Discussion on Electrical Design of Passive Residential Building

As the national buildings in each climate zone and passive low energy consumption building demonstration projects expand,there has been a wave of innovation across the construction industry.China is also becoming a hot zone for energy-efficient and high-performance passive buildings.Along with the traditional passive building structure,steel structure passive construction,assembled PC structure passive construction such as the emergence of various types of passive construction,as well as a variety of new building materials,doors and Windows,and air conditioning air equipment,put forward a new challenge for building electrical engineering design personnel and requirements.

Heating,Ventilation and Air Conditioning Design for Commercial Complex Buildings:Theory and Method Based on Inverse Problem

Scientific and technological progress and innovation help the design in­dustry,which plays an important role in sustainable development.It will improve the operation efficiency of enterprises and explore a blue sea for enterprise.In essence,design should be the process of deriving the optimal scheme from different schemes or imaginary scenes.Based on this,this paper proposes an overall optimization method for Heating,Ventilation and Air Conditioning(HVAC)design.Compared with the traditional design method,under certain constraints,it can obtain the optimal design scheme that maximizes the value of the designed product.This study provides new inverse problem ideas and methods for HVAC designers,and provides solutions for enhancing the value of HVAC design products.

A Theory on Increasing the Heat Transfer Performance of Building Wall

The target of traditional thermal conductivity of wall research is the spatial distribution form.In these studies,the change of thermal conductivity with temperature is neglected.Meanwhile,case studies are always used.This method needs large computation and it is hard to obtain the optimal result.In order to overcome the problems,a new approach has been put forward in this paper.Different from the traditional approach,the new approach solves an inverse prob­lem under the concept of passive ideal energy-saving buildings to obtain the optimal distribution of heat ability with temperature on an external wall.The result for a typical summer day shows the heat ability distribution of a wall in summer is a staircase.It is similar to the heat pipe.It is also found that the optimal heat transfer property of the exter­nal wall is closer to the heat pipe when its heat capacity per square meter(ρc_(p)L)is of extreme value.This study can provide guidance to researchers in building materials.

New Approach and Alternate Criterion for Heat-transfer Analysis of Building Walls and Its Applications

Energy consumed by buildings accounts for approximately one-third of the total energy consumption of the society.Moreover,energy systems employed in buildings emit hazardous pollutants,such as,NOx,PM2.5 and CO2,into the environment.Consequently,increasing the energy efficiency of buildings constitutes an important problem concerning the field of building-energy and environment conservation.Thermal resistance and capacitance are two important thermophysical properties of building walls significantly impacting their heat-transfer performance.Traditional theories concerning these properties,however,face certain limitations:(1)the concept of thermal resistance is only valid for one-dimensional,steady heat conduction without existence of an internal heat source;(2)thermal resistance and capacitance are relevant,and can,therefore,not be used to analyze heat-transfer and storage performance,respectively,of building walls.Based on the entransy-dissipation-based impedance theory,a new approach towards realization of heat-transfer analysis and optimization has been proposed in this study.The weightiness of thermal resistance and capacitance with regard to heat-transfer performance has been described along with deduction of the corresponding substitutional relation via illustrative examples.The proposed approach has been demonstrated to effectively overcome aforementioned limitations of building energy conservation problems.

Assessment and Optimization Strategies of Campus Sound Environment

A good sound environment is essential in creating a harmonious and peaceful campus,improving students’learning outcomes,promoting physical and mental health,and creating a green and healthy campus.This study investigated the impact of new buildings on existing ones by optimizing the spacing between new buildings and the sound insulation structure of building enclosures.The results indicated that building 4 was affected by the noise from new building 1 and its surroundings,with a maximum outdoor daytime noise level reaching 69 dB,and the indoor background noise level in the least favorable classroom was 43.73 dB,less than 45 dB,which was within the acceptable range.It is recommended that the sound insulation design be improved in the planning of new teaching buildings.Besides,the surrounding traffic conditions should be improved,and the usage time of sports facilities should be scheduled appropriately to prevent the noise from sporting activities from affecting the classroom activities.The findings of this study provide valuable references for future architectural acoustics design and campus planning,contributing to the creation of peaceful and comfortable campus environments.

STUDY OF VORTEX CHARACTERISTICS OF THE FLOW AROUND A HORIZONTAL CIRCULAR CYLINDER AT VARIOUS GAP-RATIOS IN THE CROSS-FLOW

In the gap-ratio range of 0.0≤G≤7.0, a particle image velocimetry PIV is applied to conduct a systematic experimental research of the flow around a horizontal circular cylinder in the cross-flow of shallow water. The velocity distribution of transient flow field at various gap-ratios is obtained. Based on these data, the phenomena and rules of the vortex and its course of generation, development and evolvement at various gap-ratios are analyzed, and it is found that there are similar unshedding vortex structures at G = 0.0 and G = 7.0, and others are structures of shedding vortex. The figures of typical vortex movements are given. Based on this, the differences between the transient flow field and the time-averaged flow field and the characteristics of the vortex structures are analyzed. In addition when the Strouhal number keeps constant （about 0.2） concerning vortex shedding have been discussed. The findings of this paper are of guiding significance for engineering issues with similar flowing features.