C to 49 °C, the system energy consumption and power generation were reduced by 1.86 % and 1.24 %, respectively, and the instances of unsatisfied demand for domestic hot water were reduced by 19.05 %. The soil temperature increased gradually with increasing photovoltaic/thermal collector area, but the rate of this increase slowed down at larger areas; when the area increased from 50 m2 to 100 m2, the soil temperature increased by 16.6 %, but when the area increased from 200 m2 to 250 m2, the temperature then only increased by 10.6 %. In addition, there is a specific photovoltaic/thermal collector area that can maintain the soil temperature in equilibrium. When compared with a solar-assisted ground source heat pump heating system, the photovoltaic/thermal integrated ground source heat pump heating system can save 63.2 % in terms of operating costs and can reduce the annual cost by 60.9 % over a 10-year period. The research results show that the law of the photovoltaic/collector area affects the soil heat balance, and also provide data support for promotion of photovoltaic/thermal integrated ground source heat pump systems from both performance and economic perspectives.

Development of a new rotational irrigation model in an arid basin based on ecological zoning and sluice regulation

Precise and efficient allocation of existing water resources is of great significance to protect and restore desert riparian forests in inland river basins. However, the lack of detailed ecological zoning in most basins hinders the optimization of the current ecological sluice regulation scheme, leading to low effectiveness in vegetation restoration and water resources management. To address this problem, we proposed for the first time an ecological zoning method that integrates the vegetation gradient model and control of ecological sluices. Specifically, the mainstream of Tarim River basin (China) was classified into three types of ecological functional zones, i.e., key protection, key restoration, and ecologically sensitive zones, based on the kernel NDVI (kNDVI) gradient detection framework. On this basis, the basin was divided into 27 sluice group control areas determined by the control range of ecological sluices and the study area was further divided into five grades zones of ecological rotation irrigation. Based on the results of ecological zoning and the priorities of rotational irrigation, this study proposes a new rotational irrigation model in the basin to further promote vegetation recovery. The results showed that guarantee rate of ecological water supply to vegetation protection and restoration increased from 82.3% to 101.7% before and after rotational irrigation, respectively, indicating the effectiveness of this new method. The results of this study have a practical value and may significantly contribute to the optimal allocation and management of water resources in global arid basins.

Optimal allocation planning of regional water resources with multiple objectives using improved firefly algorithm

Abstract Population growth and economic development, coupled with water pollution and the frequent occurrence of extreme weather, have led to a growing contradiction between water supply and demand in some regions. To address this challenge, rational and optimal allocation of regional water resources has emerged as a crucial approach. This study focuses on creating a comprehensive model for optimizing regional water resource allocation, taking into account social, economic, and ecological factors. In addition, three innovative modifications are introduced to the firefly algorithm (FA), resulting in the development of the improved firefly algorithm (IFA). The effectiveness of IFA is validated through experiments involving nine benchmark functions. The results highlight the improved search efficiency and convergence achieved by IFA compared to other intelligent algorithms. Moreover, the application of IFA in solving the water resource allocation challenge in Shannxi Province, China, for 2020 and 2021 demonstrates a reduction in the overall water shortage rate to 4.69 and 1.72%, at a 75% guarantee rate. This reduction in water shortages contributes to addressing future scarcities. The proposed allocation scheme offers comprehensive benefits and provides crucial technical support for water resource management. Ultimately, this study offers valuable insights and guidance for addressing the issue of water supply–demand disparities.

Estimation of ecosystem water consumption and the suitable scale of cultivated land in the Karamay region and Muzat River basin based on the optimized SEBAL energy balance model and water resource constraint model

Food security is closely related to the development of human society, and the root of food production lies in cultivated land, with water conservancy as its lifeline. This study estimates the ecological water consumption of located in the arid region of Northwest China (the Karamay region and Muzat River basin) from 1990 to 2020 based on the optimized Land Surface Energy Balance Algorithm. The verification accuracy of SEBAL energy balance model is greatly improved after optimization. It was showed an increasing trend in the Karamay region and Muzat River basin, increasing at the rates of 2.84 mm/year and 2.86 mm/year respectively. The suitability of cultivated land was evaluated by combining four periods of 30 m spatial resolution land use/land cover data from 1990, 2000, 2010, and 2020, as well as the Hydrological Statistical Yearbook and Xinjiang Statistical Yearbook. Through the analysis of spatial optimization for cultivated land, it can be inferred that the primary limiting factors affecting cultivated land suitability in the Karamay region are irrigation guarantee rate (54.03%) and soil salinity (11.98%). Muzat River region are irrigation guarantee rate (32.19%) and soil salinity (18.62%). By comparing the scenarios of setting ecological priority and cultivated land priority, it is concluded that under the conditions of water resource constraints and 50%, 75% and 90% design irrigation assurance rates, Karamay still has cultivated land expansion potential, which can be used as the main preparatory reclamation area. In addition to the traditional agriculture irrigation area, the Muzat River basin still has development potential under the condition of ecological priority and no more than 75% irrigation design assurance rate. The study on the cultivated land suitability under the condition of water resource constraints can provide new ideas for food security.

