Power supply for pumping systems in northern Chile: Photovoltaics as alternative to grid extension and diesel engines

This paper examines and compares the cost-effectiveness to energize pumping systems in remote areas on northern Chile by means of photovoltaic systems, diesel engines and grid extension. Variables such as the distance to the power grid, the voltage grid, the prices of electricity and fuel, and the required investments, are taken into account. The comparison is made for wide range of variable values, distances and pumping requirements. The results obtained are useful for choosing the best alternative for the power supply of pumping systems in wells in Northern Chile.     

Application potential of vegetable oils as alternative to diesel fuels in compression ignition engines: A review

Vegetable oils have been identified as the promising alternative source to replace fossil based fuel in the compression ignition (CI) engine. It is renewable and possesses characteristics that is similar to that of the diesel. Biodiesel, transesterifiedform of vegetable oil (VO), is now being commercially used in CI engines. However, biodiesel production from VO involves use of alcohols and chemicals which results the need of skilled labor and investment for its production. In view of this, many studies are also being carried out on the direct use of VO in the engine. The direct use of VO oil in engine is as good as that of the diesel. The superior quality of diesel however makes it better performance in engine as compared to the vegetable oil. Preheating and blending of VO are found to be the most common solution to overcome its inferior properties. The use of preheated and blended VO is found to improve the engine overall performance. This paper is focused exclusively on the one-to-one basis of study pertaining to the effect of neat, preheated and blended vegetable oils on diesel engine performance and emission through supplementation of illustrative figures from the various experimental studies.     

Performance, emission and economic assessment of clove stem oil–diesel blended fuels as alternative fuels for diesel engines

In this study the performance, emission and economic evaluation of using the clove stem oil (CSO)–diesel blended fuels as alternative fuels for diesel engine have been carried out. Experiments were performed to evaluate the impact of the CSO–diesel blended fuels on the engine performance and emissions. The societal life cycle cost (LCC) was chosen as an important indicator for comparing alternative fuel operating modes. The LCC using the pure diesel fuel, 25% CSO and 50% CSO–diesel blended fuels in diesel engine are analysed. These costs include the vehicle first cost, fuel cost and exhaust emissions cost. A complete macroeconomic assessment of the effect of introducing the CSO–diesel blended fuels to the diesel engine is not included in the study. Engine tests show that performance parameters of the CSO–diesel blended fuels do not differ greatly from those of the pure diesel fuel. Slight power losses, combined with an increase in fuel consumption, were experienced with the CSO–diesel blended fuels. This is due to the low heating value of the CSO–diesel blended fuels. Emissions of CO and HC are low for the CSO–diesel blended fuels. NO_x emissions were increased remarkably when the engine was fuelled with the 50% CSO–diesel blended fuel operation mode. A remarkable reduction in the exhaust smoke emissions can be achieved when operating on the CSO–diesel blended fuels. Based on the LCC analysis, the CSO–diesel blended fuels would not be competitive with the pure diesel fuel, even though the environmental impact of emission is valued monetarily. This is due to the high price of the CSO.     

Potential of solar energy development for water pumping in Jordan

The potential of solar energy development for water pumping in Jordan was studied. For this purpose, 10 sites were selected based on the available solar radiation data. According to the annual amount of water output, the selected sites can be divided into three different categories: the first one, which includes Taffieleh, Queira, H-4, and H-5, is considered to be “adequate” for solar water pumping. Their annual amount of water output forms about 62% of all water pumped from all the 10 sites combined. Among the four sites included in this first category, Taffieleh has the highest potential. Not only can the most annual amount of water pumped be obtained from this location, but also the largest monthly amount of water—except for the month of March—during the year. Furthermore, about 51% of the annual amount of water pumped at Taffieleh is during the summer months (May–September), when the water consumption is the highest and water pumping is a necessity. The second category, which includes Ras Muneef, Mafraq, and Hasa, is considered to be “promising”. Its water output adds up to about 29% of all water pumped from all sites. The third category, including Deir Alla, Baqura, and Wadi Yabis, is considered to be “poor”. Only about 9% of the water pumped from all sites combined can be obtained from these three locations.     

Potentials of wind energy development for water pumping in Jordan

The potential of the development of water pumping using wind energy in Jordan was studied. Underground water can be pumped using wind power. Based on available wind data eleven wind sites were considered. The results show that these sites can be divided, in terms of the annual amount of pumped water, into three categories. One is considered “favorable”, which includes Ras Muneef, Mafraq, and Aqaba. Their water output adds up to most of water produced from all eleven sites combined (about 64%). Others are considered to be “promising”, which include H-5, Irbid, and Ma'an. Their water output adds up to about to 28% of all water pumped at all sites combined. The rest of sites considered are found to be “poor”, which include H-4, Amman, Queen Alia's Airport, Shoubak, and Deiralla, with much smaller amounts of water output. Their combined water output adds up to less than 8% of all site combined.     

