Energy use in buildings has attracted more and more attention due to its significant proportion in the energy pan of the world. China is the second largest energy user, yet the situation of energy use in the China building sector remains unclear, due to problems of statistics and data processing and problematic use of these data. In this paper, a series of methods is developed, in the first place, to give strict definitions of energy data and to divide energy use into 4 sub-sectors according to the unique situation of China. Then, each sub-sector is further analyzed through international comparisons. Existing problems of energy use and solutions for energy reduction in each sub-sector are also discussed. Accordingly, it is found that China uses much less energy, in terms of both per capita and unit area, in buildings than developed countries. The difference in energy use could be attributed, in large part, to lifestyles of local people, which could determine their way of energy use but is more determined by cultural concepts than by others such as income, technique and so on, especially in China. However, to fulfill the requirements of lifestyles with higher living standards and lower energy consumption, technological innovations are needed.

The key parameters that may influence building energy performance is studied by comparing the building energy data of college buildings in two different regions (the USA and China). By introducing data-orientated approach, a study of a set of on-campus building energy demand and consumption is conducted for cooling, heating and electricity. In addition, the heating, ventilation and air conditioning (HVAC) and lighting systems are studied in great detail. The breakdown analyses of the current energy consumption data are used to focus the investigation on critical issues. The analysis shows that the energy consumption of college buildings in the USA can be 3–5 times more than that of college buildings in China. The over-high energy consumption in campus buildings in the USA is mainly caused by operation schedule, system style, cooling and heating counteraction and sensor/actuator faults in the control systems, which also leads to the discussion of energy difference on the concept of “full control” or “local improvement” in building environment control. The study also indicates that the building energy efficiency can only be achieved by adjusting the demand according to natural conditions, encouraging green life behaviors, and developing relative technical solutions coordinated with the thrift culture and human behavior.

A large scale national survey of energy consumption and indoor environment quality of China’s rural housing was conducted from 2006–2007. The survey covered 15 provinces in northern China and 9 provinces in southern China. The survey data indicate that excessive building energy consumption and poor indoor environment pose significant challenges to the sustainable development of China’s rural housing. Possible causes are analyzed, the current status explained and possible development trends predicted. Strategies for sustainable and environmentally appropriate energy development in rural areas are recommended with an example of the “Zero-Coal, Low Energy Village”.

The ground-coupled heat pump (GCHP) systems have been identified as one of the best sustainable energy technologies for space heating and cooling in residential and commercial buildings. In this paper, research on and development of the GCHP technology in China are summarized. New models are presented for efficient thermal analysis of ground heat exchangers, of which one- and two-dimensional solid cylindrical source models and their analytical solutions are devised to deal with pile ground heat exchangers. Analytical solutions are also derived for vertical and inclined finite line source models as well as for a groundwater advection model. Explicit solutions of a quasi-three-dimensional model can be used to better evaluate the thermal resistance inside boreholes. Studies on hybrid GCHP systems and the thermal response test in China are also commented.

The developments on liquid desiccant air-conditioning systems were illustrated and summarized in this paper. In order to obtain a better dehumidification (or humidification) performance, liquid desiccant should be cooled (or heated) rather than air. Two fundamental modules were proposed, including basic spray module with extra heat exchanger and total heat recovery device, which could be combined to set up various kinds of liquid desiccant air processors. The operating principle of heat pump-driven outdoor air processor as well as heat-driven outdoor air processor was analyzed. The COP_air of the heat pump (or power)-driven outdoor air processor could be as high as 5.0 both in summer and in winter operating conditions. The COP_air of the hot water-driven processor (65°C–80°C) was 1.19 and 0.93, respectively, using evaporative indoor exhaust air or cooling water to cool the dehumidification process. The liquid desiccant air processor-based temperature and humidity-independent control air-conditioning system could save 20%–30% operating energy compared with the conventional air-conditioning system.

A novel indirect evaporative chiller driven by outdoor dry air to produce cold water as the cooling source for air conditioning systems is introduced, and the principle and the structure of the chiller is presented. The cold water can be produced almost reversibly under ideal working conditions, with its temperature infinitely close to the dew point temperature of the inlet air. The key components of the chiller are an air cooler and a padding tower. To improve the heat transfer performance inside the chiller, a quasi-countercurrent air cooler was designed; a subsection linear method was used for the mathematical model of the padding tower. The first indirect evaporative chiller, designed and developed in 2005, has been in use in Kairui Building, a big hotel in Shihezi, Xinjiang Autonomous Region. The tested temperature of the water produced is below the wet bulb temperature of outdoor air and reached the average value of the dew point temperature and the wet bulb temperature of outdoor air. As the running components are only pumps and fans, the COP (cooling energy for room divided by power cost) of this chiller is high, and the drier the outdoor air, the higher COP the chiller obtained. Since no CFCs are used in this chiller, it would not cause any pollution to the aerosphere. Finally, the application prospect of the indirect evaporative chiller in the world is presented.

