Office Buildings In China Research Articles

Energy assessment of office buildings in China using China building energy codes and LEED 2.2

China building energy codes (CBEC) have been introduced for over two decades but little has been publicized in literature. LEED on the contrary is the most publicized building environmental assessment scheme. To enable better understanding of the compliance standards of CBEC, this paper presents the energy performance assessment results (represented by energy and energy cost savings) of three office buildings in China (one in Beijing and two in Shanghai) using the current versions of CBEC and LEED. The energy and energy cost savings of the three buildings were predicted based on hour-by-hour simulations using the weather data and energy tariffs of Beijing and Shanghai where the three studied buildings are located, and their actual building and system characteristics. The study revealed that LEED in general sets more stringent requirements than CBEC in indoor design conditions, building envelope characteristics and air-conditioning system features. Amongst various building end uses, energy use for air-conditioning was found dominating the assessment results, and the use of energy efficient measures not forming part of the baseline criteria, could lead to 2 to 5% reduction in the overall building energy use. The two schemes were benchmarked against BEAM Plus and their weaknesses were also unveiled.

Comparative study on the indoor environment quality of green office buildings in China with a long-term field measurement and investigation

On account of the actual performance of green building in China is not systematically researched, this paper follows the results of recent POE surveys within green and conventional office buildings in two climate zones of China. Occupants completed a questionnaire related to environmental satisfaction, meanwhile, a long-term objective measurement was proceeding to characterize the immediate environment experienced by the occupants. This study analyzes the subjective and objective measurements of indoor environment quality (IEQ) from four parts: thermal environment, indoor air quality, visual and acoustic environment. The result indicates that green buildings possess significantly higher satisfaction level than conventional buildings, and the actual performance of green buildings basically achieve the design goal of IEQ. The indoor operative temperature of buildings in both climate zones is compared to find the difference of indoor temperature in the interim period and influence of occupants' behavioral habit. At last, two typical thermal comfort model are used to assess the occupants feeling in different climate zones in China.

Data analysis and stochastic modeling of lighting energy use in large office buildings in China

Lighting consumes about 20% to 40% of the total electricity use in large office buildings in China. Commonly in building simulations, static time schedules for typical weekdays, weekends and holidays are assumed to represent the dynamics of lighting energy use in buildings. This approach does not address the stochastic nature of lighting energy use, which can be influenced by occupant behavior in buildings. This study analyzes the main characteristics of lighting energy use over various timescales, based on the statistical analysis of measured lighting energy use data from 15 large office buildings in Beijing and Hong Kong. It was found that in these large office buildings, the 24-hourly variation in lighting energy use was mainly driven by the schedules of the building occupants. Outdoor illuminance levels had little impact on lighting energy use due to the lack of automatic daylighting controls (an effective retrofit measure to reduce lighting energy use) and the relatively small perimeter area exposed to natural daylight. A stochastic lighting energy use model for large office buildings was further developed to represent diverse occupant activities, at six different time periods throughout a day, and also the annual distribution of lighting power across these periods. The model was verified using measured lighting energy use from the 15 buildings. The developed stochastic lighting model can generate more accurate lighting schedules for use in building energy simulations, improving the simulation accuracy of lighting energy use in real buildings.

The Analyses of Daylighting in High-Rise Office Buildings and the Design Essentials

Majority of office buildings in China are appeared in forms of high-rise buildings and have a character of high construction-scale and high energy-cost. The daylighting in office can not only save the energy, but also meet the physical and psychological needs for eyes, and finally lead to higher work efficiency. Solving the daylighting problems in the high-rise office buildings is urgent. The core position in the high-rise building is an important factor to affect the light in office. In this paper, the author analyses the lighting characteristics of three types of the core position, which is core in the center of the building, core at the peripheral of the building and the core separated from the building. Combined with the natural lighting assistance measures, some design essentials were raised in this paper.

Energy assessment of office buildings in China using LEED 2.2 and BEAM Plus 1.1

LEED and BEAM Plus have been formally launched for more than 10 years. They are the two most recognized building environmental assessment schemes in China. Previous works have been done on benchmarking the energy assessment of the two schemes. However, benchmarking was either based on their earlier versions of which substantial changes have been made, or focused on their assessment issues and metrics without making reference to actual building characteristics. This paper compares the energy performance assessment results of three new office buildings in China (one in Beijing and two in Shanghai) using current versions of LEED and BEAM Plus. The three office buildings were chosen for their similarities in design. The study revealed that despite the variations in different aspects between LEED and BEAM Plus, assessment results of the three studied buildings were comparable. Amongst various building end uses, energy use for air-conditioning was found dominating the assessment results. Comparison results also show that although different tariff systems are adopted in Beijing and Shanghai, the difference will not affect the assessment results as long as same tariff system is used for predicting the energy cost of the baseline and design cases.

