Reducing the Heating and Cooling Energy Consumption of Buildings

Abstract:This research aims at proposing measures to enhance the energy efficiency of buildings in the city of Guiyang. A computer simulation study was conducted on the basis of a building model using the DeST software package. The indoor temperature and year round heating and cooling loads were simulated. From analysis of the simulation results and taking into account the climate of Guiyang, three measures for energy efficient buildings in Guiyang are proposed. 1) Heating is a greater priority than cooling in comfortable air conditioning system design; 2) Natural ventilation should be given priority in cooling design and adjustment during seasonal transition is important to reducing energy consumption in building cooling; 3) Insulating the building envelope and lowering the glazing ratio of walls are critical for reducing energy consumption in heating buildings. Our conclusions will be useful for guiding energy efficient building design not only in Guiyang but also in mild climatic areas of P. R. China.     

Study on Simulation Method of Heating and Air - conditioning Energy Consumption of Residential Buildings

The heating and air conditioning energy consumption of residential buildings is influenced by the behavior of indoor living personnel.On the basis of research and analysis,two kinds of calculation modes reflecting the behavior of indoor living personnel are estimated.Under two kinds of different calculation modes,by using the building thermal environment simulation Toolkit DeST to simulate the energy consumption calculation for certain residential building in Shanghai,and the simulation results are compared with the research results.The influence of calculation mode on heating and air conditioning energy consumption of residential buildings in Shanghai is analyzed in this paper.In order to obtain the right simulation calculation method correctly reflecting the energy consumption of residential buildings.This method can be used for analysis and evaluation of heating and air conditioning energy consumption of residential buildings in Shanghai,and it can serve as instruction for right energy design of residence building.     

An Energy Conservation Correction Method for Energy Efficiency Retrofit of Public Buildings

There exists imperfections of the methods for energy conservation verification of the energy efficiency retrofit projects. A new energy conservation verification method was developed by creating energy conversion correction model and four correction coefficients and three calculation formulas were involved, The four correction coefficients were outdoor weather correction coefficient, indoor environmental correction coefficient, internal load correction coefficient and performance period correction coefficient. The three calculation formulas were heating energy conversion calculation, air-conditioning energy conversion calculation and total energy conversion calculation. The energy conversion correction model was adopted to analysis the energy conservation of an office building located in Tianjin to demonstrate the reliability of the correction model and the feasibility of the verification method, and the corrected energy conversion based on consistent conditions before and after retrofit was obtained. 10.23% difference between the corrected energy conversion and the direct energy conversion exists indicating that the correction energy conversion is necessary. The energy conservation difference of 3.03% the calculation result of energy simulation software verified the accuracy of the new verification method.     

Acceptable Temperature Range of Indoor Environment without Air Conditioning and Heating in Hot Summer and Cold Winter Zone

In order to establish “Evaluation Standard for indoor thermal environment of civil buildings”,acceptable temperature range of indoor environment without air conditioning and heating in hot summer and cold winter zone is indispensable.A two-year field measurement and questionnaire survey were carried on from 2007 to 2009 in Chongqing,which focused on office buildings and residential buildings.After the analysis of indoor and outdoor environment,occupants evaluation and thermal adaptability,a method to obtain the acceptable temperature range,was proposed.Regressing data by temperature range,and combined with human physiological and psychological experiments,the acceptable temperature range of environment without air conditioning and heating in Chongqing was determined according to outdoor air temperature changes in one year.A Comparation of methods to determine the acceptable temperature range in some international standards was discussed.     

Generic Model and Application of Environmental Impacts Exergy Analysis for Building Life Cycle

Based on the disadvantages of existing building environmental analysis methods, a generic model of exergy analysis on environmental impact of building life cycle is introduced, taking into consideration of previous models and focusing on natural environment as well as building life cycle. And three environmental impacts were analyzed, namely energy consumption, resource consumption and pollutant discharge respectively. The generic model of exergy assessment on environmental impact of building life cycle thus was formulated and building environmental sustainability was evaluated through exergy footprint of building environmental impacts. With a residential building in Chongqing for case study, it was found that environmental impacts in building operational stage accounts for 88% of building life cycle and in the breakdown, environmental impacts from energy consumption and related emission were the fundamental parts with the share of 75% and 24% respectively. And for sustainability analysis, about 169 m2 earth areas with global average productivity was required to support the building’s life cycle of one m2 floor area.     