In order to decrease the energy consumption of large-scale district heating systems with cogeneration, a district heating system is presented in this paper based on absorption heat exchange in the cogeneration system named Co-ah cycle, which means that the cogeneration system is based on absorption heat exchange. In substations of the heating system, the temperature of return water of primary heat network is reduced to about 25°C through the absorption heat-exchange units. In the thermal station of the cogeneration plant, return water is heated orderly by the exhaust steam in the condenser, the absorption heat pumps, and the peak load heater. Compared with traditional heating systems, this system runs with a greater circuit temperature drop so that the delivery capacity of the heat network increases dramatically. Moreover, by recovering the exhausted heat from the condensers, the capacity of the district heating system and the energy efficiency of the combined heat and power system (CHP system) are highly developed. Therefore, high energy and economic efficiency can be obtained.

About 67million Chinese kangs are still used by about 175million people in China today. The kang utilizes biomass burning for space heating and hence reduces the use of commercial energy. However, the existing design of kangs is largely based on the accumulated experience of craftsmen, for lack of scientific studies and engineering design guidelines. Poor construction of kangs also leads to serious indoor air pollution. In this paper, a macroscopic smoke flow and heat transfer model of an elevated kang is integrated in a widely-used building energy analysis software in China–DeST, and the integrated software can be used for the thermal performance analysis of kang-integrated houses. A typical house with kangs in various villages of northern China is chosen as a case study. The annual performance of the kang under different insulations of building envelope and climatic conditions are discussed. Based on the simulation results, it is found that the thermal comfort requirement of the outside surface of the upper kang plate can be met by a proper construction of the kang and selection of the appropriate firing pattern. The better the insulation of the building envelope is or the better the room air tightness is, the greater the indoor air temperature rise and the greater the building heating load contribution of the kang. In the eight selected cities in northern China, the use of kang can meet 50%–80% of the house heating load.

In rural areas of western China, most of the vernacular architectures are made of earth. In the process of urbanization, few residents like to build their houses with earth because the old traditional earth house cannot meet their requirement for higher standard of living. As a result, much more energy will be consumed if industrial building materials are used instead of earth. The regeneration of the traditional earth house, therefore, becomes a challenge in new village construction. This paper briefly describes a project about creating a new prototype of earth house for the migrants along the upper reaches of the Yangtze River to shed light on finding an appropriate approach for regenerating the traditional earth houses with the concept of low-energy housing. It includes an investigation of the traditional earth house and the environment condition of the new settlement, the new house design process, and the quantitative evaluation of the living quality of the new house.

This paper introduces the design idea and technique utilized in the Library of Shandong Transportation College, which ranked 1st in the 2nd National Green Buildings Innovation Award in China in March 2007 due to its low cost and climate-oriented green strategy during its design and construction phase, including land saving, energy efficiency, water conservation, and so on. Originally, the place was a landfill site with an odor pool. After reconstruction, it was changed into the construction site of the library with an area of 7000m² and a scenery pond. With the integrated use of passive shading, daylighting, ventilation with atriums, high-insulation materials, underground duct ventilation, and the substitution of cooling tower with the pond water, the HVAC load design indexes are 59 W/m² and 21.8 W/m² for space cooling and heating, respectively, much lower than the newly issued Chinese energy efficient design code for public buildings. Moreover, a set of measures is utilized for water conversation, material saving, and improvement of indoor environmental quality. After three years of operation, the real effect has been validated by electricity meter and field measurement. The total initial cost for the building with the above mentioned integrated technologies was only RMB 2150 per square meter, which was worth spending in China due to the climatic adaptability and the relative low cost.

The design, construction, operation and on-site measurement of Lhasa Railway Station was summarized. The problems and corresponding solutions during the implementation of building energy saving design and utilization of solar energy were proposed.

A new type of rural residential building that is ecological, energy efficient and comfortable was designed. Research on the new building was sponsored by the Post-disaster Reconstruction Project in Daping Village, Sichuan Province. Based on field investigation and quantitative analysis, an appropriate design strategy and technology is presented, including climatic design strategies, local material use and building energy simulation.

The total annual energy consumption of people in rural areas in China is about 190 million tons of standard coal, and is still growing rapidly with the improvement of living standards. The reduction of this energy consumption is a key issue in China’s sustainable development. Focusing on the energy conservation of cave dwellings in the Loess Plateau, this paper aims to create a new prototype of cave dwelling that not only satisfies the requirements of the modern life of the residents but also inherits the energy-efficiency of traditional cave dwellings. For this purpose, a model cave dwelling is built at Zaoyuan Village, a cave-dwelling community in Yan’an, Shaanxi Province. In this cave dwelling, modern building energy efficiency principles and strategies such as natural ventilation, natural lighting, passive solar heating and earth cooling method are adopted. From the testing and subjective survey, it can be concluded that the new cave dwelling inherits the advantages of the traditional ones and has excellent performance in energy-efficiency, thermal comfort, and natural lighting.