Energy-saving Design Research Articles

Reconfigurable, zero-energy, and wide-temperature loss-assisted thermal nonreciprocal metamaterials

Thermal nonreciprocity plays a vital role in chip heat dissipation, energy-saving design, and high-temperature hyperthermia, typically realized through the use of advanced metamaterials with nonlinear, advective, spatiotemporal, or gradient properties. However, challenges such as fixed structural designs with limited adjustability, high energy consumption, and a narrow operational temperature range remain prevalent. Here, a systematic framework is introduced to achieve reconfigurable, zero-energy, and wide-temperature thermal nonreciprocity by transforming wasteful heat loss into a valuable regulatory tool. Vertical slabs composed of natural bulk materials enable asymmetric heat loss through natural convection, disrupting the inversion symmetry of thermal conduction. The reconfigurability of this system stems from the ability to modify heat loss by adjusting thermal conductivity, size, placement, and quantity of the slabs. Moreover, this structure allows for precise control of zero-energy thermal nonreciprocity across a broad temperature spectrum, utilizing solely environmental temperature gradients without additional energy consumption. This research presents a different approach to achieving nonreciprocity, broadening the potential for nonreciprocal devices such as thermal diodes and topological edge states, and inspiring further exploration of nonreciprocity in other loss-based systems.

CFD simulation of power characteristics and flow field distribution of different spiral stirring paddles

Stirred reactors are widely used in various industries, and the stirring paddle structure has a significant effect on its power consumption. Therefore, in this study, different spiral stirring paddles were investigated. The effects of the ratio of paddle length to leads (Ls/S) design values and number of blades on the power characteristics and internal flow field of the reactor are discussed in detail, and the correlation equation of power number (Np) concerning Re and Ls/S values is fitted. It was found that the Np of stirring paddles increased and then decreased as the Ls/S value increased, and the effect of the number of blades on the Np gradually reduced. When the Ls/S value is equal to 0.6, the high-speed region of the flow field is the largest and the mixing effect is the best. The conclusions obtained can provide a reference for the energy-saving optimal design of spiral stirring paddles.

Research on multi-objective energy-saving optimization of propylene distillation column

The energy-saving optimization problem of the propylene distillation column was investigated. A PRO/II process simulation model was established based on the actual operating data of the unit and a sensitivity analysis of the operating parameters was conducted. On this basis, a multi-objective optimization model for the unit was established using regression analysis. The penalty function mechanism and dynamic search factor were incorporated into the MOGWO algorithm to solve the optimization model. The optimization results demonstrate that by optimizing multiple sets of operating parameters, the propylene distillation column can increase its production while reducing its energy consumption, achieving energy-saving optimization for the unit. This method provides a new theoretical basis for the energy-saving optimization design of propylene distillation units and other distillation processes.

Green Campus Transformation in Smart City Development: A Study on Low-Carbon and Energy-Saving Design for the Renovation of School Buildings

In the context of increasingly deteriorating global ecological conditions and rising carbon emissions from buildings, campus architecture, as the primary environment for youth learning and living, plays a crucial role in low-carbon energy-efficient design, and green environments. This paper takes the case of Yezhai Middle School in Qianshan, Anhui Province, to explore wind environment optimization and facade energy-saving strategies for mountainous campus buildings under existing building stock renovation. In the context of smart city development, integrating advanced technologies and sustainable practices into public infrastructure has become a key objective. Through wind environment simulations and facade energy retrofitting, this study reveals nonlinear increases in wind speed with building height and significant effects of ground roughness on wind speed variations. Adopting EPS panels and insulation layers in facade energy retrofitting reduces energy consumption for winter heating and summer cooling. The renovated facade effectively prevents cold air intrusion and reduces external heat gain, achieving approximately 24% energy savings. This research provides a scientific basis and practical experience for low-carbon energy retrofitting of other campus and public buildings, advancing the construction industry towards green and low-carbon development goals within the framework of smart city initiatives.

