JESA Volume 12 (abstracts only)
JESA Volume 12 (abstracts only)
Vol.12 No. 1: February 2001
• The development of a prototype external heat engine based on the Ericsson Cycle J Hussey
The continued trend for conventional engine designs to become increasingly high-tech has exposed the lack of infrastructure and service support in third-world countries. This created an opportunity to re-visit 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 1800’s is an attractive option as it has a number of advantages over the modern internal combustion engine. The project looked at old and new engines in an attempt to capture the best of both. In a hot air engine, heat is applied externally in order to raise the temperature of a working medium to provide the required degree of volumetric expansion to produce motive force . The Ericsson engine makes use of an open cycle, in which a fresh intake of working medium is induced each cycle.
• Electromechanical storage for rural electrification D.Johnson, M. Malengret and P. Pillay
The aim of this paper is to outline the design essentials, in order to establish a kinetic energy storage device, as a competitive alternative to chemical batteries commonly used in rural electrification. Solar electrification in rural Southern Africa consists mostly of a solar PV panel, combined with the use of lead acid batteries. Lead acid batteries have poor efficiencies, commonly 60 percent and less, and are very sensitive to high and deep discharging. In general, chemical batteries are made up of highly toxic and reactive chemicals. Electromechanical storage, on the other hand, has extremely high efficiencies and are chemically inert. There are some safety concerns to contain and dispose of the kinetic energy in the case of flywheel failure. Kinetic batteries have been constructed with efficiencies of 99 percent and better. The materials used are mostly composites and / or high strength metal alloys, suspended on high speed magnetic bearings, in a vacuum enclosure. These properties of kinetic storage devices sufficiently address the problems experienced by chemical batteries, but at much higher initial capital outlay.
• The potential of LP gas for household energy in South Africa PJD Lloyd and H Rukarto
The provision of household energy to households at the lower end of the economic spectrum presents grave difficulties. The primary problems arise in cooking and space heating, where a source of several kilowatts of energy is needed for periods measured in hours. Affordable energy requires a low-cost fuel and, generally, a low-cost appliance. Electricity is not available to a large number of households, and even where it is available, those households in the lowest quartile of income cannot afford it for cooking and space heating. Instead they are forced to use a range of fuels. Within about 150 km of coal mines, coal is the primary choice. Outside of those regions, paraffin use predominates. Both of these fuels create serious secondary problems. Particulates reach levels unheard of in developed society, resulting in chronic respiratory infections and early deaths. Carbon monoxide concentrations are often fatal, and usually at levels which will cause heart disease. With paraffin, there are additional problems caused by poisoning and fire. The constitutional provision, which gives every citizen a right to an environment which is not harmful to his or her health, is clearly not being met. Against this background, the role of liquefied petroleum gas [LPG] is explored. While its use presents hazards, there is clear evidence that the health, environmental and safety risks are at least an order of magnitude less than those presented by the two other fuels. It is primarily cost which prevents it being more widely employed. The costs of the fuel and the costs of appliances need to be addressed. It is suggested that a reduction in the fiscal burden and a reformulation to move from the present propane/butane mix to pure butane could go a long way to reducing the cost of the fuel at the street level, while a clear directive from government that increasing LPG use was desirable could stimulate the adoption of mass production technologies that would reduce the cost of appliances.
