Building integrated photovoltaic (BIPV) technology provides an aesthetical, economic, and technical solution for electricity self-sufficiency in buildings. As one of the most promising technologies for solar energy harvesting in urban areas, BIPV technology provides multiple benefits for buildings, including power generation from renewable energy resources, the replacement of traditional wall cladding, daytime lighting, heating/cooling load reduction, etc. This paper systematically reviews the progress of recent research on the electrical, thermal, optical, and overall energy performances of BIPV systems. Furthermore, based on the literature review on the energy payback time and the greenhouse-gas emission of various BIPV technologies, the research progress of the life-cycle assessment of BIPV systems is also discussed. It is anticipated that the review results can provide meaningful reference and support for the research and development of BIPV technology.

With continuous acceleration of urbanization, the complexity of the urban geometry leads to great changes in the surface albedo, which further affects the microclimates of urban areas, and gives rise to the urban heat island effect (UHI). The UHI effect results in a series of environmental problems, including frequent occurrence of abnormal weather conditions, pollution of atmospheric environment, increases in building energy consumption and even underlying dangers to urban residents. This paper proposes a critical review on the mechanisms and effectiveness of the major UHI mitigation strategies, i.e. using cool materials, arranging vegetation schemes, incorporating water bodies and optimizing the urban geometry. The review indicates that the ambient air temperature could be reduced by 1.4K∼3.74K, depending on the strategies employed. The previously available mitigation measures are more effective in summer cooling in Tropical, Subtropical and Mediterranean climates. With the increase of H/W (height-to-width) and SVF (sky-view factor), the cooling effects of vegetation, water body and cool materials are better. The review results can provide theoretical guidance to the planning and designing of buildings, and cities, the enhancement of the liveability of urban environment, and the sustainable development of future cities.

The impact of different parameter estimation results on the design length of a borehole heat exchanger has received very little attention. This paper provides an in-depth investigation of this problem, together with a full presentation of six data interpretation models and a comprehensive comparison of four representative sizing methods and their inter models. Six heat transfer models were employed to interpret the same thermal response test data set. It was found that the estimated parameters varied with the data interpretation model. The relative difference in borehole thermal resistance reached 34.4%, and this value was 11.9% for soil thermal conductivity. The resulting parameter estimation results were used to simulate mean fluid temperature for a single borehole and then to determine the borehole length for a large bore field. The variations in these two correlated parameters caused about 15% and 5% relative difference in mean fluid temperature in the beginning and at the end of the simulation period, respectively. For computing the borehole design length, software-based methods were more sensitive to the influence of parameter estimation results than simple equation-based methods. It is expected that these comparisons will be beneficial to anyone involved in the design of ground-coupled heat pump systems.

The development of many intelligent technologies, such as artificial intelligence and the Internet of Things, has brought new opportunities for water industry intelligence. Based on intelligent pressure regulation technology, this paper built an intelligent management platform, designed an intelligent pressure-regulating device, and combined both to form an intelligent pressure-regulating vehicle (IPRV). The IPRV has the functions of developing a pressure-regulating scheme, equipment selection, pressure reduction potential analysis, etc. It can bring convenience to the field test of the water supply network. In the field test, an intelligent pressure-regulating device was used to obtain the network data in the pilot site called S-cell. After utilizing the intelligent management platform to analyze the measured data, the water usage pattern and pressure reduction potential of the S-cell were obtained, and an optimal pressure-regulating strategy was formulated. The water pressure at the critical node always met the water demand at the critical node during the field test. In addition, no complaints were received from other users. The results show that the IPRV is not only convenient for utility managers to make decisions on building pressure-reducing stations, but also meets user needs, realizing a win–win situation for both users and companies.