A Systematic Literature Review on Energy Efficiency Analysis of Building Energy Management

Government agencies, energy consumers, and other societal groups have all shown concern and attention for the energy management of buildings. Relevant statistical data, however, indicate that most public buildings continue to consume large amounts of energy overall and that the issues of low energy usage and energy waste have not materially improved. As a result, this study reviewed the state of progress and potential directions for future research in the field of building energy management in public buildings using a data-driven approach. Relevant studies were obtained from three databases—Web of Science, Scopus, and China National Knowledge Infrastructure—based on certain search phrases. The text mining program VOS viewer was then used to examine the material. We provide a thorough examination of the study techniques and material, as well as a visual representation of the keywords and current state of the field. According to this study, the range of data processing outcomes; the flexibility of research system standards; and the availability of a comprehensive, unified assessment system are the main factors contributing to the practical issues facing building energy management today. Based on the geographic distribution and state of energy development, this study is the first to examine possible research avenues for building energy management in public buildings through cross-fusion research on passive energy-saving design and subjective behavioral energy-saving. It offers a foundation for developing the building energy management system best practice model in the future.

Optimization for the temperature range of radiator for preventing draught risk of cold window

High surface temperature of radiator can provide thermal plume with enough momentum intensity and thus counteracts the downdraft caused by window. Meanwhile, it is necessary to avoid causing indoor temperature to exceed upper limit of thermal comfort zone. In this paper, influence of heat transfer coefficients of window and exterior wall, outdoor temperature, and average surface temperature of radiator on operative temperature (Top) and temperature difference between indoor air and window (Td) was investigated. Based on response surface method, single factor and interaction effects for the four influencing factors on Top and Td were analyzed. A framework optimizing average surface temperature of radiator for preventing draught risk of window was established. When the heat transfer coefficient of window was around 1.4 W/m2·°C and satisfied related energy-conservation standard, cold draught could be eliminated without causing indoor environment overheating. Based on the optimized temperature range, the supply water temperature was controlled, and seasonal performance using the variable temperature strategy was investigated based on TRNSYS simulation. With the variable water temperature control strategy, the output hourly indoor air temperature was within the comfortable range. In the whole heating season, hours that did not meet cold draught requirement occupied 77.22 %, as the heat transfer coefficients of window dis-satisfied the energy-saving design standard. As meeting the design standard, the proportion decreased to 12.97 %. Utilizing the optimized temperature interval can prevent discomfort caused by cold draught to the greatest extent. This study is conducive to improving thermal environment with the convective–heating system and may lead to the reduction of energy consumption for heating.

Decomposition based multi-objective evolutionary algorithm for energy-saving design of homestay buildings

To improve the prediction accuracy of energy-saving design for homestay buildings, a multi-objective optimization model is studied. A model of multi-objective optimization algorithm for energy efficiency design of home stay buildings based on decomposition multi-objective evolutionary algorithm is proposed. Decomposition based multi-objective evolutionary algorithm is selected. To select the preliminary algorithm for achieving energy-saving design of homestay buildings, it divides the objectives into algorithm determination and model construction and uses multi-objective optimization algorithms to solve the proposed optimization model. The validation results show that the minimum discomfort time calculated using the non-dominated sorting genetic algorithm is 555.30 and the energy consumption is 7.68, while the minimum discomfort time calculated using the non-dominated sorting genetic algorithm method is 896 and the energy consumption is 8.92. With alternative model, the speed of multi-objective Evolutionary algorithm is the fastest, reaching 6105.44 seconds, which is 68.80% lower than the proposed method. With the help of substitutes, the computational speed of the multi-objective particle swarm optimization algorithm has been greatly improved. Its computational speed has reached 1217.231 seconds, while the fastest multi-objective particle swarm optimization algorithm among the four comparison methods is only 3868.591 seconds. Although the individual improvement is not significant, the overall optimization is still considerable and has strategic foresight in the decision-making plan of decision-makers.

