Numerical Modelling Of Heat Transfer In Geothermal And Heat Pipe Using Carbon Dioxide As Working Fluid

The present study focused on Numerical modelling of heat transfer in geothermal and heat pipe using carbon dioxide as working fluid.The rapid increase of worldwide energy demand and various environmental implications have triggered the need for a maximized use of available renewable energy potential with high efficiency,and geothermal energy have proven their reliability.However,existing power conversion technologies,typically the Organic Rankine Cycle(ORC)power plants present many environmental and efficiency problems.To that end,heat pipe utilization is the only promising solution.Firstly,in this research,The numerical model was established based on data collected about geochemical and hydrochemistry to assess the reservoir temperature of the Gisenyi thermal spring.The aim was to evaluate its capacity to produce sustainable geothermal fluid for electricity generation or for direct utilization.This section assesses the reservoir temperature of Gisenyi thermal spring using different geothermometers together with collected data with the help of MATLAB software.The electrical generating capacity of the spring has been analyzed and assessed to the optimum depth and considering the leading mode of heat transfer.Secondly,this research numerically evaluates the heat pipe utilization for geothermal exploitation using Carbone dioxide(CO2)as a working fluid for electrical generation.A C omplete CFD modeling was done to simulate heat mass transfer of CO2 during the phase transition process.The volume of fluid(VOF)model of ANSYS FLUENT is applied,whereby a User Defined Function(UDF)is assigned to the current fluent codes.The purpose of the simulation was to investigate if the output vapor parameters(pressure,temperature,vapor velocity,and vapor quality)can be qualitatively ready to run a steam turbine.Specifically,the steam turbine and the horizontal shaft have been nearly placed before the end of the adiabatic section.Considering the agreement between investigated vapor parameters and empirical correlations,it has been found that the electricity generation can be appreciated and simulation results have been used to estimate the power potential of hot spring.In comparison with existing methods of geothermal power generation like Organic Rankine Cycle(ORC),Heat pipe is a promising one as it presents double benefits in a sustainable way of power generation without the extraction of fluids.The results show that a heat pipe using CO2 as a working fluid should be applied for geothermal electrical generation as well as in large scales solar thermal electrical generation.