Study on heat exchange of groundwater under complex geological conditions in karst area of south China

Abstract

This paper takes a groundwater source heat pump in the region as the research object and based on field research, experimental tests combined with comparative analysis, the data on its operation is monitored and analyzed in terms of operation, energy saving, and environment. The results show that the cooling temperatures of the test rooms were all below 26°C, the average coefficient of performance of the units was 4.61–4.93 and the average coefficient of performance of the system was 3.08–3.27. In addition, compared to conventional water-cooled chillers, 466 tons of standard coal could be saved in one cooling season, resulting in a reduction of 1,150.8 tons of carbon dioxide emissions, 9.3 tons of sulfur dioxide emissions and 4.7 tons of dust emissions The savings in operating costs are 793,000 RMB. This shows that the groundwater source heat pump has good energy efficiency and economy. The research results obtained in this paper provide a reference for improving energy efficiency and optimizing the operation of the groundwater source heat pump system. It is of great significance to the application of groundwater source heat pump systems in areas with complex geological environments.

Numerical Study of the Thermo-Hydro-Mechanical Coupling Impacts of Shallow Geothermal Borehole Groups in Fractured Rock Mass on Geological Environment

“…Due to the effect of incomplete consolidation during backfilling, the actual porosity of backfill material is higher than that of surrounding rock mass; III. The fractured rock mass is a dual media, consisting of fractures and matrix with low porosity [2];…”

“…According to the general vertical pa ern of karstic environments [2], a representative geometric rock mass model with two horizontal fractures was assumed and established. Figure 3a,b shows the models before and after the construction of the borehole group, respectively.…”

“…Below the epikarst zone is the saturation karst zone, which is usually within a depth of 100 m. The groundwater is circulated and alternated intensely, dominated by horizontal karstification development. In deeper stratum, the hydrodynamic conditions and karstification gradually weaken [2].…”

“…Establishment of Numerical Model 4.1. Geometric ModelAccording to the general vertical pattern of karstic environments[2], a representative geometric rock mass model with two horizontal fractures was assumed and established. Figure3a,b shows the models before and after the construction of the borehole group, respectively.As shown in Figure3, the depths of simulated rock mass and the boreholes are 130 m and 120 m, respectively; the length and width of the model are 70 m and 60 m, respectively; and there are 30 boreholes, with a hole spacing of 5 m and a diameter ofEnergies 2024, 17, 1384 7 of 22 180 mm.…”