Performance Assessment of a Shell Tube Evaporator for a Model Organic Rankine Cycle for Use in Geothermal Power Plant

Haile Araya Nigusse, Hiram M. Ndiritu, Robert Kiplimo

Department of Mechanical Engineering, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.

DOI: 10.4236/jpee.2014.210002                

Abstract

The global energy demand increases with development and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining and harmful combustion byproducts are causing global warming. The Organic Rankine Cycle power plant is a very effective option for utilization of low grade heat sources for power generation. In the Organic Rankine Cycle heat exchangers such as evaporators and condensers are key components that determine its performance. Researches indicated that shell tube heat exchangers are effectively utilized in this cycle. The design of the heat exchanger involves establishing the right flow pattern of the interacting fluids. The performance of these exchangers can be optimized by inserting baffles in the shell to direct the flow of fluid across the tubes on shell side. In this work heat exchangers have been developed to improve heat recovery from geothermal brine for additional power generation. The design involved sizing of heat exchanger (evaporator) using the LMTD method based on an expected heat transfer rate. The heat exchanger of the model power plant was tested in which hot water simulated brine. The results indicated that the heat exchanger is thermally suitable for the evaporator of the model power plant.

Keywords

Shell Tube Evaporator, Heat Transfer Co-Efficient, LMTD, ORC

Conflicts of Interest

The authors declare no conflicts of interest.

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