Investigating long-term sustainability of financing photovoltaic systems, small scale inverters for the local communities in Soweto, South Africa
- Authors: Mnyani, Siphamandla
- Date: 2024-04
- Subjects: Photovoltaic power systems , Solar energy , Sustainable development -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65197 , vital:74045
- Description: The study explores the energy supply challenges faced by South Africa. The research was triggered by the decline of the social fabric and lack of economic development in communities such as Soweto due to energy crisis in South Africa. It also analyses the impact that the energy supply challenges have on communities, as well as socio-economic development, employment opportunities and human development. Hence, it provides the nexus between the feasibility of funding photovoltaic (PV) installations, supply of clean reliable energy, socio-economic development, and environmental sustainability. An in-depth literature review was conducted to obtain insights into various funding mechanisms that were adopted in Asia and the Andean countries for the installation of renewable PV systems to provide electricity in marginalised communities, with the aim of achieving sustainable development. This study was conducted using quantitative research methods, which consisted of collecting data from Soweto residents and using probability sampling method, 92 of the respondents completed the survey. The data collected was analysed using data analysis techniques such as, Pearson correlation test, Chi2 and sample T-testing analysis which were conducted to help the researcher to create knowledge and better decision-making and allowed for multiple measurements to be analysed simultaneously. The results obtained from the Pearson correlation as well as Chi2 techniques, indicated a positive relationship between the value of funding PV solar systems and the installation of small-scale inverters in Soweto Township. The analysis performed shows that funding the installation of PV solar system will contribute towards affordable, sustainable energy as well as economic growth in Soweto. Strong emphasis should be put on the analysis of funding models that will contribute towards affordable, clean, sustainable energy in the Townships. This can be achieved through tax breaks or incentives that were implemented by the national treasury in February 2023 or, the establishment of green funds coupled with incentives from the United Nations (UN) (National treasury , 2023). This study was significant in South Africa, since there are no studies of similar nature that have been conducted before, that are related to funding models, renewable energies technologies, micro grids for the marginalised communities. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-04
- Authors: Mnyani, Siphamandla
- Date: 2024-04
- Subjects: Photovoltaic power systems , Solar energy , Sustainable development -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/65197 , vital:74045
- Description: The study explores the energy supply challenges faced by South Africa. The research was triggered by the decline of the social fabric and lack of economic development in communities such as Soweto due to energy crisis in South Africa. It also analyses the impact that the energy supply challenges have on communities, as well as socio-economic development, employment opportunities and human development. Hence, it provides the nexus between the feasibility of funding photovoltaic (PV) installations, supply of clean reliable energy, socio-economic development, and environmental sustainability. An in-depth literature review was conducted to obtain insights into various funding mechanisms that were adopted in Asia and the Andean countries for the installation of renewable PV systems to provide electricity in marginalised communities, with the aim of achieving sustainable development. This study was conducted using quantitative research methods, which consisted of collecting data from Soweto residents and using probability sampling method, 92 of the respondents completed the survey. The data collected was analysed using data analysis techniques such as, Pearson correlation test, Chi2 and sample T-testing analysis which were conducted to help the researcher to create knowledge and better decision-making and allowed for multiple measurements to be analysed simultaneously. The results obtained from the Pearson correlation as well as Chi2 techniques, indicated a positive relationship between the value of funding PV solar systems and the installation of small-scale inverters in Soweto Township. The analysis performed shows that funding the installation of PV solar system will contribute towards affordable, sustainable energy as well as economic growth in Soweto. Strong emphasis should be put on the analysis of funding models that will contribute towards affordable, clean, sustainable energy in the Townships. This can be achieved through tax breaks or incentives that were implemented by the national treasury in February 2023 or, the establishment of green funds coupled with incentives from the United Nations (UN) (National treasury , 2023). This study was significant in South Africa, since there are no studies of similar nature that have been conducted before, that are related to funding models, renewable energies technologies, micro grids for the marginalised communities. , Thesis (MBA) -- Faculty of Business and Economic Sciences, Business School, 2024
- Full Text:
- Date Issued: 2024-04
Comparative performance of 3-kWp ranges Solar Photovoltaic Systems under varying meteorological conditions in Alice, Eastern Cape Province, South Africa
- Apeh, Oliver Okechukwu https://orcid.org/0000-0003-4076-0613
