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Zhou S.,Chongqing University | Cui W.,Chongqing University | Li Z.,Chongqing University | Liu X.,Nanjiang Hydrogeological and Engineering Geology Brigade
Sustainable Cities and Society

The long time running of the ground source heat pump (GSHP) system in cooling dominated areas will cause heat accumulation and then the temperature increase under the ground, resulting in the cooling performance degradation of the GSHP system, as well as other problems, such as the change of thermal and microbial environment, and even the organic carbon reserves in the soil. In order to attemper the heat accumulation, a scheme that the cooling tower be operated in transitional (mid) seasons is proposed for the hybrid GSHP system assisted with cooling tower. The temperature difference (Δt) between the air wet-bulb temperature and the ground temperature is defined as the threshold for the cooling tower to start up in transitional seasons. It has been found that the scheme can effectively alleviate the increase of the ground temperature by simulating the system performance with TRNSYS software. However, the system's total power consumption in 30 years increases due to the extra running time of the cooling tower. 8 ∼ 12°C is found to be the optimum range of Δt for the studied hybrid GSHP systems by comparing the system performances under different set values of Δt. In order to find further efficient scheme, a hybrid GSHP system combined with a chiller cooling system is also proposed and studied. However, the simulation result shows that the system power consumption has not got down effectively, for the reason that the energy efficiency ratio (EER) of the chiller used in the TRNSYS model is lower than that of the heat pump. © 2016 Elsevier B.V. All rights reserved. Source

Zhang D.-M.,Chongqing University | Li J.-F.,Nanjiang Hydrogeological and Engineering Geology Brigade | Tian G.-W.,Bureau of Geological Exploration of Chongqing | Liu G.-P.,Southwest University
Journal of Natural Disasters

By synthesis of landslide interpretation, landslide spatial database and management of geographic information system (GIS) outcomes, landslide risk and vulnerability assessment factors were scientifically selected. The author completed risk assessment and vulnerability assessment by analytic hierarchy process of statistical analysis algorithms, GIS buffer analysis, superposition analysis, statistical analysis and three-dimensional analysis to quantify the landslide factors. Based on vulnerability rank and risk classification, Kriging interpolation, re-classification, digital conversion and expert interference correction, the zoning of risk and vulnerability was implemented. Defining 0.5 as attribute data of the landslide risk and vulnerability and by linear superposition, landslide area assessed can be divided into three landslide risk areas: high risk area, medium risk area and low risk area. Source

Li J.,Nanjiang Hydrogeological and Engineering Geology Brigade | Wang L.,Chongqing Institute of Geological Environment Monitoring
Advanced Materials Research

Landslides, as a natural phenomenon, cause a large number of casualties and property losses every year, and serious problems of people's production and living, therefore, real-time monitoring of the landslide is very important.Combination landslide uncertainty, unexpected and hidden characteristics, we need to introduce a new technology to realize the all-weather monitoring of landslide strip. Therefore, this article will focus on the introduction of GPRS technology of landslide geological disaster monitoring and landslide real-time monitoring system based on GPRS technology. © (2013) Trans Tech Publications, Switzerland. Source

Yang P.-H.,Southwest University | Yang P.-H.,The Karst Dynamics Laboratory | Yang P.-H.,Field Scientific Observation and Research Base of Karst Eco environments at Nanchuan in Chongqing | Lu B.-Q.,Nanjiang Hydrogeological and Engineering Geology Brigade | And 4 more authors.
Huanjing Kexue/Environmental Science

The two-year hydrologic process, hydrochemistry, and a portion of δD, δ18O of both the surface water at the inlet and the groundwater at the outlet, were investigated to identify the spatial and temporal variations of hydrogeochemistry in the Qingmuguan karst groundwater system. Research results show that there are wet and dry periods in the groundwater system owing to the striking influence of seasonal rainfall. The evolution of the chemical compositions in the groundwater is significantly influenced by the water and rock interaction, anthropogenic activities and rainwater dilution. The variations of the chemical compositions in the groundwater exhibit obvious spatiality and temporality. The δD and δ18O of the surface water beneath the local Meteoric Water Line of Chonqing indicate that the surface water is strongly evaporated. Furthermore, the δD and δ18O of the surface water are more positive in the dry period than in the wet period, showing a distinct seasonal effect. The δD and δ18O of the groundwater are quite stable and much negative compared with those of the surface water, which suggests that the rainwater recharge the groundwater via two pathways, one directly through sinkholes and the other via the vadose zone. Source

Zhou S.,Chongqing University | Cui W.,Chongqing University | Zhao S.,Chongqing University | Zhu S.,Nanjiang Hydrogeological and Engineering Geology Brigade
Energy and Buildings

A ground-source heat pump (GSHP) system located in Chongqing, a cooling dominated region in China, was taken as an experimental system. In order to explore the operating characteristics of the GSHP system, the GSHP system was monitored with a data acquisition system. The measured data were analyzed, including the inlet/outlet water temperatures, power consumptions, EER/COP and also the ground temperature variations. The measured system EER of 2013 and 2014 are 3.01 and 2.91, respectively, while the system COP of 2013 is 2.59. A TRNSYS model was established based on the studied GSHP system. The accuracy of the model was validated by the comparison between the measured and the simulated outlet water temperatures, and also the ground temperatures. The model was then used to predict the long-term performance of the GSHP system. It has been found that after 20-years running of the system, the heat accumulation under the ground and the deterioration of system efficiency aggravate: the ground temperature would rise up to 30.5 °C from the initial value of 20 °C, while the ASPF value would descend to 2.72 from the initial value of 3.12. As a remedy for the problem, the domestic hot water (DHW) system was supposed to be operated in the following years, and the simulation showed that the operation of DHW system could effectively reduce the ground temperature and improve the system performance. © 2016 Elsevier B.V. All rights reserved. Source

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