Life cycle assessment in large air-conditioning system and evaluation framework model of energy utilization

Based on central air conditioning system of Xi'an-Xianyang international airport, energy efficient utilization with life cycle theory and analytic hierarchy process was conducted. Firstly, the application of life cycle and analytic hierarchy process to building energy was deeply studied. Secondly, life cycle inventory analysis was conducted combined with the practical cases data. And the data resource is related to the proposed model. Thirdly, On basis of analytic hierarchy framework model and analysis of energy consumption as well as potential environmental impact on air-conditioning project, the study on how to evaluate energy-consumption project with the use of life cycle impact assessment is done. Based on the life cycle assessment of practical cases data, a new hierarchical evaluation model of energy utilization is put forward. And in view of the model, several suggestions are given such as establishing energy utilization process monitoring and evaluation from the point of whole life cycle assessment. This provides a theoretical basis for policies about enormous quantity of building energy and energy saving of air conditioning system.     

Thermal Properties Optimization of Envelope in Energy-saving Renovation of Existing Residential Building

The impact of windows to wall ratio and thermodynamic performance of windows on the insulating layer thickness cannot be neglected in existent residential building energy-saving renovation because of the bigger difference of windows to wall ratio. The limited equivalent coefficient of envelope heat transfer was posed based on “Design standard for energy efficiency of residential buildings in severe cold and cold zones”. Factors of orientation, windows to wall ratio and windows types should be comprehensively considered in building calculation model of thermal insulation thickness of external wall and envelope thermodynamic performance optimization model. These models are validated by an existing residential building in Xuzhou.     

Optimizing insulation thickness of external walls for residential buildings

Many residential buildings use externally insulated wall structures in Chongqing, P.R. China. The process of determining the economic insulation thickness was based on degree days and present worth factor when wall structure adopted different insulation materials. The optimal economic insulation thickness was related to the region of the building, air conditioning operating time, and price of insulation material. Insulation materials with better thermal performance have a shorter payback time and wider prospects for application.     

Constitute of Meteorological Data in Building Energy Analysis

Building energy analysis needs representative yearly meteorological data,the data could be selected from the past years' data according to specific regulation,it can also be produced from the meteorological math model which was built with the past data. A comparison is made between F testing method and AIC criterion method, which leads a result that the F testing method is reasonable. Mixed regression model of thirteen dimensions is established using F testing stepwise method. Test is conducted on independence and distribution of model residuals, and the result shows that the model is successful and more information can be provided for establishing model with dimension number increased. Using the above established model future meteorological data of building energy analysis can be predicted.     

Study on the Application of Energy Efficiency Building Design Based on BIM Technology

In light of the current situation of energy efficiency building design in China and the situation of energy analysis tools application both at home and abroad,aiming at the fact that traditional energy efficiency building design methods cannot meet current needs,this paper puts forward a new design approach-integrating BIM technology with energy efficiency analysis to carry out energy efficiency building design.The virtual building model created with BIM technology is an electronic database containing all of the building's information.By importing this virtual building model into energy analysis tools,we can automatically identify and analyze the model's great amount of information so as to quickly and easily get the energy efficiency analysis results.     

Combined Network Model for Occupant Evacuation in Building Fires

Safe evacuation is the most fundamental requirement of fire safety measures in buildings. Many computer based evacuation models have been developed to quantify and model human movement in the buildings. Two methods are usually used to represent the building enclosure in these models: fine and coarse networks. This paper presents a fine network model and a coarse network model based on these methods respectively, and develops an integrated network model that integrates both network methods for efficient and detailed assessment of evacuation in large and complex buildings. To demonstrate the advantages of using the integrated network model, the results of its simulation for a high rise office building and a large shopping mall are discussed and compared to the simulation results of the fine network model and the coarse network model. It shows that the integrated model can be used to simulate evacuation in large and complex building and is adequate in representing details of the evacuation process.      

Analysis on Simulation Meteorological Data Under Climate Change

Climate has a determining influence on building energy consumption. Since 1980s, the global climate has appeared excessive warming, which inevitably causes the change of building energy consumption. The climatic simulation was used to forecast meteorological data from 2021 to 2050 for five cities in China. The five cities represent five different climate types in China. According to the Analysis of Energy Efficient Meteorological Year (AEEMY), model of meteorological data for building energy simulation based on TMY2 was presented. At the same time, meteorological data for DOES was also made from 1971 to 2000. A high residential building was respectively simulated in five cities under two kinds of meteorological data by using DOE2 software. The model of simulation was proved by the simulation result.     