- Authors: Apeh, Oliver Okechukwu https://orcid.org/0000-0003-4076-0613
- Date: 2021-08
- Subjects: Photovoltaic power systems , Solar energy
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21567 , vital:48888
- Description: PVsystem has recently emerged in South Africa as a way to curb the country’s persistent shortage of electricity. A wide effort for the past few decades have targeted at study, testing and demonstration of PV power systems which was established all over the country as an appropriate measure to tackle transportation, agriculture, industry, commercial as well as domestic activities. In view of these drives, both off-grid and grid-connected PV systems are being applied. However, operating a building with an off-grid system is one of the means to providing the possibility of energy access to places far away from the national grid. As an off-grid choice, 50 W SHS is being distributed to customers in distant rustic parts of the country where grid option is difficult to access. But the SHS of the stated capacity can barely generate 0.3 to 0.4 kWh of electric energy per day, even at the optimal solar radiations. In view of this, more efforts are directed at expanding the off-grid systems to accommodate large rural households in South Africa. This thesis is dedicated to a study on the various configurations and components of PV power plant as a way to enhance electricity generations in South Africa. To this effect, different power plants were considered at SolarWatt park, University of Fort Hare with the aim to conduct a comparative analysis of the charge controllers with respect to the charge and discharge rates of their respective batteries. The grid-connected PV power generation was classified into hybrid PV and grid-assisted PV, while off-grid is a BIPV. These power plants generations were installed for the purpose of research level with a total capacity of 11.4 kW. The off-grid system is made up of HIT modules, FlexMax80 charge controller, Victron energy inverter and M-Molar battery bank. The hybrid and grid-assisted systems each consist of 15 polycrystalline modules and Microcare charge controllers. In addition, hybrid comprises SMA Sunny Island inverter and Trojan battery bank whereas grid-assisted consist of Microcare inverter and Hoppercke battery bank. The first part of the experimental work was monitored, and the meteorological parameters which are ambient temperature, solar radiation, relative humidity and wind speed, were measured and evaluated while electrical parameters includes PV current and voltage, MPPT current and voltage, battery current and voltage and inverter current and voltage were also measured and evaluated in the second part of the experiment. This lasted for a period of four years, starting from 1st January 2017 to 31st December 2020. Similarly, the second aspect was to monitor the electrical performance of the three systems and was performed for a period of six months, starting from January to June 2019. During the second experiment, hybrid and grid-assisted systems were reconfigured to function as off-grid systems. Moreover, a detailed data acquisition system designed to measure and record both meteorological and electrical parameters affecting the performance of the systems. The electrical parameters include PV current and voltage, MPPT current, battery current and voltage and inverter current and voltage. Other parameters in the measurements are; inverter efficiency, active and apparent power, while meteorological parameters include; solar irradiance, ambient temperature, relative humidity, wind speed and direction. The meteorological results show that the maximum and minimum mean amount of global solar radiation was 7.34 kWh/m2/day in December and 3.03 kWh/m2/day in June, respectively, while the average radiation and temperature for the typical year were 4.98 kWh/m2/day and 16.88 oC respectively. The solar radiations obtained are within the range in major places in South Africa. Similarly, an average wind speed of 2.5 m/s is experienced in Alice in a year and average solar radiation of 606.06 W/m2 in summer and 346.17 W/m2 in winter. The three lead-acid battery systems monitored under the electrical aspect are M-Molar, Trojan and Hoppecke battery systems. It was established that the charging current decreases gradually from 27.7 to 18.5 A for the M-Molar while Hoppecke and Trojan deceased respectively from 15 to 10 A and 23 to 13 A at the end of each phase by charging it at the maximum power point of the PV array. It was equally found that the M-Molar battery current has the highest rate of charging and quickest rate of discharging in comparison to the other two batteries. Finally, from the results gotten from this research, we may propose that the solar PV system contributes significantly to the satisfaction of the needed electricity in South Africa. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-08
- Authors: Apeh, Oliver Okechukwu https://orcid.org/0000-0003-4076-0613
- Date: 2021-08
- Subjects: Photovoltaic power systems , Solar energy
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21567 , vital:48888