Study of post-earthquake train running performance considering earthquake-induced track irregularity

It is necessary to study the dynamic performance of high-speed trains to obtain the safe operation. In this paper, a seismic analysis of a track-bridge system subjected to near-field random earthquakes is carried out, and the geometric distribution of the residual and dynamic irregularities of rails after earthquake is explored. Based on the reliability theory and probability guarantee rate, an equivalent coefficient of earthquake-induced dynamic irregularity is proposed. The dynamic analysis of the train-track-bridge system is carried out, considering earthquake-induced track irregularity, and the speed limit of high-speed trains after the seismic event is proposed, ensuring the running safety. The results show that the amplitude of residual irregularity is much larger than that of the dynamic irregularity. The influence of the earthquake-induced track irregularity on the derailment coefficient and transverse acceleration of high-speed trains is significant increasing with the increase of the train operation speed. The earthquake-induced track irregularity has small effect on the vertical dynamic performance of high-speed trains. Based on probability guarantee rate, considering the random initial track irregularity, the operation speed limit of high-speed trains is set to 72 km/h. The research results can provide certain theoretical basis for the post-earthquake running safety evaluation of high-speed trains.

Impact of vertical girder deformations on the high-speed train operation performance

The deformation of bridge structures will cause deterioration of geometry on the rail surface during the service period, which will threaten the normal operation of train. A train–track–bridge coupling dynamics model was established. In order to simulate real operational conditions, initial geometric irregularity was taken into account, which was combined with rail irregularity caused by different vertical deformation of girder and was superimposed as external excitation. The probabilistic and statistical characteristics of operational performance indexes were analysed. The sensitivity of operational performance indexes to different deformation modes was studied. The vertical deformation thresholds of girder based on probability guarantee rate were obtained. The results show that unloading rate of wheel and wheel/track vertical force are more sensitive to single vertical rotation deformation mode. Vertical acceleration of the train and sperling index are more sensitive to bilateral vertical rotation deformation mode. Unloading rate of wheel is more sensitive to single vertical translation deformation mode. In the process of enhancing daily operation, single vertical rotation and multiple vertical translation should receive significant attention.

Experimental research of photovoltaic-valley power hybrid heating system with phase change material thermal storage

The widespread integration of high-ratio distributed photovoltaic (PV) systems in buildings calls for flexible load management to align with municipal power peaks and PV variability. To address the timing and demand mismatches between PV generation and building energy needs, energy storage systems are used to manage PV excess, aid in grid peak shaving, and support building heating. This research develops a Photovoltaic-Valley power complementary phase change energy storage heating system, designed to consume photovoltaic and valley power for the decentralized heating of individual rooms, thus optimizing distributed energy utilization. A CPCM of magnesium chloride hexahydrate, EG, and calcium hydroxide, designed for indoor heating, was created with a phase change temperature around 117.9 °C and an enthalpy of 106.2 kJ/kg. An experimental platform was established to test the system and its control strategy, showing that the PV-powered phase change energy storage heater effectively keeps indoor temperatures above the thermal comfort minimum of 18 °C. As the PV guarantee rate increases, the system improves indoor temperature regulation and significantly reduces fluctuations. Operating costs are over 30% lower than those of traditional heating networks and natural gas systems, underscoring substantial energy savings and emission reductions. This research provides an integrated approach for optimizing building PV consumption, managing grid peaks, and regulating indoor temperatures with phase change energy storage heating systems.

An ordered multi-objective fuzzy stochastic approach to sustainable water resources management: a case study from Taiyuan City, China

Abstract The uncertainty of socioeconomic development and climate change poses challenges to the sustainable management of water resources in Taiyuan, China. The study proposes a type-2 fuzzy chance-constrained ordered multi-objective fractional programming (T2FCC-ORMOFP) model to address the allocation of water under uncertainties. The model incorporates type-2 fuzzy programming and chance-constrained programming into an overall framework to handle multiple uncertainties under multi-level and multi-objective conflicts, while using fractional programming to reflect the marginal benefits of the system. It prioritizes the principles of optimal, fair, and stable distribution by the upper-level governing authorities, while considering the social and economic environmental benefits of lower-level decision-making. The optimal water allocation scenarios were obtained under different hydrological guarantee rates, violation levels of water supply constraints, and net economic benefits of type-2 fuzzy numbers for 2030. Additionally, groundwater is replaced by reclaimed water in varying proportions for flexible water supply. The results show that the water demand in Taiyuan cannot be ignored, and the risk of water shortage is more sensitive for the agricultural and industrial sectors. The recycled water substitution strategy can optimize the water supply structure and improve social and economic benefits (9–12%). Also T2FCC-ORMOFP can improve overall efficiency (20%) compared with a single-level model.