The development of a prototype external heat engine based on the Ericsson cycle
| dc.contributor.advisor | Yates, Andrew | en_ZA |
| dc.contributor.author | Hussey, Joseph | en_ZA |
| dc.date.accessioned | 2014-09-25T08:49:36Z | |
| dc.date.available | 2014-09-25T08:49:36Z | |
| dc.date.issued | 2000 | en_ZA |
| dc.description | Includes bibliographical references. | en_ZA |
| dc.description.abstract | The aim of this thesis was to develop a prototype external heat engine based on the Ericsson cycle, as an alternative to the internal combustion engine, to be used as a small-scale power source for rural Africa. Subsequently test and evaluate its viability and potential to fulfil the requirements of such an application. Despite the wide range of possible prime movers, it appears there is still a need for a simple, low-tech, low-output power plant for developing countries. This created an opportunity to revisit the origins of basic engine design in order to seek an alternative solution to the modern internal combustion engine. The hot air or external heat engine developed in the l800's provides an attractive alternative as it has a number of advantages over the modem internal combustion engine. A hot air engine is a cyclical heat engine that uses an external heat source, heat exchangers, pistons and a gaseous working fluid contained within the engine to convert heat to mechanical work by volumetric expansion. The project looked at old and new engines in an attempt to capture the best of both. Two experimental engines were constructed during the course of this project, the first engine was built to provide insight into the functioning of an unconventional external heat engine and to test the validity of theoretical predictions made using a thermodynamic computer model. This engine was designed to function off a cycle consisting of a polytropic compression, a polytropic expansion with heat addition and a constant volume heat rejection process, achieved using a two-stroke principal to exchange the hot exhaust gas with cold recharge gas. Based on experience gained from this model, the second generation engine was designed to circumvent the problems experienced with the first engine. It functioned off a near Ericsson cycle, with the compression and expansion truncated for practical purposes and valve control being achieved with solenoid valves controlled by a computer. A thermodynamic computer model similar to the one used for the first engine was employed to optimise the design of this engine. Experimental investigations were carried out with the Ericsson engine to examine how closely the actual cycle resembled that predicted by the thermodynamic model and to determine engine performance. The power and mean effective pressure produced by the engine were determined and compared with friction data. Hence the potential of this engine to meet the criteria necessary to function as a small-scale rural power source was judged and resultant conclusions as to the engines feasibility were drawn. The actual pressure-volume diagrams obtained closely conformed to the theoretical expectations for the cycle and the truncated Ericsson cycle functioned sufficiently well. However, the friction in the system was too high a percentage of the total engine output and therefore the engine was unable to operate unaided. Although the hot air engine has the potential to provide cheap power efficiently, in practice these engines need to be highly pressurised and run at temperatures close to their material limit in order to obtain useful work from them. Therefore, although with the use of low friction seals and high pressurisation the engine could potentially produce the 5kW design target, due to the complexity these efforts would add to the engine it is recommended that other options be explored for rural power generation in Africa. | en_ZA |
| dc.identifier.apacitation | Hussey, J. (2000). <i>The development of a prototype external heat engine based on the Ericsson cycle</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering. Retrieved from http://hdl.handle.net/11427/7687 | en_ZA |
| dc.identifier.chicagocitation | Hussey, Joseph. <i>"The development of a prototype external heat engine based on the Ericsson cycle."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2000. http://hdl.handle.net/11427/7687 | en_ZA |
| dc.identifier.citation | Hussey, J. 2000. The development of a prototype external heat engine based on the Ericsson cycle. University of Cape Town. | en_ZA |
| dc.identifier.ris | TY - Thesis / Dissertation AU - Hussey, Joseph AB - The aim of this thesis was to develop a prototype external heat engine based on the Ericsson cycle, as an alternative to the internal combustion engine, to be used as a small-scale power source for rural Africa. Subsequently test and evaluate its viability and potential to fulfil the requirements of such an application. Despite the wide range of possible prime movers, it appears there is still a need for a simple, low-tech, low-output power plant for developing countries. This created an opportunity to revisit the origins of basic engine design in order to seek an alternative solution to the modern internal combustion engine. The hot air or external heat engine developed in the l800's provides an attractive alternative as it has a number of advantages over the modem internal combustion engine. A hot air engine is a cyclical heat engine that uses an external heat source, heat exchangers, pistons and a gaseous working fluid contained within the engine to convert heat to mechanical work by volumetric expansion. The project looked at old and new engines in an attempt to capture the best of both. Two experimental engines were constructed during the course of this project, the first engine was built to provide insight into the functioning of an unconventional external heat engine and to test the validity of theoretical predictions made using a thermodynamic computer model. This engine was designed to function off a cycle consisting of a polytropic compression, a polytropic expansion with heat addition and a constant volume heat rejection process, achieved using a two-stroke principal to exchange the hot exhaust gas with cold recharge gas. Based on experience gained from this model, the second generation engine was designed to circumvent the problems experienced with the first engine. It functioned off a near Ericsson cycle, with the compression and expansion truncated for practical purposes and valve control being achieved with solenoid valves controlled by a computer. A thermodynamic computer model similar to the one used for the first engine was employed to optimise the design of this engine. Experimental investigations were carried out with the Ericsson engine to examine how closely the actual cycle resembled that predicted by the thermodynamic model and to determine engine performance. The power and mean effective pressure produced by the engine were determined and compared with friction data. Hence the potential of this engine to meet the criteria necessary to function as a small-scale rural power source was judged and resultant conclusions as to the engines feasibility were drawn. The actual pressure-volume diagrams obtained closely conformed to the theoretical expectations for the cycle and the truncated Ericsson cycle functioned sufficiently well. However, the friction in the system was too high a percentage of the total engine output and therefore the engine was unable to operate unaided. Although the hot air engine has the potential to provide cheap power efficiently, in practice these engines need to be highly pressurised and run at temperatures close to their material limit in order to obtain useful work from them. Therefore, although with the use of low friction seals and high pressurisation the engine could potentially produce the 5kW design target, due to the complexity these efforts would add to the engine it is recommended that other options be explored for rural power generation in Africa. DA - 2000 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2000 T1 - The development of a prototype external heat engine based on the Ericsson cycle TI - The development of a prototype external heat engine based on the Ericsson cycle UR - http://hdl.handle.net/11427/7687 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/7687 | |
| dc.identifier.vancouvercitation | Hussey J. The development of a prototype external heat engine based on the Ericsson cycle. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Mechanical Engineering, 2000 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/7687 | en_ZA |
| dc.language.iso | eng | en_ZA |
| dc.publisher.department | Department of Mechanical Engineering | en_ZA |
| dc.publisher.faculty | Faculty of Engineering and the Built Environment | |
| dc.publisher.institution | University of Cape Town | |
| dc.subject.other | Mechanical Engineering | en_ZA |
| dc.title | The development of a prototype external heat engine based on the Ericsson cycle | en_ZA |
| dc.type | Master Thesis | |
| dc.type.qualificationlevel | Masters | |
| dc.type.qualificationname | MSc | en_ZA |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Thesis | en_ZA |
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