Design, modelling and optimisation of a small-scale Solar Organic Rankine Cycle system for rural power generation

L F Patiño,L Castro,P Gauthier-Maradei,C P Tavera-Ruiz,U Azimov,J M Castellanos

doi:10.1088/1755-1315/897/1/012003

Abstract

This research study develops the design and model of a Solar Organic Rankine Cycle (SORC) coupled to a bio-digester for small-scale generation in rural areas, in Betulia, Colombia. Moreover, the model is optimised employing a Genetic Algorithm with the software Matlab and the thermodynamic library CoolProp. The objective variables were the mass flow rate of the working fluid, the pressure and temperature of the expander inlet, the solar collectors’ type and the temperature of the water circuit for the bio-digester. The results indicate an overall efficiency between 8.42 and 9.45% with a Levelized Cost of Energy (LCE) between 3.85 and 5.63 £/W. Additionally, the power output is directly related to the mass flow rate of the working fluid. Likewise, increasing the scale of the SORC decreases the LCE. Finally, the results suggest that a superheated fluid reduces the efficiency and the LCE and can deliver more heat to the bio-digester. It is advisable the utilisation of a scroll expander and a counter-flow plate exchanger with a Direct Vapour Generation configuration. The model is a flexible tool capable of integrating more equations and components, with the evaluation of different fitness functions.

Highlights

The high consumption of resources such as coal, oil, natural gas and other fossil fuels coincides with the increase of environmental problems, especially the global warming, water contamination and solid waste [1]
The present study describes the development of an optimisation model of a small-scale Solar Organic Rankine Cycle focused on rural areas, coupled with a bio-digester
The final aim is to continue the improvement of the model, to build a real project in Betulia, a village located in Colombia

Summary

Introduction

The high consumption of resources such as coal, oil, natural gas and other fossil fuels coincides with the increase of environmental problems, especially the global warming, water contamination and solid waste [1]. Several renewable technologies have been improving during the last decade to relieve this harm to the environment. Some of them can be expensive for small scale and remote areas, where exist a lack of energy that requires attention, using simple but efficient technology. In Colombia, according to reports from the Mining and Energy Planning Unit (UPME), around 66% of the national territory does not have public electricity service through the National Interconnected System (SIN). This is mainly due to the fact that in remote locations with difficult access it is costly and not feasible to carry out civil interconnection works.

Objectives

Methods

Results

Conclusion