- Description: PVsystem has recently emerged in South Africa as a way to curb the country’s persistent shortage of electricity. A wide effort for the past few decades have targeted at study, testing and demonstration of PV power systems which was established all over the country as an appropriate measure to tackle transportation, agriculture, industry, commercial as well as domestic activities. In view of these drives, both off-grid and grid-connected PV systems are being applied. However, operating a building with an off-grid system is one of the means to providing the possibility of energy access to places far away from the national grid. As an off-grid choice, 50 W SHS is being distributed to customers in distant rustic parts of the country where grid option is difficult to access. But the SHS of the stated capacity can barely generate 0.3 to 0.4 kWh of electric energy per day, even at the optimal solar radiations. In view of this, more efforts are directed at expanding the off-grid systems to accommodate large rural households in South Africa. This thesis is dedicated to a study on the various configurations and components of PV power plant as a way to enhance electricity generations in South Africa. To this effect, different power plants were considered at SolarWatt park, University of Fort Hare with the aim to conduct a comparative analysis of the charge controllers with respect to the charge and discharge rates of their respective batteries. The grid-connected PV power generation was classified into hybrid PV and grid-assisted PV, while off-grid is a BIPV. These power plants generations were installed for the purpose of research level with a total capacity of 11.4 kW. The off-grid system is made up of HIT modules, FlexMax80 charge controller, Victron energy inverter and M-Molar battery bank. The hybrid and grid-assisted systems each consist of 15 polycrystalline modules and Microcare charge controllers. In addition, hybrid comprises SMA Sunny Island inverter and Trojan battery bank whereas grid-assisted consist of Microcare inverter and Hoppercke battery bank. The first part of the experimental work was monitored, and the meteorological parameters which are ambient temperature, solar radiation, relative humidity and wind speed, were measured and evaluated while electrical parameters includes PV current and voltage, MPPT current and voltage, battery current and voltage and inverter current and voltage were also measured and evaluated in the second part of the experiment. This lasted for a period of four years, starting from 1st January 2017 to 31st December 2020. Similarly, the second aspect was to monitor the electrical performance of the three systems and was performed for a period of six months, starting from January to June 2019. During the second experiment, hybrid and grid-assisted systems were reconfigured to function as off-grid systems. Moreover, a detailed data acquisition system designed to measure and record both meteorological and electrical parameters affecting the performance of the systems. The electrical parameters include PV current and voltage, MPPT current, battery current and voltage and inverter current and voltage. Other parameters in the measurements are; inverter efficiency, active and apparent power, while meteorological parameters include; solar irradiance, ambient temperature, relative humidity, wind speed and direction. The meteorological results show that the maximum and minimum mean amount of global solar radiation was 7.34 kWh/m2/day in December and 3.03 kWh/m2/day in June, respectively, while the average radiation and temperature for the typical year were 4.98 kWh/m2/day and 16.88 oC respectively. The solar radiations obtained are within the range in major places in South Africa. Similarly, an average wind speed of 2.5 m/s is experienced in Alice in a year and average solar radiation of 606.06 W/m2 in summer and 346.17 W/m2 in winter. The three lead-acid battery systems monitored under the electrical aspect are M-Molar, Trojan and Hoppecke battery systems. It was established that the charging current decreases gradually from 27.7 to 18.5 A for the M-Molar while Hoppecke and Trojan deceased respectively from 15 to 10 A and 23 to 13 A at the end of each phase by charging it at the maximum power point of the PV array. It was equally found that the M-Molar battery current has the highest rate of charging and quickest rate of discharging in comparison to the other two batteries. Finally, from the results gotten from this research, we may propose that the solar PV system contributes significantly to the satisfaction of the needed electricity in South Africa. , Thesis (PhD) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-08
Design and Characterization of a 5 kw Xe-Lamp Solar Simulator
- Authors: Nwodo, Julian Chizoba
- Date: 2019
- Subjects: Solar energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14671 , vital:40042
- Description: The design and characterisation of a 5kW Xenon lamp solar simulator is presented. This was accomplished through considering the design features of an ellipsoidal reflector, Xe lamp characteristics and casing, and power supply; assembly of an ellipsoidal, Xe-lamp simulator; design and building of an automated control system capable of remotely controlling the operating mode of the simulator; establishing the 3 scenarios that must be met to conform to a AAA class simulator; characterization of the simulator in terms of temporal stability, irradiance uniformity and spectral match; and application of the simulator and comparing it with STC rated values. The considerations for the type of material used for housing the components of the solar simulator were made. A 5kW DC power supply and igniter for the Xe-lamp was carefully selected since they provide necessary power for running the simulator. The simulator has the ability to be used in either horizontal or vertical position by adjusting the reflector. An automated control system capable of remotely controlling the operating mode of the simulator was built for this study, this system enables the simulator to be operated in either auto or manual modes. It also incorporates an irradiance, temperature, current and voltage feedback. The characterisation of the solar simulator was over a 2.1 m X 1.6 m test plane. The area under which the characterisation was carried out within the test plane is 110 cm x 129.5 cm. At the end of the steady state large area solar simulator characterisation, a class A spectral match, class A spatial uniformity, and a class B temporal instability was obtained