Energy management algorithm for an optimum control of a photovoltaic water pumping system

The effectiveness of photovoltaic water pumping systems depends on the adequacy between the generated energy and the volume of pumped water. This paper presents an intelligent algorithm which makes decision on the interconnection modes and instants of photovoltaic installation components: battery, water pump and photovoltaic panel. The decision is made by fuzzy rules on the basis of the Photovoltaic Panel Generation (PVPG) forecast during a considered day, on the load required power, and by considering the battery safety. The algorithm aims to extend operation time of the water pump by controlling a switching unit which links the system components with respect to multi objective management criteria. The algorithm implementation demonstrates that the approach extends the pumping period for more than 5 h a day which gives a mean daily improvement of 97% of the water pumped volume.     

Techno-economic analysis of photovoltaic pumping system for rural water supply in Ethiopia

The diesel-driven water pumping systems have a great impact on rural water supply in Ethiopia in past decades due to the lack of access to grid electricity and associated capital intensive nature of grid expansion to rural areas. However, the requirement of diesel generator for frequent maintenance and soaring fuel cost encourages the government and concerned bodies such as NGO to go for most reliable and cost-effective alternatives. In this paper, direct coupled photovoltaic (PV) pumping system has been designed for hypothetical rural village in southern region near Arba Minch (latitude 6.02^″N, Longitude 37.54^″E) to show techno-economic feasibility of the technology. The result shows that direct coupled PV pumping system is cost-effective in terms of life cycle cost and technologically feasible for rural water supply by virtue of its very low running cost and high reliability of the component and the system as a whole.     

Applying grid-connected photovoltaic system as alternative source of electricity to supplement hydro power instead of using diesel in Uganda

Uganda’s electricity sector for long has been depending on hydro as a base power source. Diesel is currently the second source of electricity which supplements the hydro power. The use of diesel has some implications; first, the price of fuel is high and therefore the energy produced is also expensive. Secondly, diesel power would not be a better option because of its immediate and long term effect on environment due to carbon emission and other pollutants that are often injected into atmosphere from diesel. This paper therefore examines the possibility of using solar PV systems as alternative to diesel as a source of electricity. The paper has also established that the tendency of depending on non-renewable sources of electricity can be minimized and at the same time reducing the cost of energy in the future.     

Suitability of eccentric helical pumps for turbid water deep well pumping in photovoltaic systems

The inherently slim design of the eccentric helical pump appears to make this type of pump to be attractive for delivering water from deep wells, as compared with multistage centrifugal pumps. The basis shape of the volumeflow-head (V-H characteristics) of displacement pumps promises a more economical use of the available solar energy than possible with centrifugal pumps. This article presents the results of experiments concerning the wear in eccentric helical pumps operating with water containing abrasive particles. The temporary stability of the fluid flow and of the efficiency during delivery of abrasive suspensions is demonstrated. The results are used to derive a prognosis for the expectable service life of such a pump system.     

Efficiencies of heat engines and fuel cells: The methanol fuel cell as a competitor to otto and diesel engines

As the real cost of fuel rises the efficiency of energy conversion devices will become of increasing importance. Efficiency is a variable factor depending inter alia on load factor. Whereas heat engines commonly yield optimum efficiencies at near to maximum power, fuel cells yield optimum efficiencies at zero power. Projections based on realistic developments suggest that fuel cells will operate overall with higher efficiencies than heat engines when load factors are below ～45%. Road transportation generally operates at load factors much lower than this and represents a suitable market for fuel cells.     

R407C as an alternative to R22 in vapour compression plant: an experimental study

The problem of HCFC22 phase-out in refrigeration plants is analysed. A comparison is performed between R22 and R407C. The latter seems a promising drop-in substitute. Indeed, its use in existing plants would only require discharge of mineral oil and refilling with a compatible polyolester oil. The experimental tests are performed in a plant consisting in a water-cooled vapor-compression circuit employed for cooling a water–glycol mixture in a closed-loop system. Both the thermodynamic properties and general performance of R407C are comparable with those of R22. The COP, however, is 5–17% lower. As a consequence, in order to provide the same refrigerating load, a plant working with R407C requires higher electric-power consumption. The operational behaviour of R407C is increasingly better with increasing condensation and evaporation temperature. Therefore, R407C is a good R22 substitute in all applications requiring high evaporation temperatures, such as air-conditioning plants. © 1997 John Wiley & Sons, Ltd.     