Multiple regression models for energy consumption of office buildings in different climates in China

The energy consumption of office buildings in China has been growing significantly in recent years. Obviously, there are significant relationships between building envelope and the energy consumption of office buildings. The 8 key building envelope influencing factors were found in this paper to evaluate their effects on the energy consumption of the air-conditioning system. The typical combinations of the key influencing factors were performed in Trnsy simulation. Then on the basis of the simulated results, the multiple regression models were developed respectively for the four climates of China—hot summer and warm winter, hot summer and cold winter, cold, and severely cold. According to the analysis of regression coefficients, the appropriate building envelope design schemes were discussed in different climates. At last, the regression model evaluations consisting of the simulation evaluations and the actual case evaluations were performed to verify the feasibility and accuracy of the regression models. The error rates are within ±5% in the simulation evaluations and within ±15% in the actual case evaluations. It is believed that the regression models developed in this paper can be used to estimate the energy consumption of office buildings in different climates when various building envelope designs are considered.

The reality and statistical distribution of energy consumption in office buildings in China

This paper analyzed the energy consumption of office buildings in several provinces and municipalities directly under the control of the Central Government of China, utilizing data from the first national survey of about 4600 samples which was conducted in 2007. The Electricity Use Intensity excluding District Heating (EUI excl. DH) of different cities or provinces was analyzed. By conducting a cluster analysis, it was found that a unique “Dual Sector Distribution” feature exists in office buildings in China, compared to a “Single-peak Distribution” characteristic in Japan and the US. The research also intended to explain the possible reasons behind this phenomenon. The Lorenz Curve and Gini Coefficient methods were used as references in order to reveal the regional disparity in China. The results suggested that: (1) EUI excl. DH of office buildings in each city or province in China appeared two different groups, most of them distributed on the lower range from 33.6 to 77.5kWhe/(m2a),111kWhe means 1kWh of electricity, distinguished from 1kWh heating (illustrating as kWhh) or 1kWh cooling (kWhc). excluding district heating energy use, while some of buildings fell within a higher range from 51.8 to 107.0kWhe/(m2a). (2) The Gini Coefficient illustrated that the more developed of urbanization, the less significant of distribution difference, and the higher the EUI excl. DH of office building in China.

Erratum to: Life cycle energy consumption and CO2 emission of an office building in China

Erratum to: Life cycle energy consumption and CO2 emission of an office building in China

Life cycle energy consumption and CO2 emission of an office building in China

Purpose Building is one of the main factors of energy use and greenhouse gas emissions. Reducing energy consumption and carbon dioxide (CO2) emission from building is urgent for environmental protection and sustainable development. The objective of this study is to develop a life cycle assessment (LCA) model for an office building in China to assess its energy consumption and CO2 emission, determine the whole life cycle phases, and the significant environmental aspects that contribute most to the impact.

Subjective and Objective Evaluation of the Thermal Environment in a Three-Star Green Office Building in China

A post-occupancy study was carried out to investigate the thermal environment in a high-standard office building certified by China Three-star Green Building Label. The study included a subjective evaluation of the indoor environment quality and work performance. A total of 182 office workers responded to the questionnaire survey based on the Building Use Studies (BUS) Occupant Survey and Reporting Method. Objective measurements of the thermal environment (temperature and relative humidity) under mechanically and naturally ventilated conditions were also carried out in the building. Although the thermal environment satisfied the majority of respondents, 12% and 20% reported dissatisfaction with summer and winter temperatures, respectively. The complaint on summer temperature was mainly from those working close to the chilled air outlets of the air-conditioners. The perception of cold winter temperatures revealed the potential shortcomings of sustainable building design in humid subtropical climates, where natural ventilation and passive cooling would predominate in the sustainable design while cold air in winter would tend to be neglected. The purpose of this study was to investigate the reasons why green buildings succeeded or failed to meet occupants’ perception and this could have an implication in the design decisions for green building practice.

COMPARISON OF ENERGY CONSUMPTION AND CO2 EMISSION DUE TO BUILDING CONSTRUCTION BETWEEN CHINA AND JAPAN

Energy consumption and CO2 emission due to construction of buildings in China and Japan are described in this report. As more than 400 industrial sectors are contained in Japanese IO table and 30 sectors in Chinese IO tables, energy consumption and CO2 intensities of dominant materials used in building are derived from energy consumption in factories and equipments are derived from IO analysis. Energy and CO2 intensities of main materials used in building construction in China and Japan and the calculation methods are shown in this report. Office buildings in both countries are calculated as a case study. The intensities of materials in China are 2-3 times larger than Japan and energy consumption and CO2 emission due to construction of office building in China is 10-20% larger than in Japan. Though energy consumption of structure in China is 2-3 times larger than in Japan, interior finish works and equipments for air conditioning etc. are smaller. Energy consumption due to Chinese office building construction are almost same as Japanese.

Energy Conservation Using Variable-speed Chilled Water Pumps for Single-loop Chilled Water Systems with Fan-coil Units

ABSTRACT This article addresses the need to reduce energy consumption by chilled water pumps in air conditioning systems. In particular, this article considers the use of variable-speed pumping systems. Many office buildings in China utilize air conditioning systems with fan-coil units (FCUs) and a primary/secondary chilled water system without secondary pumps. The simulated air conditioning system performance analysis showed that the single-loop chilled water system with variable-speed chilled water pumps could be used in most office buildings where the cooling loads were synchronized to save energy. Installation of the new systems in two office buildings reduced the energy consumption of the chilled-water pumps by almost 50 percent.