- Full Text:
- Date Issued: 2019
- Authors: Nwodo, Julian Chizoba
- Date: 2019
- Subjects: Solar energy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/14671 , vital:40042
- Description: The design and characterisation of a 5kW Xenon lamp solar simulator is presented. This was accomplished through considering the design features of an ellipsoidal reflector, Xe lamp characteristics and casing, and power supply; assembly of an ellipsoidal, Xe-lamp simulator; design and building of an automated control system capable of remotely controlling the operating mode of the simulator; establishing the 3 scenarios that must be met to conform to a AAA class simulator; characterization of the simulator in terms of temporal stability, irradiance uniformity and spectral match; and application of the simulator and comparing it with STC rated values. The considerations for the type of material used for housing the components of the solar simulator were made. A 5kW DC power supply and igniter for the Xe-lamp was carefully selected since they provide necessary power for running the simulator. The simulator has the ability to be used in either horizontal or vertical position by adjusting the reflector. An automated control system capable of remotely controlling the operating mode of the simulator was built for this study, this system enables the simulator to be operated in either auto or manual modes. It also incorporates an irradiance, temperature, current and voltage feedback. The characterisation of the solar simulator was over a 2.1 m X 1.6 m test plane. The area under which the characterisation was carried out within the test plane is 110 cm x 129.5 cm. At the end of the steady state large area solar simulator characterisation, a class A spectral match, class A spatial uniformity, and a class B temporal instability was obtained
- Full Text:
- Date Issued: 2019
Potable water production from atmospheric vapour using an ejector evacuated solar powered refrigeration system
- Authors: Cawood, John Henry
- Date: 2018
- Subjects: Solar energy , Solar radiation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/23481 , vital:30567
- Description: This research project explores the possibility of using solar radiation energy to produce safe liquid water through the condensation of atmospheric water vapour for human consumption, livestock watering and also for small scale high value crop irrigation. The research activities are comprised of a literature study, comparison of similar devices in use, a design and prototyping exercise, a measure of development work to enhance the performance of the prototype and testing in Al-Batinah province in the Sultanate of Oman, where the author is currently on a work assignment. This dissertation describes the research activities performed to answer the following question: ‘Is it possible to economically produce sufficient quantities of liquid water from atmospheric vapour using only heat energy from the sun?’ This question poses a further two questions which need to be answered in the literature study. These are: ‘What is an economical price for clean drinking water?’ and ‘What is a sufficient quantity of water?’ The purpose of producing liquid water from atmospheric water vapour is an attempt to develop the technology to harvest an alternative and almost inexhaustible water source. The reason for requiring a new source of water is due to the fact that the available fresh water resources of the world are diminishing due to pollution, extensive utilisation and salination. Several references indicate that the problem is compounding itself due the increasing demand on a diminishing resource, with deepening negative effects on agriculture1, health2, economy3, industry and lifestyle4. Many future scenarios depict clean water as a scarce and expensive commodity, unaffordable to many. The condensation of atmospheric vapour is not a new concept. The literature study explores historical attempts to achieve this, as well as detailing the shortcomings of contemporary vapour condensation units as the modern state of the art. This survey covers the spectrum from large versions deployed by military and remote area construction operations to produce water for all purposes, to small desktop electrical water producing machines. The focus of the research is on a more environmentally conscious process, attempting to use a simple ejector driven device with sunshine as the energy source and water as the refrigerant. A further environmental enhancement of the concept is that of designing the machine to last for an extremely long working life, thereby diluting the carbon footprint of manufacture over a great number of years. A portion of the research is devoted to the development of a basic model which takes into account the climatic and meteorological variables to accurately predict a water harvest. The development of the model is then used to optimise the process, narrow the variability of assumptions and assist with the design. The model also serves to predict the performance of the unit in other locations under different prevailing climatic conditions. A design specification and a prototype are produced and tested. Finally the design is scrutinised using value engineering principles to reduce cost, effort and environmental impact and also to reduce the overall cost to provide a more economically viable appliance. The prototype device used in this study will use a collector area of 1 square meter, roughly equivalent to 1000 Watts of solar power under ideal conditions.
