Using thermal and stored heat energy to drive a Stirling engine for power generation

Abstract

South Africa’s national power grid is currently in dire straits. The lack of a dependable power supplier and rising electricity costs force the public and businesses to look for alternatives to meet their energy needs. These alternatives are costly to implement and beyond the financial reach of most South Africans. Currently, the most common alternative energy source is solar PV systems with large battery banks to survive the long, regular load-shedding schedules implemented by Eskom.

This research aim is to design and simulate a combined solar-thermal and sensible heat energy powered by a Stirling engine. The research philosophy is applied research, and the empirical study is experimental. The output of the research prototype will be compared to a standard photovoltaic installation of similar power output. The data collection methodology is quantitative in nature. The results for this paper will be generated from the simulation software package MATLAB. Such a system must have a lower capital cost to compete with solar PV systems with battery backup.

The simulation results proved that the proposed system could be built from the ground up at a lower capital cost than commercially available solar PV systems. The Stirling system was compared to a two solar PV system with a deep-cycle gel battery backup and PV solar with a lithium iron phosphate battery backup. The Stirling system was roughly 6 per cent cheaper than the deep-cycle gel system and about 11 per cent cheaper than the PV system using lithium iron phosphate.

Future research could be done to prove the simulation by building a working prototype based on this paper. If the prototype proves the simulation results, it can be refined and investigated for possible mass production, further reducing per unit.