Investigation of convective-conductive heat transfer in geothermal system

Publication date: Available online 11 July 2018Source: Results in PhysicsAuthor(s): P. Jalili, D.D. Ganji, S.S. NourazarAbstractGeothermal energy is one of the well-known types of renewable energies that can be considered as a promising alternative to fossil fuels in order to mitigate the CO2 emission in atmosphere. Geothermal energy has recently been used for heating and cooling systems in many countries of the world. Therefore, studying such kind of energy seems important and necessary. This paper studies the heat transfer processes in a borehole heat exchanger (BHE). The flow of fluid in a BHE has been considered with different geometries and heat transfer processes are modeled numerically and in a finite volume method through convection and conductivity. First, a single U-shaped BHE was modeled and its thermal properties were investigated and then other geometries were studied to obtain the best geometry and heat transfer efficiency. In order to increase the heat transfer in the inner part of the pipes, the fin with the given specifications was used and the modeling was carried out and the thermal parameters were compared for three BHE’s with different geometries. In the final part, optimization results are presented, and the interaction of parameters on the Nusselt number and friction coefficient have been investigated. Also, the desirability of optimization and reliability is given to the results presented in percentage terms. Comparing the results of this article...
Source: Results in Physics - Category: Physics Source Type: research

Related Links:

Source: Pediatric Neurology - Category: Neurology Source Type: research
Source: Pediatric Neurology - Category: Neurology Source Type: research
Source: Pediatric Neurology - Category: Neurology Source Type: research
CONCLUSION: Sputum suction and alveolar lavage with portable fibrobronchoscope can significantly improve the hypoxia and pulmonary infections, reduce the inflammatory response, and thus improve the prognosis, rendering suction and alveolar lavage with portable fibrobronchoscope as a safe and effective treatment for non-severe ischemic SAP patients with dysphagia. PMID: 30657017 [PubMed - as supplied by publisher]
Source: Neurological Research - Category: Neurology Tags: Neurol Res Source Type: research
Authors: Jensen P, Frisk R, Spedden ME, Geertsen SS, Bouyer LJ, Halliday DM, Nielsen JB Abstract The present study used coherence and directionality analyses to explore whether the motor cortex contributes to plantar flexor muscle activity during the stance phase and push-off phase during gait. Subjects walked on a treadmill, while EEG over the leg motorcortex area and EMG from the medial gastrocnemius and soleus muscles was recorded. Corticomuscular and intermuscular coherence were calculated from pair-wise recordings. Significant EEG-EMG and EMG-EMG coherence in the beta and gamma frequency bands was found throug...
Source: Journal of Motor Behavior - Category: Neurology Tags: J Mot Behav Source Type: research
Authors: Watanabe R, Wagman JB, Higuchi T Abstract We investigated perception of the extent of an object held in the hand or attached to the head during walking. Participants wielded an occluded, weighted rod by hand and by head and reported the perceived location of the rod end (relative to a virtual vertical line) while walking and while standing. There was an unexpected effect of body part on perceived location of the rod end. In particular, participants stood or walked so that the rod end was farther away from the vertical line when wielding with the head than wielding with the hand. It is possible that differe...
Source: Journal of Motor Behavior - Category: Neurology Tags: J Mot Behav Source Type: research
Authors: Mumic de Melo L, Hotta Ansai J, Giusti Rossi P, Carvalho Vale FA, Cristhine de Medeiros Takahashi A, Pires de Andrade L Abstract In clinical practice, older people with cognitive impairment may have difficulties to understand the instructions of the Timed Up-and-Go (TUGT) test and present a bad performance. The purpose of this study was to identify differences in the TUGT performance, in an adapted version, between older adults with preserved cognition (PC), mild cognitive impairment (MCI) and Alzheimer's disease (AD), and to identify the association between the adapted TUGT performance and cognition among...
Source: Journal of Motor Behavior - Category: Neurology Tags: J Mot Behav Source Type: research
Source: Gastrointestinal Endoscopy - Category: Gastroenterology Source Type: research
Source: Gastrointestinal Endoscopy - Category: Gastroenterology Source Type: research
Source: Gastrointestinal Endoscopy - Category: Gastroenterology Source Type: research
More News: Physics | Study