Vol.12 No. 2: May 2001
• A synthesis of the National Energy Sector Research and Technology Foresight Project as conducted by the Department of Arts, Culture, Science and Technology J. A. Basson and J. Strydom
A foresight study was conducted for the energy sector in 1998 and 1999 as part of a national project for the Department of Arts, Culture, Science and Technology (DACST). Most of the work was done by the Energy Sector Working Group of 29 nominated experts that met in eight workshops during the course of the study. Their mission was to identify strategic research and technology (R & T) topics and strategies for the energy sector in South Africa that would realize sustainable economic and social benefits for the country over the next 15 to 20 years. Priority R & T challenges for implementation in the medium term, listed in priority order, are uses of coal discards, low-cost solar water heating systems, low-cost photovoltaic solar home systems, low-cost paraffin appliances, knowledge-based energy information and energy simulation and modelling systems, low-cost electricity distribution, reticulation and metering technologies, economic insulation for low-cost housing, innovative energy applications for gas, small-scale energy storage for stand-alone applications and energy-efficient buildings. Those for implementation in the medium to long term are end-use technologies to improve industrial competitiveness; biotechnology for energy, bulk solar thermal, high-efficiency power generation, alternate energy delivery for rural small and medium enterprises (SMMEs), low-cost hydrogen production, large-scale electricity storage and high-efficiency electrical transmission. The Foresight project implemented the clause of the White Paper on Energy Policy of developing national research and development priorities. It was also clear that national energy policy and R&T strategies are directly linked and it is recommended that the Department of Minerals and Energy have to carry out a number of actions in terms of this study.
• Criteria for renewable energy strategies in developing countries D. Holm
This paper suggests prioritised principles for a robust and flexible strategy for a rapid and sustained market transformation. The focus is on development, rather than only the use of specific technologies. It is argued that a strategy should include intermediate steps of business plans with quantified achievable targets, responsibilities, authorities and resources. A long-term government commitment enables industry and academia to invest with confidence. Learning from international best practice and the International Solar Energy Society (ISES) and the Solar Energy Society of Southern Africa (SESSA), obviates reinventing the wheel.
• Development and application of a 24-hour temperature approximation model for South Africa L.J Grobler and W.l.R den Heijer
During energy studies of buildings, data on temperature is required to determine the effect of the outside air temperature on a building’s monthly energy consumption as well as the maximum demand and energy accounts. Historical temperature data is available for a number of towns and cities in South Africa, although not for all of them. Limited typical temperature data was, however, available for almost all locations in South Africa. However, the detail level of the data was so limited, that it was of little use during energy studies of buildings. A model was subsequently developed to “expand” any two known daily temperatures into a complete typical day profile for each month. If these typical days are repeated for the number of days in each month, a year’s hourly data could be created. The model is extremely effective in the sense that it remains unchanged, regardless of the location in South Africa where it is being applied. With the help of the model and the above-mentioned rationale, only 24 known temperature values were used to generate 8760 temperatures for the year, a temperature value for each hour of every day. The degree-days were calculated from the limited summary data and the model as well as the original data from the Council for Scientific and Industrial Research (CSIR) used to develop the model. The calculated degree-days indicated that in those cases where detailed temperature data was not available, the model could be used with confidence to approximate detailed data. The model was also used to generate hourly temperature data for a year, which was used in weather files for different locations. Weather files were created for the same locations by using detailed temperature data from the South African Weather Bureau. These weather files were used in building energy simulations where all other variables, parameters and influences remained unchanged except the temperature data for each location. The results found only small differences in the monthly and annual energy consumption, accounts and monthly maximum demand resulting from the simulations. The applications proved that the model could be used with confidence to generate temperature data for use in energy studies of buildings and the calculation of degree-days.
• The potential needs and barriers to emission trading, joint implementation and the clean development mechanism in South Africa L. J. Grobler and W.l.R. den Heijer
Climate change is fast becoming one of the most topical issues around the world with more countries becoming involved and realizing the potential hazard. The problems of global warming and greenhouse gas emissions have resulted in international efforts to reduce these harmful emissions through the collective effort of the Kyoto Protocol. The Protocol has included a number of flexibility mechanisms to facilitate flexibility, cost-effectiveness and participation in emission reduction efforts. These mechanisms are emission trading, joint implementation, the clean development mechanisms and the use of carbon sinks. These mechanisms enable cooperation between developed countries that have ratified the Protocol, as well as developing countries that have not ratified the Protocol. South Africa has not ratified the Kyoto Protocol, but is currently in the process. This will however still take some time. It is for this reason that the clean development mechanism holds the most promise for South Africa to participate in international greenhouse gas emission reduction projects, together with developed countries. The question is however: What does South Africa need to participate? South Africa is vulnerable to climate change. It is also economically vulnerable to the Kyoto Protocol’s scenario of emission reductions. South Africa has a carbon and energy intensive economy and is one of the top twenty greenhouse gas emitters in the world, and the largest one on the African continent. The potential for emission reductions and energy efficiency is however significant. The South African situation is briefly stated in this paper. The potential markets for emission reduction and energy improvement projects are estimated. The sectors on which the focus for such projects must be placed are identified based on their energy use and greenhouse gas emissions. The needs and barriers for South African participation in global efforts are then stated.