Research on energy consumption evaluation and energy-saving design of cranes in service based on structure-mechanism coupling

Aiming at the problem that the life cycle energy consumption index of hoisting machinery is difficult to be objectively quantified, a crane energy consumption evaluation calculation method based on the working cycle of the service period is proposed, the typical service working mode of the crane is analyzed, and the working cycle process of the mechanism is clarified. On this basis, the stress cycle characteristics of the crane structure during the service period are determined based on the coupling relationship between the mechanism and the structure, which lays the foundation for accurately evaluating the life index of the crane. According to the relationship between the load rate and effective power of each mechanism during the service period of the crane, the calculation method for the evaluation and calculation of the structure energy consumption during the service period of the crane is studied. Finally, the crane is designed based on the concept of absolute service safety, and an optimal design model of the main girder structure of the crane with the goal of the lowest energy consumption in service is established. Using the research method of this paper to study a certain type of bridge crane, the energy consumption of the hoisting machinery during its service period is not only related to the accumulation of the operating characteristics of the mechanism but also related to the characteristic parameters such as the structure self-weight. The comprehensive evaluation of energy consumption provides an effective quantitative method and a reliable green design theory for crane design.

Rotational motion of skyrmion driven by optical vortex in frustrated magnets

Effective control of skyrmion rotation is of significant importance in designing skyrmion-based nano-oscillators. In this work, we numerically study the optical vortex-driven skyrmion rotation in frustrated magnets using the Landau–Lifshitz–Gilbert simulations. The skyrmion rotation is induced by the orbital angular momentum (OAM) transfer from the optical vortex to the skyrmion, which is regardless of the sign of the OAM quantum number m due to the helicity degree of freedom of the frustrated skyrmion. This property highly broadens the parameter range of the optical vortex in controlling the skyrmion rotation. The direction of the rotation is determined by the sign of m, and the radius and angular velocity depend on the magnitude of m, light polarization, and intensity. Interestingly, the helicity oscillation induced by the linearly polarized beam is much slower than that driven by the circularly polarized beam with a same intensity, resulting in a faster rotation of the skyrmion. This phenomenon demonstrates the advantage of the linearly polarized beam in controlling the dynamics of the frustrated skyrmion, benefiting energy-saving and high-efficient device design.

Exploration of Energy-Saving Technologies in Building Electrical System Design

Green energy conservation is the mainstream trend in the current development of the construction industry. The application of energy-saving technology in building electrical system design can effectively reduce energy consumption, avoid unnecessary energy consumption, and truly achieve energy conservation and environmental protection. Based on this, the article elaborates on the principles of energy-saving design in building electrical systems, and actively explores the application of energy-saving technologies from different perspectives such as optimizing power supply and distribution system design, adopting high-efficiency energy-saving lighting equipment, applying renewable energy, promoting smart home technology, and improving the efficiency of building electrical equipment.

MULTI-OBJECTIVE OPTIMIZATION STUDY OF RESIDENTIAL ENERGY CONSUMPTION BASED ON EDH AND THE STOCHASTIC OPERATION OF AIR CONDITIONING

ABSTRACT Current requirements for residential energy-efficient design solutions in China are relatively homogeneous, requiring only improvements in overall building energy performance, often ignoring the energy differences between different residential housing units. This paper proposes a multi-objective research framework based on an occupant behavior model of air conditioning and a Non-dominated Sorting Genetic Algorithm-II (NSGA-II) to study energy-efficient design solutions for residential envelopes. The optimal energy-saving design scheme has a 22.56% and 35.34% reduction in energy consumption difference between residential units and overall building energy consumption, respectively, both of which have been optimized substantially. Moreover, the overall energy performance of the building can be improved when the “energy performance difference between housing units” (EDH) is reduced, which verifies that EDH is an important criterion for improving the energy performance of residential housing units.

Indoor Radon Concentrations in Severe Cold Area and Cold Area and Impact of Energy-saving Design on Indoor Radon in China.

This study investigated indoor radon concentrations in modern residential buildings in the Cold Area and Severe Cold Area in China. A total of 19 cities covering 16 provinces were selected with 1,610 dwellings measured for indoor radon concentration. The arithmetic mean and geometric mean of indoor radon concentration were 68 Bq m-3 and 57 Bq m-3, respectively. It was found that indoor radon concentrations were much higher in the Severe Cold Area than those in the Cold Area. The indoor radon concentrations showed an increasing trend for newly constructed buildings. It was estimated that the average effective dose from inhalation of indoor radon is 2.15 mSv and 1.60 mSv for the Severe Cold Area and Cold Area, respectively. The more and more rigid energy-saving design for residential buildings in the Severe Cold Area and Cold Area has an obvious impact on the increased trend of indoor radon due to extremely low air exchange rate in China.

