Evaluating energy savings in Chinese residential buildings (ESCRB) plays an important role in Chinese building energyefficiency work. However, the said work is currently challenged by the lack of effective method for estimating ESCRB data by summarizing all the quantifiable and unquantifiable impact factors. To overcome this problem, this study employed the equation of Human Impact, Population, Affluence, and Technology (IPAT), and the index decomposition of Logarithmic Mean Divisia Index (LMDI) to establish an effective ESCRB estimation method, and then calculated ESCRB data during the period of 2001-2015. Results of this study reflect that ESCRB has significantly accumulated with the rapid development of Chinese building energy-efficiency work in the past 15 years. In particular, ESCRB data

Examining the driving factors of Chinese commercial building energy consumption (CCBEC) plays an important role in Chinese building energy efficiency work. However, Chinese building energy efficiency work is currently challenged by the lack of effective approaches to examine the driving factors affecting CCBEC. To improve the constitution of the CCBEC reduction measures and strategies, the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model and ridge regression analysis were applied to examine the driving factors of CCBEC data. Results show that: (1) All of the five driving factors (i.e., population, urbanization rate, floor area per capita of existing Chinese commercial buildings, GDP index in the Chinese tertiary industry sector, and CCBEC intensity) have positive effects on CCBEC during the period of 2000-2015. (2) The importance of the five driving factors can be expressed by their different standardized beta values in decreasing order, as follows: CCBEC intensity (21.03%), floor area per capita of existing Chinese commercial buildings (20.93%), population in China (20.68%), urbanization rate in China (20.64%), and GDP index in the Chinese tertiary industry sector (19.24%). (3) The goodness of fit for the regression analysis proves that the proposed method is also applicable at the provincial or regional level. Furthermore, this study proves the feasibility of examining the driving factors affecting CCBEC using the STIRPAT model and ridge regression analysis and provides new approaches for improving the constitution of the CCBEC reduction measures and strategies.

This paper summarizes existing evaluation methods of ground heat exchanger performance. Based on the characteristics of heat transfer in variable flow, comprehensively considering the similarity law of momentum transfer and heat transfer law, the performance of ground heat exchanger was evaluated in winter conditions by a comprehensive heat performance evaluation method – a combination of unit tube length for heat and pumps power consumption.

A theoretical study of the performance of a CCHP system using natural gas as fuel which consists of gas turbine-steam turbine combined cycle, absorption refrigeration unit and exhaust heat boiler under variable loads was carried out. Two methods to adjust the electric and cooling loads are employed here. One method is to increase the outlet pressure of the steam turbine in the Rankine cycle. Another way is to change the air coefficient of the gas turbine. The calculation results show that the first method can obtain higher energy efficient and is the preferred method. The second way can be employed in case that further more cooling is required.