Masters Degrees (Centre for Renewable and Sustainable Energy Studies)

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This collection contains dissertations sponsored by the Centre for Renewable and Sustainable Energy Studies.

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Browsing Masters Degrees (Centre for Renewable and Sustainable Energy Studies) by browse.metadata.advisor "Harms, T. M."

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    Steam jet ejector cooling powered by low grade waste or solar heat
    (Stellenbosch : University of Stellenbosch, 2006-12) Meyer, Adriaan Jacobus; Harms, T. M.; Dobson, R. T.; University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    A small scale steam jet ejector experimental setup was designed and manufactured. This ejector setup is of an open loop configuration and the boiler can operate in the temperature range of Tb = 85 °C to 140 °C. The typical evaporator liquid temperatures range from Te = 5 °C t o 10 °C while the typical water cooled condenser presure ranges from Pc = 1 . 70 kPa t o 5. 63 kPa (Tc = 15 °C to 35 °C). The boiler is powered by by two 4kW electric elements, while a 3kW electric element simulates the cooling load in the evaporator. The electric elements are controlled by means of variacs. The function ...
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    Technical and economic evaluation of the utilisation of solar energy at South Africa's Sanae IV Base in Antarctica
    (Stellenbosch : University of Stellenbosch, 2005-12) Olivier, Jurgen Richter; Harms, T. M.; University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    There are numerous challenges that have to be overcome in order to generate the electrical and thermal energy required to power Antarctic research stations in a technically, economically and environmentally suitable manner. Consequently the costs associated with generating energy at these latitudes are high, and ways are constantly being sought to improve energy generation methods and protect the pristine environment. These endeavours are strongly encouraged by the Antarctic Treaty. This thesis aims to investigate the technical and economic feasibility of using solar energy at South Africa’s SANAE IV (South African National Antarctic Expedition IV) station in Antarctica. The idea of using solar energy in Antarctica is not novel, and as is shown a number of stations have already capitalised on opportunities to generate savings in this manner. Similarly, at SANAE IV, there exists the opportunity to alleviate an increased summer energy load on the station and reduce diesel consumption through the proper implementation of such a system. There is also ample scope to use wind energy, which would have a marked positive impact on the base’s operation. The data used in this thesis was obtained mainly during the 2004/2005 takeover expedition to South Africa’s SANAE IV station in Antarctica. Included are measurements of total and diffuse radiation that were measured during the months of January and February 2005, and which form an important part of the investigation. Since there are currently no radiation sensors, or any historical record of measured radiation at the station, the only measured data available from SANAE IV was the data recorded during the 2004/2005 takeover expedition. By further collecting archived values of fuel consumption, electricity generation and load profiles, an energy audit of the station was also completed during the 2004/2005 takeover expedition. The expected savings that could be generated by solar systems were calculated by considering the use of both photovoltaic and solar thermal devices at the South African station. The 40 kW photovoltaic system that was investigated was able to significantly reduce the load on the dieselelectric generators, however it was only possible to fully recover the initial costs sunk into commissioning the system after 21 years. The installation of such a system would equate to a Net Present Value of 302 915 Rand at the end of the 25 year system lifetime (assuming a real hurdle rate of 8 % and fuel price escalation rate of 5 %), saving 9 958 litres of diesel annually generating energy at a cost of 3.20 Rand/kWh. It should be noted, however, that under more ideal conditions (i.e. less attractive alternative investment opportunities, higher fuel price escalation rates and a stronger emphasis on environmental concerns) investment into a photovoltaic system could potentially breakeven after approximately 10-15 years, while simultaneously significantly improving base operation. Furthermore, it was found that a flat-plate solar thermal collector utilised with the snow smelter at SANAE IV is better suited to generating savings than photovoltaic devices. The average cost of generating electricity after commissioning such a system with a 143 m2 collector field would be approximately 3.13 Rand/kWh, as opposed to the 3.21 Rand/kWh of the current diesel-only system, and would realise an annual fuel saving of approximately 12 245 litres. The system would arrive at a breakeven point after approximately 6 years, and represent a Net Present Value of 2 148 811 Rand after 25 years. By further considering environmental factors such as the cost of removing soiled snow from Antarctica and diesel fuel emissions the magnitude of the net present savings would increase by approximately 500 000 Rand over the expected 25 year project lifetime. The opportunity to install a solar energy system at SANAE IV therefore warrants action. There is potential not only to generate savings over the operational lifetime but also to preserve the environment in accordance with the desires of the Antarctic Treaty. It is firmly believed that with careful planning and implementation such a project can and should be successfully undertaken.