Energy-saving Design of Heating Ventilating Air Conditioning for Tall Space Structures

Energy-saving Design of Heating Ventilating Air Conditioning for Tall Space Structures

Roof Shape Design for Ice Rinks in Cold Regions under Carbon Reduction Targets

In the midst of today’s energy crisis, carbon emissions from ice rinks in cold regions present a significant environmental challenge. The shape of an ice rink’s roof significantly influences these emissions. This study developed a methodology to quantify the carbon emissions of ice rinks and explained how their roof shapes impact emissions during the operational phase. Roof shapes were divided into the following three categories: flat, curved, and combined torsion shell. Carbon emission modeling was established and calibrated using the Ladybug + Honeybee platform, followed by regression analyses on the slope and curvature of each roof type. The findings indicate a robust correlation between the carbon emissions of an ice rink and the slope and curvature of its roof. Roof shape influences approximately 2% of carbon emissions during the operational phase of an ice rink. Among the various roof shapes, the curved dome roof demonstrates the most effective overall carbon savings, at a rate of 0.93% compared to the flat roof. Selecting an appropriate roof shape has significant carbon-saving potential for ice rinks. The findings of this study may serve as a valuable reference for the formulation of energy-saving design standards in cold regions.

Green Building Performance Analysis and Energy-Saving Design Strategies in Dalian, China

Green Building Performance Analysis and Energy-Saving Design Strategies in Dalian, China

Energy-saving design of azeotropic distillation for the separation of methanol–methyl methacrylate azeotrope from industrial effluent

For the purpose of separating the binary methanol–methyl methacrylate (MMA) azeotrope in light boiling residues and preventing MMA polymerization from acetone cyanohydrin process, low pressure heterogeneous azeotropic distillation (HAD) with process intensification was adopted. The binary interaction parameters of the azeotrope were obtained by correlating and regressing the experimental data of isobaric vapor–liquid equilibrium at low pressures (75, 50 and 26 kPa for methanol-MMA and 26 kPa for cyclohexane-MMA). The residue curve map at 26 kPa was plotted under the UNIQUAC model, and the optimal parameters of its conventional process were achieved through sequential iterative optimization procedure. The purity of MMA and methanol was 99.99 wt% and 99.90 wt%, respectively. Subsequently, in order to further reduce costs and energy consumption, dividing wall column (ADWC), heat pump distillation (HP-AD), and heat pump assisted azeotropic dividing wall column (HP-ADWC), three technical approaches were explored and compared. Total annual cost (TAC), total energy consumption (TEC), and CO2 emissions were used as evaluation indicators. Among them, ADWC reduced its annual capital investment by 14.48 % through special structural design. HP-AD effectively reduced TEC by 27.30 %. HP-ADWC combined the advantages of both, effectively reducing costs and saving energy (12.88 % in TAC). At present, the purity and energy saving of the product meet industrial expectations, providing valuable insights for enhanced methanol-MMA azeotrope recovery from industrial effluent.

A globalized methodology of energy-saving solar greenhouse design in high latitudes

The energy-saving solar greenhouse (ESSG) represents a Chinese-type agricultural building of facilitating low-energy and zero-carbon vegetable overwintering production in high latitudes and cold regions. However, its application benefit outside of China has been limited. To establish an operational ESSG design scheme applicable worldwide, this study developed a comprehensive methodology and specific parameters for different latitudinal regions. The ESSG design was determined based on considerations of daylighting, thermal insulation, heat storage-release capacity, and structural safety. Through validation in six representative regions, the reliability of the ESSG design methodology was confirmed. The optimal design values for front roof angle, ridge height, and back wall height were identified across different latitudes. ESSG in various latitudinal regions from 32°N to 48°N exhibited annual cumulative temperatures could reach 8 × 103∼1.3 × 104°C and accumulated light interception could reach 2 × 1012∼4 × 1012J. Even in the 48°N region, the average internal temperature of the greenhouse exceeded 8 °C, with a nighttime cooling rate lower than 0.75 °C/h and a maximum temperature difference between internal and external environments exceeding 40 °C. This suggests the ESSG fully meets the non-heated overwintering production requirements for common vegetables. The research findings provide crucial theoretical foundations for the global promotion of ESSG, contributing to the reduction of energy consumption and carbon emissions in the sustainable agriculture.