A real time monitoring method of energy consumption based on data mining

A real time monitoring method of energy consumption based on data mining techniques is proposed to compensate the deficiency of common energy consumption methods in real time and intelligence. The new method can identify energy consumption patterns by clustering analysis of historical energy consumption data, get the decision tree of energy consumption pattern by classifying the energy consumption data, match the real time energy consumption data with the energy consumption patterns, make outlier analysis with historical data of the same pattern, and then determine whether the current energy consumption is abnormal. The experiment with energy consumption data from the comprehensive building proves that the new method is effective in detecting the abnormal data of energy consumption real timely.     

Application of Fractals in Architectural Shape Design

A computer aided method for architectural shape design was developed based on the L systems algorithm, the shape grammar and the space surface equation theory. Various 3D entities such as building grounds, building walls and building domes with fractal characteristics could be generated in a short time by using the computer program. These generative 3D entities were saved in a component database which could help to accumulate design knowledge through continuous expansion. A building could successfully be formed by the designers through selecting proper building grounds, walls and domes from this database. The effectiveness of the proposed method was approved with a case study.     

Investigation and Analyses of Building Energy Consumptionof Government Office Buildings in Chongqing Area

This article classifies the buildings by the time before and after energy-saving standard executed, based on the investigation of energy consumption in government office buildings of Chongqing, and analyses the energy distribution characteristics of these buildings, in which factors like the building area、air-conditioning 、management system are taken into account .Finally we acquire the energy consumption characteristics in government office buildings of Chongqing.     

Technical Solutions for Low Energy Consumption Residences in Subtropical Regions

Based on the climatic conditions and residential energy consumption in regions with hot summers and cold winters, three principles of building energy efficiency were used to explain the technical system and technical solutions for low energy consumption residence. To improve the energy efficiency in residences, and to produce more comfort as well, we should adjust sunlight, improve ventilation, reasonably insulate houses, make full use of natural energy sources, and choose high COP(Coefficient of Performance) equipments. Making reasonable use of local resources while planning and designing a residence is the key to low energy consumption. The solution given in this paper provides references for development of low energy consumption residences in regions of this type.     

Analysis of the Coupling Modeling Method with CATIA-FLAC 3D and Its Application

Numerical models based on FLAC 3D are difficult to build. A new kind of method modeling and meshing in the CATIA software, named the CATIA-FLAC 3D coupled modeling method, was proposed. This method utilizes the powerful geological modeling capabilities of CATIA for three-dimensional geological body modeling and meshing. And then, the interface program of CATIA-FLAC 3D is adopted to export the information into FLAC 3D, which is coded by visual basic language based on the variance of nodes and elements between the two software. The new proposed method was used in a bias tunnel through a mountain, and the results verified the feasibility and effectiveness of the proposed method.     

Calculation of environmental cost in the structural optimization of super tall buildings

Chinese mainland has seen a rapid construction speed of super tall buildings in recent years. Due to its huge quantity material and energy assumption, the super tall buildings exert great impact on the environment. An innovative new life cycle model is proposed for assess and optimize the life cycle environmental cost of super tall buildings. The new life cycle model has two features. Firstly the space distribution of the building materials is considered besides the time dimension, and secondly the single life cycle concept is extended to multiple life cycles to investigate the carbon footprint from the perspective of more than one life cycle. A benchmark super tall building is established to illustrate the application of the proposed new life cycle model. According to the case study results, a remarkable difference would be made in carbon emissions if the life cycle environmental cost based structural optimization method could be applied.     

Effects of Operation Mode of Air Conditioning on Energy Consumption of Heating and Air Conditioning in Residential Buildings

By using the building thermal environment simulation Toolkit DeST to simulation calculation of a residential building in Shanghai,the quantitative relationship between the factors of operation mode of air conditioning affecting the energy consumption of heating and air conditioning in residential buildings has been obtained in this paper,moreover,it has come to a conclusion that the tolerable temperature is superior to control temperature of air conditioning in respect of sensitivity and the living mode of indoor personnel has certain effect on the cold energy consumption.     

Building Energy Efficiency Design Procedure Based on Digital Technology

Abstract:Digital design technology is crucial for building energy efficiency design, while the key of building energy efficiency design is to analyze the entire design process, dynamic balance and energy cost. Through the application of digital technology in architectural design during its earlier phases, we can analyze such factors as local climate and terrain, create a "virtual building", simulate its actual condition, and conduct a scientific quantitative analysis of the key problems in architectural design. These actions will optimize the proposed design in a timely manner and achieve energy efficient design under the guidance of scientific analysis. Meanwhile, by exploring energy efficiency design procedure based on digital technology, we can adapt to a higher standard of energy efficient design in our new times.