- Full Text:
- Date Issued: 2018
- Authors: Cawood, John Henry
- Date: 2018
- Subjects: Solar energy , Solar radiation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/23481 , vital:30567
- Description: This research project explores the possibility of using solar radiation energy to produce safe liquid water through the condensation of atmospheric water vapour for human consumption, livestock watering and also for small scale high value crop irrigation. The research activities are comprised of a literature study, comparison of similar devices in use, a design and prototyping exercise, a measure of development work to enhance the performance of the prototype and testing in Al-Batinah province in the Sultanate of Oman, where the author is currently on a work assignment. This dissertation describes the research activities performed to answer the following question: ‘Is it possible to economically produce sufficient quantities of liquid water from atmospheric vapour using only heat energy from the sun?’ This question poses a further two questions which need to be answered in the literature study. These are: ‘What is an economical price for clean drinking water?’ and ‘What is a sufficient quantity of water?’ The purpose of producing liquid water from atmospheric water vapour is an attempt to develop the technology to harvest an alternative and almost inexhaustible water source. The reason for requiring a new source of water is due to the fact that the available fresh water resources of the world are diminishing due to pollution, extensive utilisation and salination. Several references indicate that the problem is compounding itself due the increasing demand on a diminishing resource, with deepening negative effects on agriculture1, health2, economy3, industry and lifestyle4. Many future scenarios depict clean water as a scarce and expensive commodity, unaffordable to many. The condensation of atmospheric vapour is not a new concept. The literature study explores historical attempts to achieve this, as well as detailing the shortcomings of contemporary vapour condensation units as the modern state of the art. This survey covers the spectrum from large versions deployed by military and remote area construction operations to produce water for all purposes, to small desktop electrical water producing machines. The focus of the research is on a more environmentally conscious process, attempting to use a simple ejector driven device with sunshine as the energy source and water as the refrigerant. A further environmental enhancement of the concept is that of designing the machine to last for an extremely long working life, thereby diluting the carbon footprint of manufacture over a great number of years. A portion of the research is devoted to the development of a basic model which takes into account the climatic and meteorological variables to accurately predict a water harvest. The development of the model is then used to optimise the process, narrow the variability of assumptions and assist with the design. The model also serves to predict the performance of the unit in other locations under different prevailing climatic conditions. A design specification and a prototype are produced and tested. Finally the design is scrutinised using value engineering principles to reduce cost, effort and environmental impact and also to reduce the overall cost to provide a more economically viable appliance. The prototype device used in this study will use a collector area of 1 square meter, roughly equivalent to 1000 Watts of solar power under ideal conditions.
- Full Text:
- Date Issued: 2018
Solar thermal performance of a conical helix receiver tube mounted on a parabolic dish
- Nandjembo, Frans Nelongo Pandeni
- Authors: Nandjembo, Frans Nelongo Pandeni
- Date: 2018
- Subjects: Solar energy , Power resources Energy conversion
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/32860 , vital:32379
- Description: This report presents the investigation of a conical helix receiver tube with a zero shading factor to achieve optimal performance of a small concentrating solar thermal collector. In order to understand the working performance of the conical helix receiver tube, it was compared to that of a flat spiral receiver tube. This was done by measuring temperatures at various points as well as the volume airflow rate. Optical studies were achieved using SolTrace to quantify spillage losses and optical efficiency of the dish used in the study from the parabolic dish using a simulation in SolTrace. Comparative tests were conducted between the conical receiver tube and equivalent flat receiver tube at volume air flow rates between 30 m3.h−1 and 45 m3.h−1. The conical helix receiver tube showed a linear temperature distribution, from the outer surface tube towards the inner surface tube in an ascending order, while the flat spiral receiver tube showed a non-linear temperature distribution, its temperature increased in the middle section and decreased towards the inner surface tube. The research showed that an optimally configured helical receiver tube with linear temperature change along its length outperformed the flat receiver tube.
- Full Text:
- Date Issued: 2018
- Authors: Nandjembo, Frans Nelongo Pandeni
- Date: 2018
- Subjects: Solar energy , Power resources Energy conversion
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/32860 , vital:32379
- Description: This report presents the investigation of a conical helix receiver tube with a zero shading factor to achieve optimal performance of a small concentrating solar thermal collector. In order to understand the working performance of the conical helix receiver tube, it was compared to that of a flat spiral receiver tube. This was done by measuring temperatures at various points as well as the volume airflow rate. Optical studies were achieved using SolTrace to quantify spillage losses and optical efficiency of the dish used in the study from the parabolic dish using a simulation in SolTrace. Comparative tests were conducted between the conical receiver tube and equivalent flat receiver tube at volume air flow rates between 30 m3.h−1 and 45 m3.h−1. The conical helix receiver tube showed a linear temperature distribution, from the outer surface tube towards the inner surface tube in an ascending order, while the flat spiral receiver tube showed a non-linear temperature distribution, its temperature increased in the middle section and decreased towards the inner surface tube. The research showed that an optimally configured helical receiver tube with linear temperature change along its length outperformed the flat receiver tube.