Vol.12 No. 3: August 2001
• Scope of carbon dioxide as a natural refrigerant for replacements of CFCs G. N. Halder and S. C. Sarkar
Most of the conventional refrigeration systems use chlorofluorocarbons (CFCs). The ozone layer in the stratosphere, which protects life on earth from the sun’s harmful ultraviolet radiation, is getting depleted due to the use of CFCs and other harmful substances. The problem threatens not only human beings, but also the plants and animal kingdom on the earth surface. In view of this alarming problem, replacements of CFCs by eco-friendly refrigerants becomes an urgent necessity. Carbon dioxide, the old refrigerant in its new form, appears to be a viable alternative refrigerant for the future in the context of CFC phase out and waste gas utilization. This paper is a state of the art report concerning the various possible alternative refrigeration cycles based on carbon dioxide as a natural refrigerant and the current understanding of the role of this refrigerant in environmental protection.
• Removal of carbon dioxide from biogas for methane generation S. Jana, N. R. Chakrabarty and S. C. Sarkar
Biogas generally contains about 60-65% methane, 35% carbon dioxide and a small amount of other impurities. The presence of carbon dioxide does not contribute any fuel value for the gas but lowers its total calorific value. Removal of carbon dioxide from the gas mixture not only helps reduce the greenhouse gas but also enriches the fuel value of biogas to a great extent. Removal of carbon dioxide from biogas can be achieved in several ways such as chemical separation, membrane separation, cryogenic separation as well as adsorption separation, the latter playing a vital role if suitable adsorbent material and adsorption-desorption devices are available. This paper makes an experimental study on the feasibility of enrichment of methane in biogas using indigenously developed coconut shell based active carbon on a gas adsorption system, specially designed for the purpose. It is shown that it is feasible to increase the calorific value of biogas following the method and the adsorbent.
• Improving modern energy access to the urban poor in Tanzania Maneno J.J. Katyega
Tanzania has over the last four decades experienced high urbanisation trends. The urban sector energy usage has been increasing with the urban population. The majority of the urban poor households depend on traditional energy sources. Their access to modern energy sources is low. This paper attempts to investigate the urban poor energy consumption patterns in relation to their incomes, their affordability of traditional and modern energy sources, and hence, policy options on how to improve their access to modern energy services. The study is undertaken as part of the African Energy Policy Research Network funded regional study, which includes Zimbabwe, Ethiopia and Uganda. The major findings in the article indicate that poverty is a major barrier for the urban poor to access modern energy services. Moreover, the article suggests some policy interventions on how to address this precarious situation.
• Transfer pricing: A capital investment approach I.J. Lambrechts
This paper examines the determination of transfer/ regulated prices in industry. Although generally applicable to industry, it is of interest particularly to the energy industry in South Africa at the present time. Fresh attention was focused on transfer pricing aspects due to the trends of unbundling, globalisation and ringfencing. In the electricity industry, unbundling of the main divisions, i.e. generation, transmission and distribution, is to occur in the near future. Transfer pricing therefore is a vital component of pricing and regulation at this stage. The same applies to the liquid fuels industry. In this paper a scientific approach, based on capital investment theory, is developed to calculate transfer prices. The sensitivity of the determining factors is also tested. The results of this approach, which involves the calculation of internal rates of return (IRR), are compared with those of the more widely used approach of accounting return on investment (ROI). Emphasis is also placed on the calculation of real rates (no inflation). The capital investment approach is superior to the calculation of transfer prices based on ROI, as the latter can result in major mistakes. The differences between these approaches are also illustrated. One of the most sensitive factors in respect of ROI and the difference between ROI and IRR is the ratio of plant and equipment to total assets. This finding highlights the need for each enterprise to focus on its unique characteristics in calculating transfer prices.