Energy efficiency improvement of heavy-load hydraulic fine blanking press for sustainable manufacturing assisted by multi-stages pressure source system

The fine blanking process has the highest forming accuracy in the field of metal forming and its production volume has increased sharply. However, hydraulic fine blanking presses (HFBP) – the core equipment of the fine blanking process, have suffered from significant energy loss due to the inefficient hydraulic system. To enhance the energy efficiency of the hydraulic system, this study introduced a novel approach – a multi-stage pressure source system comprised of distinct pump-accumulator groups, each operating at varied supplied pressures to narrow the mismatch of the installed and demanded power. This adaptive system is capable of automatic adjustments to align with the required pressure, thereby mitigating energy losses while concurrently preserving superior dynamic working performance. First, this study commenced with a theoretical analysis of the system configuration and energy characteristics of HFBP. Subsequently, a comprehensive exploration into the inherent inefficiencies of the hydraulic system is undertaken by formulating a precise energy consumption model. Finally, a novel energy-saving optimization design was carried out on the fast-approaching subsystem. The results demonstrated that the implementation of the proposed system led to a notable reduction of 76.87% in energy loss within the flow-regulating module, and an overall diminution of 13.53% in energy dissipation compared to the conventional system. This study will significantly advance sustainable manufacturing practices within the metal-forming domain by reducing electricity consumption and production cost.

Passive energy-saving design strategy and realization on high window-wall ratio buildings in subtropical regions

Indoor overheating in high window-wall ratio (WWR) buildings has drawn widespread attention, but there is limited research on it during winter. Similarly, the application of radiative cooling (RC) technology on high-WWR facades and the effectiveness of combining RC with phase change materials (PCMs) need exploration. In Guangzhou, typical rooms in commercial buildings were studied, revealing that high-WWR buildings experience greater indoor overheating in winter compared to summer. For a 100 % WWR, the total equivalent energy consumption (EEC) is 71.389 kWh·m−2 in winters, 7.8 % higher than summer. Using RC glass with high solar (diffuse) reflectivity (0.65) on south-facing windows reduced EEC by over 70 %. RC glass also provided significant cooling capacity during unoccupied periods, which is sufficient to meet daytime cooling needs. In the case of a 100 % WWR, the proportion of available cooling capacity (37.5 %) during unoccupied period exceeded daytime cooling EEC (24.9 %). Therefore, PCMs were adopted to store this cooling capacity and transfer it for release during the occupied period, which bring an additional improvement in energy-saving performance by 4.7 %. The combination of PCMs and RC technology further achieves building energy efficiency. This study offers insights for addressing winter indoor overheating in high-WWR buildings.

Analysis and Reflection on the Green, Low-Carbon, and Energy-Saving Design of the Super High-Rise Building

Shanghai Tower has become a new landmark of Shanghai. In the current trend advocating green building and energy efficiency, considerations of wind loads and thermal characteristics of the perimeter structure of Shanghai Tower are crucial. This paper conducts comparative simulation studies on the wind environment of Shanghai Tower using Ecotect software, and stress analyses and thermal simulations of the perimeter structure using ANSYS software. The study compared three buildings’ surface wind pressure distributions using models with equal-volume and circular cross-sections. We found that the unique exterior design of the Shanghai Tower results in a more regular and uniform distribution of wind pressure on its surface compared to both circular and square planar models, with a lower average wind pressure value. In addition, the stress analysis results indicate significant differences in deformation and stress distribution between the windward and leeward sides. Enhancing the bending moment detection of the peripheral structure and optimizing the layout of detection points are recommended. Thermal simulation results show excessive heat conduction flux in winter conditions, suggesting optimization using passive energy-saving methods such as light-sensitive thermal insulation materials during winter. This research is a reference for designing other super-tall buildings prioritizing low-carbon energy efficiency and structural safety.