- Full Text:
- Date Issued: 2018
On the design, evaluation and performance of an energy efficient solar house with integrated photovoltaics
- Authors: Ziuku, Sosten
- Date: 2011-06
- Subjects: Solar energy , Solar energy -- Environmental aspects , Photovoltaic power generation
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27473 , vital:67331
- Description: The design, construction and performance monitoring of an energy efficient house with integrated photovoltaics is considered. Unlike conventional housing, the house design combines energy efficiency measures and renewable energy technologies into one building structure. The objective of the study was to investigate the feasibility of using energy efficient solar designs to regulate indoor thermal environment, and determine thecost effectiveness and environmental benefits of such housing designs. The use of ordinary photovoltaic panels as a building element for South Africa’s latitude and meteorological conditions was also investigated. The house model was designed using Autodesk Revit architecture and Ecotect building simulation software. Electrical performance was analyzed using RETScreen and PVDesignPRO software. In addition to passive solar design features and clerestory windows, the design has solar water heaters for hot water supply. The designed energy efficient building integrated photovoltaic (EEBIPV) house was built at the University of Fort Hare. A 3.8 kW BIPV generator was mounted on the north facing roof in such a way that the solar panels replace conventional roofing material. A data acquisition system that monitors thermal and electrical performance was installed. The grid independent house has been occupied since February 2009 and its winter indoor thermal efficiency improved from 70 to more than 78% after ceiling installation. Models for indoor thermal performance and BIPV energy and exergy contributions were developed. The avoided energy consumption from the grid has potential to reduce carbon emissions by 12.41 tons per annum. The total building cost per m2 of floor area compares favourably with the cost of commercial middle-to-upper income domestic housing units without energy efficiency measures and building integrated photovoltaics. The research output provides a good framework for the integration of passive solar designs, natural ventilation and lighting, solar water heaters and building integrated photovoltaics into new and existing housing units. , Thesis (MSci) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Date Issued: 2011-06
- Authors: Ziuku, Sosten
- Date: 2011-06
- Subjects: Solar energy , Solar energy -- Environmental aspects , Photovoltaic power generation
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/27473 , vital:67331
- Description: The design, construction and performance monitoring of an energy efficient house with integrated photovoltaics is considered. Unlike conventional housing, the house design combines energy efficiency measures and renewable energy technologies into one building structure. The objective of the study was to investigate the feasibility of using energy efficient solar designs to regulate indoor thermal environment, and determine thecost effectiveness and environmental benefits of such housing designs. The use of ordinary photovoltaic panels as a building element for South Africa’s latitude and meteorological conditions was also investigated. The house model was designed using Autodesk Revit architecture and Ecotect building simulation software. Electrical performance was analyzed using RETScreen and PVDesignPRO software. In addition to passive solar design features and clerestory windows, the design has solar water heaters for hot water supply. The designed energy efficient building integrated photovoltaic (EEBIPV) house was built at the University of Fort Hare. A 3.8 kW BIPV generator was mounted on the north facing roof in such a way that the solar panels replace conventional roofing material. A data acquisition system that monitors thermal and electrical performance was installed. The grid independent house has been occupied since February 2009 and its winter indoor thermal efficiency improved from 70 to more than 78% after ceiling installation. Models for indoor thermal performance and BIPV energy and exergy contributions were developed. The avoided energy consumption from the grid has potential to reduce carbon emissions by 12.41 tons per annum. The total building cost per m2 of floor area compares favourably with the cost of commercial middle-to-upper income domestic housing units without energy efficiency measures and building integrated photovoltaics. The research output provides a good framework for the integration of passive solar designs, natural ventilation and lighting, solar water heaters and building integrated photovoltaics into new and existing housing units. , Thesis (MSci) -- Faculty of Science and Agriculture, 2011
- Full Text:
- Date Issued: 2011-06
On the evaluation of spectral effects on photovoltaic modules performance parameters and hotspots in solar cells
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
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