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The study proposes a new low-grade energy utilization system, i.e. a pipe-embedded wall integrated with ground source-coupled heat exchanger, and investigates its energy saving potentials in five typical climate regions of China. The cool/hot water produced by the ground source-coupled heat exchanger is supplied to the pipe-embedded wall to intercept the heat gain/loss through the wall. A real-scale building energy simulation platform has been developed for estimating the energy saving potentials. The study results show that the energy saving potential of the proposed system varies with the climate regions. With the same sized pipe-embedded wall system, the building in warm climate regions achieves the largest energy saving percentage. It is followed by the buildings in the hot summer and cold winter climate region, the severe cold climate region, the cold climate region, and the hot summer and warm winter climate region in the declining sequence of energy saving. Meanwhile, a multi-criteria performance evaluation has been conducted to search for the optimal size of the low-grade-energy system in each climate region. The proposed system can be utilized in practice for energy saving, and the study results are helpful in guiding the practical applications of the pipe-embedded wall system in different climate regions. [ABSTRACT FROM AUTHOR]

Abstract Aerogel insulating panels (AIPs) exhibit extensive prospects for application in aerospace, industry and buildings as excellent energy-saving thermal insulators owing to their ultra-low thermal conductivity. This work aims to numerically and experimentally investigate the thermal performance of AIPs in building energy efficiency. The AIPs were prepared and used as an insulation layer in an insulating cell. Three insulating cells with three different insulating materials as the insulation layer were prepared to measure and comparatively analyse their thermal performances. A resistance-capacitance thermal network model to predict the thermal performance of the insulating cells was developed and validated with the experimental data. The thermal indices of cells, i.e. the time lag, decrement factor and daily heat loss, were explored under periodic disturbances of exterior air temperature. Furthermore, the thermal performance of AIPs for exterior walls was predicted by adopting the typical wall structure in the hot summer and warm winter zone of China. The results showed that the AIP wall has decreases of ∼20% and ∼40% in the fluctuation amplitude of the internal temperature and heat flow, respectively, compared with the traditional insulating walls. Highlights • A method to indicate thermal performance of AIP for energy efficiency is proposed. • Three insulating cells with EPS, GF and AIP are prepared and compared. • AIP cell shows twice time lag, 40% less decrement factor and 35% less daily heat loss. • AIP wall has ∼20% and ∼40% decreases in amplitudes of temperature and heat flow. [ABSTRACT FROM AUTHOR]

This study investigated the backwater effect of the eight bridges along the Huaihe River in China using physical model experiments. The experimental data obtained were used to derive equations to parameterise the backwater effect of a single bridge. The cumulative effect of two bridges was then analysed, using the backwater effect of a single bridge as a reference. It was found that, in order to eliminate the cumulative effect, the minimum distance between two bridges should be no less than 215 times the bridge pier width. [ABSTRACT FROM AUTHOR]

Effective evaluation on the thermal performance of envelope plays an important role towards the reduction of energy consumption for space cooling and heating. In order to calculate the energy consumption for cooling and heating and assess the whole energy efficiency of envelop designs, a new evaluation index on energy and thermal performance for office building envelop (EETPO) is put forward. Three cities of Shenyang, Wuhan and Guangzhou in China are selected for EETPO analysis, which represent the cold zone, hot summer cold winter zone and hot summer warm winter zone, respectively. The regression equations between EETPO and energy use for cooling/heating are studied in three cities, illustrations indicate that the regression lines fit extremely well and the algorithm is accurate and simple. According to the compulsory indices stipulated by standard (GB50189-2005), the maximum allowable values of EETPO are determined in three cities, the maximum EETPO c in cooling period is 1.750 W/m 3 K in Wuhan and 1.733 W/m 3 K in Guangzhou, the maximum EETPO h in heating period is 0.200 W/m 3 K in Shenyang and 0.414 W/m 3 K in Wuhan. This index and energy use calculation method can help designers to evaluate the whole energy and thermal performance of the proposed envelopes and analyze energy saving effects for different energy conservation measures. [ABSTRACT FROM AUTHOR]

Abstract: Heat pumps could be used to produce hot water for hybrid cooling towers for preventing the occurrence of plume in subtropical regions. The evaporative side of the heat pump system could be arranged either at the inlet side or at the outlet side of these cooling towers for cooling down the cooling water temperature. Alternatively, the evaporative side of the heat pump system could also be arranged at the evaporative side of chillers to reduce return chilled water temperature and therefore to reduce the cooling load of chillers. This study presents the evaluation of the impacts of these three arrangements of the heat pump system on the plume control performance and the energy performance in a large-scale chiller plant in Hong Kong. The performance prediction and evaluation of the chiller plant and the plume abatement system were conducted on a dynamic simulation platform. The results show that these three arrangements have almost the same plume control performance with sufficient plume control capability. The results also show that the arrangement of the evaporative side of the heat pump system for cooling down return chilled water temperature has much better performance that the other two arrangements for improving the overall energy efficiency. [Copyright &y& Elsevier]

Highlights: [•] Sensitivity analysis of energy performance is performed for residential envelope. [•] EETP method is introduced to calculate cooling and heating energy use. [•] Shading coefficient and window to wall ratio are the most vital factors in summer. [•] Wall heat transfer coefficient and shape coefficient have crucial effect in winter. [•] Wall heat transfer coefficient and window to wall ratio weight the most in a year. [ABSTRACT FROM AUTHOR]