PDF Publication Title:
Text from PDF Page: 012
Energies 2022, 15, 6385 12 of 13 In general, convective heat transfer enhanced the heat transfer of the U pipes, and the heat supplementation brought by the flowing water, which was proportional to the cubic of the fracture width, significantly enhanced the thermal recovery ability. To compare, the non-fracture rock could only recover its temperature by heat conduction through its boundaries with the surrounding formation. 4. Conclusions In this paper, an experiment and a numerical simulation were performed to investigate the influencing mechanism of fracture water on the temperature field in a rock mass during a GCHP operation under steady-state conditions. A heat exchange laboratorial platform of a rock mass with a fracture was built. The impact of the fracture water on the temperature field at cooling and heating conditions was investigated through a laboratorial experiment and a numerical simulation. The results of the physical experiments and numerical simulations support the following conclusions: (1) For U pipes buried in karst areas with dense and low-permeability carbonate rock masses, the heat transfer between the U pipes and the rock mainly depends on heat conduction instead of convection. Therefore, the energy in the rock mass is difficult to dissipate to the surrounding formations in time, and it is possible that a thermal imbalance in the underground heat exchange area will occur. However, a rock mass with abundant fracture groundwater offers opportunities to mitigate the thermal imbalance with convection brought by water flow. The contribution of fracture water to the thermal balance of the rock mass is obvious because the energy carried by the flow of water is tremendous. In the simulated cooling period in the experiment, the rock body with one horizontal fracture was heated, and the center temperature of the rock mass was affected by the existence of fracture water. The differences in temperature at different depths were 7.5 K, 7.5 K, and 2 K, respectively, compared with the non-fracture rock mass. However, the effect of the fracture water was constrained in areas close to the fracture. (2) In the simulated heating period in winter, regardless of whether the rock mass had one fracture or two fractures, the temperature of the surrounding rock mass around the fracture was higher than that of the area without the fracture. The gradient of temperature curve of the rock mass nearby the fracture water was flattened due to the existence of the flowing fracture water. It is obvious that when the number of fractures increased, the effect was enhanced. (3) The rock mass with the fracture had a small temperature variation during the opera- tion, and the temperature also recovered more quickly during the shutdown period. This is because the fracture water flow volume was proportional to the cubic of the fracture width, so the supplementary energy it carried was significant and effectively enhanced the thermal recovery ability of the rock mass. (4) Artificial fractures might be used to enhance water flow and heat transfer, but such an approach might be constrained or forbidden in project sites or urban areas. Therefore, it is proposed that the U pipes should be located at zones with abundant fracture water if the construction condition permits. U pipes that are near the fractures should share more of the load or a denser layout could be possible as their heat transfer capacity is improved by the water flow. Author Contributions: Conceptualization, P.P.; Formal analysis, C.W.; Software, J.W.; Supervision, L.T.; Writing—original draft, T.L. All authors have read and agreed to the published version of the manuscript. Funding: This work was supported by the National Natural Science Foundation of China (Grant Number: 52066005), the Natural Science Foundation of Guizhou Province (Grant Number: [2020]2Y025), and the Natural Science Foundation of Guizhou Province (Grant Number: [2022]232). Institutional Review Board Statement: Review board has reviewed the manuscript and confirmed.PDF Image | Research on the Application of Fracture Water
PDF Search Title:
Research on the Application of Fracture WaterOriginal File Name Searched:
energies-15-06385.pdfDIY PDF Search: Google It | Yahoo | Bing
Turbine and System Plans CAD CAM: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. More Info
Waste Heat Power Technology: Organic Rankine Cycle uses waste heat to make electricity, shaft horsepower and cooling. More Info
All Turbine and System Products: Infinity Turbine ORD systems, turbine generator sets, build plans and more to use your waste heat from 30C to 100C. More Info
CO2 Phase Change Demonstrator: CO2 goes supercritical at 30 C. This is a experimental platform which you can use to demonstrate phase change with low heat. Includes integration area for small CO2 turbine, static generator, and more. This can also be used for a GTL Gas to Liquids experimental platform. More Info
Introducing the Infinity Turbine Products Infinity Turbine develops and builds systems for making power from waste heat. It also is working on innovative strategies for storing, making, and deploying energy. More Info
Need Strategy? Use our Consulting and analyst services Infinity Turbine LLC is pleased to announce its consulting and analyst services. We have worked in the renewable energy industry as a researcher, developing sales and markets, along with may inventions and innovations. More Info
Made in USA with Global Energy Millennial Web Engine These pages were made with the Global Energy Web PDF Engine using Filemaker (Claris) software.
Sand Battery Sand and Paraffin for TES Thermo Energy Storage More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)