On the policy of photovoltaic and diesel generation mix for an off-grid site: East Malaysian perspectives

The recent policy of the Malaysian government to promote use of renewable, especially photovoltaic, energy has warranted a feasibility study on supplementing diesel generation in off-grid sites by solar (photovoltaic) electricity to be done in the Malaysian context. This paper addresses the technical viability and economy of using a photovoltaic (PV) system to supplement an existing diesel generator-based supply in a typical secondary school located at an interior, off-grid and rural site of Sarawak state in East Malaysia. The findings of the present study, would therefore, help the Government with a realistic picture of the techno-economic aspects in implementing its vision regarding renewable energy. Presently, a 150 kW diesel generator supplies electricity to the considered school. The study required simulation of the load sharing pattern of the PV–diesel hybrid system taking into account varied weather and insolation conditions of the chosen site. Also, the purchase price as well as the size of the supplementing PV system that would give the lowest life cycle cost have been determined. The PV system was considered in both forms, i.e. with and without battery back-up. It has been found that if the market price for purchasing a PV system would drop to RM 11.02/W_P (Ringgit Malaysia; US$1.00=RM 3.80) i.e. US$2.90/W_P, a 35 kW_P PV system without battery back-up in conjunction with the diesel generator would be able to supply the selected school’s demand at a marginally lower energy cost than the existing diesel-only system. With continuous research and developments, PV price would keep falling in the near future so that a PV–diesel hybrid system with a higher sized PV is expected to be economically more viable. The reported feasibility study can serve as a guideline for making similar studies in the context of another off-grid site.     

Estimation of the potential array output charge in the performance analysis of stand-alone photovoltaic systems without MPPT (Case study: Mediterranean climate)

The potential array output energy, E_P, stated by the Joint Research Centre (JRC) in their European Guidelines for the Assessment of Photovoltaic Plants and the IEC Standard 61724 does not estimate properly the potential array output of stand-alone photovoltaic (SAPV) systems without maximum power point tracker (MPPT) as it is the case for SAPV systems with MPPT and grid connected systems. In this way, the main purpose of this paper is to validate an expression that compromises simplicity and accuracy when estimating the potential array output of SAPV systems without MPPT. This issue can be of high interest to photovoltaic (PV) practitioners and experts as it can improve the analysis performance of this type of systems, helping to discriminate better the different losses in this kind of systems. Furthermore, a study of the array potential estimation through different expressions will be developed in order to evaluate which matches better the array potential output in SAPV system without MPPT. Although the analysis will be focused especially in Mediterranean climates, it will be derived some general conclusions that can be considered in other climates.     

Use of crude filtered vegetable oil as a fuel in diesel engines state of the art: Literature review

Many studies have been published on vegetable oil use in diesel engines. The different authors unanimously acknowledge the potential and merits of this renewable fuel. Typically, Straight Vegetable Oils (SVOs) produced locally on a small scale, have proven to be easy to produce with very little environmental impact. However, as their physico-chemical characteristics differ from those of diesel oil, their use in diesel engines can lead to a certain number of technical problems over time. In bibliography, there is substantial disagreement between authors regarding the advanced phenomena linked to this problems and the recommended solutions. Some of these publications treat options individually without any real comparison between them. Another observation is that the literature rarely tackles problems linked to vegetable oil quality. This paper sets out to review the state of the art for SVO use as fuel in diesel engines, based on a bibliographic study (literature review). The first section of the document examines the influence of the type and quality of vegetable oils for fuel use in diesel engines. The second section discusses the advantages and disadvantages of two options recommended for SVO use in diesel engines: dual fuelling and blending with diesel fuel.     

Techno-economic feasibility of photovoltaic,wind, diesel and hybrid electrification systems for off-grid rural electrification in Colombia

Electrification to rural and remote areas with limited or no access to grid connection is one of the most challenging issues in developing countries like Colombia. Due to the recent concerns about the global climatic change and diminishing fuel prices, searching for reliable, environmental friendly and renewable energy sources to satisfy the rising electrical energy demand has become vital. This study aims at analyzing the application of photovoltaic (PV) panels, wind turbines and diesel generators in a stand-alone hybrid power generation system for rural electrification in three off-grid villages in Colombia with different climatic characteristics. The areas have been selected according to the “Colombia’s development plan 2011–2030 for non-conventional sources of energy”. First, different combinations of wind turbine, PV, and diesel generator are modeled and optimized to determine the most energy-efficient and cost-effective configuration for each location. HOMER software has been used to perform a techno-economic feasibility of the proposed hybrid systems, taking into account net present cost, initial capital cost, and cost of energy as economic indicators.     