Vol.12 No. 4: November 2001
• A methodology and procedure for the thermal characterisation of buildings C.A. van der Merwe and L.J. Grobler
During the simulation of a building, much time and effort is used to obtain information on the building and its systems. Then additional time and effort is used to “fit” the simulation to the real-life scenario. Only when the simulation achieves a certain accuracy relative to real-life, can a base-year be created and the real simulation be started. The Characterisation Model aims to reduce the time and effort spent to “fit” a simulation to the real life scenario. The Characterisation Model uses measured inside and outside temperature to obtain the effective thermal characteristics of the structure. This methodology in itself also possesses the ability to increase the accuracy of a simulation. Obviously the characterisation is structure or building specific and can therefore not be used on other buildings. This paper discusses the concept, development and the contributions of the Characterisation Model. Then two structures are used to demonstrate the use and accuracy of the Characterisation Model.
• Energy efficiency in south african housing – Community perceptions of the success of the IIEC’s Eco-Home Advisors programme M. Wentzel E. de Lange and T. Nkambule
Energy efficient housing design is of critical importance in South Africa where a large numbers of houses are being built to address the housing backlog. Energy efficient housing design can contribute to improved indoor comfort levels, energy savings as a result of reduced energy input requirements, monetary savings, improved health and safety due to a reduction in indoor air pollution, environmental benefits as well as improved waste and water consumption. The International Institute for Energy Conservation (IIEC's) Eco Home Advisors (EHA) programme is aimed at improving the quality of low cost housing delivered in South Africa by promoting energy efficient housing design. This paper focuses on the effectiveness and impact of the approach to use energy advisors to disseminate information regarding energy efficient housing and other sustainable environment options, to potential as well as existing homeowners. From the evaluation results, it was concluded that the programme was viewed a general success by all role-players. A high level of community perception of programme success indicated community acceptance and exposure. The increased capacity of the EHA’s and participating organisations will hopefully be harnessed to continue this most important service.
• Evaluation of the South African energy and demand efficiency standard through a case study L.J. Grobler and C.A. van der Merwe
The South African Energy and Demand Efficiency Standard (SAEDES) is an energy-efficiency guideline developed by the Department of Minerals and Energy. This guideline aims to reduce the energy consumption and/or demand of commercial buildings. A pilot project is currently underway to evaluate its applicability and practicality in South Africa. Mutual Park is one of the demonstration buildings chosen to implement and evaluate SAEDES upon. The Initial SAEDES Prescriptive Evaluation produced a compliance of about 68%. This evaluation indicated several entities such as air-conditioning equipment and hot-water generators that did not comply with SAEDES Prescriptions. The Performance Evaluation showed that a possible saving of R819 171 (9.2% of annual energy bill) could be achieved by cost-effectively upgrading most non-compliant entities to comply with SAEDES. When the cost-effective entities are upgraded, Mutual Park will achieve 100% SAEDES compliance. A small number of prescriptions did show that SAEDES has its weak-points that need some attention. This includes prescriptions such as the specified minimum infiltration rate; information that is not available in South Africa yet and that are very difficult to determine. Issues like these will be addressed in future during the final evaluation of SAEDES. Overall, the evaluation of Mutual Park indicated that SAEDES Prescriptions are practical and achievable even on existing buildings. However, better compliance results would have been obtained if SAEDES was used to evaluate the design of the buildings, therefore eliminating costly
• Multi-project baselines for potential Clean Development Mechanism projects in the electricity sector in South Africa H. Winkler R. Spalding-Fecher J. Sathaye and L. Price
This article contributed to a larger research effort co-ordinated by the Lawrence Berkeley National Laboratory (LBNL). Similar studies were also being conducted in Brazil, India and China. LBNL supported the presentation of the results of this research at the Sixth Conference of the Parties (COP-6) to the UN Framework Convention on Climate Change, held in The Hague, Netherlands from 13 – 25 November 2000.