The feasibility of renewable energy sources for pumping clean water in sub-Saharan Africa: A case study for Central Nigeria

With less than 6 mm of rain from November through February every year, the central regions of Nigeria are in acute need of safe and consistent water supplies for drinking and other domestic or agricultural uses. Borehole supplies are capable of meeting a significant proportion of water needs, but ongoing fuel costs to power a generator and pump add a heavy burden to already disadvantaged communities. In this study, a techno-economic analysis is carried out in order to assess the feasibility of renewable energy sources and technologies to substitute for fossil-fuel powered pumping platforms. The results indicate that there is sufficient solar resource throughout these regions to facilitate relatively cost effective water pumping solutions, as well as a potentially effective wind resource depending on the exact location of the pumping station. Although systems based on these resources have high capital costs compared to petrol or diesel-based platforms, over a 20-year project life, the analysis indicates that ongoing fuel costs for a fossil-fuel-based system greatly outweigh the increased up-front costs of renewable alternatives. In conclusion, the results indicate that if the water demand at a particular site exceeds the capabilities of a hand pump, a renewable energy-powered pumping system is an attractive option, both economically and logistically in comparison to fossil-fuel-powered alternatives.     

Performance and emission study in manifold hydrogen injection with diesel as an ignition source for different start of injection

Over the past two decades there has been a considerable effort to develop and introduce alternative transportation fuels to replace conventional fuels, gasoline and diesel. Environmental issues are the principal driving forces behind this effort. To date the bulk of research has focused on the carbon-based fuels such as reformulated gasoline, methanol and natural gas. One alternative fuel to carbon-based fuels is hydrogen which is considered to be low polluting fuel. In the present experimental investigation hydrogen was injected into the intake manifold by using an injector. Using an electronic control unit (ECU) the injection timing and the duration were controlled. From the results it is observed that the optimum injection timing is at gas exchange top dead center (GTDC). The efficiency improved by about 15% with an increase in NO_X emission by 3% compared to diesel. The smoke emission decreased by almost 100%. A net reduction in carbon emissions was also noticed due to the use of hydrogen. By adopting manifold injection technique the hydrogen–diesel dual fuel engine operates smoothly with a significant improvement in performance and reduction in emissions.     

Biodiesel production from inedible animal tallow and an experimental investigation of its use as alternative fuel in a direct injection diesel engine

In this study, a substitute fuel for diesel engines was produced from inedible animal tallow and its usability was investigated as pure biodiesel and its blends with petroleum diesel fuel in a diesel engine. Tallow methyl ester as biodiesel fuel was prepared by base-catalyzed transesterification of the fat with methanol in the presence of NaOH as catalyst. Fuel properties of methyl ester, diesel fuel and blends of them (5%, 20% and 50% by volume) were determined. Viscosity and density of fatty acid methyl ester have been found to meet ASTM D6751 and EN 14214 specifications. Viscosity and density of tallow methyl esters are found to be very close to that of diesel. The calorific value of biodiesel is found to be slightly lower than that of diesel. An experimental study was carried out in order to investigate of its usability as alternative fuel of tallow methyl ester in a direct injection diesel engine. It was observed that the addition of biodiesel to the diesel fuel decreases the effective efficiency of engine and increases the specific fuel consumption. This is due to the lower heating value of biodiesel compared to diesel fuel. However, the effective engine power was comparable by biodiesel compared with diesel fuel. Emissions of carbon monoxide (CO), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and smoke opacity were reduced around 15%, 38.5%, 72.7% and 56.8%, respectively, in case of tallow methyl esters (B100) compared to diesel fuel. Besides, the lowest CO, NO_x emissions and the highest exhaust temperature were obtained for B20 among all other fuels. The reductions in exhaust emissions made tallow methyl esters and its blends, especially B20 a suitable alternative fuel for diesel and thus could help in controlling air pollution. Based on this study, animal tallow methyl esters and its blends with petroleum diesel fuel can be used a substitute for diesel in direct injection diesel engines without any engine modification.     

Lime treatment program: an alternative cooling water treatment program for geothermal power plants in the philippines

The National Power Corporation (NAPOCOR) of the Philippines spends millions of pesos annually for treatment of cooling water and preventive maintenance work to ensure the efficient operation of its geothermal power plants supplied by liquid-dominated reservoirs. Therefore, NAPOCOR deemed it worthwhile to look for cheaper water treatment alternatives for the benefit not only of the geothermal power plants, but the whole country as well, in terms of lower power generation costs and improved plant operation. The results of tests on the use of lime in the cooling water of NAPOCOR geothermal power plants are presented in this paper. Initial results show substantial savings in water treatment costs and a significant decrease in corrosion rates on metal parts and equipment.